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Wangrawa DW, Odero JO, Baldini F, Okumu F, Badolo A. Distribution and insecticide resistance profile of the major malaria vector Anopheles funestus group across the African continent. MEDICAL AND VETERINARY ENTOMOLOGY 2024; 38:119-137. [PMID: 38303659 DOI: 10.1111/mve.12706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 01/10/2024] [Indexed: 02/03/2024]
Abstract
There has been significant progress in malaria control in the last 2 decades, with a decline in mortality and morbidity. However, these gains are jeopardised by insecticide resistance, which negatively impacts the core interventions, such as insecticide-treated nets (ITN) and indoor residual spraying (IRS). While most malaria control and research efforts are still focused on Anopheles gambiae complex mosquitoes, Anopheles funestus remains an important vector in many countries and, in some cases, contributes to most of the local transmission. As countries move towards malaria elimination, it is important to ensure that all dominant vector species, including An. funestus, an important vector in some countries, are targeted. The objective of this review is to compile and discuss information related to A. funestus populations' resistance to insecticides and the mechanisms involved across Africa, emphasising the sibling species and their resistance profiles in relation to malaria elimination goals. Data on insecticide resistance in An. funestus malaria vectors in Africa were extracted from published studies. Online bibliographic databases, including Google Scholar and PubMed, were used to search for relevant studies. Articles published between 2000 and May 2023 reporting resistance of An. funestus to insecticides and associated mechanisms were included. Those reporting only bionomics were excluded. Spatial variation in species distribution and resistance to insecticides was recorded from 174 articles that met the selection criteria. It was found that An. funestus was increasingly resistant to the four classes of insecticides recommended by the World Health Organisation for malaria vector control; however, this varied by country. Insecticide resistance appears to reduce the effectiveness of vector control methods, particularly IRS and ITN. Biochemical resistance due to detoxification enzymes (P450s and glutathione-S-transferases [GSTs]) in An. funestus was widely recorded. However, An. funestus in Africa remains susceptible to other insecticide classes, such as organophosphates and neonicotinoids. This review highlights the increasing insecticide resistance of An. funestus mosquitoes, which are important malaria vectors in Africa, posing a significant challenge to malaria control efforts. While An. funestus has shown resistance to the recommended insecticide classes, notably pyrethroids and, in some cases, organochlorides and carbamates, it remains susceptible to other classes of insecticides such as organophosphates and neonicotinoids, providing potential alternative options for vector control strategies. The study underscores the need for targeted interventions that consider the population structure and geographical distribution of An. funestus, including its sibling species and their insecticide resistance profiles, to effectively achieve malaria elimination goals.
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Affiliation(s)
- Dimitri W Wangrawa
- Laboratoire d'Entomologie Fondamentale et Appliquée, Université Joseph Ki-Zerbo, Ouagadougou, Burkina Faso
- Département des Sciences de la Vie et de la Terre, Université Norbert Zongo, Koudougou, Burkina Faso
| | - Joel O Odero
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Francesco Baldini
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Athanase Badolo
- Laboratoire d'Entomologie Fondamentale et Appliquée, Université Joseph Ki-Zerbo, Ouagadougou, Burkina Faso
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Odero JO, Nambunga IH, Masalu JP, Mkandawile G, Bwanary H, Hape EE, Njalambaha RM, Tungu P, Ngowo HS, Kaindoa EW, Mapua SA, Kahamba NF, Nelli L, Wondji C, Koekemoer LL, Weetman D, Ferguson HM, Baldini F, Okumu FO. Genetic markers associated with the widespread insecticide resistance in malaria vector Anopheles funestus populations across Tanzania. Parasit Vectors 2024; 17:230. [PMID: 38760849 PMCID: PMC11100202 DOI: 10.1186/s13071-024-06315-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Accepted: 05/03/2024] [Indexed: 05/19/2024] Open
Abstract
BACKGROUND Anopheles funestus is a leading vector of malaria in most parts of East and Southern Africa, yet its ecology and responses to vector control remain poorly understood compared with other vectors such as Anopheles gambiae and Anopheles arabiensis. This study presents the first large-scale survey of the genetic and phenotypic expression of insecticide resistance in An. funestus populations in Tanzania. METHODS We performed insecticide susceptibility bioassays on An. funestus mosquitoes in nine regions with moderate-to-high malaria prevalence in Tanzania, followed by genotyping for resistance-associated mutations (CYP6P9a, CYP6P9b, L119F-GSTe2) and structural variants (SV4.3 kb, SV6.5 kb). Generalized linear models were used to assess relationships between genetic markers and phenotypic resistance. An interactive R Shiny tool was created to visualize the data and support evidence-based interventions. RESULTS Pyrethroid resistance was universal but reversible by piperonyl-butoxide (PBO). However, carbamate resistance was observed in only five of the nine districts, and dichloro-diphenyl-trichloroethane (DDT) resistance was found only in the Kilombero valley, south-eastern Tanzania. Conversely, there was universal susceptibility to the organophosphate pirimiphos-methyl in all sites. Genetic markers of resistance had distinct geographical patterns, with CYP6P9a-R and CYP6P9b-R alleles, and the SV6.5 kb structural variant absent or undetectable in the north-west but prevalent in all other sites, while SV4.3 kb was prevalent in the north-western and western regions but absent elsewhere. Emergent L119F-GSTe2, associated with deltamethrin resistance, was detected in heterozygous form in districts bordering Mozambique, Malawi and the Democratic Republic of Congo. The resistance landscape was most complex in western Tanzania, in Tanganyika district, where all five genetic markers were detected. There was a notable south-to-north spread of resistance genes, especially CYP6P9a-R, though this appears to be interrupted, possibly by the Rift Valley. CONCLUSIONS This study underscores the need to expand resistance monitoring to include An. funestus alongside other vector species, and to screen for both the genetic and phenotypic signatures of resistance. The findings can be visualized online via an interactive user interface and could inform data-driven decision-making for resistance management and vector control. Since this was the first large-scale survey of resistance in Tanzania's An. funestus, we recommend regular updates with greater geographical and temporal coverage.
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Affiliation(s)
- Joel O Odero
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Ismail H Nambunga
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - John P Masalu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Gustav Mkandawile
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Hamis Bwanary
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Emmanuel E Hape
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, South Africa
| | - Rukiyah M Njalambaha
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Patrick Tungu
- Amani Medical Research Centre, National Institute for Medical Research, Muheza, Tanzania
| | - Halfan S Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Emmanuel W Kaindoa
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- School of Life Science and Biotechnology, Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania
| | - Salum A Mapua
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Najat F Kahamba
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Luca Nelli
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Charles Wondji
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
- Department of Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaoundé 5, Cameroon
| | - Lizette L Koekemoer
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, South Africa
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, A Division of the National Health Laboratory Service, Johannesburg, South Africa
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Heather M Ferguson
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Francesco Baldini
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.
- School of Life Science and Biotechnology, Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania.
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Sagna AB, Zéla L, Ouedraogo COW, Pooda SH, Porciani A, Furnival-Adams J, Lado P, Somé AF, Pennetier C, Chaccour CJ, Dabiré RK, Mouline K. Ivermectin as a novel malaria control tool: Getting ahead of the resistance curse. Acta Trop 2023; 245:106973. [PMID: 37352998 DOI: 10.1016/j.actatropica.2023.106973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/25/2023]
Abstract
Reduction in malaria clinical cases is strongly dependent on the ability to prevent Anopheles infectious bites. Vector control strategies using long-lasting insecticidal nets and indoor residual spraying with insecticides have contributed to significantly reduce the incidence of malaria in many endemic countries, especially in the Sub-Saharan region. However, global progress in reducing malaria cases has plateaued since 2015 mostly due to the increased insecticide resistance and behavioral changes in Anopheles vectors. Additional control strategies are thus required to further reduce the burden of malaria and contain the spread of resistant and invasive Anopheles vectors. The use of endectocides such as ivermectin as an additional malaria control tool is now receiving increased attention, driven by its different mode of action compared to insecticides used so far and its excellent safety record for humans. In this opinion article, we discuss the advantages and disadvantages of using ivermectin for malaria control with a focus on the risk of selecting ivermectin resistance in malaria vectors. We also highlight the importance of understanding how ivermectin resistance could develop in mosquitoes and what its underlying mechanisms and associated molecular markers are, and propose a research agenda to manage this phenomenon.
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Affiliation(s)
- André B Sagna
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France.
| | - Lamidi Zéla
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
| | - Cheick Oumar W Ouedraogo
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Sié H Pooda
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso; Université de Dédougou, Dédougou, Burkina Faso
| | | | | | - Paula Lado
- Center for Vector-borne Infectious Diseases, Colorado State University, Fort Collins, CO, USA
| | - Anyirékun F Somé
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Cédric Pennetier
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
| | - Carlos J Chaccour
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Infecciosas, Madrid, Spain; Universidad de Navarra, Pamplona, Spain
| | - Roch K Dabiré
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Karine Mouline
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
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Bam V, Mohammed A, Kusi-Amponsah A, Armah J, Lomotey AY, Budu HI, Atta Poku C, Kyei-Dompim J, Dwumfour C. Caregivers' perception and acceptance of malaria vaccine for Children. PLoS One 2023; 18:e0288686. [PMID: 37494408 PMCID: PMC10370692 DOI: 10.1371/journal.pone.0288686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 06/30/2023] [Indexed: 07/28/2023] Open
Abstract
BACKGROUND Malaria is a disease of public health concern and in endemic areas, pregnant women and children under-five years are vulnerable to the disease. The introduction of the pilot program of a malaria vaccine for children under-five years in Ghana is an intervention to further reduce the burden of the disease. However, the availability of the vaccine does not necessarily mean it will be accepted by the public. This is why the perceptions and acceptance of the vaccine among mothers of these children are worth exploring. METHOD A descriptive qualitative study, with the aid of a semi-structured interview guide, was utilized in collecting data from ten (10) purposively sampled mothers whose children were taking the malaria vaccine in a municipality in Ghana. Written informed consent was obtained from all participants. The audiotaped interviews were transcribed verbatim and inductively analyzed into themes describing their perceptions and acceptance. RESULTS Participants were aged between 22 and 40 years with eight (8) of them married. Three themes emerged from the study. "Awareness of malaria and the malaria vaccine" (1), "Insight into the malaria vaccine" (2), where participants communicated the beliefs and judgments formed on the vaccine, its benefits, and the need for vaccinating their children. With the third theme "Reaction to vaccine" (3), participants communicated their motivation to vaccinate their children and their concerns about the administration of the vaccine. CONCLUSION The caregivers had positive perceptions about the malaria vaccine for children, with fewer hospital admissions and saving money as some benefits. Healthworkers played a significant role in influencing the acceptance of the vaccine. However, the fear of the unknown concerning the side effects of the vaccine serve as a possible barrier to recommending the vaccine to other caregivers. Health education must also address the fears of caregivers in order to enhance recommending the malaria vaccine to other caregivers and promote uptake of the vaccination.
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Affiliation(s)
- Victoria Bam
- Department of Nursing, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Abdulai Mohammed
- Department of Nursing, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
- Midwifery Training College, Tumu, Tumu Upper West Region, Ghana
| | - Abigail Kusi-Amponsah
- Department of Nursing, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
- Department of Nursing Science, Faculty of Medicine, University of Turku, Turku, Finland
| | - Jerry Armah
- Department of Nursing, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | | | - Hayford Isaac Budu
- Department of Nursing, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Collins Atta Poku
- Department of Nursing, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Joana Kyei-Dompim
- Department of Nursing, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Catherine Dwumfour
- Department of Nursing, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
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Mugenzi LMJ, A. Tekoh T, S. Ibrahim S, Muhammad A, Kouamo M, Wondji MJ, Irving H, Hearn J, Wondji CS. The duplicated P450s CYP6P9a/b drive carbamates and pyrethroids cross-resistance in the major African malaria vector Anopheles funestus. PLoS Genet 2023; 19:e1010678. [PMID: 36972302 PMCID: PMC10089315 DOI: 10.1371/journal.pgen.1010678] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 04/11/2023] [Accepted: 02/23/2023] [Indexed: 03/29/2023] Open
Abstract
Cross-resistance to insecticides in multiple resistant malaria vectors is hampering resistance management. Understanding its underlying molecular basis is critical to implementation of suitable insecticide-based interventions. Here, we established that the tandemly duplicated cytochrome P450s, CYP6P9a/b are driving carbamate and pyrethroid cross-resistance in Southern African populations of the major malaria vector Anopheles funestus. Transcriptome sequencing revealed that cytochrome P450s are the most over-expressed genes in bendiocarb and permethrin-resistant An. funestus. The CYP6P9a and CYP6P9b genes are overexpressed in resistant An. funestus from Southern Africa (Malawi) versus susceptible An. funestus (Fold change (FC) is 53.4 and 17 respectively), while the CYP6P4a and CYP6P4b genes are overexpressed in resistant An. funestus in Ghana, West Africa, (FC is 41.1 and 17.2 respectively). Other up-regulated genes in resistant An. funestus include several additional cytochrome P450s (e.g. CYP9J5, CYP6P2, CYP6P5), glutathione-S transferases, ATP-binding cassette transporters, digestive enzymes, microRNA and transcription factors (FC<7). Targeted enrichment sequencing strongly linked a known major pyrethroid resistance locus (rp1) to carbamate resistance centering around CYP6P9a/b. In bendiocarb resistant An. funestus, this locus exhibits a reduced nucleotide diversity, significant p-values when comparing allele frequencies, and the most non-synonymous substitutions. Recombinant enzyme metabolism assays showed that both CYP6P9a/b metabolize carbamates. Transgenic expression of CYP6P9a/b in Drosophila melanogaster revealed that flies expressing both genes were significantly more resistant to carbamates than controls. Furthermore, a strong correlation was observed between carbamate resistance and CYP6P9a genotypes with homozygote resistant An. funestus (CYP6P9a and the 6.5kb enhancer structural variant) exhibiting a greater ability to withstand bendiocarb/propoxur exposure than homozygote CYP6P9a_susceptible (e.g Odds ratio = 20.8, P<0.0001 for bendiocarb) and heterozygotes (OR = 9.7, P<0.0001). Double homozygote resistant genotype (RR/RR) were even more able to survive than any other genotype combination showing an additive effect. This study highlights the risk that pyrethroid resistance escalation poses to the efficacy of other classes of insecticides. Available metabolic resistance DNA-based diagnostic assays should be used by control programs to monitor cross-resistance between insecticides before implementing new interventions.
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Affiliation(s)
- Leon M. J. Mugenzi
- LSTM Research Unit, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Theofelix A. Tekoh
- LSTM Research Unit, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Biochemistry and Molecular Biology, Faculty of Science University of Buea, Buea, Cameroon
| | - Sulaiman S. Ibrahim
- LSTM Research Unit, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
- Department of Biochemistry, Bayero University, Kano, Nigeria
| | - Abdullahi Muhammad
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Mersimine Kouamo
- LSTM Research Unit, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Murielle J. Wondji
- LSTM Research Unit, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Helen Irving
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Jack Hearn
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
- Centre for Epidemiology and Planetary Health, Department of Veterinary and Animal Science, North Faculty, Scotland’s Rural College, An Lòchran, 10 Inverness Campus, Inverness, Scotland, United Kingdom
| | - Charles S. Wondji
- LSTM Research Unit, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
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Vinti G, Bauza V, Clasen T, Tudor T, Zurbrügg C, Vaccari M. Health risks of solid waste management practices in rural Ghana: A semi-quantitative approach toward a solid waste safety plan. ENVIRONMENTAL RESEARCH 2023; 216:114728. [PMID: 36343708 DOI: 10.1016/j.envres.2022.114728] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 10/18/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
Inadequate solid waste management (SWM) can lead to environmental contamination and human health risks. The health risks from poor SWM can vary based on specific practices and exposure pathways. Thus, it is necessary to adequately understand the local context. This information, however, is rarely available in low-resource settings, particularly in rural areas. A solid waste safety plan could be helpful in these settings for gathering necessary data to assess and minimize health risks. As a step in developing such a tool, a semi-quantitative health risk analysis of SWM practices in nine Ghanaian rural villages was undertaken. Data on SWM in each village were collected through qualitative field observations and semi-structured interviews with local stakeholders. SWM-related health risks were assessed using the collected data, similar case studies in the scientific literature and dialogue among an assembled team of experts. The analysis identified context-specific practices and exposure pathways that may present the most substantial health risks as well as targeted solutions for mitigation risks. A risk assessment matrix was developed to quantify SWM risks as low, medium, high, or very high based on the likelihood and severity of identified hazards. The highest SWM risks were identified from dumpsites and uncontrolled burying of solid waste. More specifically, a very high or high risk of infectious and vector-borne diseases from SWM in the villages was identified, both in the disposal of solid waste in dumpsites and uncontrolled burying of solid waste. Additionally, a very high or high risk of inhalation, ingestion or dermal contact with contaminants was found in the disposal of solid waste in dumpsites, open burning of waste and reuse of waste from dumpsites as compost. The results demonstrate the potential value of a solid waste safety plan and a parsimonious approach to collect key local data to inform its contents.
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Affiliation(s)
- Giovanni Vinti
- CeTAmb (Research Center for Appropriate Technologies for Environmental Management in Resource-limited Countries), University of Brescia, 25123, Brescia, Italy.
| | - Valerie Bauza
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, 30322, USA
| | - Thomas Clasen
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, 30322, USA
| | - Terry Tudor
- SusConnect Ltd. Weedon Bec, Northamptonshire, NN7 4PS, UK
| | - Christian Zurbrügg
- Department of Sanitation, Water and Solid Waste for Development (Sandec), Eawag-Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600, Dübendorf, Switzerland
| | - Mentore Vaccari
- CeTAmb (Research Center for Appropriate Technologies for Environmental Management in Resource-limited Countries), University of Brescia, 25123, Brescia, Italy
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Mugenzi LMJ, Akosah-Brempong G, Tchouakui M, Menze BD, Tekoh TA, Tchoupo M, Nkemngo FN, Wondji MJ, Nwaefuna EK, Osae M, Wondji CS. Escalating pyrethroid resistance in two major malaria vectors Anopheles funestus and Anopheles gambiae (s.l.) in Atatam, Southern Ghana. BMC Infect Dis 2022; 22:799. [PMID: 36284278 PMCID: PMC9597992 DOI: 10.1186/s12879-022-07795-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 09/15/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aggravation of insecticide resistance in malaria vectors is threatening the efforts to control malaria by reducing the efficacy of insecticide-based interventions hence needs to be closely monitored. This study investigated the intensity of insecticide resistance of two major malaria vectors An. funestus sensu stricto (s.s.) and An. gambiae sensu lato (s.l.) collected in southern Ghana and assessed the bio-efficacy of several long-lasting insecticidal nets (LLINs) against these mosquito populations. METHODS The insecticide susceptibility profiles of Anopheles funestus s.s. and Anopheles gambiae s.l. populations from Obuasi region (Atatam), southern Ghana were characterized and the bio-efficacy of some LLINs was assessed to determine the impact of insecticide resistance on the effectiveness of these tools. Furthermore, molecular markers associated with insecticide resistance in both species were characterized in the F0 and F1 populations using PCR and qPCR methods. RESULTS Anopheles funestus s.s. was the predominant species and was resistant to pyrethroids, organochlorine and carbamate insecticides, but fully susceptible to organophosphates. An. gambiae s.l. was resistant to all four insecticide classes. High intensity of resistance to 5 × and 10 × the discriminating concentration (DC) of pyrethroids was observed in both species inducing a considerable loss of efficacy of long-lasting insecticidal nets (LLINs). Temporal expression analysis revealed a massive 12-fold increase in expression of the CYP6P4a cytochrome P450 gene in An. funestus s.s., initially from a fold change of 41 (2014) to 500 (2021). For both species, the expression of candidate genes did not vary according to discriminating doses. An. gambiae s.l. exhibited high frequencies of target-site resistance including Vgsc-1014F (90%) and Ace-1 (50%) while these mutations were absent in An. funestus s.s. CONCLUSIONS The multiple and high intensity of resistance observed in both malaria vectors highlights the need to implement resistance management strategies and the introduction of new insecticide chemistries.
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Affiliation(s)
- Leon M J Mugenzi
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13501, Yaoundé, Cameroon.
| | - Gabriel Akosah-Brempong
- African Regional Postgraduate Program in Insect Science, University of Ghana, Legon, Accra, Ghana
- Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, Accra, Ghana
| | - Magellan Tchouakui
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13501, Yaoundé, Cameroon
| | - Benjamin D Menze
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13501, Yaoundé, Cameroon
| | - Theofelix A Tekoh
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13501, Yaoundé, Cameroon
| | - Micareme Tchoupo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13501, Yaoundé, Cameroon
| | - Francis N Nkemngo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13501, Yaoundé, Cameroon
| | - Murielle J Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13501, Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Ekene K Nwaefuna
- Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, Accra, Ghana
| | - Michael Osae
- Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, Accra, Ghana
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13501, Yaoundé, Cameroon.
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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8
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Tao F, Si FL, Hong R, He X, Li XY, Qiao L, He ZB, Yan ZT, He SL, Chen B. Glutathione S-transferase (GST) genes and their function associated with pyrethroid resistance in the malaria vector Anopheles sinensis. PEST MANAGEMENT SCIENCE 2022; 78:4127-4139. [PMID: 35662391 DOI: 10.1002/ps.7031] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Glutathione S-transferases (GSTs), a multifunctional protein family, are involved in insecticide resistance. However, a systematic analysis of GSTs in Anopheles sinensis, an important vector for malaria transmission, is lacking. In this study, we investigated the diversity and characteristics of GST genes, and analyzed their expression patterns and functions associated with insecticide resistance in this species. RESULTS We identified 32 putative cytosolic and three putative microsomal GST genes in the An. sinensis genome. Transcriptome analysis showed that GSTs were highly expressed in larvae, and mainly expressed in the antennae, midgut and Malpighian tubules of adults. In addition, we found that GSTd2 and GSTe2 were significantly upregulated in four An. sinensis pyrethroid-resistant field populations. Furthermore, silencing of GSTd2 and GSTe2 significantly increased the susceptibility of An. sinensis to deltamethrin, and recombinant GSTd2 and GSTe2 exhibited high enzymatic activity in the metabolism of 1-chloro-2,4-dinitrobenzene and dichlorodiphenyltrichloroethane (DDT). CONCLUSION These results showed that GSTs are involved in the development of insecticide resistance in An. sinensis through transcriptional overexpression and enzymatic metabolization, facilitating our understanding of insecticide resistance in insects. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Fei Tao
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, People's Republic of China
| | - Feng-Ling Si
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, People's Republic of China
| | - Rui Hong
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, People's Republic of China
| | - Xiu He
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, People's Republic of China
| | - Xiang-Ying Li
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, People's Republic of China
| | - Liang Qiao
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, People's Republic of China
| | - Zheng-Bo He
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, People's Republic of China
| | - Zhen-Tian Yan
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, People's Republic of China
| | - Shu-Lin He
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, People's Republic of China
| | - Bin Chen
- Chongqing Key Laboratory of Vector Insects; Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, People's Republic of China
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9
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Agyekum TP, Arko-Mensah J, Botwe PK, Hogarh JN, Issah I, Dwomoh D, Billah MK, Dadzie SK, Robins TG, Fobil JN. Effects of Elevated Temperatures on the Growth and Development of Adult Anopheles gambiae (s.l.) (Diptera: Culicidae) Mosquitoes. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1413-1420. [PMID: 35452118 PMCID: PMC9278826 DOI: 10.1093/jme/tjac046] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Indexed: 06/01/2023]
Abstract
Higher temperatures expected in a future warmer climate could adversely affect the growth and development of mosquitoes. This study investigated the effects of elevated temperatures on longevity, gonotrophic cycle length, biting rate, fecundity, and body size of Anopheles gambiae (s.l.) (Diptera: Culicidae) mosquitoes. Anopheles gambiae (s.l.) eggs obtained from laboratory established colonies were reared under eight temperature regimes (25, 28, 30, 32, 34, 36, 38, and 40°C), and 80 ± 10% RH. All adults were allowed to feed on a 10% sugar solution soaked in cotton wool; however, some mosquitoes were provided blood meal using guinea pig. Longevity was estimated for both blood-fed and non-blood-fed mosquitoes and analyzed using the Kaplan-Meier survival analysis. One-way ANOVA was used to test the effect of temperature on gonotrophic cycle length, biting rate, and fecundity. Adult measurement data were log-transformed and analyzed using ordinary least square regression with robust standard errors. Increasing temperature significantly decreased the longevity of both blood-fed (Log-rank test; X2(4) = 904.15, P < 0.001) and non-blood-fed (Log-rank test; X2(4) = 1163.60, P < 0.001) mosquitoes. In addition, the fecundity of mosquitoes decreased significantly (ANOVA; F(2,57) = 3.46, P = 0.038) with an increase in temperature. Body size (β = 0.14, 95% CI, 0.16, 0.12, P < 0.001) and proboscis length (β = 0.13, 95% CI, 0.17, 0.09, P < 0.001) significantly decreased with increasing temperature from 25 to 34°C. Increased temperatures expected in a future warmer climate could cause some unexpected effects on mosquitoes by directly influencing population dynamics and malaria transmission.
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Affiliation(s)
| | - John Arko-Mensah
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Paul K Botwe
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Jonathan N Hogarh
- Department of Environmental Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Ibrahim Issah
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Duah Dwomoh
- Department of Biostatistics, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Maxwell K Billah
- Department of Animal Biology and Conservation Science, University of Ghana, Accra, Ghana
| | - Samuel K Dadzie
- Parasitology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Thomas G Robins
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Julius N Fobil
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
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10
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Nkemngo FN, Mugenzi LMJ, Tchouakui M, Nguiffo-Nguete D, Wondji MJ, Mbakam B, Tchoupo M, Ndo C, Wanji S, Wondji CS. Xeno-monitoring of molecular drivers of artemisinin and partner drug resistance in P. falciparum populations in malaria vectors across Cameroon. Gene 2022; 821:146339. [PMID: 35183684 PMCID: PMC8942117 DOI: 10.1016/j.gene.2022.146339] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/10/2022] [Accepted: 02/14/2022] [Indexed: 01/29/2023]
Abstract
High Plasmodium infection rate in the major Anopheles vectors across Cameroon. Emerging signal of the R575I polymorphism in the k13 propeller domain backbone. Dominance of the N86F184mdr1 variants in natural P. falciparum populations. Low k13 and mdr1 genetic diversity in P. falciparum-infected mosquitoes.
Background Monitoring of drug resistance in Plasmodium populations is crucial for malaria control. This has primarily been performed in humans and rarely in mosquitoes where parasites genetic recombination occurs. Here, we characterized the Plasmodium spp populations in wild Anopheles vectors by analyzing the genetic diversity of the P. falciparum kelch13 and mdr1 gene fragments implicated in artemisinin and partner drug resistance across Cameroon in three major malaria vectors. Methods Anopheles mosquitoes were collected across nine localities in Cameroon and dissected into the head/thorax (H/T) and abdomen (Abd) after species identification. A TaqMan assay was performed to detect Plasmodium infection. Fragments of the Kelch 13 and mdr1 genes were amplified in P. falciparum positive samples and directly sequenced to assess their drug resistance polymorphisms and genetic diversity profile. Results The study revealed a high Plasmodium infection rate in the major Anopheles vectors across Cameroon. Notably, An. funestus vector recorded the highest sporozoite (8.0%) and oocyst (14.4%) infection rates. A high P. falciparum sporozoite rate (80.08%) alongside epidemiological signatures of significant P. malariae (15.9%) circulation were recorded in these vectors. Low genetic diversity with six (A578S, R575I, G450R, L663L, G453D, N458D) and eight (H53H, V62L, V77E, N86Y, G102G, L132I, H143H, Y184F) point mutations were observed in the k13 and mdr1 backbones respectively. Remarkably, the R575I (4.4%) k13 and Y184F (64.2%) mdr1 mutations were the predominant variants in the P. falciparum populations. Conclusion The emerging signal of the R575I polymorphism in the Pfk13 propeller backbone entails the regular surveillance of molecular markers to inform evidence-based policy decisions. Moreover, the high frequency of the 86N184F allele highlights concerns on the plausible decline in efficacy of artemisinin-combination therapies (ACTs); further implying that parasite genotyping from mosquitoes can provide a more relevant scale for quantifying resistance epidemiology in the field.
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Affiliation(s)
- Francis N Nkemngo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.
| | - Leon M J Mugenzi
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Magellan Tchouakui
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Daniel Nguiffo-Nguete
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Murielle J Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
| | - Bertrand Mbakam
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Micareme Tchoupo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Cyrille Ndo
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon.
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon; Research Foundation in Tropical Diseases and Environment, Buea, Cameroon.
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
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11
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Oliver SV, Lyons CL, Brooke BD. The effect of blood feeding on insecticide resistance intensity and adult longevity in the major malaria vector Anopheles funestus (Diptera: Culicidae). Sci Rep 2022; 12:3877. [PMID: 35264696 PMCID: PMC8907345 DOI: 10.1038/s41598-022-07798-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 02/18/2022] [Indexed: 11/09/2022] Open
Abstract
Insecticide-based vector control is key to the reduction and elimination of malaria. Although insecticide resistance is common in malaria vector populations, the operational implications are often unclear. High intensity pyrethroid resistance in the major malaria vector Anopheles funestus has been linked to control failure in Southern Africa. The aim of this study was to assess linkages between mosquito age, blood feeding and the intensity of pyrethroid resistance in two An. funestus laboratory strains that originate from southern Mozambique, namely the moderately pyrethroid resistant FUMOZ and the highly resistant FUMOZ-R. Resistance tended to decline with age. This effect was significantly mitigated by blood feeding and was most apparent in cohorts that received multiple blood meals. In the absence of insecticide exposure, blood feeding tended to increase longevity of An. funestus females and, following insecticide exposure, enhanced their levels of deltamethrin resistance, even in older age groups. These effects were more marked in FUMOZ-R compared to FUMOZ. In terms of programmatic decision-making, these data suggest that it would be useful to assess the level and intensity of resistance in older female cohorts wherever possible, notwithstanding the standard protocols for resistance testing using age-standardised samples.
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Affiliation(s)
- Shüné V Oliver
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, 1 Modderfontein Road, Sandringham, Johannesburg, 2192, South Africa. .,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2193, South Africa.
| | - Candice L Lyons
- Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa
| | - Basil D Brooke
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, 1 Modderfontein Road, Sandringham, Johannesburg, 2192, South Africa.,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2193, South Africa
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12
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Omotayo AI, Ande AT, Oduola AO, Adelaja OJ, Adesalu O, Jimoh TR, Ghazali AI, Awolola ST. Multiple insecticide resistance mechanisms in urban population of Anopheles coluzzii (Diptera: culicidae) from Lagos, South-West Nigeria. Acta Trop 2022; 227:106291. [PMID: 34958768 DOI: 10.1016/j.actatropica.2021.106291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 12/18/2021] [Accepted: 12/21/2021] [Indexed: 11/01/2022]
Abstract
Malaria is a major public health challenge in Africa with Nigeria accounting for the highest burden of the disease in the world. Vector control has proved to be a highly effective component of malaria control, however, the development and spread of insecticide resistance in major vectors of malaria have been a major challenge. This study assessed resistance mechanisms in Anopheles coluzzii populations from Kosofe, Lagos mainland and Ojo Local Government Areas in Lagos, Nigeria where An. gambiae s.l is resistant to DDT and Permethrin. WHO susceptibility bioassay test was used in determining resistance status of An. coluzzii to discriminating doses of DDT and Permethrin while synergist assay was used to assess the involvement of monooxygenases in resistance development. Sub-species of An. gambiae s.l (An. gambiae and An. coluzzii) were identified using polymerase chain reaction (PCR) and Restriction Fragment Length Polymorphism (PCR-RFLP) while Allele-Specific Polymerase Chain Reaction (AS-PCR) assay was used to detect knockdown mutation (kdr-West; L1014F). Biochemical assays were used in determining the activities of metabolic enzymes. High DDT resistance was recorded in An. coluzzii populations from the three sites. Mortality rate of mosquitoes exposed confirmed Permethrin resistance in Kosofe (50%) and Lagos mainland (48%) but resistance was suspected in Ojo (96%). All specimens tested were confirmed as An. coluzzii with low kdr frequency; 11.6%, 16.4% and 6.7% in Kosofe, Lagos mainland and Ojo respectively. Pre-exposure to synergist (PBO) before exposure to Permethrin led to increased mortality in all populations. Esterase activity was insignificantly overexpressed in Kosofe (p = 0.849) and Lagos mainland (p = 0.229) populations. In contrast, GST activity was significantly lower in populations from Lagos mainland (63.650 ± 9.861; p = 0.007) and Ojo (91.765 ± 4.959; p = 0.042) than Kisumu susceptible strains (120.250 ± 13.972). Monooxygenase activity was higher in Lagos mainland (2.371 ± 0.261) and Ojo (1.361 ± 0.067) populations, albeit significantly in Lagos mainland (p = 0.007) only. Presence of target-site mutation in all populations, increased mortality with pre-exposure to PBO and elevated monooxygenase in Lagos mainland population were confirmed. Multiple resistance mechanisms in some urban populations of An. coluzzii from Lagos, Nigeria calls for appropriate resistance management strategies.
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13
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Wamba ANR, Ibrahim SS, Kusimo MO, Muhammad A, Mugenzi LMJ, Irving H, Wondji MJ, Hearn J, Bigoga JD, Wondji CS. The cytochrome P450 CYP325A is a major driver of pyrethroid resistance in the major malaria vector Anopheles funestus in Central Africa. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 138:103647. [PMID: 34530119 DOI: 10.1016/j.ibmb.2021.103647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/20/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
The overexpression and overactivity of key cytochrome P450s (CYP450) genes are major drivers of metabolic resistance to insecticides in African malaria vectors such as Anopheles funestus s.s. Previous RNAseq-based transcription analyses revealed elevated expression of CYP325A specific to Central African populations but its role in conferring resistance has not previously been demonstrated. In this study, RT-qPCR consistently confirmed that CYP325A is highly over-expressed in pyrethroid-resistant An. funestus from Cameroon, compared with a control strain and insecticide-unexposed mosquitoes. A synergist bioassay with PBO significantly recovered susceptibility for permethrin and deltamethrin indicating P450-based metabolic resistance. Analyses of the coding sequence of CYP325A Africa-wide detected high-levels of polymorphism, but with no predominant alleles selected by pyrethroid resistance. Geographical amino acid changes were detected notably in Cameroon. In silico homology modelling and molecular docking simulations predicted that CYP325A binds and metabolises type I and type II pyrethroids. Heterologous expression of recombinant CYP325A and metabolic assays confirmed that the most-common Cameroonian haplotype metabolises both type I and type II pyrethroids with depletion rate twice that the of the DR Congo haplotype. Analysis of the 1 kb putative promoter of CYP325A revealed reduced diversity in resistant mosquitoes compared to susceptible ones, suggesting a potential selective sweep in this region. The establishment of CYP325A as a pyrethroid resistance metabolising gene further explains pyrethroid resistance in Central African populations of An. funestus. Our work will facilitate future efforts to detect the causative resistance markers in the promoter region of CYP325A to design field applicable DNA-based diagnostic tools.
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Affiliation(s)
- Amelie N R Wamba
- Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon; Faculty of Science, Department of Biochemistry, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon.
| | - Sulaiman S Ibrahim
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, L3 5QA, UK; Department of Biochemistry, Bayero University, PMB, 3011, Kano, Nigeria.
| | - Michael O Kusimo
- Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon.
| | - Abdullahi Muhammad
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, L3 5QA, UK; Centre for Biotechnology Research, Bayero University, Kano, PMB, 3011, Kano Nigeria.
| | - Leon M J Mugenzi
- Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon; Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.
| | - Helen Irving
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, L3 5QA, UK.
| | - Murielle J Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon; Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, L3 5QA, UK.
| | - Jack Hearn
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, L3 5QA, UK.
| | - Jude D Bigoga
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, L3 5QA, UK; Laboratory for Vector Biology and Control, National Reference Unit for Vector Control, The Biotechnology Centre, Nkolbisson - University of Yaoundé I, P.O. Box 3851, Messa, Yaoundé, Cameroon.
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon; Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, L3 5QA, UK.
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14
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Nambunga IH, Msugupakulya BJ, Hape EE, Mshani IH, Kahamba NF, Mkandawile G, Mabula DM, Njalambaha RM, Kaindoa EW, Muyaga LL, Hermy MRG, Tripet F, Ferguson HM, Ngowo HS, Okumu FO. Wild populations of malaria vectors can mate both inside and outside human dwellings. Parasit Vectors 2021; 14:514. [PMID: 34620227 PMCID: PMC8499572 DOI: 10.1186/s13071-021-04989-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Wild populations of Anopheles mosquitoes are generally thought to mate outdoors in swarms, although once colonized, they also mate readily inside laboratory cages. This study investigated whether the malaria vectors Anopheles funestus and Anopheles arabiensis can also naturally mate inside human dwellings. METHOD Mosquitoes were sampled from three volunteer-occupied experimental huts in a rural Tanzanian village at 6:00 p.m. each evening, after which the huts were completely sealed and sampling was repeated at 11:00 p.m and 6 a.m. the next morning to compare the proportions of inseminated females. Similarly timed collections were done inside local unsealed village houses. Lastly, wild-caught larvae and pupae were introduced inside or outside experimental huts constructed inside two semi-field screened chambers. The huts were then sealed and fitted with exit traps, allowing mosquito egress but not entry. Mating was assessed in subsequent days by sampling and dissecting emergent adults caught indoors, outdoors and in exit traps. RESULTS Proportions of inseminated females inside the experimental huts in the village increased from approximately 60% at 6 p.m. to approximately 90% the following morning despite no new mosquitoes entering the huts after 6 p.m. Insemination in the local homes increased from approximately 78% to approximately 93% over the same time points. In the semi-field observations of wild-caught captive mosquitoes, the proportions of inseminated An. funestus were 20.9% (95% confidence interval [CI]: ± 2.8) outdoors, 25.2% (95% CI: ± 3.4) indoors and 16.8% (± 8.3) in exit traps, while the proportions of inseminated An. arabiensis were 42.3% (95% CI: ± 5.5) outdoors, 47.4% (95% CI: ± 4.7) indoors and 37.1% (CI: ± 6.8) in exit traps. CONCLUSION Wild populations of An. funestus and An. arabiensis in these study villages can mate both inside and outside human dwellings. Most of the mating clearly happens before the mosquitoes enter houses, but additional mating happens indoors. The ecological significance of such indoor mating remains to be determined. The observed insemination inside the experimental huts fitted with exit traps and in the unsealed village houses suggests that the indoor mating happens voluntarily even under unrestricted egress. These findings may inspire improved vector control, such as by targeting males indoors, and potentially inform alternative methods for colonizing strongly eurygamic Anopheles species (e.g. An. funestus) inside laboratories or semi-field chambers.
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Affiliation(s)
- Ismail H. Nambunga
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Betwel J. Msugupakulya
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- School of Life Science and Bioengineering, The Nelson Mandela African Institution of Sciences & Technology, Arusha, Tanzania
| | - Emmanuel E. Hape
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Issa H. Mshani
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Najat F. Kahamba
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
- School of Life Science and Bioengineering, The Nelson Mandela African Institution of Sciences & Technology, Arusha, Tanzania
| | - Gustav Mkandawile
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Daniel M. Mabula
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Rukiyah M. Njalambaha
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Emmanuel W. Kaindoa
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- School of Life Science and Bioengineering, The Nelson Mandela African Institution of Sciences & Technology, Arusha, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Park Town, Republic of South Africa
| | - Letus L. Muyaga
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Marie R. G. Hermy
- Disease Vector Group, Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Newcastle-under-Lyme, UK
| | - Heather M. Ferguson
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Halfan S. Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Fredros O. Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
- School of Life Science and Bioengineering, The Nelson Mandela African Institution of Sciences & Technology, Arusha, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Park Town, Republic of South Africa
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Kareemi TI, Mishra AK, Chand SK, Nirankar JK, Vishwakarma AK, Tiwari A, Bharti PK. Analysis of the insecticide resistance mechanism in Anopheles culicifacies sensu lato from a malaria-endemic state in India. Trans R Soc Trop Med Hyg 2021; 116:252-260. [PMID: 34423836 DOI: 10.1093/trstmh/trab110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/26/2021] [Accepted: 07/13/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Understanding the dynamics and mechanisms of insecticide resistance in malaria vectors is crucial for vector control activities. The present study investigates the level of insecticide resistance in Anopheles culicifacies and explores the role of two main mechanisms in conferring resistance target site insensitivity and metabolic resistance. METHODS A. culicifacies mosquitoes were collected and the voltage-gated sodium channel (VGSC) gene was amplified and sequenced to analyse the knockdown resistance (kdr) mutations. Further, a non-experimental homology model was generated to investigate the effect of kdr mutations on the conformation of protein. Metabolic resistance was determined using bioassay-based resistant and susceptible mosquitoes and the expression levels of the genes CYP6Z1 and GSTe2 were compared between the two groups. RESULTS Sequence analysis of the VGSC gene revealed the presence of L1014F (n=48 [17%]), L1014S and V1010L (n=5 [1.7%]) mutations in the study area. In gene expression studies, a significant upregulation of CYP6Z1 in deltamethrin-resistant (fold change 243.62; p=0.02) mosquitoes and that of GSTe2 in dichlorodiphenyltrichloroethane (fold change 403.45; p=0.01) and alpha-cypemethrin resistant (fold change 217.51; p=0.0005) mosquitoes was observed. CONCLUSIONS The study revealed that expression of the genes (CYP6Z1 and GSTe2) conferring metabolic resistance play a key role in insecticide resistance in A. culicifacies populations in central India. However, mutations L101F, L10104S and V10101L also have a role to some extent in spreading resistance. GeneBank accession numbers: MW559058, MW559059 and MW559060 Cover Image: Workflow of Chimera-Modeller interface. In the top window of Chimera's multi-align viewer the sequence alignment of VGSC proteins of human (pdb id_6AGF), cockroach (pdb id 5XOM) and A. culicifacies (ACT176122.1) is shown. The dialog box in the middle is of the comparative modelling tool of Modeller. The A. culicifacies sequence is designated as the target while human and cockroach sequences are templates. Upon selection of the template sequences in the dialog box, the structures of the respective proteins are displayed in the Chimera window. As the run is completed, the results are displayed in the form of a list of models with their scores in a table.
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Affiliation(s)
- Tazeen I Kareemi
- Division of Vector Borne Diseases, ICMR-National Institute of Research in Tribal Health, Jabalpur, 482003, Madhya Pradesh, India.,School of Biotechnology, Rajeev Gandhi Technical University, Airport Bypass Road, Bhopal, 462033, Madhya Pradesh, India
| | - Ashok K Mishra
- Division of Vector Borne Diseases, ICMR-National Institute of Research in Tribal Health, Jabalpur, 482003, Madhya Pradesh, India
| | - Sunil K Chand
- Division of Vector Borne Diseases, ICMR-National Institute of Malaria Research, Field Unit, Nagpur Road, Garha Jabalpur, 482003, Madhya Pradesh, India
| | - Jitendra K Nirankar
- Division of Vector Borne Diseases, ICMR-National Institute of Research in Tribal Health, Jabalpur, 482003, Madhya Pradesh, India
| | - Anup K Vishwakarma
- Division of Vector Borne Diseases, ICMR-National Institute of Research in Tribal Health, Jabalpur, 482003, Madhya Pradesh, India
| | - Archana Tiwari
- School of Biotechnology, Rajeev Gandhi Technical University, Airport Bypass Road, Bhopal, 462033, Madhya Pradesh, India
| | - Praveen K Bharti
- Division of Vector Borne Diseases, ICMR-National Institute of Research in Tribal Health, Jabalpur, 482003, Madhya Pradesh, India
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An increasing role of pyrethroid-resistant Anopheles funestus in malaria transmission in the Lake Zone, Tanzania. Sci Rep 2021; 11:13457. [PMID: 34188090 PMCID: PMC8241841 DOI: 10.1038/s41598-021-92741-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/08/2021] [Indexed: 02/06/2023] Open
Abstract
Anopheles funestus is playing an increasing role in malaria transmission in parts of sub-Saharan Africa, where An. gambiae s.s. has been effectively controlled by long-lasting insecticidal nets. We investigated vector population bionomics, insecticide resistance and malaria transmission dynamics in 86 study clusters in North-West Tanzania. An. funestus s.l. represented 94.5% (4740/5016) of all vectors and was responsible for the majority of malaria transmission (96.5%), with a sporozoite rate of 3.4% and average monthly entomological inoculation rate (EIR) of 4.57 per house. Micro-geographical heterogeneity in species composition, abundance and transmission was observed across the study district in relation to key ecological differences between northern and southern clusters, with significantly higher densities, proportions and EIR of An. funestus s.l. collected from the South. An. gambiae s.l. (5.5%) density, principally An. arabiensis (81.1%) and An. gambiae s.s. (18.9%), was much lower and closely correlated with seasonal rainfall. Both An. funestus s.l. and An. gambiae s.l. were similarly resistant to alpha-cypermethrin and permethrin. Overexpression of CYP9K1, CYP6P3, CYP6P4 and CYP6M2 and high L1014S-kdr mutation frequency were detected in An. gambiae s.s. populations. Study findings highlight the urgent need for novel vector control tools to tackle persistent malaria transmission in the Lake Region of Tanzania.
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de Souza DK, Thomas R, Bradley J, Leyrat C, Boakye DA, Okebe J. Ivermectin treatment in humans for reducing malaria transmission. Cochrane Database Syst Rev 2021; 6:CD013117. [PMID: 34184757 PMCID: PMC8240090 DOI: 10.1002/14651858.cd013117.pub2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Malaria is transmitted through the bite of Plasmodium-infected adult female Anopheles mosquitoes. Ivermectin, an anti-parasitic drug, acts by killing mosquitoes that are exposed to the drug while feeding on the blood of people (known as blood feeds) who have ingested the drug. This effect on mosquitoes has been demonstrated by individual randomized trials. This effect has generated interest in using ivermectin as a tool for malaria control. OBJECTIVES To assess the effect of community administration of ivermectin on malaria transmission. SEARCH METHODS We searched the Cochrane Infectious Diseases Group (CIDG) Specialized Register, CENTRAL, MEDLINE, Embase, LILACS, Science Citation index - expanded, the World Health Organization (WHO) International Clinical Trials Registry Platform, ClinicalTrials.gov, and the National Institutes of Health (NIH) RePORTER database to 14 January 2021. We checked the reference lists of included studies for other potentially relevant studies, and contacted researchers working in the field for unpublished and ongoing trials. SELECTION CRITERIA We included cluster-randomized controlled trials (cRCTs) that compared ivermectin, as single or multiple doses, with a control treatment or placebo given to populations living in malaria-endemic areas, in the context of mass drug administration. Primary outcomes were prevalence of malaria parasite infection and incidence of clinical malaria in the community. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data on the number of events and the number of participants in each trial arm at the time of assessment. For rate data, we noted the total time at risk in each trial arm. To assess risk of bias, we used Cochrane's RoB 2 tool for cRCTs. We documented the method of data analysis, any adjustments for clustering or other covariates, and recorded the estimate of the intra-cluster correlation (ICC) coefficient. We re-analysed the trial data provided by the trial authors to adjust for cluster effects. We used a Poisson mixed-effect model with small sample size correction, and a cluster-level analysis using the linear weighted model to adequately adjust for clustering. MAIN RESULTS: We included one cRCT and identified six ongoing trials. The included cRCT examined the incidence of malaria in eight villages in Burkina Faso, randomized to two arms. Both trial arms received a single dose of ivermectin 150 µg/kg to 200 µg/kg, together with a dose of albendazole. The villages in the intervention arm received an additional five doses of ivermectin, once every three weeks. Children were enrolled into an active cohort, in which they were repeatedly screened for malaria infection. The primary outcome was the cumulative incidence of uncomplicated malaria in a cohort of children aged five years and younger, over the 18-week study. We judged the study to be at high risk of bias, as the analysis did not account for clustering or correlation between participants in the same village. The study did not demonstrate an effect of Ivermectin on the cumulative incidence of uncomplicated malaria in the cohort of children over the 18-week study (risk ratio 0.86, 95% confidence interval (CI) 0.62 to 1.17; P = 0.2607; very low-certainty evidence). AUTHORS' CONCLUSIONS We are uncertain whether community administration of ivermectin has an effect on malaria transmission, based on one trial published to date.
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Affiliation(s)
- Dziedzom K de Souza
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Rebecca Thomas
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene & Tropical Medicine, London, UK
| | - Clemence Leyrat
- Medical Statistics Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Daniel A Boakye
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Joseph Okebe
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, UK
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Black WC, Snell TK, Saavedra-Rodriguez K, Kading RC, Campbell CL. From Global to Local-New Insights into Features of Pyrethroid Detoxification in Vector Mosquitoes. INSECTS 2021; 12:insects12040276. [PMID: 33804964 PMCID: PMC8063960 DOI: 10.3390/insects12040276] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/18/2021] [Accepted: 03/20/2021] [Indexed: 02/04/2023]
Abstract
The threat of mosquito-borne diseases continues to be a problem for public health in subtropical and tropical regions of the world; in response, there has been increased use of adulticidal insecticides, such as pyrethroids, in human habitation areas over the last thirty years. As a result, the prevalence of pyrethroid-resistant genetic markers in natural mosquito populations has increased at an alarming rate. This review details recent advances in the understanding of specific mechanisms associated with pyrethroid resistance, with emphasis on features of insecticide detoxification and the interdependence of multiple cellular pathways. Together, these advances add important context to the understanding of the processes that are selected in resistant mosquitoes. Specifically, before pyrethroids bind to their targets on motoneurons, they must first permeate the outer cuticle and diffuse to inner tissues. Resistant mosquitoes have evolved detoxification mechanisms that rely on cytochrome P450s (CYP), esterases, carboxyesterases, and other oxidation/reduction (redox) components to effectively detoxify pyrethroids to nontoxic breakdown products that are then excreted. Enhanced resistance mechanisms have evolved to include alteration of gene copy number, transcriptional and post-transcriptional regulation of gene expression, as well as changes to cellular signaling mechanisms. Here, we outline the variety of ways in which detoxification has been selected in various mosquito populations, as well as key gene categories involved. Pathways associated with potential new genes of interest are proposed. Consideration of multiple cellular pathways could provide opportunities for development of new insecticides.
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Tchigossou GM, Atoyebi SM, Akoton R, Tossou E, Innocent D, Riveron J, Irving H, Yessoufou A, Wondji C, Djouaka R. Investigation of DDT resistance mechanisms in Anopheles funestus populations from northern and southern Benin reveals a key role of the GSTe2 gene. Malar J 2020; 19:456. [PMID: 33334345 PMCID: PMC7745352 DOI: 10.1186/s12936-020-03503-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 11/17/2020] [Indexed: 11/25/2022] Open
Abstract
Background Understanding the molecular basis of insecticide resistance in mosquito, such as Anopheles funestus, is an important step in developing strategies to mitigate the resistance problem. This study aims to assess the role of the GSTe2 gene in DDT resistance and determine the genetic diversity of this gene in An. funestus. Methods Gene expression analysis was performed using microarrays and PCR while the potential mutation associated with resistance was determined using sequencing. Results Low expression level of GSTe2 gene was recorded in Burkina-Faso samples with a fold change of 3.3 while high expression (FC 35.6) was recorded in southern Benin in Pahou (FC 35.6) and Kpome (FC 13.3). The sequencing of GSTe2 gene in six localities showed that L119F-GSTe2 mutation is almost getting fixed in highly DDT-resistant Benin (Pahou, Kpome, Doukonta) and Nigeria (Akaka Remo) mosquitoes with a low mutation rate observed in Tanongou (Benin) and Burkina-Faso mosquitoes. Conclusion This study shows the key role of the GSTe2 gene in DDT resistant An. funestus in Benin. Polymorphism analysis of this gene across Benin revealed possible barriers to gene flow, which could impact the design and implementation of resistance management strategies in the country.
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Affiliation(s)
- Genevieve M Tchigossou
- International Institute of Tropical Agriculture, Cotonou, 08 BP 0932, Benin.,University of Abomey Calavi, BP 526, Cotonou, Benin
| | - Seun M Atoyebi
- Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Oyo, Oya State, Nigeria
| | - Romaric Akoton
- International Institute of Tropical Agriculture, Cotonou, 08 BP 0932, Benin.,University of Abomey Calavi, BP 526, Cotonou, Benin
| | - Eric Tossou
- International Institute of Tropical Agriculture, Cotonou, 08 BP 0932, Benin.,University of Abomey Calavi, BP 526, Cotonou, Benin
| | - Djegbe Innocent
- Technologies, Engineering and Mathematics, National University of Sciences, Ecole Normale Supérieure de Natitingou, Natitingou, BP 123, Benin
| | - Jacob Riveron
- Liverpool School of Tropical Medicine, Pembroke PlaceLiverpool, L3 5QA, UK
| | - Helen Irving
- Liverpool School of Tropical Medicine, Pembroke PlaceLiverpool, L3 5QA, UK
| | - Akadiri Yessoufou
- International Institute of Tropical Agriculture, Cotonou, 08 BP 0932, Benin
| | - Charles Wondji
- Liverpool School of Tropical Medicine, Pembroke PlaceLiverpool, L3 5QA, UK.,Center for Research in Infectious Diseases (CRID), Yaoundé, Centre Region, Cameroon
| | - Rousseau Djouaka
- International Institute of Tropical Agriculture, Cotonou, 08 BP 0932, Benin.
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20
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Pinda PG, Eichenberger C, Ngowo HS, Msaky DS, Abbasi S, Kihonda J, Bwanaly H, Okumu FO. Comparative assessment of insecticide resistance phenotypes in two major malaria vectors, Anopheles funestus and Anopheles arabiensis in south-eastern Tanzania. Malar J 2020; 19:408. [PMID: 33176805 PMCID: PMC7661194 DOI: 10.1186/s12936-020-03483-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 11/05/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS) have greatly reduced malaria transmission in sub-Saharan Africa, but are threatened by insecticide resistance. In south-eastern Tanzania, pyrethroid-resistant Anopheles funestus are now implicated in > 80% of malaria infections, even in villages where the species occurs at lower densities than the other vector, Anopheles arabiensis. This study compared the insecticide resistance phenotypes between the two malaria vectors in an area where pyrethroid-LLINs are widely used. METHODS The study used the World Health Organization (WHO) assays with 1×, 5× and 10× insecticide doses to assess levels of resistance, followed by synergist bioassays to understand possible mechanisms of the observed resistance phenotypes. The tests involved adult mosquitoes collected from three villages across two districts in south-eastern Tanzania and included four insecticide classes. FINDINGS At baseline doses (1×), both species were resistant to the two candidate pyrethroids (permethrin and deltamethrin), but susceptible to the organophosphate (pirimiphos-methyl). Anopheles funestus, but not An. arabiensis was also resistant to the carbamate (bendiocarb). Both species were resistant to DDT in all villages except in one village where An. arabiensis was susceptible. Anopheles funestus showed strong resistance to pyrethroids, surviving the 5× and 10× doses, while An. arabiensis reverted to susceptibility at the 5× dose. Pre-exposure to the synergist, piperonyl butoxide (PBO), enhanced the potency of the pyrethroids against both species and resulted in full susceptibility of An. arabiensis (> 98% mortality). However, for An. funestus from two villages, permethrin-associated mortalities after pre-exposure to PBO only exceeded 90% but not 98%. CONCLUSIONS In south-eastern Tanzania, where An. funestus dominates malaria transmission, the species also has much stronger resistance to pyrethroids than its counterpart, An. arabiensis, and can survive more classes of insecticides. The pyrethroid resistance in both species appears to be mostly metabolic and may be partially addressed using synergists, e.g. PBO. These findings may explain the continued persistence and dominance of An. funestus despite widespread use of pyrethroid-treated LLINs, and inform new intervention choices for such settings. In short and medium-term, these may include PBO-based LLINs or improved IRS with compounds to which the vectors are still susceptible.
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Affiliation(s)
- Polius G Pinda
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania.
| | - Claudia Eichenberger
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Halfan S Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Dickson S Msaky
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Said Abbasi
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Japhet Kihonda
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Hamis Bwanaly
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania. .,Nelson Mandela African Institution of Science and Technology, School of Life Sciences and Biotechnology, Arusha, United Republic of Tanzania. .,School of Public Health, University of the Witwatersrand, Parktown, South Africa. .,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.
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21
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Sandeu MM, Mulamba C, Weedall GD, Wondji CS. A differential expression of pyrethroid resistance genes in the malaria vector Anopheles funestus across Uganda is associated with patterns of gene flow. PLoS One 2020; 15:e0240743. [PMID: 33170837 PMCID: PMC7654797 DOI: 10.1371/journal.pone.0240743] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 10/01/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Insecticide resistance is challenging the effectiveness of insecticide-based control interventions to reduce malaria burden in Africa. Understanding the molecular basis of insecticides resistance and patterns of gene flow in major malaria vectors such as Anopheles funestus are important steps for designing effective resistance management strategies. Here, we investigated the association between patterns of genetic structure and expression profiles of genes involved in the pyrethroid resistance in An. funestus across Uganda and neighboring Kenya. METHODS Blood-fed mosquitoes An. funestus were collected across the four localities in Uganda and neighboring Kenya. A Microarray-based genome-wide transcription analysis was performed to identify the set of genes associated with permethrin resistance. 17 microsatellites markers were genotyped and used to establish patterns of genetic differentiation. RESULTS Microarray-based genome-wide transcription profiling of pyrethroid resistance in four locations across Uganda (Arua, Bulambuli, Lira, and Tororo) and Kenya (Kisumu) revealed that resistance was mainly driven by metabolic resistance. The most commonly up-regulated genes in pyrethroid resistance mosquitoes include cytochrome P450s (CYP9K1, CYP6M7, CYP4H18, CYP4H17, CYP4C36). However, expression levels of key genes vary geographically such as the P450 CYP6M7 [Fold-change (FC) = 115.8 (Arua) vs 24.05 (Tororo) and 16.9 (Kisumu)]. In addition, several genes from other families were also over-expressed including Glutathione S-transferases (GSTs), carboxylesterases, trypsin, glycogenin, and nucleotide binding protein which probably contribute to insecticide resistance across Uganda and Kenya. Genotyping of 17 microsatellite loci in the five locations provided evidence that a geographical shift in the resistance mechanisms could be associated with patterns of population structure throughout East Africa. Genetic and population structure analyses indicated significant genetic differentiation between Arua and other localities (FST>0.03) and revealed a barrier to gene flow between Arua and other areas, possibly associated with Rift Valley. CONCLUSION The correlation between patterns of genetic structure and variation in gene expression could be used to inform future interventions especially as new insecticides are gradually introduced.
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Affiliation(s)
- Maurice Marcel Sandeu
- Department of Medical Entomology, Centre for Research in Infectious Diseases (CRID), LSTM Research Unit, Yaoundé, Cameroon
- Department of Microbiology and Infectious Diseases, School of Veterinary Medicine and Sciences, University of Ngaoundéré, Ngaoundéré, Cameroon
| | - Charles Mulamba
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Uganda Virus Research Institute, Entebbe, Uganda
| | - Gareth D. Weedall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Charles S. Wondji
- Department of Medical Entomology, Centre for Research in Infectious Diseases (CRID), LSTM Research Unit, Yaoundé, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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22
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Nkemngo FN, Mugenzi LMJ, Terence E, Niang A, Wondji MJ, Tchoupo M, Nguete ND, Tchapga W, Irving H, Ntabi JDM, Agonhossou R, Boussougou-Sambe TS, Akoton RB, Koukouikila-Koussounda F, Pinilla YT, Ntoumi F, Djogbenou LS, Ghogomu SM, Ndo C, Adegnika AA, Borrmann S, Wondji CS. Multiple insecticide resistance and Plasmodium infection in the principal malaria vectors Anopheles funestus and Anopheles gambiae in a forested locality close to the Yaoundé airport, Cameroon. Wellcome Open Res 2020; 5:146. [PMID: 33204845 PMCID: PMC7667521 DOI: 10.12688/wellcomeopenres.15818.2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2020] [Indexed: 11/20/2022] Open
Abstract
Background: Reducing the burden of malaria requires better understanding of vector populations, particularly in forested regions where the incidence remains elevated. Here, we characterized malaria vectors in a locality near the Yaoundé international airport, Cameroon, including species composition, abundance, Plasmodium infection rate, insecticide resistance profiles and underlying resistance mechanisms. Methods: Blood-fed adult mosquitoes resting indoors were aspirated from houses in April 2019 at Elende, a locality situated 2 km from the Yaoundé-Nsimalen airport. Female mosquitoes were forced to lay eggs to generate F 1 adults. Bioassays were performed to assess resistance profile to the four insecticides classes. The threshold of insecticide susceptibility was defined above 98% mortality rate and mortality rates below 90% were indicative of confirmed insecticide resistance. Furthermore, the molecular basis of resistance and Plasmodium infection rates were investigated. Results: Anopheles funestus s.s. was the most abundant species in Elende (85%) followed by Anopheles gambiae s.s. (15%) with both having similar sporozoite rate. Both species exhibited high levels of resistance to the pyrethroids, permethrin and deltamethrin (<40% mortality). An. gambiae s.s. was resistant to DDT (9.9% mortality) and bendiocarb (54% mortality) while susceptible to organophosphate. An. funestus s.s. was resistant to dieldrin (1% mortality), DDT (86% mortality) but susceptible to carbamates and organophosphates. The L119F-GSTe2 resistance allele (8%) and G119S ace-1 resistance allele (15%) were detected in An. funestus s.s. and An. gambiae s.s., respectively . Furthermore, the high pyrethroid/DDT resistances in An. gambiae corresponded with an increase frequency of 1014F kdr allele (95%). Transcriptional profiling of candidate cytochrome P450 genes reveals the over-expression of CYP6P5, CYP6P9a and CYP6P9b. Conclusion: The resistance to multiple insecticide classes observed in these vector populations alongside the significant Plasmodium sporozoite rate highlights the challenges that vector control programs encounter in sustaining the regular benefits of contemporary insecticide-based control interventions in forested areas.
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Affiliation(s)
- Francis N. Nkemngo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Microbiology and Parasitology, University of Buea, Buea, South West, 237, Cameroon
| | - Leon M. J. Mugenzi
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, South West, 237, Cameroon
| | - Ebai Terence
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Abdoulaye Niang
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Murielle J. Wondji
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Micareme Tchoupo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Nguiffo D. Nguete
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Williams Tchapga
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Helen Irving
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Jacques D. M. Ntabi
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
| | - Romuald Agonhossou
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Terence S. Boussougou-Sambe
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Romaric B. Akoton
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Felix Koukouikila-Koussounda
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
| | - Yudi T. Pinilla
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Francine Ntoumi
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Luc S. Djogbenou
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Stephen M. Ghogomu
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, South West, 237, Cameroon
| | - Cyrille Ndo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Ayola A. Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
- Eberhard Karls Universität Tübingen,, Tübingen, Germany
- German Center for Infection Research (DZIF), Tübingen, Germany
| | - Steffen Borrmann
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Tübingen, Germany
| | - Charles S. Wondji
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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23
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Nambunga IH, Ngowo HS, Mapua SA, Hape EE, Msugupakulya BJ, Msaky DS, Mhumbira NT, Mchwembo KR, Tamayamali GZ, Mlembe SV, Njalambaha RM, Lwetoijera DW, Finda MF, Govella NJ, Matoke-Muhia D, Kaindoa EW, Okumu FO. Aquatic habitats of the malaria vector Anopheles funestus in rural south-eastern Tanzania. Malar J 2020; 19:219. [PMID: 32576200 PMCID: PMC7310514 DOI: 10.1186/s12936-020-03295-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/17/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND In rural south-eastern Tanzania, Anopheles funestus is a major malaria vector, and has been implicated in nearly 90% of all infective bites. Unfortunately, little is known about the natural ecological requirements and survival strategies of this mosquito species. METHODS Potential mosquito aquatic habitats were systematically searched along 1000 m transects from the centres of six villages in south-eastern Tanzania. All water bodies were geo-referenced, characterized and examined for presence of Anopheles larvae using standard 350 mLs dippers or 10 L buckets. Larvae were collected for rearing, and the emergent adults identified to confirm habitats containing An. funestus. RESULTS One hundred and eleven habitats were identified and assessed from the first five villages (all < 300 m altitude). Of these, 36 (32.4%) had An. funestus co-occurring with other mosquito species. Another 47 (42.3%) had other Anopheles species and/or culicines, but not An. funestus, and 28 (25.2%) had no mosquitoes. There were three main habitat types occupied by An. funestus, namely: (a) small spring-fed pools with well-defined perimeters (36.1%), (b) medium-sized natural ponds retaining water most of the year (16.7%), and (c) slow-moving waters along river tributaries (47.2%). The habitats generally had clear waters with emergent surface vegetation, depths > 0.5 m and distances < 100 m from human dwellings. They were permanent or semi-permanent, retaining water most of the year. Water temperatures ranged from 25.2 to 28.8 °C, pH from 6.5 to 6.7, turbidity from 26.6 to 54.8 NTU and total dissolved solids from 60.5 to 80.3 mg/L. In the sixth village (altitude > 400 m), very high densities of An. funestus were found along rivers with slow-moving clear waters and emergent vegetation. CONCLUSION This study has documented the diversity and key characteristics of aquatic habitats of An. funestus across villages in south-eastern Tanzania, and will form an important basis for further studies to improve malaria control. The observations suggest that An. funestus habitats in the area can indeed be described as fixed, few and findable based on their unique characteristics. Future studies should investigate the potential of targeting these habitats with larviciding or larval source management to complement malaria control efforts in areas dominated by this vector species.
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Affiliation(s)
- Ismail H Nambunga
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.
| | - Halfan S Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Salum A Mapua
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Newcastle-under-Lyme, UK
| | - Emmanuel E Hape
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Betwel J Msugupakulya
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- School of Life Science and Bioengineering, Nelson Mandela African Institution of Science & Technology, Arusha, Tanzania
| | - Dickson S Msaky
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Nicolaus T Mhumbira
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Karim R Mchwembo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Gerald Z Tamayamali
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Slyakus V Mlembe
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Rukiyah M Njalambaha
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Dickson W Lwetoijera
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- School of Life Science and Bioengineering, Nelson Mandela African Institution of Science & Technology, Arusha, Tanzania
| | - Marceline F Finda
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Park Town, Republic of South Africa
| | - Nicodem J Govella
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
- School of Life Science and Bioengineering, Nelson Mandela African Institution of Science & Technology, Arusha, Tanzania
| | - Damaris Matoke-Muhia
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- Center for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Emmanuel W Kaindoa
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Park Town, Republic of South Africa
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Park Town, Republic of South Africa.
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.
- School of Life Science and Bioengineering, Nelson Mandela African Institution of Science & Technology, Arusha, Tanzania.
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24
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Nkemngo FN, Mugenzi LMJ, Terence E, Niang A, Wondji MJ, Tchoupo M, Nguete ND, Tchapga W, Irving H, Ntabi JDM, Agonhossou R, Boussougou-Sambe TS, Akoton RB, Koukouikila-Koussounda F, Pinilla YT, Ntoumi F, Djogbenou LS, Ghogomu SM, Ndo C, Adegnika AA, Borrmann S, Wondji CS. Elevated Plasmodium sporozoite infection and multiple insecticide resistance in the principal malaria vectors Anopheles funestus and Anopheles gambiae in a forested locality close to the Yaoundé airport, Cameroon. Wellcome Open Res 2020; 5:146. [PMID: 33204845 PMCID: PMC7667521 DOI: 10.12688/wellcomeopenres.15818.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2020] [Indexed: 11/13/2023] Open
Abstract
Background: Reducing the burden of malaria requires better understanding of vector populations, particularly in forested regions where the incidence remains elevated. Here, we characterized malaria vectors in a locality near the Yaoundé international airport, Cameroon, including species composition, abundance, Plasmodium infection rate, insecticide resistance profiles and underlying resistance mechanisms. Methods: Blood-fed adult mosquitoes resting indoors were aspirated from houses in April 2019 at Elende, a village located 2 km from the Yaoundé-Nsimalen airport. Female mosquitoes were forced to lay eggs to generate F 1 adult progeny. Bioassays were performed to assess resistance profile to insecticides. The threshold of insecticide susceptibility was defined above 98% mortality rate and mortality rates below 90% were indicative of confirmed insecticide resistance. Furthermore, the molecular basis of resistance and Plasmodium infection rates were investigated. Results: Anopheles funestus s.s. was most abundant species in Elende (85%) followed by Anopheles gambiae s.s. (15%) with both having a similar sporozoite rate. Both species exhibited high levels of resistance to pyrethroids (<40% mortality). An. gambiae s.s. was also resistant to DDT (9.9% mortality) and bendiocarb (54% mortality) while susceptible to organophosphate. An. funestus s.s. was resistant to dieldrin (1% mortality), DDT (86% mortality) but susceptible to carbamates and organophosphates. The L119F-GSTe2 resistance allele (8%) and G119S ace-1 resistance allele (15%) were detected in An. funestus s.s. and An. gambiae s.s., respectively . Furthermore, the high pyrethroid/DDT resistances in An. gambiae s.s. corresponded with an increase frequency of 1014F kdr allele (95%). Transcriptional profiling of candidate cytochrome P450 genes reveals the over-expression of CYP6P5, CYP6P9a and CYP6P9b. Conclusion: The resistance to multiple insecticide classes observed in these vector populations alongside the high Plasmodium sporozoite rate highlights the challenges that vector control programs encounter in sustaining the regular benefits of contemporary insecticide-based control interventions in forested areas.
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Affiliation(s)
- Francis N. Nkemngo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Microbiology and Parasitology, University of Buea, Buea, South West, 237, Cameroon
| | - Leon M. J. Mugenzi
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, South West, 237, Cameroon
| | - Ebai Terence
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Abdoulaye Niang
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Murielle J. Wondji
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Micareme Tchoupo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Nguiffo D. Nguete
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Williams Tchapga
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Helen Irving
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Jacques D. M. Ntabi
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
| | - Romuald Agonhossou
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Terence S. Boussougou-Sambe
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Romaric B. Akoton
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Felix Koukouikila-Koussounda
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
| | - Yudi T. Pinilla
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Francine Ntoumi
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Luc S. Djogbenou
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Stephen M. Ghogomu
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, South West, 237, Cameroon
| | - Cyrille Ndo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Ayola A. Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
- Eberhard Karls Universität Tübingen,, Tübingen, Germany
- German Center for Infection Research (DZIF), Tübingen, Germany
| | - Steffen Borrmann
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Tübingen, Germany
| | - Charles S. Wondji
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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25
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Weedall GD, Riveron JM, Hearn J, Irving H, Kamdem C, Fouet C, White BJ, Wondji CS. An Africa-wide genomic evolution of insecticide resistance in the malaria vector Anopheles funestus involves selective sweeps, copy number variations, gene conversion and transposons. PLoS Genet 2020; 16:e1008822. [PMID: 32497040 PMCID: PMC7297382 DOI: 10.1371/journal.pgen.1008822] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 06/16/2020] [Accepted: 05/01/2020] [Indexed: 01/05/2023] Open
Abstract
Insecticide resistance in malaria vectors threatens to reverse recent gains in malaria control. Deciphering patterns of gene flow and resistance evolution in malaria vectors is crucial to improving control strategies and preventing malaria resurgence. A genome-wide survey of Anopheles funestus genetic diversity Africa-wide revealed evidences of a major division between southern Africa and elsewhere, associated with different population histories. Three genomic regions exhibited strong signatures of selective sweeps, each spanning major resistance loci (CYP6P9a/b, GSTe2 and CYP9K1). However, a sharp regional contrast was observed between populations correlating with gene flow barriers. Signatures of complex molecular evolution of resistance were detected with evidence of copy number variation, transposon insertion and a gene conversion between CYP6P9a/b paralog genes. Temporal analyses of samples before and after bed net scale up suggest that these genomic changes are driven by this control intervention. Multiple independent selective sweeps at the same locus in different parts of Africa suggests that local evolution of resistance in malaria vectors may be a greater threat than trans-regional spread of resistance haplotypes. Malaria control currently relies heavily on insecticide-based vector control interventions. Unfortunately, resistance to insecticides is threatening their continued effectiveness. Metabolic resistance has the greatest operational significance, yet it remains unclear how mosquito populations evolutionarily respond to the massive selection pressure from control interventions including insecticide-treated nets. Deciphering patterns of gene flow between populations of major malaria vectors such as Anopheles funestus and elucidating genomic signature of resistance evolution are crucial for designing resistance management strategies and preventing malaria resurgence. Here, we performed a genome-wide survey of An. funestus genetic diversity from across its continental range using reduced-genome representation (ddRADseq) and whole genome (PoolSeq) approaches revealing evidence of significant barriers to gene flow impacting the spread of insecticide resistance alleles. This study detected signatures of strong selective sweeps occurring in genomic regions controlling cytochrome P450-based and glutathione s-transferase metabolic resistance to insecticides in this species. Fine-scale analysis of the major pyrethroid resistance-associated genomic regions revealed complex molecular evolution with evidence of copy number variation, transposon insertion and gene conversion highlighting the risk that if this level of selection and spread of resistance continues unabated, our ability to control malaria with current interventions will be compromised.
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Affiliation(s)
- Gareth D. Weedall
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, United Kingdom
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
- * E-mail: (GDW); (CSW)
| | - Jacob M. Riveron
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, United Kingdom
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- LSTM Research Unit at CRID, Yaoundé, Cameroon
| | - Jack Hearn
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, United Kingdom
| | - Helen Irving
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, United Kingdom
| | - Colince Kamdem
- LSTM Research Unit at CRID, Yaoundé, Cameroon
- Department of Entomology, University of California, Riverside, California, United States of America
| | - Caroline Fouet
- LSTM Research Unit at CRID, Yaoundé, Cameroon
- Department of Entomology, University of California, Riverside, California, United States of America
| | - Bradley J. White
- Department of Entomology, University of California, Riverside, California, United States of America
- Verily Life Sciences, South San Francisco, California, United States of America
| | - Charles S. Wondji
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, United Kingdom
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- LSTM Research Unit at CRID, Yaoundé, Cameroon
- * E-mail: (GDW); (CSW)
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26
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Marcombe S, Thammavong P, Luangamath P, Chonephetsarath S, Phommavanh N, Lakeomany K, Nilaxay S, Rahmani Z, Saverton PJ, Abdullateef OH, Forward J, Jacob AE, Khadam S, Ali W, Boer C, Kakinuma H, Hawkins J, Longstreeth R, Portwood NM, Smee M, Brown N, Kuyucu NC, Lechmere S, Stieger G, Maithaviphet S, Nambanya S, Brey PT, Jones AK. Malaria and Dengue Mosquito Vectors from Lao PDR Show a Lack of the rdl Mutant Allele Responsible for Cyclodiene Insecticide Resistance. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:815-823. [PMID: 31807752 DOI: 10.1093/jme/tjz227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Indexed: 06/10/2023]
Abstract
The gamma-aminobutyric acid (GABA) receptor, RDL, plays important roles in neuronal signaling and is the target of highly effective insecticides. A mutation in RDL, commonly A296S, underlies resistance to several insecticides such as cyclodienes. Even though the use of cyclodienes has been banned, the occurrence of mutations substituting A296 is notably high in mosquitoes from several countries. Here, we report a survey investigating the prevalence of the Rdl mutant allele in mosquitoes from Laos, a country where mosquito-borne diseases such as malaria and dengue fever are health concerns. Anopheles and Aedes mosquitoes were collected from 12 provinces in Laos. Adult bioassays on Aedes aegypti (Linnaeus) (Diptera: Culicidae) and Aedes albopictus (Skuse) (Diptera: Culicidae) showed that all the populations tested were susceptible to dieldrin (4%) following WHO protocols. Exon 7 from a total of 791 mosquitoes was sequenced to identify the amino acid encoded for at 296 of RDL. Only one of these mosquitoes, Anopheles maculatus rampae Harbach and Somboon (Diptera: Culicidae) from Attapeu, carried the mutant allele being heterozygous for A296S. We therefore found a general lack of the Rdl mutant allele indicating that mosquitoes from Laos are not exposed to insecticides that act on the GABA receptor compared to mosquitoes in several other countries. Identifying the prevalence of the Rdl mutation may help inform the potential use of alternative insecticides that act on the GABA receptor should there be a need to replace pyrethroids in order to prevent/manage resistance.
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Affiliation(s)
- Sebastien Marcombe
- Institut Pasteur du Laos, Department of Entomology, Ministry of Health, Vientiane, Lao PDR
| | - Phoutmany Thammavong
- Institut Pasteur du Laos, Department of Entomology, Ministry of Health, Vientiane, Lao PDR
| | - Phonesavanh Luangamath
- Institut Pasteur du Laos, Department of Entomology, Ministry of Health, Vientiane, Lao PDR
| | | | - Nothasin Phommavanh
- Institut Pasteur du Laos, Department of Entomology, Ministry of Health, Vientiane, Lao PDR
| | - Khaitong Lakeomany
- Institut Pasteur du Laos, Department of Entomology, Ministry of Health, Vientiane, Lao PDR
| | - Somphat Nilaxay
- Institut Pasteur du Laos, Department of Entomology, Ministry of Health, Vientiane, Lao PDR
| | - Zuhal Rahmani
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Penelope J Saverton
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Omobolanle H Abdullateef
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Jordan Forward
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Anna E Jacob
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Safina Khadam
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Wlaa Ali
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Chloé Boer
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Hayato Kakinuma
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Joseph Hawkins
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Rosie Longstreeth
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Natalie M Portwood
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Madeleine Smee
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Natasha Brown
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Nursu C Kuyucu
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Susannah Lechmere
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Gabriela Stieger
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
| | - Santi Maithaviphet
- Center for Malariology, Parasitology and Entomology, Department of Entomology, Ministry of Health, Vientiane, Lao PDR
| | - Simone Nambanya
- Center for Malariology, Parasitology and Entomology, Department of Entomology, Ministry of Health, Vientiane, Lao PDR
| | - Paul T Brey
- Institut Pasteur du Laos, Department of Entomology, Ministry of Health, Vientiane, Lao PDR
| | - Andrew K Jones
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, UK
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27
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Exploring the Mechanisms of Multiple Insecticide Resistance in a Highly Plasmodium-Infected Malaria Vector Anopheles funestus Sensu Stricto from Sahel of Northern Nigeria. Genes (Basel) 2020; 11:genes11040454. [PMID: 32331386 PMCID: PMC7230678 DOI: 10.3390/genes11040454] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/17/2020] [Accepted: 04/20/2020] [Indexed: 11/30/2022] Open
Abstract
The Nigerian Government is scaling up the distribution of insecticide-treated bed nets for malaria control, but the lack of surveillance data, especially in the Sudan/Sahel region of the country, may hinder targeting priority populations. Here, the vectorial role and insecticide resistance profile of a population of a major malaria vector Anopheles funestus sensu stricto from Sahel of Nigeria was characterised. An. funestus s.s. was the only vector found, with a high human blood index (100%) and a biting rate of 5.3/person/night. High Plasmodium falciparum infection was discovered (sporozoite rate = 54.55%). The population is resistant to permethrin (mortality = 48.30%, LT50 = 65.76 min), deltamethrin, DDT (dichlorodiphenyltrichloroethane) and bendiocarb, with mortalities of 29.44%, 56.34% and 54.05%, respectively. Cone-bioassays established loss of efficacy of the pyrethroid-only long-lasting insecticidal nets (LLINs); but 100% recovery of susceptibility was obtained for piperonylbutoxide (PBO)-containing PermaNet®3.0. Synergist bioassays with PBO and diethyl maleate recovered susceptibility, implicating CYP450s (permethrin mortality = 78.73%, χ2 = 22.33, P < 0.0001) and GSTs (DDT mortality = 81.44%, χ2 = 19.12, P < 0.0001). A high frequency of 119F GSTe2 mutation (0.84) was observed (OR = 16, χ2 = 3.40, P = 0.05), suggesting the preeminent role of metabolic resistance. These findings highlight challenges associated with deployment of LLINs and indoor residual spraying (IRS) in Nigeria.
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28
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Weedall GD, Mugenzi LMJ, Menze BD, Tchouakui M, Ibrahim SS, Amvongo-Adjia N, Irving H, Wondji MJ, Tchoupo M, Djouaka R, Riveron JM, Wondji CS. A cytochrome P450 allele confers pyrethroid resistance on a major African malaria vector, reducing insecticide-treated bednet efficacy. Sci Transl Med 2020; 11:11/484/eaat7386. [PMID: 30894503 DOI: 10.1126/scitranslmed.aat7386] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 10/09/2018] [Indexed: 11/02/2022]
Abstract
Metabolic resistance to insecticides such as pyrethroids in mosquito vectors threatens control of malaria in Africa. Unless it is managed, recent gains in reducing malaria transmission could be lost. To improve monitoring and assess the impact of insecticide resistance on malaria control interventions, we elucidated the molecular basis of pyrethroid resistance in the major African malaria vector, Anopheles funestus We showed that a single cytochrome P450 allele (CYP6P9a_R) in A. funestus reduced the efficacy of insecticide-treated bednets for preventing transmission of malaria in southern Africa. Expression of key insecticide resistance genes was detected in populations of this mosquito vector throughout Africa but varied according to the region. Signatures of selection and adaptive evolutionary traits including structural polymorphisms and cis-regulatory transcription factor binding sites were detected with evidence of selection due to the scale-up of insecticide-treated bednet use. A cis-regulatory polymorphism driving the overexpression of the major resistance gene CYP6P9a allowed us to design a DNA-based assay for cytochrome P450-mediated resistance to pyrethroid insecticides. Using this assay, we tracked the spread of pyrethroid resistance and found that it was almost fixed in mosquitoes from southern Africa but was absent from mosquitoes collected elsewhere in Africa. Furthermore, a field study in experimental huts in Cameroon demonstrated that mosquitoes carrying the resistance CYP6P9a_R allele survived and succeeded in blood feeding more often than did mosquitoes that lacked this allele. Our findings highlight the need to introduce a new generation of insecticide-treated bednets for malaria control that do not rely on pyrethroid insecticides.
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Affiliation(s)
- Gareth D Weedall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.,School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool L3 3AF, U.K
| | - Leon M J Mugenzi
- LSTM Research Unit at the Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Benjamin D Menze
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.,LSTM Research Unit at the Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Magellan Tchouakui
- LSTM Research Unit at the Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Sulaiman S Ibrahim
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.,Department of Biochemistry, Bayero University, PMB 3011, Kano, Nigeria
| | - Nathalie Amvongo-Adjia
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.,Centre for Medical Research, Institute of Medical Research and Medicinal Plants Studies (IMPM), P.O. Box 13033, Yaoundé, Cameroon
| | - Helen Irving
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Murielle J Wondji
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.,LSTM Research Unit at the Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Micareme Tchoupo
- LSTM Research Unit at the Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Rousseau Djouaka
- International Institute of Tropical Agriculture (IITA), Cotonou 08 BP 0932, Benin
| | - Jacob M Riveron
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.,LSTM Research Unit at the Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Charles S Wondji
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK. .,LSTM Research Unit at the Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
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An Experimental Hut Evaluation of PBO-Based and Pyrethroid-Only Nets against the Malaria Vector Anopheles funestus Reveals a Loss of Bed Nets Efficacy Associated with GSTe2 Metabolic Resistance. Genes (Basel) 2020; 11:genes11020143. [PMID: 32013227 PMCID: PMC7073577 DOI: 10.3390/genes11020143] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/14/2019] [Accepted: 12/16/2019] [Indexed: 11/16/2022] Open
Abstract
Growing insecticide resistance in malaria vectors is threatening the effectiveness of insecticide-based interventions, including Long Lasting Insecticidal Nets (LLINs). However, the impact of metabolic resistance on the effectiveness of these tools remains poorly characterized. Using experimental hut trials and genotyping of a glutathione S-transferase resistance marker (L119F-GSTe2), we established that GST-mediated resistance is reducing the efficacy of LLINs against Anopheles funestus. Hut trials performed in Cameroon revealed that Piperonyl butoxide (PBO)-based nets induced a significantly higher mortality against pyrethroid resistant An. funestus than pyrethroid-only nets. Blood feeding rate and deterrence were significantly higher in all LLINs than control. Genotyping the L119F-GSTe2 mutation revealed that, for permethrin-based nets, 119F-GSTe2 resistant mosquitoes have a greater ability to blood feed than susceptible while the opposite effect is observed for deltamethrin-based nets. For Olyset Plus, a significant association with exophily was observed in resistant mosquitoes (OR = 11.7; p < 0.01). Furthermore, GSTe2-resistant mosquitoes (cone assays) significantly survived with PermaNet 2.0 (OR = 2.1; p < 0.01) and PermaNet 3.0 (side) (OR = 30.1; p < 0.001) but not for Olyset Plus. This study shows that the efficacy of PBO-based nets (e.g., blood feeding inhibition) against pyrethroid resistant malaria vectors could be impacted by other mechanisms including GST-mediated metabolic resistance not affected by the synergistic action of PBO. Mosaic LLINs incorporating a GST inhibitor (diethyl maleate) could help improve their efficacy in areas of GST-mediated resistance.
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Gunasekaran K, Sahu SS, Vijayakumar T, Subramanian S, Rahi M, Jambulingam P. Evaluation of DawaPlus 3.0 and DawaPlus 4.0, deltamethrin-PBO combination nets against pyrethroid-resistant Anopheles culicifacies in experimental huts in India. Malar J 2020; 19:43. [PMID: 31973734 PMCID: PMC6979062 DOI: 10.1186/s12936-020-3119-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/13/2020] [Indexed: 12/02/2022] Open
Abstract
Background The development of resistance in vectors is one of the major impediments for malaria control. Adding synergists to insecticides has proven to be an alternative choice for controlling resistant mosquitoes. DawaPlus 3.0 and DawaPlus 4.0 are new long-lasting insecticidal nets (LLINs) in which deltamethrin and a synergist, piperonyl butoxide (PBO) are added into filaments and their efficacy was tested against resistant malaria vector, Anopheles culicifacies in experimental huts in India. Methods The performance of two trial nets in terms of deterrence induced exiting, blood-feeding inhibition and mortality of An. culicifacies was compared with DawaPlus 2.0 and untreated net. Results There was a significant reduction in entry, blood feeding and mortality (p < 0.05) and increase in exit rates of An. culicifacies in the treatment arms compared to untreated arm. But, both candidate LNs washed 20 times could not perform better than the washed reference net (DawaPlus 2.0). Cone bioassay results showed that all the treatment arms (both washed and unwashed) produced < 80% mortality of An. culicifacies before and after hut evaluation. Conclusions DawaPlus 3.0 and DawaPlus 4.0 with their current specification may not be as effective as required to control the resistant vector, An. culicifacies, in east-central India.
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Affiliation(s)
- Kasinathan Gunasekaran
- Vector Control Research Centre, Indian Council of Medical Research, Indira Nagar, Pondicherry, 605006, India
| | - Sudhansu Sekhar Sahu
- Vector Control Research Centre, Indian Council of Medical Research, Indira Nagar, Pondicherry, 605006, India.
| | - Tharmalingam Vijayakumar
- Vector Control Research Centre, Indian Council of Medical Research, Indira Nagar, Pondicherry, 605006, India
| | - Swaminathan Subramanian
- Vector Control Research Centre, Indian Council of Medical Research, Indira Nagar, Pondicherry, 605006, India
| | - Manju Rahi
- Indian Council of Medical Research, New Delhi, India
| | - Purushothaman Jambulingam
- Vector Control Research Centre, Indian Council of Medical Research, Indira Nagar, Pondicherry, 605006, India
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Mugenzi LMJ, Menze BD, Tchouakui M, Wondji MJ, Irving H, Tchoupo M, Hearn J, Weedall GD, Riveron JM, Wondji CS. Cis-regulatory CYP6P9b P450 variants associated with loss of insecticide-treated bed net efficacy against Anopheles funestus. Nat Commun 2019; 10:4652. [PMID: 31604938 PMCID: PMC6789023 DOI: 10.1038/s41467-019-12686-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 09/21/2019] [Indexed: 11/09/2022] Open
Abstract
Elucidating the genetic basis of metabolic resistance to insecticides in malaria vectors is crucial to prolonging the effectiveness of insecticide-based control tools including long lasting insecticidal nets (LLINs). Here, we show that cis-regulatory variants of the cytochrome P450 gene, CYP6P9b, are associated with pyrethroid resistance in the African malaria vector Anopheles funestus. A DNA-based assay is designed to track this resistance that occurs near fixation in southern Africa but not in West/Central Africa. Applying this assay we demonstrate, using semi-field experimental huts, that CYP6P9b-mediated resistance associates with reduced effectiveness of LLINs. Furthermore, we establish that CYP6P9b combines with another P450, CYP6P9a, to additively exacerbate the reduced efficacy of insecticide-treated nets. Double homozygote resistant mosquitoes (RR/RR) significantly survive exposure to insecticide-treated nets and successfully blood feed more than other genotypes. This study provides tools to track and assess the impact of multi-gene driven metabolic resistance to pyrethroids, helping improve resistance management. Bed nets treated with insecticides have been instrumental in reducing malaria mortality, but insecticide resistance is on the rise. Here, Mugenzi et al. identify genetic variants in the P450 gene CYP6P9b of Anopheles funestus that associate with insecticide resistance and develop a PCR-based diagnostic assay to help identify pyrethroid-resistant strains.
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Affiliation(s)
- Leon M J Mugenzi
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Centre for Research in Infectious Diseases (CRID), P.O. Box, 13501, Yaoundé, Cameroon.,Department of Biochemistry and Molecular Biology, Faculty of Science University of Buea, P.O. Box, 63, Buea, Cameroon
| | - Benjamin D Menze
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Centre for Research in Infectious Diseases (CRID), P.O. Box, 13501, Yaoundé, Cameroon
| | - Magellan Tchouakui
- Centre for Research in Infectious Diseases (CRID), P.O. Box, 13501, Yaoundé, Cameroon
| | - Murielle J Wondji
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Centre for Research in Infectious Diseases (CRID), P.O. Box, 13501, Yaoundé, Cameroon
| | - Helen Irving
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Micareme Tchoupo
- Centre for Research in Infectious Diseases (CRID), P.O. Box, 13501, Yaoundé, Cameroon
| | - Jack Hearn
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Gareth D Weedall
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,School of Natural Sciences and Psychology, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Jacob M Riveron
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Centre for Research in Infectious Diseases (CRID), P.O. Box, 13501, Yaoundé, Cameroon
| | - Charles S Wondji
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK. .,Centre for Research in Infectious Diseases (CRID), P.O. Box, 13501, Yaoundé, Cameroon.
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Nararak J, Sathantriphop S, Kongmee M, Mahiou-Leddet V, Ollivier E, Manguin S, Chareonviriyaphap T. Excito-repellent activity of β-caryophyllene oxide against Aedes aegypti and Anopheles minimus. Acta Trop 2019; 197:105030. [PMID: 31121148 DOI: 10.1016/j.actatropica.2019.05.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 02/26/2019] [Accepted: 05/17/2019] [Indexed: 02/02/2023]
Abstract
Contact irritant and non-contact repellent activities of β-caryophyllene oxide were evaluated against laboratory strains of female Aedes aegypti (USDA strain), a major arbovirus vector and Anopheles minimus (KU strain), a major malaria parasite vector, compared with the synthetic repellent DEET, using an excito-repellency test system. β-caryophyllene oxide and DEET were tested at concentrations of 0.1, 0.25, 0.5 and 1.0% (v/v). Anopheles minimus was found to be more sensitive to β-caryophyllene oxide than that of Ae. aegypti and exhibited high avoidance response rates (86-96% escape) at 0.5% and 1.0% concentrations in contact and non-contact trials compared with Ae. aegypti (22-59% escape). However, at the same concentrations, DEET displayed lower irritancy and repellency capacities against these two mosquito species (range 0-54% escape) compared to β-caryophyllene oxide. The analysis of escape responses showed significant differences between mosquito species at all concentrations (P < 0.05) except for 0.1%. For both species, there were significant differences in irritant and repellent responses between β-caryophyllene oxide and DEET at higher concentrations (0.5 and 1.0%).
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Chen S, Qin Q, Zhong D, Fang X, He H, Wang L, Dong L, Lin H, Zhang M, Cui L, Yan G. Insecticide Resistance Status and Mechanisms of Anopheles sinensis (Diptera: Culicidae) in Wenzhou, an Important Coastal Port City in China. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:803-810. [PMID: 30715428 PMCID: PMC6467641 DOI: 10.1093/jme/tjz001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Indexed: 06/04/2023]
Abstract
Although scaled-up interventions and effective control efforts have drastically reduced malaria morbidity and mortality, malaria remains a serious threat to public health worldwide. Anopheles sinensis Wiedemann 1828 is a historically important vector of Plasmodium vivax (Haemosporida: Plasmodiidae) malaria in China. Insecticide resistance has become a major obstacle to vector-borne disease control. However, little is known about the insecticide resistance of An. sinensis in Wenzhou, an important coastal port city in Zhejiang province, China. The aim of this study was to examine insecticide resistance and mechanisms in An. sinensis field mosquito populations. Evidence of multiple insecticide resistance was found in An. sinensis adult female populations. Medium to high frequencies of target site kdr together with fixed ace-1 mutations was detected in both the Ruian and Yongjia populations. Both populations showed an association between kdr L1014 mutation and resistance phenotype when tested against deltamethrin and DDT. Significantly different metabolic enzyme activities were found between the susceptible laboratory strain and field-collected mosquitoes from both Ruian and Yongjia. Both field collected An. sinensis populations exhibited significantly higher P450 enzyme activity compared with the laboratory strain, while the field-collected resistant mosquitoes exhibited various GST and COE enzyme activities. These results indicate multiple resistance mechanisms in An. sinensis field populations. Effective implementation of insecticide resistance management strategies is urgently needed. The data collected in this study will be valuable for modeling insecticide resistance spread and vector-control interventions.
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Affiliation(s)
- Shixin Chen
- College of Medical and Health, Lishui University, Lishui, China
| | - Qian Qin
- College of Medical and Health, Lishui University, Lishui, China
- Department of Parasitology, Wenzhou Medical University, Wenzhou, China
| | - Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA
| | - Xia Fang
- Department of Parasitology, Wenzhou Medical University, Wenzhou, China
| | - Hanjiang He
- College of Medical and Health, Lishui University, Lishui, China
| | - Linlin Wang
- Department of Parasitology, Wenzhou Medical University, Wenzhou, China
| | - Lingjun Dong
- Department of Parasitology, Wenzhou Medical University, Wenzhou, China
| | - Haiping Lin
- Department of Parasitology, Wenzhou Medical University, Wenzhou, China
| | - Mengqi Zhang
- Department of Parasitology, Wenzhou Medical University, Wenzhou, China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA
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Tchouakui M, Chiang MC, Ndo C, Kuicheu CK, Amvongo-Adjia N, Wondji MJ, Tchoupo M, Kusimo MO, Riveron JM, Wondji CS. A marker of glutathione S-transferase-mediated resistance to insecticides is associated with higher Plasmodium infection in the African malaria vector Anopheles funestus. Sci Rep 2019; 9:5772. [PMID: 30962458 PMCID: PMC6453935 DOI: 10.1038/s41598-019-42015-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 03/13/2019] [Indexed: 01/02/2023] Open
Abstract
Metabolic resistance to insecticides is threatening malaria control in Africa. However, the extent to which it impacts malaria transmission remains unclear. Here, we investigated the association between a marker of glutathione S-transferase mediated metabolic resistance and Plasmodium infection in field population of Anopheles funestus s.s. in comparison to the A296S-RDL target site mutation. The 119F-GSTe2 resistant allele was present in southern (Obout) (56%) and central (Mibellon) (25%) regions of Cameroon whereas the 296S-RDL resistant allele was detected at 98.5% and 15% respectively. The whole mosquito Plasmodium and sporozoite infection rates were 57% and 14.8% respectively in Obout (n = 508) and 19.7% and 5% in Mibellon (n = 360). No association was found between L119F-GSTe2 genotypes and whole mosquito infection status. However, when analyzing oocyst and sporozoite infection rates separately, the resistant homozygote 119F/F genotype was significantly more associated with Plasmodium infection in Obout than both heterozygote (OR = 2.5; P = 0.012) and homozygote susceptible (L/L119) genotypes (OR = 2.10; P = 0.013). In contrast, homozygote RDL susceptible mosquitoes (A/A296) were associated more frequently with Plasmodium infection than other genotypes (OR = 4; P = 0.03). No additive interaction was found between L119F and A296S. Sequencing of the GSTe2 gene showed no association between the polymorphism of this gene and Plasmodium infection. Glutathione S-transferase metabolic resistance is potentially increasing the vectorial capacity of resistant An. funestus mosquitoes. This could result in a possible exacerbation of malaria transmission in areas of high GSTe2-based metabolic resistance to insecticides.
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Affiliation(s)
- Magellan Tchouakui
- Research Unit LSTM/OCEAC, P.O. BOX 288, Yaoundé, Cameroon. .,Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon. .,Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon.
| | - Mu-Chun Chiang
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L35QA, Liverpool, UK
| | - Cyrille Ndo
- Research Unit LSTM/OCEAC, P.O. BOX 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon.,University of Douala, P.O. Box 2701, Douala, Cameroon
| | - Carine K Kuicheu
- Research Unit LSTM/OCEAC, P.O. BOX 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon.,Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Nathalie Amvongo-Adjia
- Research Unit LSTM/OCEAC, P.O. BOX 288, Yaoundé, Cameroon.,Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon.,Centre for Medical Research, Institute of Medical Research and Medicinal Plants Studies (IMPM), P.O. Box 13033, Yaoundé, Cameroon
| | - Murielle J Wondji
- Research Unit LSTM/OCEAC, P.O. BOX 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon.,Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L35QA, Liverpool, UK
| | - Micareme Tchoupo
- Research Unit LSTM/OCEAC, P.O. BOX 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
| | - Michael O Kusimo
- Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
| | - Jacob M Riveron
- Research Unit LSTM/OCEAC, P.O. BOX 288, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon.,Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L35QA, Liverpool, UK
| | - Charles S Wondji
- Research Unit LSTM/OCEAC, P.O. BOX 288, Yaoundé, Cameroon. .,Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon. .,Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L35QA, Liverpool, UK.
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Tchouakui M, Fossog BT, Ngannang BV, Djonabaye D, Tchapga W, Njiokou F, Wondji CS. Investigation of the influence of a glutathione S-transferase metabolic resistance to pyrethroids/DDT on mating competitiveness in males of the African malaria vector, Anopheles funestus. Wellcome Open Res 2019; 4:13. [PMID: 31069259 PMCID: PMC6480967 DOI: 10.12688/wellcomeopenres.15013.2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2019] [Indexed: 01/16/2023] Open
Abstract
Background: Metabolic resistance is a serious challenge to current insecticide-based interventions. The extent to which it affects natural populations of mosquitoes including their reproduction ability remains uncharacterised. Here, we investigated the potential impact of the glutathione S-transferase L119F-GSTe2 resistance on the mating competitiveness of male Anopheles funestus, in Cameroon. Methods: Swarms and indoor resting collections took place in March, 2018 in Tibati, Cameroon. WHO tube and cone assays were performed on F 1 mosquitoes from indoor collected females to assess the susceptibility profile of malaria vectors. Mosquitoes mated and unmated males collected in the swarms were genotyped for the L119F metabolic marker to assess its association with mating male competitiveness. Results: Susceptibility and synergist assays, showed that this population was multiple resistant to pyrethroids, DDT and carbamates, likely driven by metabolic resistance mechanisms. Cone assays revealed a reduced efficacy of standard pyrethroid-nets (Olyset and PermaNet 2.0) with low mortality (<25%) whereas synergist PBO-Nets (Olyset Plus and PermaNet 3.0) retained greater efficacy with higher mortality (>80%). The L119F-GSTe2 mutation, conferring pyrethroid/DDT resistance, was detected in this An. funestus population at a frequency of 28.8%. In addition, a total of 15 mating swarms were identified and 21 An. funestus couples were isolated from those swarms. A comparative genotyping of the L119F-GSTe2 mutation between mated and unmated males revealed that heterozygote males 119L/F-RS were less able to mate than homozygote susceptible (OR=7.2, P<0.0001). Surprisingly, heterozygote mosquitoes were also less able to mate than homozygote resistant (OR=4.2, P=0.010) suggesting the presence of a heterozygote disadvantage effect. Overall, mosquitoes bearing the L119-S susceptible allele were significantly more able to mate than those with 119F-R resistant allele (OR=2.1, P=0.03). Conclusion: This study provides preliminary evidences that metabolic resistance potentially exerts a fitness cost on mating competiveness in resistant mosquitoes.
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Affiliation(s)
- Magellan Tchouakui
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
| | - Billy Tene Fossog
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
| | - Brigitte Vanessa Ngannang
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
- Department of Biochemistry, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
| | - Doumani Djonabaye
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
- Department of Biochemistry, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
| | - Williams Tchapga
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
| | - Flobert Njiokou
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
| | - Charles S. Wondji
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine,, Pembroke Place, L35QA, Liverpool, UK, UK
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Gouignard N, Cherrier F, Brito-Fravallo E, Pain A, Zmarlak NM, Cailliau K, Genève C, Vernick KD, Dissous C, Mitri C. Dual role of the Anopheles coluzzii Venus Kinase Receptor in both larval growth and immunity. Sci Rep 2019; 9:3615. [PMID: 30837655 PMCID: PMC6401105 DOI: 10.1038/s41598-019-40407-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 02/12/2019] [Indexed: 11/24/2022] Open
Abstract
Vector-borne diseases and especially malaria are responsible for more than half million deaths annually. The increase of insecticide resistance in wild populations of Anopheles malaria vectors emphasises the need for novel vector control strategies as well as for identifying novel vector targets. Venus kinase receptors (VKRs) constitute a Receptor Tyrosine Kinase (RTK) family only found in invertebrates. In this study we functionally characterized Anopheles VKR in the Gambiae complex member, Anophelescoluzzii. Results showed that Anopheles VKR can be activated by L-amino acids, with L-arginine as the most potent agonist. VKR was not required for the fecundity of A. coluzzii, in contrast to reports from other insects, but VKR function is required in both Anopheles males and females for development of larval progeny. Anopheles VKR function is also required for protection against infection by Plasmodium parasites, thus identifying a novel linkage between reproduction and immunity in Anopheles. The insect specificity of VKRs as well as the essential function for reproduction and immunity suggest that Anopheles VKR could be a potentially druggable target for novel vector control strategies.
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Affiliation(s)
- Nadège Gouignard
- CIIL- Institut Biologie de Lille, Inserm U1019, CNRS UMR 8204, Institut Pasteur Lille, Lille, France.,Department of Basic Science & Craniofacial Biology, New York University, College of Dentistry, New York, USA
| | - Floriane Cherrier
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique, UMR2000, Paris, France.,Oncogenesis of Lymphoma unit, INSERM U1053 - BaRITOn, Bordeaux, France
| | - Emma Brito-Fravallo
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique, UMR2000, Paris, France
| | - Adrien Pain
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique, UMR2000, Paris, France.,Institut Pasteur - Bioinformatics and Biostatistics Hub - C3BI, USR, 3756 IP CNRS, Paris, France
| | - Natalia Marta Zmarlak
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique, UMR2000, Paris, France
| | - Katia Cailliau
- Team "Signal Division Regulation", CNRS UMR 8576, University of Lille, Lille, France
| | - Corinne Genève
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique, UMR2000, Paris, France
| | - Kenneth D Vernick
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique, UMR2000, Paris, France
| | - Colette Dissous
- CIIL- Institut Biologie de Lille, Inserm U1019, CNRS UMR 8204, Institut Pasteur Lille, Lille, France.
| | - Christian Mitri
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France. .,Centre National de la Recherche Scientifique, UMR2000, Paris, France.
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Alonso Aguirre A, Basu N, Kahn LH, Morin XK, Echaubard P, Wilcox BA, Beasley VR. Transdisciplinary and social-ecological health frameworks-Novel approaches to emerging parasitic and vector-borne diseases. Parasite Epidemiol Control 2019; 4:e00084. [PMID: 30701206 PMCID: PMC6348238 DOI: 10.1016/j.parepi.2019.e00084] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 01/05/2019] [Accepted: 01/05/2019] [Indexed: 12/21/2022] Open
Abstract
Ecosystem Health, Conservation Medicine, EcoHealth, One Health, Planetary Health and GeoHealth are inter-related disciplines that underpin a shared understanding of the functional prerequisites of health, sustainable vitality and wellbeing. All of these are based on recognition that health interconnects species across the planet, and they offer ways to more effectively tackle complex real-world challenges. Herein we present a bibliometric analysis to document usage of a subset of such terms by journals over time. We also provide examples of parasitic and vector-borne diseases, including malaria, toxoplasmosis, baylisascariasis, and Lyme disease. These and many other diseases have persisted, emerged or re-emerged, and caused great harm to human and animal populations in developed and low income, biodiverse nations around the world, largely because of societal drivers that undermined natural processes of disease prevention and control, which had developed through co-evolution over millennia. Shortcomings in addressing drivers has arisen from a lack or coordinated efforts among researchers, health stewards, societies at large, and governments. Fortunately, specialists collaborating under transdisciplinary and socio-ecological health umbrellas are increasingly integrating established and new techniques for disease modeling, prediction, diagnosis, treatment, control, and prevention. Such approaches often emphasize conservation of biodiversity for health protection, and they provide novel opportunities to increase the efficiency and probability of success.
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Affiliation(s)
- A. Alonso Aguirre
- Department of Environmental Science and Policy, College of Science, George Mason University, Fairfax, VA, USA
| | - Niladri Basu
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Canada
| | - Laura H. Kahn
- Program on Science and Global Security, Woodrow Wilson School of Public & International Affairs, Princeton University, Princeton, NJ, USA
| | - Xenia K. Morin
- Department of Plant Biology, Rutgers University, NJ, USA
| | - Pierre Echaubard
- Global Health Asia Institute, Faculty of Public Health, Mahidol University, Thailand
| | - Bruce A. Wilcox
- Global Health Asia Institute, Faculty of Public Health, Mahidol University, Thailand
| | - Val R. Beasley
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, USA
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Tchouakui M, Fossog BT, Ngannang BV, Djonabaye D, Tchapga W, Njiokou F, Wondji CS. Investigation of the influence of a glutathione S-transferase metabolic resistance to pyrethroids/DDT on mating competitiveness in males Anopheles funestus, African malaria vector. Wellcome Open Res 2019; 4:13. [PMID: 31069259 PMCID: PMC6480967 DOI: 10.12688/wellcomeopenres.15013.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2019] [Indexed: 10/12/2023] Open
Abstract
Background: Metabolic resistance is a serious challenge to current insecticide-based interventions. The extent to which it affects natural populations of mosquitoes including their reproduction ability remains uncharacterised. Here, we investigated the potential impact of the glutathione S-transferase L119F-GSTe2 resistance on the mating competitiveness of male Anopheles funestus, in Cameroon. Methods: Swarms and indoor resting collections took place in March, 2018 in Tibati, Cameroon. WHO tube and cone assays were performed on F 1 mosquitoes from indoor collected females to assess the susceptibility profile of malaria vectors. Mosquitoes mated and unmated males collected in the swarms were genotyped for the L119F metabolic marker to assess its association with mating male competitiveness. Results: Susceptibility and synergist assays, showed that this population was multiple resistant to pyrethroids, DDT and carbamates, likely driven by metabolic resistance mechanisms. Cone assays revealed a reduced efficacy of standard pyrethroid-nets (Olyset and PermaNet 2.0) with low mortality (<25%) whereas synergist PBO-Nets (Olyset Plus and PermaNet 3.0) retained greater efficacy with higher mortality (>80%). The L119F-GSTe2 mutation, conferring pyrethroid/DDT resistance, was detected in this An.funestus population at a frequency of 28.8%. In addition, a total of 15 mating swarms were identified and 21 An. funestus couples were isolated from those swarms. A comparative genotyping of the L119F-GSTe2 mutation between mated and unmated males revealed that heterozygote males 119L/F-RS were less able to mate than homozygote susceptible (OR=7.2, P<0.0001). Surprisingly, heterozygote mosquitoes were also less able to mate than homozygote resistant (OR=4.2, P=0.010) suggesting the presence of a heterozygote disadvantage effect. Overall, mosquitoes bearing the L119-S susceptible allele were significantly more able to mate than those with 119F-R resistant allele (OR=2.1, P=0.03). Conclusion: This study provides preliminary evidences that metabolic resistance potentially exerts a fitness cost on mating competiveness in resistant mosquitoes.
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Affiliation(s)
- Magellan Tchouakui
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
| | - Billy Tene Fossog
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
| | - Brigitte Vanessa Ngannang
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
- Department of Biochemistry, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
| | - Doumani Djonabaye
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
- Department of Biochemistry, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
| | - Williams Tchapga
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
| | - Flobert Njiokou
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
| | - Charles S. Wondji
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine,, Pembroke Place, L35QA, Liverpool, UK, UK
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Mashatola T, Ndo C, Koekemoer LL, Dandalo LC, Wood OR, Malakoane L, Poumachu Y, Lobb LN, Kaiser M, Bourtzis K, Munhenga G. A review on the progress of sex-separation techniques for sterile insect technique applications against Anopheles arabiensis. Parasit Vectors 2018; 11:646. [PMID: 30583746 PMCID: PMC6304763 DOI: 10.1186/s13071-018-3219-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The feasibility of the sterile insect technique (SIT) as a malaria vector control strategy against Anopheles arabiensis has been under investigation over the past decade. One of the critical steps required for the application of this technique to mosquito control is the availability of an efficient and effective sex-separation system. Sex-separation systems eliminate female mosquitoes from the production line prior to irradiation and field release of sterile males. This is necessary because female mosquitoes can transmit pathogens such as malaria and, therefore, their release must be prevented. Sex separation also increases the efficiency of an SIT programme. Various sex-separation strategies have been explored including the exploitation of developmental and behavioural differences between male and female mosquitoes, and genetic approaches. Most of these are however species-specific and are not indicated for the major African malaria vectors such as An. arabiensis. As there is currently no reliable sex-separation method for An. arabiensis, various strategies were explored in an attempt to develop a robust system that can be applied on a mass-rearing scale. The progress and challenges faced during the development of a sexing system for future pilot and/or large-scale SIT release programmes against An. arabiensis are reviewed here. Three methods of sex separation were examined. The first is the use of pupal size for gender prediction. The second is the elimination of blood-feeding adult females through the addition of an endectocide to a blood meal source. The third is the establishment of a genetic sexing strain (GSS) carrying an insecticide resistance selectable marker (dieldrin-resistance rdl gene and/or other GABA receptor antagonists that can be used as alternative insecticides to dieldrin) or a temperature-sensitive lethal marker.
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Affiliation(s)
- Thabo Mashatola
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Cyrille Ndo
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de recherche de Yaoundé (IRY), Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Centre for Research in Infectious Disease (CRI), Yaoundé, Cameroon
| | - Lizette L. Koekemoer
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Leonard C. Dandalo
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Oliver R. Wood
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Lerato Malakoane
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Yacouba Poumachu
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de recherche de Yaoundé (IRY), Yaoundé, Cameroon
- Vector Borne Disease Laboratory of the Applied Biology and Ecology Research Unit (VBDL-URBEA) Department of Animal Biology, Faculty of Sciences of the University of Dschang, Dschang, Cameroon
| | - Leanne N. Lobb
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Maria Kaiser
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Givemore Munhenga
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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40
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Tchouakui M, Riveron JM, Djonabaye D, Tchapga W, Irving H, Soh Takam P, Njiokou F, Wondji CS. Fitness Costs of the Glutathione S-Transferase Epsilon 2 (L119F-GSTe2) Mediated Metabolic Resistance to Insecticides in the Major African Malaria Vector Anopheles Funestus. Genes (Basel) 2018; 9:E645. [PMID: 30572680 PMCID: PMC6316527 DOI: 10.3390/genes9120645] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/07/2018] [Accepted: 12/17/2018] [Indexed: 01/18/2023] Open
Abstract
Metabolic resistance to insecticides threatens malaria control. However, little is known about its fitness cost in field populations of malaria vectors, thus limiting the design of suitable resistance management strategies. Here, we assessed the association between the glutathione S-transferase GSTe2-mediated metabolic resistance and life-traits of natural populations of Anopheles funestus. A total of 1200 indoor resting blood-fed female An. funestus (F₀) were collected in Mibellon, Cameroon (2016/2017), and allowed to lay eggs individually. Genotyping of F1 mosquitoes for the L119F-GSTE2 mutation revealed that L/L119-homozygote susceptible (SS) mosquitoes significantly laid more eggs than heterozygotes L119F-RS (odds ratio (OR) = 2.06; p < 0.0001) and homozygote resistant 119F/F-RR (OR = 2.93; p < 0.0001). L/L119-SS susceptible mosquitoes also showed the higher ability for oviposition than 119F/F-RR resistant (OR = 2.68; p = 0.0002) indicating a reduced fecundity in resistant mosquitoes. Furthermore, L119F-RS larvae developed faster (nine days) than L119F-RR and L119F-SS (11 days) (X² = 11.052; degree of freedom (df) = 4; p = 0.02) suggesting a heterozygote advantage effect for larval development. Interestingly, L/L119-SS developed faster than 119F/F-RR (OR = 5.3; p < 0.0001) revealing an increased developmental time in resistant mosquitoes. However, genotyping and sequencing revealed that L119F-RR mosquitoes exhibited a higher adult longevity compared to RS (OR > 2.2; p < 0.05) and SS (OR > 2.1; p < 0.05) with an increased frequency of GSTe2-resistant haplotypes in mosquitoes of D30 after adult emergence. Additionally, comparison of the expression of GSTe2 revealed a significantly increased expression from D1-D30 after emergence of adults (Anova test (F) = 8; df= 3; p = 0.008). The negative association between GSTe2 and some life traits of An. funestus could facilitate new resistance management strategies. However, the increased longevity of GSTe2-resistant mosquitoes suggests that an increase in resistance could exacerbate malaria transmission.
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Affiliation(s)
- Magellan Tchouakui
- LSTM Research Unit at the Centre for Research in Infectious Diseases (CRID), P.O. Box 13591 Yaoundé, Cameroon.
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812 Yaoundé, Cameroon.
| | - Jacob M Riveron
- LSTM Research Unit at the Centre for Research in Infectious Diseases (CRID), P.O. Box 13591 Yaoundé, Cameroon.
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L35QA, UK.
| | - Doumani Djonabaye
- LSTM Research Unit at the Centre for Research in Infectious Diseases (CRID), P.O. Box 13591 Yaoundé, Cameroon.
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812 Yaoundé, Cameroon.
| | - Williams Tchapga
- LSTM Research Unit at the Centre for Research in Infectious Diseases (CRID), P.O. Box 13591 Yaoundé, Cameroon.
| | - Helen Irving
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L35QA, UK.
| | - Patrice Soh Takam
- Department of Mathematics, Faculty of Science, University of Yaoundé 1, P.O. Box 812 Yaoundé, Cameroon.
| | - Flobert Njiokou
- LSTM Research Unit at the Centre for Research in Infectious Diseases (CRID), P.O. Box 13591 Yaoundé, Cameroon.
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812 Yaoundé, Cameroon.
| | - Charles S Wondji
- LSTM Research Unit at the Centre for Research in Infectious Diseases (CRID), P.O. Box 13591 Yaoundé, Cameroon.
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L35QA, UK.
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Akoton R, Tchigossou GM, Djègbè I, Yessoufou A, Atoyebi MS, Tossou E, Zeukeng F, Boko P, Irving H, Adéoti R, Riveron J, Wondji CS, Moutairou K, Djouaka R. Experimental huts trial of the efficacy of pyrethroids/piperonyl butoxide (PBO) net treatments for controlling multi-resistant populations of Anopheles funestus s.s. in Kpomè, Southern Benin. Wellcome Open Res 2018; 3:71. [PMID: 30175242 PMCID: PMC6113884 DOI: 10.12688/wellcomeopenres.14589.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2018] [Indexed: 01/23/2023] Open
Abstract
Background: Insecticides resistance in
Anopheles mosquitoes limits Long-Lasting Insecticidal Nets (LLIN) used for malaria control in Africa, especially Benin. This study aimed to evaluate the bio-efficacy of current LLINs in an area where
An. funestus s.l. and
An. gambiae have developed multi-resistance to insecticides, and to assess in experimental huts the performance of a mixed combination of pyrethroids and piperonyl butoxide (PBO) treated nets on these resistant mosquitoes. Methods: The study was conducted at Kpomè, Southern Benin. The bio-efficacy of LLINs against
An. funestus and An. gambiae was assessed using the World Health Organization (WHO) cone and tunnel tests. A released/recapture experiment following WHO procedures was conducted to compare the efficacy of conventional LLINs treated with pyrethroids only and LLINs with combinations of pyrethroids and PBO. Prior to huts trials, we confirmed the level of insecticide and PBO residues in tested nets using high performance liquid chromatography (HPLC). Results: Conventional LLINs (Type 2 and Type 4) have the lowest effect against local multi-resistant
An. funestus s.s. and An. coluzzii populations from Kpomè. Conversely, when LLINs containing mixtures of pyrethroids and PBO (Type 1 and Type 3) were introduced in trial huts, we recorded a greater effect against the two mosquito populations (P < 0.0001). Tunnel test with
An. funestus s.s. revealed mortalities of over 80% with this new generation of LLINs (Type 1 and Type 3),while conventional LLINs produced 65.53 ± 8.33% mortalities for Type 2 and 71.25 ±7.92% mortalities for Type 4. Similarly, mortalities ranging from 77 to 87% were recorded with the local populations of
An. coluzzii. Conclusion: This study suggests the reduced efficacy of conventional LLINs (Pyrethroids alone) currently distributed in Benin communities where
Anopheles populations have developed multi-insecticide resistance. The new generation nets (pyrethroids+PBO) proved to be more effective on multi-resistant populations of mosquitoes.
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Affiliation(s)
- Romaric Akoton
- University of Abomey, Calavi, Abomey-Calavi, 526, Benin.,AgroEcoHealth Platform, International Institute of Tropical Agriculture, Cotonou, 0932, Benin
| | - Genevieve M Tchigossou
- University of Abomey, Calavi, Abomey-Calavi, 526, Benin.,AgroEcoHealth Platform, International Institute of Tropical Agriculture, Cotonou, 0932, Benin
| | - Innocent Djègbè
- AgroEcoHealth Platform, International Institute of Tropical Agriculture, Cotonou, 0932, Benin.,National University of Sciences, Technologies, Engineering and Mathematics of Abomey, Abomey, 123, Benin
| | | | - Michael Seun Atoyebi
- AgroEcoHealth Platform, International Institute of Tropical Agriculture, Cotonou, 0932, Benin.,Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Eric Tossou
- University of Abomey, Calavi, Abomey-Calavi, 526, Benin.,AgroEcoHealth Platform, International Institute of Tropical Agriculture, Cotonou, 0932, Benin
| | - Francis Zeukeng
- Faculty of Sciences, Department of Biochemistry, University of Yaounde I, Yaounde, 812, Cameroon
| | - Pelagie Boko
- National malaria and Neglected diseases control program, Ministry of Health, Cotonou, Benin
| | - Helen Irving
- Liverpool School of Tropical Medicine, Liverpool, L3 5QA , UK
| | - Razack Adéoti
- AgroEcoHealth Platform, International Institute of Tropical Agriculture, Cotonou, 0932, Benin
| | - Jacob Riveron
- Liverpool School of Tropical Medicine, Liverpool, L3 5QA , UK
| | | | | | - Rousseau Djouaka
- AgroEcoHealth Platform, International Institute of Tropical Agriculture, Cotonou, 0932, Benin
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Huijben S, Paaijmans KP. Putting evolution in elimination: Winning our ongoing battle with evolving malaria mosquitoes and parasites. Evol Appl 2018; 11:415-430. [PMID: 29636796 PMCID: PMC5891050 DOI: 10.1111/eva.12530] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/01/2017] [Indexed: 12/17/2022] Open
Abstract
Since 2000, the world has made significant progress in reducing malaria morbidity and mortality, and several countries in Africa, South America and South-East Asia are working hard to eliminate the disease. These elimination efforts continue to rely heavily on antimalarial drugs and insecticide-based interventions, which remain the cornerstones of malaria treatment and prevention. However, resistance has emerged against nearly every antimalarial drug and insecticide that is available. In this review we discuss the evolutionary consequences of the way we currently implement antimalarial interventions, which is leading to resistance and may ultimately lead to control failure, but also how evolutionary principles can be applied to extend the lifespan of current and novel interventions. A greater understanding of the general evolutionary principles that are at the core of emerging resistance is urgently needed if we are to develop improved resistance management strategies with the ultimate goal to achieve a malaria-free world.
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Affiliation(s)
- Silvie Huijben
- ISGlobalBarcelona Ctr. Int. Health Res. (CRESIB)Hospital Clínic ‐ Universitat de BarcelonaBarcelonaSpain
| | - Krijn P. Paaijmans
- ISGlobalBarcelona Ctr. Int. Health Res. (CRESIB)Hospital Clínic ‐ Universitat de BarcelonaBarcelonaSpain
- Centro de Investigação em Saúde de ManhiçaMaputoMozambique
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43
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Pyrethroid Resistance in the Major Malaria Vector Anopheles funestus is Exacerbated by Overexpression and Overactivity of the P450 CYP6AA1 Across Africa. Genes (Basel) 2018; 9:genes9030140. [PMID: 29498712 PMCID: PMC5867861 DOI: 10.3390/genes9030140] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 02/24/2018] [Accepted: 02/28/2018] [Indexed: 12/02/2022] Open
Abstract
Resistance to pyrethroids (the ingredients in bed net insecticides) in the major malaria vector Anopheles funestus is threatening recent gains in the fight against malaria. Here, we established the role of an over-expressed P450, A. funestus CYP6AA1 in insecticides resistance. Transcription profiling of CYP6AA1 across Africa using microarray and quantitative reverse transcription polymerase chain reaction (qRT-PCR) revealed that it is significantly more over-expressed in southern African populations compared to West (Benin) and East African (Uganda). Heterologous expression in Escherichia coli coupled with metabolism assays demonstrated that CYP6AA1 metabolises type I (permethrin) and type II (deltamethrin) pyrethroids, as well as bendiocarb (a carbamate). Transgenic Drosophila melanogaster flies over-expressing CYP6AA1 were significantly more resistant to pyrethroid insecticides, permethrin and deltamethrin compared with control flies not expressing the gene, validating the role of this gene in pyrethroid resistance. In silico modelling and docking simulations predicted the intermolecular receptor-ligand interactions which allow this P450 to metabolise the pyrethroids and bendiocarb. Validation of CYP6AA1 as a pyrethroid resistance gene makes it possible to monitor the spread of resistance in the field where this P450 is over-expressed. Its potential cross-resistance role makes it necessary to monitor the gene closely to inform control programs on molecular basis of multiple resistance in the field.
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Riveron JM, Watsenga F, Irving H, Irish SR, Wondji CS. High Plasmodium Infection Rate and Reduced Bed Net Efficacy in Multiple Insecticide-Resistant Malaria Vectors in Kinshasa, Democratic Republic of Congo. J Infect Dis 2018; 217:320-328. [PMID: 29087484 PMCID: PMC5853898 DOI: 10.1093/infdis/jix570] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Accounting for approximately 11% of all malaria cases, the Democratic Republic of the Congo (DRC) is central to malaria elimination efforts. To support vector control interventions in DRC, we characterized the dynamics and impact of insecticide resistance in major malaria vectors in 2015. High Plasmodium infection rates were recorded in Anopheles gambiae and Anopheles funestus, with Plasmodium falciparum predominant over Plasmodium malariae. Both mosquito species exhibited high and multiple resistance to major public health insecticide classes. The extremely high resistance to permethrin and DDT (dichlorodiphenyltrichloroethane) in An. gambiae (low mortalities after 6 hours exposure) is worrisome, and is supported by a reduced insecticidal effect of bed nets against both mosquito species in laboratory tests. Metabolic and target site insensitivity mechanisms are driving this resistance in An. gambiae, but only the former was observed in An. funestus. These findings highlight the urgent need for actions to prolong the effectiveness of insecticide-based interventions in DRC.
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Affiliation(s)
- Jacob M Riveron
- Vector Biology Department, Liverpool School of Tropical Medicine, United Kingdom
- Research Unit, Liverpool School of Tropical Medicine (LSTM)/Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC) Research Unit, Yaoundé, Cameroon
| | - Francis Watsenga
- Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of Congo
| | - Helen Irving
- Vector Biology Department, Liverpool School of Tropical Medicine, United Kingdom
| | - Seth R Irish
- US President’s Malaria Initiative, Entomology Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Charles S Wondji
- Vector Biology Department, Liverpool School of Tropical Medicine, United Kingdom
- Research Unit, Liverpool School of Tropical Medicine (LSTM)/Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC) Research Unit, Yaoundé, Cameroon
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Dieme C, Rotureau B, Mitri C. Microbial Pre-exposure and Vectorial Competence of Anopheles Mosquitoes. Front Cell Infect Microbiol 2017; 7:508. [PMID: 29376030 PMCID: PMC5770632 DOI: 10.3389/fcimb.2017.00508] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/23/2017] [Indexed: 11/16/2022] Open
Abstract
Anopheles female mosquitoes can transmit Plasmodium, the malaria parasite. During their aquatic life, wild Anopheles mosquito larvae are exposed to a huge diversity of microbes present in their breeding sites. Later, adult females often take successive blood meals that might also carry different micro-organisms, including parasites, bacteria, and viruses. Therefore, prior to Plasmodium ingestion, the mosquito biology could be modulated at different life stages by a suite of microbes present in larval breeding sites, as well as in the adult environment. In this article, we highlight several naturally relevant scenarios of Anopheles microbial pre-exposure that we assume might impact mosquito vectorial competence for the malaria parasite: (i) larval microbial exposures; (ii) protist co-infections; (iii) virus co-infections; and (iv) pathogenic bacteria co-infections. In addition, significant behavioral changes in African Anopheles vectors have been associated with increasing insecticide resistance. We discuss how these ethological modifications may also increase the repertoire of microbes to which mosquitoes could be exposed, and that might also influence their vectorial competence. Studying Plasmodium–Anopheles interactions in natural microbial environments would efficiently contribute to refining the transmission risks.
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Affiliation(s)
- Constentin Dieme
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Institut National de la Santé et de la Recherche Médicale U1201 and Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Christian Mitri
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique Unit of Hosts, Vectors and Pathogens (URA3012), Paris, France
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Nardini L, Hunt RH, Dahan-Moss YL, Christie N, Christian RN, Coetzee M, Koekemoer LL. Malaria vectors in the Democratic Republic of the Congo: the mechanisms that confer insecticide resistance in Anopheles gambiae and Anopheles funestus. Malar J 2017; 16:448. [PMID: 29115954 PMCID: PMC5678590 DOI: 10.1186/s12936-017-2099-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 10/28/2017] [Indexed: 11/22/2022] Open
Abstract
Background The Democratic Republic of the Congo (DRC) is characterized as a holoendemic malaria area with the main vectors being Anopheles funestus and members of the Anopheles gambiae complex. Due to political instability and socio-economic challenges in the region, knowledge of insecticide resistance status and resistance mechanisms in these vectors is limited. Mosquitoes were collected from a mining site in the north-eastern part of the country and, following identification, were subjected to extensive testing for the target-site and biochemical basis of resistance. Quantitative real-time PCR was used to assess a suite of 10 genes frequently involved in pyrethroid and dichlorodiphenyltrichloroethane (DDT) resistance in An. gambiae females and males. In An. funestus, gene expression microarray analysis was carried out on female mosquitoes. Results In both species, deltamethrin resistance was recorded along with high resistance and suspected resistance to DDT in An. gambiae and An. funestus, respectively. A total of 85% of An. gambiae carried the kdr mutations as either homozygous resistant (RR) (L1014S, L1014F or both) or heterozygous (RS), however only 3% carried the rdl mutant allele (RS) and no ace-1 mutations were recorded. Synergist assays indicated a strong role for P450s in deltamethrin resistance in both species. In An. gambiae, analysis of transcription levels showed that the glutathione-S-transferase, GSTS1-2, produced the highest fold change in expression (7.6-fold in females and 31-fold in males) followed by GSTE2, thioredoxin peroxidase (TPX2), and cytochrome oxidases (CYP6M2 and CYP6P1). All other genes tested produced fold change values below 2. Microarray analysis revealed significant over-transcription of cuticular proteins as well as CYP6M7, CYP6P9a and CYP6P9b in insecticide resistant An. funestus. Conclusions These data show that high levels of deltamethrin resistance in the main malaria vector species, conferred by enzymatic detoxification, are present in the DRC. Electronic supplementary material The online version of this article (10.1186/s12936-017-2099-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Luisa Nardini
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2000, South Africa.,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, 2131, South Africa
| | - Richard H Hunt
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2000, South Africa.,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, 2131, South Africa
| | - Yael L Dahan-Moss
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2000, South Africa.,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, 2131, South Africa
| | - Nanette Christie
- Department of Genetics, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, 0028, South Africa
| | - Riann N Christian
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2000, South Africa.,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, 2131, South Africa
| | - Maureen Coetzee
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2000, South Africa.,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, 2131, South Africa
| | - Lizette L Koekemoer
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2000, South Africa. .,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, 2131, South Africa.
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Genome-Wide Transcription and Functional Analyses Reveal Heterogeneous Molecular Mechanisms Driving Pyrethroids Resistance in the Major Malaria Vector Anopheles funestus Across Africa. G3-GENES GENOMES GENETICS 2017; 7:1819-1832. [PMID: 28428243 PMCID: PMC5473761 DOI: 10.1534/g3.117.040147] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Pyrethroid resistance in malaria vector, An. funestus is increasingly reported across Africa, threatening the sustainability of pyrethroid-based control interventions, including long lasting insecticidal nets (LLINs). Managing this problem requires understanding of the molecular basis of the resistance from different regions of the continent, to establish whether it is being driven by a single or independent selective events. Here, using a genome-wide transcription profiling of pyrethroid resistant populations from southern (Malawi), East (Uganda), and West Africa (Benin), we investigated the molecular basis of resistance, revealing strong differences between the different African regions. The duplicated cytochrome P450 genes (CYP6P9a and CYP6P9b) which were highly overexpressed in southern Africa are not the most upregulated in other regions, where other genes are more overexpressed, including GSTe2 in West (Benin) and CYP9K1 in East (Uganda). The lack of directional selection on both CYP6P9a and CYP6P9b in Uganda in contrast to southern Africa further supports the limited role of these genes outside southern Africa. However, other genes such as the P450 CYP9J11 are commonly overexpressed in all countries across Africa. Here, CYP9J11 is functionally characterized and shown to confer resistance to pyrethroids and moderate cross-resistance to carbamates (bendiocarb). The consistent overexpression of GSTe2 in Benin is coupled with a role of allelic variation at this gene as GAL4-UAS transgenic expression in Drosophila flies showed that the resistant 119F allele is highly efficient in conferring both DDT and permethrin resistance than the L119. The heterogeneity in the molecular basis of resistance and cross-resistance to insecticides in An. funestus populations throughout sub-Saharan African should be taken into account in designing resistance management strategies.
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Coleman M, Hemingway J, Gleave KA, Wiebe A, Gething PW, Moyes CL. Developing global maps of insecticide resistance risk to improve vector control. Malar J 2017; 16:86. [PMID: 28222727 PMCID: PMC5320685 DOI: 10.1186/s12936-017-1733-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/09/2017] [Indexed: 11/18/2022] Open
Abstract
Background Significant reductions in malaria transmission have been achieved over the last 15 years with elimination occurring in a small number of countries, however, increasing drug and insecticide resistance threatens these gains. Insecticide resistance has decreased the observed mortality to the most commonly used insecticide class, the pyrethroids, and the number of alternative classes approved for use in public health is limited. Disease prevention and elimination relies on operational control of Anopheles malaria vectors, which requires the deployment of effective insecticides. Resistance is a rapidly evolving phenomena and the resources and human capacity to continuously monitor vast numbers of mosquito populations in numerous locations simultaneously are not available. Methods Resistance data are obtained from published articles, by contacting authors and custodians of unpublished data sets. Where possible data is disaggregated to single sites and collection periods to give a fine spatial resolution. Results Currently the data set includes data from 1955 to October 2016 from 71 malaria endemic countries and 74 anopheline species. This includes data for all four classes of insecticides and associated resistance mechanisms. Conclusions Resistance is a rapidly evolving phenomena and the resources and human capacity to continuously monitor vast numbers of mosquito populations in numerous locations simultaneously are not available. The Malaria Atlas Project-Insecticide Resistance (MAP-IR) venture has been established to develop tools that will use available data to provide best estimates of the spatial distribution of insecticide resistance and help guide control programmes on this serious issue. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1733-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael Coleman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Janet Hemingway
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Katherine Ann Gleave
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Antoinette Wiebe
- Malaria Atlas Project, Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7BN, UK
| | - Peter W Gething
- Malaria Atlas Project, Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7BN, UK
| | - Catherine L Moyes
- Malaria Atlas Project, Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7BN, UK.
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Djouaka R, Akoton R, Tchigossou GM, Atoyebi SM, Irving H, Kusimo MO, Djegbe I, Riveron JM, Tossou E, Yessoufou A, Wondji CS. Mapping the distribution of Anopheles funestus across Benin highlights a sharp contrast of susceptibility to insecticides and infection rate to Plasmodium between southern and northern populations. Wellcome Open Res 2016. [PMID: 28191507 DOI: 10.12688/wellcomeopenres.10213.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background. Malaria remains an important public health issue in Benin, with Anopheles gambiae s.l. and Anopheles funestus s.s being the predominant vectors. This study was designed to generate information on An. funestus distribution, molecular speciation, Plasmodium infection rate and insecticide susceptibility status across Benin. Methods. Mosquito samples were collected from December 2014 to January 2016 in 46 localities in Benin. These samples were mapped and An. funestus collected were speciated to the molecular level. Plasmodium infection rate was determined using a Taqman assay and susceptibility to insecticides was assessed using the WHO guidelines. The genotyping of the L119F- Gste2 mutation was also carried out. Results. An. funestus was found in 8 out of the 46 localities surveyed with a high presence in Tanongou (wet Sudanese ecological zone), Kpome, Doukonta and Pahou (sub-equatorial ecological zone). Molecular identifications revealed that only An. funestuss.s was present in southern Benin, whereas in Tanongou (northern Benin) An. funestus s.s. and An. leesoni were found in sympatry at proportions of 77.7% and 22.3% respectively. Plasmodium infection rate of An. funestus was higher in southern Benin at a range of 13 to 18% compared to 5.6% recorded in Tanongou. High DDT (8±0.5%) and permethrin (11±0.5%) resistance were observed in Doukonta, Kpome and Pahou, contrasting with relatively low resistance profiles: mortality-DDT=90±3.18% and mortality-permethrin=100% in Tanongou. Genotyping analysis revealed high frequency of the resistant 119F allele in the South (Kpome and Doukonta) compared to the North (Tanongou). Discussion and Conclusion. The high presence of An. funestus in the South compared to the North could be due to favorable environmental and climatic conditions found in both regions. A significant Plasmodium infection rate was recorded across the country. A high resistance profile was recorded in the southern Benin; this raises the need for further investigations on resistance selection factors.
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Affiliation(s)
| | - Romaric Akoton
- International Institute of Tropical Agriculture, Cotonou, Benin.,University of Abomey-Calavi, Cotonou, Benin
| | - Genevieve M Tchigossou
- International Institute of Tropical Agriculture, Cotonou, Benin.,University of Abomey-Calavi, Cotonou, Benin
| | - Seun M Atoyebi
- International Institute of Tropical Agriculture, Cotonou, Benin.,Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Helen Irving
- Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Innocent Djegbe
- University of Sciences, Arts and Techniques of Natitingou, Ecole Normale Supérieure de Natitingou, Natitingou, Benin
| | | | - Eric Tossou
- International Institute of Tropical Agriculture, Cotonou, Benin.,University of Abomey-Calavi, Cotonou, Benin
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Djouaka R, Akoton R, Tchigossou GM, Atoyebi SM, Irving H, Kusimo MO, Djegbe I, Riveron JM, Tossou E, Yessoufou A, Wondji CS. Mapping the distribution of Anopheles funestus across Benin highlights a sharp contrast of susceptibility to insecticides and infection rate to Plasmodium between southern and northern populations. Wellcome Open Res 2016; 1:28. [PMID: 28191507 PMCID: PMC5300096 DOI: 10.12688/wellcomeopenres.10213.2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2017] [Indexed: 11/20/2022] Open
Abstract
Background. Malaria remains an important public health issue in Benin, with Anopheles gambiae s.l. and Anopheles funestus s.s being the predominant vectors. This study was designed to generate information on An. funestus distribution, molecular speciation, Plasmodium infection rate and insecticide susceptibility status across Benin. Methods. Mosquito samples were collected from December 2014 to January 2016 in 46 localities in Benin. These samples were mapped and An. funestus collected were speciated to the molecular level. Plasmodium infection rate was determined using a Taqman assay and susceptibility to insecticides was assessed using the WHO guidelines. The genotyping of the L119F- Gste2 mutation was also carried out. Results. An. funestus was found in 8 out of the 46 localities surveyed with a high presence in Tanongou (wet Sudanese ecological zone), Kpome, Doukonta and Pahou (sub-equatorial ecological zone). Molecular identifications revealed that only An. funestuss.s was present in southern Benin, whereas in Tanongou (northern Benin) An. funestus s.s. and An. leesoni were found in sympatry at proportions of 77.7% and 22.3% respectively. Plasmodium infection rate of An. funestus was higher in southern Benin at a range of 13 to 18% compared to 5.6% recorded in Tanongou. High DDT (8±0.5%) and permethrin (11±0.5%) resistance were observed in Doukonta, Kpome and Pahou, contrasting with relatively low resistance profiles: mortality-DDT=90±3.18% and mortality-permethrin=100% in Tanongou. Genotyping analysis revealed high frequency of the resistant 119F allele in the South (Kpome and Doukonta) compared to the North (Tanongou). Discussion and Conclusion. The high presence of An. funestus in the South compared to the North could be due to favorable environmental and climatic conditions found in both regions. A significant Plasmodium infection rate was recorded across the country. A high resistance profile was recorded in the southern Benin; this raises the need for further investigations on resistance selection factors.
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Affiliation(s)
| | - Romaric Akoton
- International Institute of Tropical Agriculture, Cotonou, Benin
- University of Abomey-Calavi, Cotonou, Benin
| | - Genevieve M. Tchigossou
- International Institute of Tropical Agriculture, Cotonou, Benin
- University of Abomey-Calavi, Cotonou, Benin
| | - Seun M. Atoyebi
- International Institute of Tropical Agriculture, Cotonou, Benin
- Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Helen Irving
- Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Innocent Djegbe
- University of Sciences, Arts and Techniques of Natitingou, Ecole Normale Supérieure de Natitingou, Natitingou, Benin
| | | | - Eric Tossou
- International Institute of Tropical Agriculture, Cotonou, Benin
- University of Abomey-Calavi, Cotonou, Benin
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