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Debrah I, Zhong D, Machani MG, Nattoh G, Ochwedo KO, Morang'a CM, Lee MC, Amoah LE, Githeko AK, Afrane YA, Yan G. Non-Coding RNAs Potentially Involved in Pyrethroid Resistance of Anopheles funestus Population in Western Kenya. RESEARCH SQUARE 2024:rs.3.rs-3979432. [PMID: 38464038 PMCID: PMC10925441 DOI: 10.21203/rs.3.rs-3979432/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Backgrounds The resurgence of Anopheles funestus , a dominant vector of human malaria in western Kenya was partly attributed to insecticide resistance. However, evidence on the molecular basis of pyrethroid resistance in western Kenya is limited. Noncoding RNAs (ncRNAs) form a vast class of RNAs that do not code for proteins and are ubiquitous in the insect genome. Here, we demonstrated that multiple ncRNAs could play a potential role in An. funestus resistance to pyrethroid in western Kenya. Materials and Methods Anopheles funestus mosquitoes were sampled by aspiration methods in Bungoma, Teso, Siaya, Port Victoria and Kombewa in western Kenya. The F1 progenies were exposed to deltamethrin (0.05%), permethrin (0.75%), DDT (4%) and pirimiphos-methyl (0.25%) following WHO test guidelines. A synergist assay using piperonyl butoxide (PBO) (4%) was conducted to determine cytochrome P450s' role in pyrethroid resistance. RNA-seq was conducted on a combined pool of specimens that were resistant and unexposed, and the results were compared with those of the FANG susceptible strain. This approach aimed to uncover the molecular mechanisms underlying pyrethroid resistance. Results Pyrethroid resistance was observed in all the sites with an average mortality rate of 57.6%. Port Victoria had the highest level of resistance to permethrin (MR=53%) and deltamethrin (MR=11%) pyrethroids. Teso had the lowest level of resistance to permethrin (MR=70%) and deltamethrin (MR=87%). Resistance to DDT was observed only in Kombewa (MR=89%) and Port Victoria (MR=85%). A full susceptibility to P-methyl (0.25%) was observed in all the sites. PBO synergist assay revealed high susceptibility (>98%) to the pyrethroids in all the sites except for Port Victoria (MR=96%, n=100). Whole transcriptomic analysis showed that most of the gene families associated with pyrethroid resistance comprised non-coding RNAs (67%), followed by imipenemase (10%),cytochrome P450s (6%), cuticular proteins (5%), olfactory proteins (4%), glutathione S-transferases (3%), UDP-glycosyltransferases (2%), ATP-binding cassettes (2%) and carboxylesterases(1%). Conclusions This study unveils the molecular basis of insecticide resistance in An. funestus in western Kenya, highlighting for the first time the potential role of non-coding RNAs in pyrethroid resistance. Targeting non-coding RNAs for intervention development could help in insecticide resistance management.
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Wotodjo AN, Doucoure S, Diagne N, Sarr FD, Sokhna C. Malaria epidemics associated with low net use in preadolescent and young adult population in Dielmo (Senegal), a malaria pre-elimination area. Parasit Vectors 2024; 17:74. [PMID: 38374068 PMCID: PMC10877880 DOI: 10.1186/s13071-024-06172-1] [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: 08/10/2023] [Accepted: 01/30/2024] [Indexed: 02/21/2024] Open
Abstract
BACKGROUND The epidemic rebounds observed in 2010 and 2013 in Dielmo, a Senegalese village, during a decade (2008-2019) of universal coverage using a long-lasting insecticidal net (LLIN) strategy could have contributed to the resurgence of malaria. Thus, this study was undertaken to understand the implications of net ownership and use on malaria rebound events. METHODS A longitudinal study was carried out in Dielmo with 11 years of LLIN implementation from July 2008 to June 2019 with successive net renewals in 2011, 2014, 2016 and 2019. Quarterly cross-sectional surveys were performed to assess LLIN ownership and use by different age groups in the population. In addition, malaria incidence and transmission were assessed during the study period. RESULTS Ownership of LLINs decreased significantly from 88% in the 1st year of net implementation to 70% during the first malaria upsurge and 72% during the second upsurge while net use decreased significantly from 66% during the 1st year to 58% during the first malaria upsurge and 53% during the second upsurge. Among young adults aged 15-29 years, net use decreased significantly from the 2nd year (51%) of net use to reach 43% during the first malaria upsurge and only 32% use during the second malaria upsurge. During the second malaria upsurge, net use was significantly lower among older children aged 10-14 years old than during the 1st year of net use (p < 0.001). During the first and the second malaria upsurges, the malaria incidence was significantly higher among children aged 10-14 years old (0.4 attacks per person-year) and young adults aged 15-29 years old (0.3 and 0.4 attacks per person, respectively) than during that the 1st year of net implementation (only 0.02 attacks per person-year for 10-14 year olds and 0.04 for 15-29 year olds; p < 0.001). CONCLUSIONS The first malaria upsurge occurred following a progressive decrease in net use after the 2nd year of their implementation with an important increase in malaria incidence among older children while the second malaria upsurge was significantly associated with the decrease of net use among older children and young adults. The regular use of nets in all age groups prevented the occurrence of a third malaria upsurge in Dielmo.
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Affiliation(s)
- Amélé Nyedzie Wotodjo
- UMR VITROME (Vecteurs - Infections Tropicales et Méditerranéennes) Campus International IRD-UCAD, Dakar, Senegal.
| | - Souleymane Doucoure
- UMR VITROME (Vecteurs - Infections Tropicales et Méditerranéennes) Campus International IRD-UCAD, Dakar, Senegal
| | - Nafissatou Diagne
- UMR VITROME (Vecteurs - Infections Tropicales et Méditerranéennes) Campus International IRD-UCAD, Dakar, Senegal
| | | | - Cheikh Sokhna
- UMR VITROME (Vecteurs - Infections Tropicales et Méditerranéennes) Campus International IRD-UCAD, Dakar, Senegal
- Aix-Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France
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Akuoko OK, Dhikrullahi SB, Hinne IA, Mohammed AR, Owusu-Asenso CM, Coleman S, Dadzie SK, Kyerematen R, Boakye DA, Wilson MD, Afrane YA. Biting behaviour, spatio-temporal dynamics, and the insecticide resistance status of malaria vectors in different ecological zones in Ghana. Parasit Vectors 2024; 17:16. [PMID: 38195546 PMCID: PMC10775458 DOI: 10.1186/s13071-023-06065-9] [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: 01/22/2023] [Accepted: 11/20/2023] [Indexed: 01/11/2024] Open
Abstract
BACKGROUND A significant decrease in malaria morbidity and mortality has been attained using long-lasting insecticide-treated nets and indoor residual spraying. Selective pressure from these control methods influences changes in vector bionomics and behavioural pattern. There is a need to understand how insecticide resistance drives behavioural changes within vector species. This study aimed to determine the spatio-temporal dynamics and biting behaviour of malaria vectors in different ecological zones in Ghana in an era of high insecticide use for public health vector control. METHODS Adult mosquitoes were collected during the dry and rainy seasons in 2017 and 2018 from five study sites in Ghana in different ecological zones. Indoor- and outdoor-biting mosquitoes were collected per hour from 18:00 to 06:00 h employing the human landing catch (HLC) technique. Morphological and molecular species identifications of vectors were done using identification keys and PCR respectively. Genotyping of insecticide-resistant markers was done using the TaqMan SNP genotyping probe-based assays. Detection of Plasmodium falciparum sporozoites was determined using PCR. RESULTS A total of 50,322 mosquitoes belonging to four different genera were collected from all the study sites during the sampling seasons in 2017 and 2018. Among the Anophelines were Anopheles gambiae s.l. 93.2%, (31,055/33,334), An. funestus 2.1%, (690/33,334), An. pharoensis 4.6%, (1545/33,334), and An. rufipes 0.1% (44/33,334). Overall, 76.4%, (25,468/33,334) of Anopheles mosquitoes were collected in the rainy season and 23.6%, (7866/33,334) in the dry season. There was a significant difference (Z = 2.410; P = 0.0160) between indoor-biting (51.1%; 15,866/31,055) and outdoor-biting An. gambiae s.l. (48.9%; 15,189/31,055). The frequency of the Vgsc-1014F mutation was slightly higher in indoor-biting mosquitoes (54.9%) than outdoors (45.1%). Overall, 44 pools of samples were positive for P. falciparum CSP giving an overall sporozoite rate of 0.1%. CONCLUSION Anopheles gambiae s.l. were more abundant indoors across all ecological zones of Ghana. The frequency of G119S was higher indoors than outdoors from all the study sites, but with higher sporozoite rates in outdoor mosquitoes in Dodowa and Kpalsogu. There is, therefore, an urgent need for a supplementary malaria control intervention to control outdoor-biting mosquitoes.
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Affiliation(s)
- Osei K Akuoko
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
- African Regional Post-Graduate Programme in Insect Science, College of Basic and Applied Science, University of Ghana, Legon, Accra, Ghana
| | - Shittu B Dhikrullahi
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Isaac A Hinne
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
- Department of Biochemistry and Molecular Biology, CABNR, University of Nevada, Reno, NV, USA
| | - Abdul R Mohammed
- African Regional Post-Graduate Programme in Insect Science, College of Basic and Applied Science, University of Ghana, Legon, Accra, Ghana
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Christopher M Owusu-Asenso
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Sylvester Coleman
- Department of Clinical Microbiology - Vector Biology Laboratory, School of Medicine and Dentistry (SMD)-College of Health Sciences, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Samuel K Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Rosina Kyerematen
- African Regional Post-Graduate Programme in Insect Science, College of Basic and Applied Science, University of Ghana, Legon, Accra, Ghana
- Department of Animal Biology and Conservation Science, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Daniel A Boakye
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Michael D Wilson
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Yaw A Afrane
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana.
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Wotodjo AN, Oboh MA, Sokhna C, Diagne N, Diène-Sarr F, Trape JF, Doucouré S, Amambua-Ngwa A, D'Alessandro U. Plasmodium falciparum population structure and genetic diversity of cell traversal protein for ookinetes and sporozoites (CelTOS) during malaria resurgences in Dielmo, Senegal. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2023; 116:105535. [PMID: 38030029 DOI: 10.1016/j.meegid.2023.105535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 11/20/2023] [Accepted: 11/25/2023] [Indexed: 12/01/2023]
Abstract
The ability to accurately measure the intensity of malaria transmission in areas with low transmission is extremely important to guide elimination efforts. Plasmodium falciparum Cell-traversal protein for ookinetes and sporozoites (PfCelTOS) is an important conserved sporozoite antigen reported as one of the promising malaria vaccine candidates, and could be used to estimate malaria transmission intensity. This study aimed at determining whether the diversity of PfCelTOS gene reflects the changes in malaria transmission that occurred between 2007 and 2014 in Dielmo, a Senegalese village, before and after the implementation of insecticide treated bed nets (ITNs). Of the 109 samples positive for PfCelTOS PCR, 96 (88%) were successfully sequenced and analysed for polymorphisms and population diversity. The number of segregating sites was higher during the pre-intervention period (13) and the malaria resurgences (11) than during the intervention period (5). Similarly, the number and diversity of haplotypes were higher during the pre-intervention period (16 and 0.914, respectively) and the malaria resurgences (6 and 0.821, respectively) than during the intervention period (4 and 0.758, respectively). Moreover, the average number of nucleotide differences was higher during the pre-intervention (3.792) and during malaria resurgences (3.467) than during the intervention period (2.189). The 3D7 KSSFNEP haplotype was only observed during the intervention period. Only two haplotypes were shared in both the pre-intervention and intervention periods while four haplotypes were shared between the pre-intervention and the malaria resurgences. The Fst values indicate moderate differentiation between pre-intervention and intervention periods (0.17433), and between intervention and malaria resurgences period (0.19198) as well as between pre-intervention and malaria resurgences periods (0.06607). PfCelTOS genetic diversity reflected changes of malaria transmission, with higher polymorphisms recorded before the large-scale implementation of ITNs and during the malaria resurgences. PfCelTOS is also a candidate vaccine; mapping its diversity across multiple endemic environments will facilitate the design and optimisation of a broad and efficacious vaccine.
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Affiliation(s)
- Amélé Nyedzie Wotodjo
- VITROME, UMR 257 IRD, Campus UCAD-IRD, Dakar, Senegal; Medical Research Council Unit, The Gambia, at the London School of Hygiene and Tropical Medicine, Fajara, Gambia.
| | - Mary Aigbiremo Oboh
- Medical Research Council Unit, The Gambia, at the London School of Hygiene and Tropical Medicine, Fajara, Gambia; Department of Biological Sciences, University of Medical Sciences, Ondo, Nigeria; Department of Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America
| | - Cheikh Sokhna
- VITROME, UMR 257 IRD, Campus UCAD-IRD, Dakar, Senegal
| | | | | | - Jean-François Trape
- UMR MIVEGEC, Laboratoire de Paludologie et Zoologie Médicale, IRD, Dakar, Senegal
| | | | - Alfred Amambua-Ngwa
- Medical Research Council Unit, The Gambia, at the London School of Hygiene and Tropical Medicine, Fajara, Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit, The Gambia, at the London School of Hygiene and Tropical Medicine, Fajara, Gambia
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Wotodjo AN, Oboh MA, Doucoure S, Diagne N, Diène-Sarr F, Niang M, Trape JF, Sokhna C, Amambua-Ngwa A, D'Alessandro U. Rebound of multiple infections and prevalence of anti-malarial resistance associated markers following malaria upsurges in Dielmo village, Senegal, West Africa. Malar J 2023; 22:257. [PMID: 37670357 PMCID: PMC10478411 DOI: 10.1186/s12936-023-04694-0] [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: 02/18/2023] [Accepted: 08/29/2023] [Indexed: 09/07/2023] Open
Abstract
BACKGROUND Thanks to the scale up of malaria control interventions, the malaria burden in Senegal has decreased substantially to the point that the National Malaria Control Programme plans to achieve malaria elimination by 2030. To guide such efforts, measuring and monitoring parasite population evolution and anti-malarial drugs resistance is extremely important. Information on the prevalence of parasite mutations related to drug resistance can provide a first signal of emergence, introduction and selection that can help with refining drug interventions. The aim of this study was to analyse the prevalence of anti-malarial drug resistance-associated markers before and after the implementation of artemisinin-based combination therapy (ACT) from 2005 to 2014 in Dielmo, a model site for malaria intervention studies in Senegal. METHODS Samples from both malaria patients and Plasmodium falciparum asymptomatic carriers were analysed with high resolution melting (HRM) technique to genotype P. falciparum chloroquine resistance transporter (Pfcrt) gene haplotypes and multidrug-resistant protein 1 (Pfmdr1) gene at codons N86 and Y184. RESULTS Among the 539 samples analysed, 474, 486, and 511 were successfully genotyped for Pfmdr1 N86, Y184, and Pfcrt, respectively. The prevalence of drug resistance markers was high, particularly during the malaria upsurges. Following the scale-up in bed net distribution, only the mutant (86F-like) variant of Pfmdr1 86 was present while during the malaria upsurges the predominance of two types 86Y-86N (43%) and 86F-like (56%) were observed. Most infections (87%) carried the wild type Y-allele at Pfmdr1 184 during the period of nets scale-up while during the malaria upsurges only 16% of infections had wild type and 79% of infections had mixed (mutant/wild) type. The frequency of the mixed genotypes SVMNT-like_CVMNK and SVMNT-like_CVIET within Pfcrt gene was particularly low during bednet scale up. Their frequency increased significantly (P < 0.001) during the malaria upsurges. CONCLUSION This data demonstrated the effect of multiple interventions on the dynamics of drug resistance-associated mutations in the main malaria parasite P. falciparum in an endemic village in Senegal. Monitoring drug resistance markers should be conducted periodically to detect threats of emergence or resurgence that could compromise the efficacy of anti-malarial drugs.
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Affiliation(s)
- Amélé Nyedzie Wotodjo
- VITROME, UMR 257 IRD, Campus UCAD-IRD, Dakar, Senegal.
- Medical Research Council Unit, London School of Hygiene and Tropical Medicine, Fajara, The Gambia.
| | - Mary Aigbiremo Oboh
- Medical Research Council Unit, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
- Department of Biological Sciences, University of Medical Sciences, Ondo, Nigeria
- Department of Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, USA
| | | | | | | | - Makhtar Niang
- Institut Pasteur de Dakar, 36 Avenue Pasteur, 220, Dakar, Senegal
| | - Jean-François Trape
- UMR MIVEGEC, Laboratoire de Paludologie et Zoologie Médicale, IRD, Dakar, Senegal
| | - Cheikh Sokhna
- VITROME, UMR 257 IRD, Campus UCAD-IRD, Dakar, Senegal
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
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Onen H, Luzala MM, Kigozi S, Sikumbili RM, Muanga CJK, Zola EN, Wendji SN, Buya AB, Balciunaitiene A, Viškelis J, Kaddumukasa MA, Memvanga PB. Mosquito-Borne Diseases and Their Control Strategies: An Overview Focused on Green Synthesized Plant-Based Metallic Nanoparticles. INSECTS 2023; 14:221. [PMID: 36975906 PMCID: PMC10059804 DOI: 10.3390/insects14030221] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/12/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Mosquitoes act as vectors of pathogens that cause most life-threatening diseases, such as malaria, Dengue, Chikungunya, Yellow fever, Zika, West Nile, Lymphatic filariasis, etc. To reduce the transmission of these mosquito-borne diseases in humans, several chemical, biological, mechanical, and pharmaceutical methods of control are used. However, these different strategies are facing important and timely challenges that include the rapid spread of highly invasive mosquitoes worldwide, the development of resistance in several mosquito species, and the recent outbreaks of novel arthropod-borne viruses (e.g., Dengue, Rift Valley fever, tick-borne encephalitis, West Nile, yellow fever, etc.). Therefore, the development of novel and effective methods of control is urgently needed to manage mosquito vectors. Adapting the principles of nanobiotechnology to mosquito vector control is one of the current approaches. As a single-step, eco-friendly, and biodegradable method that does not require the use of toxic chemicals, the green synthesis of nanoparticles using active toxic agents from plant extracts available since ancient times exhibits antagonistic responses and broad-spectrum target-specific activities against different species of vector mosquitoes. In this article, the current state of knowledge on the different mosquito control strategies in general, and on repellent and mosquitocidal plant-mediated synthesis of nanoparticles in particular, has been reviewed. By doing so, this review may open new doors for research on mosquito-borne diseases.
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Affiliation(s)
- Hudson Onen
- Department of Entomology, Uganda Virus Research Institute, Plot 51/59 Nakiwogo Road, Entebbe P.O. Box 49, Uganda
| | - Miryam M. Luzala
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
- Centre de Recherche et d’Innovation Technologique en Environnement et en Sciences de la Santé (CRITESS), University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
| | - Stephen Kigozi
- Department of Biological Sciences, Faculty of Science, Kyambogo University, Kampala P.O. Box 1, Uganda
| | - Rebecca M. Sikumbili
- Centre de Recherche et d’Innovation Technologique en Environnement et en Sciences de la Santé (CRITESS), University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
- Department of Chemistry, Faculty of Science, University of Kinshasa, Kinshasa B.P. 190, Democratic Republic of the Congo
| | - Claude-Josué K. Muanga
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
- Centre de Recherche et d’Innovation Technologique en Environnement et en Sciences de la Santé (CRITESS), University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
| | - Eunice N. Zola
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
- Centre de Recherche et d’Innovation Technologique en Environnement et en Sciences de la Santé (CRITESS), University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
| | - Sébastien N. Wendji
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
- Centre de Recherche et d’Innovation Technologique en Environnement et en Sciences de la Santé (CRITESS), University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
| | - Aristote B. Buya
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
- Centre de Recherche et d’Innovation Technologique en Environnement et en Sciences de la Santé (CRITESS), University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
| | - Aiste Balciunaitiene
- Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry, 54333 Babtai, Lithuania
| | - Jonas Viškelis
- Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry, 54333 Babtai, Lithuania
| | - Martha A. Kaddumukasa
- Department of Biological Sciences, Faculty of Science, Kyambogo University, Kampala P.O. Box 1, Uganda
| | - Patrick B. Memvanga
- Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
- Centre de Recherche et d’Innovation Technologique en Environnement et en Sciences de la Santé (CRITESS), University of Kinshasa, Kinshasa B.P. 212, Democratic Republic of the Congo
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Ngonghala CN. Assessing the impact of insecticide-treated nets in the face of insecticide resistance on malaria control. J Theor Biol 2022; 555:111281. [PMID: 36154815 DOI: 10.1016/j.jtbi.2022.111281] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 09/01/2022] [Accepted: 09/17/2022] [Indexed: 01/14/2023]
Abstract
The mosquito-borne disease, malaria, continues to impose a devastating health and economic burden worldwide. In malaria-endemic areas, insecticide-treated nets (ITNs) have been useful in curtailing the burden of the disease. However, mosquito resistance to insecticides, decay in ITN efficacy, net attrition, etc., undermine the effectiveness of ITNs in combatting malaria. In this study, mathematical models that account for asymptomatic infectious humans (through a partially immune class or a separate asymptomatic infectious class), insecticide resistance, and decay in ITN efficacy are proposed and analyzed. Analytical and numerical results of the models when ITN efficacy is constant show that there are parameter regimes for which a backward bifurcation occurs. Local and global sensitivity analyses are performed to identify parameters (some of which are potential targets for disease control) with the most significant influence on the control reproduction (Rc) and disease prevalence. These influential parameters include the maximum biting rate of resistant mosquitoes, ITN coverage, initial ITN efficacy against sensitive mosquitoes, the probability that an infectious mosquito (human) infects a susceptible human (mosquito), and the rate at which adult mosquitoes develop (lose) resistance to insecticides. Simulations of the models show that accounting for asymptomatic infectious humans through a separate class, or not accounting for the decay in ITN efficacy leads to an underestimation of disease burden. In particular, if the initial efficacy of ITNs against sensitive and resistance mosquitoes is 96%, the minimum ITN coverage required to reduce Rc below one (and hence, contain malaria) is approximately 11% (27%) lower when ITN efficacy is averaged (constant) for a model with a separate asymptomatic class. For the model with a partially immune class and decaying ITN efficacy, reducing Rc below one is impossible even if the entire populace uses ITNs. The study shows that replacing ITNs before their prescribed lifespans, or designing ITNs with longer lifespans is important for malaria control. Furthermore, the study shows that piperonyl butoxide (PBO) ITNs (which inhibit or reverse insecticide resistance) outperform regular ITNs in malaria control. Hence, prospects for effectively controlling malaria are enhanced by widespread use of high quality ITNs (e.g. PBO ITNs), especially if the useful lifespans of the ITNs are long enough and the ITNs are replaced before the end of their useful lifespans.
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Affiliation(s)
- Calistus N Ngonghala
- Department of Mathematics, University of Florida, 1400 Stadium Rd, Gainesville, FL 32611, United States of America; Emerging Pathogens Institute, University of Florida, 2055 Mowry Rd, Gainesville, FL 32610, United States of America; Center for African Studies, University of Florida, 427 Grinter Hall 1523 Union Rd, Gainesville, FL 32611, United States of America.
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Oladipo HJ. Increasing challenges of malaria control in sub-Saharan Africa: Priorities for public health research and policymakers. Ann Med Surg (Lond) 2022; 81:104366. [PMID: 36046715 PMCID: PMC9421173 DOI: 10.1016/j.amsu.2022.104366] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 08/11/2022] [Indexed: 11/21/2022] Open
Abstract
The ever-increasing cases and mortality due to malaria remains one of the most important public health threats, especially in sub-Saharan Africa-where this burden is considerably high. In 2020, sub-Saharan Africa accounted for about 95% of all cases and 96% of all malaria deaths with about 80% of these deaths reported in children under the age of 5. This review, adopting a public health focus, aimed to understand the challenges of malaria control in sub-Saharan Africa despite ongoing public health interventions. Our review highlights two important findings. First, the increasing resistance of malaria parasites to artemisinin-based combination therapy (ACT) and its partner drugs coupled with increased vector resistance to pyrethroids and insecticides is reversing the progress of public health interventions in keeping malaria under control. Second, the wanning for the efficacy of the WHO-approved vaccine i.e. RTS,S from 60 to 70% following 18 months of observation, and its short-term availability remains an impediment to achieving the WHO target of producing malaria vaccines with more than 75% efficacy by 2030. Our findings underline the need to reassess research priorities with a focus on vaccine production in sub-Saharan Africa. Furthermore, African governments and policymakers must be committed to invest both the political and financial capital in vaccine production and distribution.
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St. Leger RJ. From the Lab to the Last Mile: Deploying Transgenic Approaches Against Mosquitoes. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.804066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Ingenious exploitation of transgenic approaches to produce malaria resistant or sterile mosquitoes, or hypervirulent mosquito pathogens, has produced many potential solutions to vector borne diseases. However, in spite of technological feasibility, it has not been determined how well these new methods will work, and how they should be tested and regulated. Some self-limiting transgenic fungal pathogens and mosquitoes are almost field ready, and may be easier to regulate than self-sustaining strategies. However, they require repeat sales and so must show business viability; low-cost mass production is just one of a number of technical constraints that are sometimes treated as an afterthought in technology deployment. No transgenic self-sustaining approach to anopheline control has ever been deployed because of unresolved ethical, social and regulatory issues. These overlapping issues include: 1) the transparency challenge, which requires public discourse, particularly in Africa where releases are proposed, to determine what society is willing to risk given the potential benefits; 2) the transboundary challenge, self-sustaining mosquitoes or pathogens are potentially capable of crossing national boundaries and irreversibly altering ecosystems, and 3) the risk assessment challenge. The polarized debate as to whether these technologies will ever be used to save lives is ongoing; they will founder without a political answer as to how do we interpret the precautionary principle, as exemplified in the Cartagena protocol, in the global context of technological changes.
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Niang M, Sandfort M, Mbodj AF, Diouf B, Talla C, Faye J, Sane R, Thiam LG, Thiam A, Badiane A, Vigan-Womas I, Diagne N, Diene Sarr F, Mueller I, Sokhna C, White M, Toure-Balde A. Fine-scale Spatiotemporal Mapping of Asymptomatic and Clinical Plasmodium falciparum Infections: Epidemiological Evidence for Targeted Malaria Elimination Interventions. Clin Infect Dis 2021; 73:2175-2183. [PMID: 33677477 DOI: 10.1093/cid/ciab161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND A detailed understanding of the contribution of the asymptomatic Plasmodium reservoir to the occurrence of clinical malaria at individual and community levels is needed to guide effective elimination interventions. This study investigated the relationship between asymptomatic Plasmodium falciparum carriage and subsequent clinical malaria episodes in the Dielmo and Ndiop villages in Senegal. METHODS The study used a total of 2792 venous and capillary blood samples obtained from asymptomatic individuals and clinical malaria datasets collected from 2013 to 2016. Mapping, spatial clustering of infections, and risk analysis were performed using georeferenced households. RESULTS High incidences of clinical malaria episodes were observed to occur predominantly in households of asymptomatic P falciparum carriers. A statistically significant association was found between asymptomatic carriage in a household and subsequent episode of clinical malaria occurring in that household for each individual year (P values were 0.0017, 6 × 10-5, 0.005, and 0.008 for the years 2013, 2014, 2015, and 2016 respectively) and the combined years (P = 8.5 × 10-8), which was not found at the individual level. In both villages, no significant patterns of spatial clustering of P falciparum clinical cases were found, but there was a higher risk of clinical episodes <25 m from asymptomatic individuals in Ndiop attributable to clustering within households. CONCLUSION The findings provide strong epidemiological evidence linking the asymptomatic P falciparum reservoir to clinical malaria episodes at household scale in Dielmo and Ndiop villagers. This argues for a likely success of a mass testing and treatment intervention to move towards the elimination of malaria in the villages of Dielmo and Ndiop.
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Affiliation(s)
- Makhtar Niang
- Institut Pasteur Dakar, Pôle Immunophysiopathologie & Maladies Infectieuses, Dakar, Sénégal
| | - Mirco Sandfort
- Malaria: Parasites and Hosts Unit, Department of Parasites & Insect Vectors, Institut Pasteur, Paris, France.,Sorbonne Université, Collège doctoral, Paris, France
| | - Adja Fatou Mbodj
- Institut Pasteur Dakar, Pôle Immunophysiopathologie & Maladies Infectieuses, Dakar, Sénégal
| | - Babacar Diouf
- Institut Pasteur Dakar, Pôle Immunophysiopathologie & Maladies Infectieuses, Dakar, Sénégal
| | - Cheikh Talla
- Institut Pasteur Dakar, Pôle Epidémiologie, Recherche Clinique et Science des données, Dakar, Sénégal
| | - Joseph Faye
- Institut Pasteur Dakar, Pôle Epidémiologie, Recherche Clinique et Science des données, Dakar, Sénégal
| | - Rokhaya Sane
- Institut Pasteur Dakar, Pôle Immunophysiopathologie & Maladies Infectieuses, Dakar, Sénégal
| | - Laty Gaye Thiam
- Institut Pasteur Dakar, Pôle Immunophysiopathologie & Maladies Infectieuses, Dakar, Sénégal
| | - Alassane Thiam
- Institut Pasteur Dakar, Pôle Immunophysiopathologie & Maladies Infectieuses, Dakar, Sénégal
| | - Abdoulaye Badiane
- Institut Pasteur Dakar, Pôle Epidémiologie, Recherche Clinique et Science des données, Dakar, Sénégal
| | - Ines Vigan-Womas
- Institut Pasteur Dakar, Pôle Immunophysiopathologie & Maladies Infectieuses, Dakar, Sénégal
| | | | - Fatoumata Diene Sarr
- Institut Pasteur Dakar, Pôle Epidémiologie, Recherche Clinique et Science des données, Dakar, Sénégal
| | - Ivo Mueller
- Malaria: Parasites and Hosts Unit, Department of Parasites & Insect Vectors, Institut Pasteur, Paris, France
| | - Cheikh Sokhna
- VITROME, Campus international IRD-UCAD, Dakar, Sénégal
| | - Michael White
- Malaria: Parasites and Hosts Unit, Department of Parasites & Insect Vectors, Institut Pasteur, Paris, France
| | - Aissatou Toure-Balde
- Institut Pasteur Dakar, Pôle Immunophysiopathologie & Maladies Infectieuses, Dakar, Sénégal
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Mwagira-Maina S, Runo S, Wachira L, Kitur S, Nyasende S, Kemei B, Ochomo E, Matoke-Muhia D, Mbogo C, Kamau L. Genetic markers associated with insecticide resistance and resting behaviour in Anopheles gambiae mosquitoes in selected sites in Kenya. Malar J 2021; 20:461. [PMID: 34903240 PMCID: PMC8670025 DOI: 10.1186/s12936-021-03997-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 11/28/2021] [Indexed: 11/16/2022] Open
Abstract
Background Molecular diagnostic tools have been incorporated in insecticide resistance monitoring programmes to identify underlying genetic basis of resistance and develop early warning systems of vector control failure. Identifying genetic markers of insecticide resistance is crucial in enhancing the ability to mitigate potential effects of resistance. The knockdown resistance (kdr) mutation associated with resistance to DDT and pyrethroids, the acetylcholinesterase-1 (ace-1R) mutation associated with resistance to organophosphates and carbamates and 2La chromosomal inversion associated with indoor resting behaviour, were investigated in the present study. Methods Anopheles mosquitoes sampled from different sites in Kenya and collected within the context of malaria vector surveillance were analysed. Mosquitoes were collected indoors using light traps, pyrethrum spray and hand catches between August 2016 and November 2017. Mosquitoes were identified using morphological keys and Anopheles gambiae sensu lato (s.l.) mosquitoes further identified into sibling species by the polymerase chain reaction method following DNA extraction by alcohol precipitation. Anopheles gambiae and Anopheles arabiensis were analysed for the presence of the kdr and ace-1R mutations, while 2La inversion was only screened for in An. gambiae where it is polymorphic. Chi-square statistics were used to determine correlation between the 2La inversion karyotype and kdr-east mutation. Results The kdr-east mutation occurred at frequencies ranging from 0.5 to 65.6% between sites. The kdr-west mutation was only found in Migori at a total frequency of 5.3% (n = 124). No kdr mutants were detected in Tana River. The ace-1R mutation was absent in all populations. The 2La chromosomal inversion screened in An. gambiae occurred at frequencies of 87% (n = 30), 80% (n = 10) and 52% (n = 50) in Baringo, Tana River and Migori, respectively. A significant association between the 2La chromosomal inversion and the kdr-east mutation was found. Conclusion The significant association between the 2La inversion karyotype and kdr-east mutation suggests that pyrethroid resistant An. gambiae continue to rest indoors regardless of the presence of treated bed nets and residual sprays, a persistence further substantiated by studies documenting continued mosquito abundance indoors. Behavioural resistance by which Anopheles vectors prefer not to rest indoors may, therefore, not be a factor of concern in this study’s malaria vector populations.
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Affiliation(s)
- Sharon Mwagira-Maina
- Department of Biochemistry and Biotechnology, Kenyatta University, P.O Box 43844-00100, Nairobi, Kenya.
| | - Steven Runo
- Department of Biochemistry and Biotechnology, Kenyatta University, P.O Box 43844-00100, Nairobi, Kenya
| | - Lucy Wachira
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya
| | - Stanley Kitur
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya
| | - Sarah Nyasende
- Institute of Tropical Medicine and Infectious Diseases (ITROMID), P.O. Box 54840-00200, Nairobi, Kenya
| | - Brigid Kemei
- Centre for Global Health Research, KEMRI_CDC, P.O Box 1578-40100, Kisumu, Kenya
| | - Eric Ochomo
- Centre for Global Health Research, KEMRI_CDC, P.O Box 1578-40100, Kisumu, Kenya
| | - Damaris Matoke-Muhia
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya
| | - Charles Mbogo
- KEMRI -Wellcome Trust Research Programme, Public Health Unit, P.O. Box 43640-00100, Nairobi, Kenya
| | - Luna Kamau
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya
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12
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Metelo-Matubi E, Zanga J, Binene G, Mvuama N, Ngamukie S, Nkey J, Schopp P, Bamba M, Irish S, Nguya-Kalemba-Maniania J, Fasine S, Nagahuedi J, Muyembe JJ, Mansiangi P. The effect of a mass distribution of insecticide-treated nets on insecticide resistance and entomological inoculation rates of Anopheles gambiae s.l. in Bandundu City, Democratic Repub`lic of Congo. Pan Afr Med J 2021; 40:118. [PMID: 34887992 PMCID: PMC8627145 DOI: 10.11604/pamj.2021.40.118.27365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 10/10/2021] [Indexed: 11/26/2022] Open
Abstract
Introduction insecticide-treated nets (ITNs) remain the mainstay of malaria vector control in the Democratic Republic of Congo. However, insecticide resistance of malaria vectors threatens their effectiveness. Entomological inoculation rates and insecticide susceptibility in Anopheles gambiae s.l. were evaluated before and after mass distribution of ITNs in Bandundu City for possible occurrence of resistance. Methods a cross-sectional study was conducted from 15th July 2015 to 15th June 2016. Adult mosquitoes were collected using pyrethrum spray catches and human landing catches and identified to species level and tested for the presence of sporozoites. Bioassays were carried out before and after distribution of ITNs to assess the susceptibility of adult mosquitoes to insecticides. Synergist bioassays were also conducted and target site mutations assessed using Polymerase chain reaction (PCR). Results a total of 1754 female An. gambiae s.l. were collected before and after deployment of ITNs. Fewer mosquitoes were collected after the distribution of ITNs. However, there was no significant difference in sporozoite rates or the overall entomological inoculation rate before and after the distribution of ITNs. Test-mosquitoes were resistant to deltamethrin, permethrin, and Dichlorodiphenyltrichloroethane but susceptible to bendiocarb. Pre-exposure of mosquitoes to Piperonyl butoxide increased their mortality after exposure to permethrin and deltamethrin. The frequency of the Kinase insert domain receptor (kdr)-West gene increased from 92 to 99% before and after the distribution of nets, respectively. Conclusion seasonal impacts could be a limiting factor in the analysis of these data; however, the lack of decrease in transmission after the distribution of new nets could be explained by the high-level of resistance to pyrethroid.
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Affiliation(s)
- Emery Metelo-Matubi
- Faculté de Médecine, Université de Bandundu, B.P 548 Bandundu-ville, Bandundu, République Démocratique de Congo.,Institut National de Recherche Biomédicale, B.P 1197 KIN 1, Kinshasa, République Démocratique de Congo.,Faculté des Sciences, Département de Biologie, Unité de Recherche Entomologique, B.P 190 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
| | - Josué Zanga
- Faculté de Médecine, Ecole de Santé Publique, Département de Santé Environnementale, B.P 834 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
| | - Guillaume Binene
- Institut National de Recherche Biomédicale, B.P 1197 KIN 1, Kinshasa, République Démocratique de Congo
| | - Nono Mvuama
- Faculté de Médecine, Ecole de Santé Publique, Département de Santé Environnementale, B.P 834 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
| | - Solange Ngamukie
- Faculté de Médecine, Ecole de Santé Publique, Département de Santé Environnementale, B.P 834 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
| | - Jadis Nkey
- Faculté de Médecine, Université de Bandundu, B.P 548 Bandundu-ville, Bandundu, République Démocratique de Congo
| | - Pauline Schopp
- United States President´s Malaria Initiative and Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30329, USA
| | - Maxwell Bamba
- Faculté de Médecine, Ecole de Santé Publique, Département de Santé Environnementale, B.P 834 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
| | - Seth Irish
- United States President´s Malaria Initiative and Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30329, USA
| | | | - Sylvie Fasine
- Institut National de Recherche Biomédicale, B.P 1197 KIN 1, Kinshasa, République Démocratique de Congo
| | - Jonas Nagahuedi
- Faculté des Sciences, Département de Biologie, Unité de Recherche Entomologique, B.P 190 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
| | - Jean-Jacques Muyembe
- Institut National de Recherche Biomédicale, B.P 1197 KIN 1, Kinshasa, République Démocratique de Congo
| | - Paul Mansiangi
- Faculté de Médecine, Ecole de Santé Publique, Département de Santé Environnementale, B.P 834 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
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Yovogan B, Sovi A, Padonou GG, Adoha CJ, Akinro B, Chitou S, Accrombessi M, Dangbénon E, Akpovi H, Messenger LA, Ossè R, Hounto AO, Cook J, Kleinschmidt I, Ngufor C, Rowland M, Protopopoff N, Akogbéto MC. Pre-intervention characteristics of the mosquito species in Benin in preparation for a randomized controlled trial assessing the efficacy of dual active-ingredient long-lasting insecticidal nets for controlling insecticide-resistant malaria vectors. PLoS One 2021; 16:e0251742. [PMID: 34014982 PMCID: PMC8136630 DOI: 10.1371/journal.pone.0251742] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 05/01/2021] [Indexed: 11/18/2022] Open
Abstract
Background This study provides detailed characteristics of vector populations in preparation for a three-arm cluster randomized controlled trial (RCT) aiming to compare the community impact of dual active-ingredient (AI) long-lasting insecticidal nets (LLINs) that combine two novel insecticide classes–chlorfenapyr or pyriproxifen–with alpha-cypermethrin to improve the prevention of malaria transmitted by insecticide-resistant vectors compared to standard pyrethroid LLINs. Methods The study was carried out in 60 villages across Cove, Zangnanando and Ouinhi districts, southern Benin. Mosquito collections were performed using human landing catches (HLCs). After morphological identification, a sub-sample of Anopheles gambiae s.l. were dissected for parity, analyzed by PCR for species and presence of L1014F kdr mutation and by ELISA-CSP to identify Plasmodium falciparum sporozoite infection. WHO susceptibility tube tests were performed by exposing adult An. gambiae s.l., collected as larvae from each district, to 0.05% alphacypermethrin, 0.75% permethrin, 0.1% bendiocarb and 0.25% pirimiphos-methyl. Synergist assays were also conducted with exposure first to 4% PBO followed by alpha-cypermethrin. Results An. gambiae s.l. (n = 10807) was the main malaria vector complex found followed by Anopheles funestus s.l. (n = 397) and Anopheles nili (n = 82). An. gambiae s.l. was comprised of An. coluzzii (53.9%) and An. gambiae s.s. (46.1%), both displaying a frequency of the L1014F kdr mutation >80%. Although more than 80% of people slept under standard LLIN, human biting rate (HBR) in An. gambiae s.l. was higher indoors [26.5 bite/person/night (95% CI: 25.2–27.9)] than outdoors [18.5 b/p/n (95% CI: 17.4–19.6)], as were the trends for sporozoite rate (SR) [2.9% (95% CI: 1.7–4.8) vs 1.8% (95% CI: 0.6–3.8)] and entomological inoculation rate (EIR) [21.6 infected bites/person/month (95% CI: 20.4–22.8) vs 5.4 (95% CI: 4.8–6.0)]. Parous rate was 81.6% (95%CI: 75.4–88.4). An. gambiae s.l. was resistant to alpha-cypermethrin and permethrin but, fully susceptible to bendiocarb and pirimiphos-methyl. PBO pre-exposure followed by alpha-cypermethrin treatment induced a higher 24 hours mortality compared to alphacypermethrin alone but not exceeding 40%. Conclusions Despite a high usage of standard pyrethroid LLINs, the study area is characterized by intense malaria transmission. The main vectors An. coluzzii and An. gambiae s.s. were both highly resistant to pyrethroids and displayed multiple resistance mechanisms, L1014F kdr mutation and mixed function oxidases. These conditions of the study area make it an appropriate site to conduct the trial that aims to assess the effect of novel dual-AI LLINs on malaria transmitted by insecticide-resistant vectors.
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Affiliation(s)
- Boulais Yovogan
- Faculté des Sciences et Techniques de l’Université d’Abomey-Calavi, Abomey-Calavi, Benin
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Arthur Sovi
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Faculté d’Agronomie, Université de Parakou, Parakou, Benin
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
| | - Gil G. Padonou
- Faculté des Sciences et Techniques de l’Université d’Abomey-Calavi, Abomey-Calavi, Benin
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Constantin J. Adoha
- Faculté des Sciences et Techniques de l’Université d’Abomey-Calavi, Abomey-Calavi, Benin
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Bruno Akinro
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Saïd Chitou
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Manfred Accrombessi
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Institut de Recherche Clinique du Bénin, Abomey-Calavi, Benin
| | | | - Hilaire Akpovi
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Louisa A. Messenger
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
- American Society for Microbiology, Washington, DC, United States of America
| | - Razaki Ossè
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Ecole de Gestion et d’Exploitation des Systèmes d’Elevage, Université Nationale d’Agriculture, Kétou, Benin
| | - Aurore Ogouyemi Hounto
- Programme Nationale de Lutte Contre Le Paludisme (PNLP), Cotonou, Benin
- Faculté des Sciences de la Santé, Université d’Abomey-Calavi, Cotonou, Benin
| | - Jackie Cook
- Medical Research Council (MRC) Tropical International Statistics and Epidemiology Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Immo Kleinschmidt
- Medical Research Council (MRC) Tropical International Statistics and Epidemiology Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
- School of Pathology, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa
- Southern African Development Community Malaria Elimination Eight Secretariat, Windhoek, Namibia
| | - Corine Ngufor
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Mark Rowland
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Natacha Protopopoff
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Connolly JB, Mumford JD, Fuchs S, Turner G, Beech C, North AR, Burt A. Systematic identification of plausible pathways to potential harm via problem formulation for investigational releases of a population suppression gene drive to control the human malaria vector Anopheles gambiae in West Africa. Malar J 2021; 20:170. [PMID: 33781254 PMCID: PMC8006393 DOI: 10.1186/s12936-021-03674-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Population suppression gene drive has been proposed as a strategy for malaria vector control. A CRISPR-Cas9-based transgene homing at the doublesex locus (dsxFCRISPRh) has recently been shown to increase rapidly in frequency in, and suppress, caged laboratory populations of the malaria mosquito vector Anopheles gambiae. Here, problem formulation, an initial step in environmental risk assessment (ERA), was performed for simulated field releases of the dsxFCRISPRh transgene in West Africa. METHODS Building on consultative workshops in Africa that previously identified relevant environmental and health protection goals for ERA of gene drive in malaria vector control, 8 potentially harmful effects from these simulated releases were identified. These were stratified into 46 plausible pathways describing the causal chain of events that would be required for potential harms to occur. Risk hypotheses to interrogate critical steps in each pathway, and an analysis plan involving experiments, modelling and literature review to test each of those risk hypotheses, were developed. RESULTS Most potential harms involved increased human (n = 13) or animal (n = 13) disease transmission, emphasizing the importance to subsequent stages of ERA of data on vectorial capacity comparing transgenics to non-transgenics. Although some of the pathways (n = 14) were based on known anatomical alterations in dsxFCRISPRh homozygotes, many could also be applicable to field releases of a range of other transgenic strains of mosquito (n = 18). In addition to population suppression of target organisms being an accepted outcome for existing vector control programmes, these investigations also revealed that the efficacy of population suppression caused by the dsxFCRISPRh transgene should itself directly affect most pathways (n = 35). CONCLUSIONS Modelling will play an essential role in subsequent stages of ERA by clarifying the dynamics of this relationship between population suppression and reduction in exposure to specific potential harms. This analysis represents a comprehensive identification of plausible pathways to potential harm using problem formulation for a specific gene drive transgene and organism, and a transparent communication tool that could inform future regulatory studies, guide subsequent stages of ERA, and stimulate further, broader engagement on the use of population suppression gene drive to control malaria vectors in West Africa.
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Affiliation(s)
- John B Connolly
- Department of Life Sciences, Imperial College London, London, UK.
| | - John D Mumford
- Centre for Environmental Policy, Imperial College London, London, UK
| | - Silke Fuchs
- Department of Life Sciences, Imperial College London, London, UK
| | - Geoff Turner
- Department of Life Sciences, Imperial College London, London, UK
| | | | - Ace R North
- Department of Zoology, University of Oxford, Oxford, UK
| | - Austin Burt
- Department of Life Sciences, Imperial College London, London, UK
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15
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Population Dynamics and Insecticide Susceptibility of Anopheles culicifacies in Malaria Endemic Districts of Chhattisgarh, India. INSECTS 2021; 12:insects12040284. [PMID: 33806071 PMCID: PMC8064500 DOI: 10.3390/insects12040284] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/13/2021] [Accepted: 03/20/2021] [Indexed: 11/22/2022]
Abstract
Simple Summary Malaria is a complex disease in part due to multiple vectors having different biological characteristics. In India, there are six primary vectors of malaria viz., Anopheles culicifacies, An. fluviatitlis, An. stephensi, An. subpictus, An. Minimus, and An. epiroticus. All these vectors have different ecological and seasonal distributions, transmission potential, and insecticide susceptibility status. In addition, except An. stephensi, all the five vectors comprise species complexes having sibling species which again differ in characteristics. Therefore, it is imperative to know the characteristics of the local vector population when it comes to planning control strategies. We carried out a study in tribal areas of Chhattisgarh state to investigate the seasonal and ecotype-wise distribution, breeding habits, sibling species composition, insecticide susceptibility, and role in the transmission of the local vector population. A high diversity of species was observed with around 16 species of Anopheles. An. culicifacies was the most dominant species and also was found to play a role in malaria transmission. The species was found to be resistant to dichlorodiphenyltrichloroethane (DDT) and Malathion, while an increasing trend of pyrethroid resistance was observed at some sites. Overall, our findings provide a picture of the characteristics of the local vector population in malaria-endemic regions. Abstract A study was undertaken in the villages of Korea and Bastar district (Chhattisgarh) during the years 2012–2015 to investigate the bionomics of malaria vectors and the prevalence of their sibling species complexes. Entomological surveys carried out every month included indoor resting collections, pyrethrum spray catches, light trap catches, and insecticide susceptibility status of Anopheles culicifacies using World Health Organization (WHO) methods. Anopheles culicifacies and Anopheles fluviatilis species were assayed by polymerase chain reaction (PCR) for the detection of malaria parasite, and sibling species were identified using PCR and DNA sequencing. A total of 13,186 samples of Anopheles comprising 15 species from Bastar and 16 from Korea were collected. An. Culicifacies was recorded as the most dominant species and also the only active vector at both sites. This species was found to be resistant to dichlorodiphenyltrichloroethane (DDT) and Malathion, showing signs of emerging resistance against pyrethroids. Among the sibling species of An. culicifacies, the group BCE was found in maximum numbers, while sibling species T of the An. fluviatilis was recorded to be dominant among its complex. The study provides a comprehensive view of the vector bionomics in the highly malarious regions of India that may have importance in developing vector control strategies.
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Owuor KO, Machani MG, Mukabana WR, Munga SO, Yan G, Ochomo E, Afrane YA. Insecticide resistance status of indoor and outdoor resting malaria vectors in a highland and lowland site in Western Kenya. PLoS One 2021; 16:e0240771. [PMID: 33647049 PMCID: PMC7920366 DOI: 10.1371/journal.pone.0240771] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/16/2021] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Long Lasting Insecticidal Nets (LLINs) and indoor residual spraying (IRS) represent powerful tools for controlling malaria vectors in sub-Saharan Africa. The success of these interventions relies on their capability to inhibit indoor feeding and resting of malaria mosquitoes. This study sought to understand the interaction of insecticide resistance with indoor and outdoor resting behavioral responses of malaria vectors from Western Kenya. METHODS The status of insecticide resistance among indoor and outdoor resting anopheline mosquitoes was compared in Anopheles mosquitoes collected from Kisumu and Bungoma counties in Western Kenya. The level and intensity of resistance were measured using WHO-tube and CDC-bottle bioassays, respectively. The synergist piperonyl butoxide (PBO) was used to determine if metabolic activity (monooxygenase enzymes) explained the resistance observed. The mutations at the voltage-gated sodium channel (Vgsc) gene and Ace 1 gene were characterized using PCR methods. Microplate assays were used to measure levels of detoxification enzymes if present. RESULTS A total of 1094 samples were discriminated within Anopheles gambiae s.l. and 289 within An. funestus s.l. In Kisian (Kisumu county), the dominant species was Anopheles arabiensis 75.2% (391/520) while in Kimaeti (Bungoma county) collections the dominant sibling species was Anopheles gambiae s.s 96.5% (554/574). The An. funestus s.l samples analysed were all An. funestus s.s from both sites. Pyrethroid resistance of An.gambiae s.l F1 progeny was observed in all sites. Lower mortality was observed against deltamethrin for the progeny of indoor resting mosquitoes compared to outdoor resting mosquitoes (Mortality rate: 37% vs 51%, P = 0.044). The intensity assays showed moderate-intensity resistance to deltamethrin in the progeny of mosquitoes collected from indoors and outdoors in both study sites. In Kisian, the frequency of vgsc-L1014S and vgsc-L1014F mutation was 0.14 and 0.19 respectively in indoor resting malaria mosquitoes while those of the outdoor resting mosquitoes were 0.12 and 0.12 respectively. The ace 1 mutation was present in higher frequency in the F1 of mosquitoes resting indoors (0.23) compared to those of mosquitoes resting outdoors (0.12). In Kimaeti, the frequencies of vgsc-L1014S and vgsc-L1014F were 0.75 and 0.05 respectively for the F1 of mosquitoes collected indoors whereas those of outdoor resting ones were 0.67 and 0.03 respectively. The ace 1 G119S mutation was present in progeny of mosquitoes from Kimaeti resting indoors (0.05) whereas it was absent in those resting outdoors. Monooxygenase activity was elevated by 1.83 folds in Kisian and by 1.33 folds in Kimaeti for mosquitoes resting indoors than those resting outdoors respectively. CONCLUSION The study recorded high phenotypic, metabolic and genotypic insecticide resistance in indoor resting populations of malaria vectors compared to their outdoor resting counterparts. The indication of moderate resistance intensity for the indoor resting mosquitoes is alarming as it could have an operational impact on the efficacy of the existing pyrethroid based vector control tools. The use of synergist (PBO) in LLINs may be a better alternative for widespread use in these regions recording high insecticide resistance.
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Affiliation(s)
- Kevin O. Owuor
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Maxwell G. Machani
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Wolfgang R. Mukabana
- School of Biological Sciences, University of Nairobi, Nairobi, Kenya
- Science for Health Society, Nairobi, Kenya
| | - Stephen O. Munga
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California, Irvine, California, United States of America
| | - Eric Ochomo
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Yaw A. Afrane
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Accra, Ghana
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Zhou G, Yu L, Wang X, Zhong D, Lee MC, Kibret S, Yan G. Behavioral response of insecticide-resistant mosquitoes against spatial repellent: A modified self-propelled particle model simulation. PLoS One 2020; 15:e0244447. [PMID: 33373422 PMCID: PMC7771694 DOI: 10.1371/journal.pone.0244447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/09/2020] [Indexed: 11/19/2022] Open
Abstract
Rapidly increasing pyrethroid insecticide resistance and changes in vector biting and resting behavior pose serious challenges in malaria control. Mosquito repellents, especially spatial repellents, have received much attention from industry. We attempted to simulate interactions between mosquitoes and repellents using a machine learning method, the Self-Propelled Particle (SPP) model, which we modified to include attractiveness/repellency effects. We simulated a random walk scenario and scenarios with insecticide susceptible/resistant mosquitoes against repellent alone and against repellent plus attractant (to mimic a human host). Simulation results indicated that without attractant/repellent, mosquitoes would fly anywhere in the cage at random. With attractant, all mosquitoes were attracted to the source of the odor by the end. With repellent, all insecticide-susceptible mosquitoes eventually moved to the corner of the cage farthest from the repellent release point, whereas, a high proportion of highly resistant mosquitoes might reach the attractant release point (the human) earlier in the simulation. At fixed concentration, a high proportion of mosquitoes could be able to reach the host when the relative repellency efficacy (compare to attractant efficacy) was <1, whereas, no mosquitoes reached the host when the relative repellency efficacy was > 1. This result implies that repellent may not be sufficient against highly physiologically insecticide resistant mosquitoes, since very high concentrations of repellent are neither practically feasible nor cost-effective.
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Affiliation(s)
- Guofa Zhou
- Program in Public Health, University of California, Irvine, California, United States of America
| | - Leonard Yu
- Program in Public Health, University of California, Irvine, California, United States of America
| | - Xiaoming Wang
- Program in Public Health, University of California, Irvine, California, United States of America
| | - Daibin Zhong
- Program in Public Health, University of California, Irvine, California, United States of America
| | - Ming-chieh Lee
- Program in Public Health, University of California, Irvine, California, United States of America
| | - Solomon Kibret
- Program in Public Health, University of California, Irvine, California, United States of America
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, California, United States of America
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Topazian HM, Gumbo A, Puerto-Meredith S, Njiko R, Mwanza A, Kayange M, Mwalilino D, Mvula B, Tegha G, Mvalo T, Edwards JK, Emch M, Pettifor A, Smith JS, Hoffman I, Meshnick SR, Juliano JJ. Asymptomatic Plasmodium falciparum malaria prevalence among adolescents and adults in Malawi, 2015-2016. Sci Rep 2020; 10:18740. [PMID: 33127922 PMCID: PMC7603306 DOI: 10.1038/s41598-020-75261-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 10/13/2020] [Indexed: 11/25/2022] Open
Abstract
Malaria remains a significant cause of morbidity and mortality in Malawi, with an estimated 18–19% prevalence of Plasmodium falciparum in children 2–10 years in 2015–2016. While children report the highest rates of clinical disease, adults are thought to be an important reservoir to sustained transmission due to persistent asymptomatic infection. The 2015–2016 Malawi Demographic and Health Survey was a nationally representative household survey which collected dried blood spots from 15,125 asymptomatic individuals ages 15–54 between October 2015 and February 2016. We performed quantitative polymerase chain reaction on 7,393 samples, detecting an overall P. falciparum prevalence of 31.1% (SE = 1.1). Most infections (55.6%) had parasitemias ≤ 10 parasites/µL. While 66.2% of individuals lived in a household that owned a bed net, only 36.6% reported sleeping under a long-lasting insecticide-treated net (LLIN) the previous night. Protective factors included urbanicity, greater wealth, higher education, and lower environmental temperatures. Living in a household with a bed net (prevalence difference 0.02, 95% CI − 0.02 to 0.05) and sleeping under an LLIN (0.01; − 0.02 to 0.04) were not protective against infection. Our findings demonstrate a higher parasite prevalence in adults than published estimates among children. Understanding the prevalence and distribution of asymptomatic infection is essential for targeted interventions.
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Affiliation(s)
- Hillary M Topazian
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA.
| | - Austin Gumbo
- National Malaria Control Programme, Malawi Ministry of Health, Lilongwe, Malawi
| | | | - Ruth Njiko
- University of North Carolina Project-Malawi, Lilongwe, Malawi
| | - Alexis Mwanza
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA
| | - Michael Kayange
- National Malaria Control Programme, Malawi Ministry of Health, Lilongwe, Malawi
| | - David Mwalilino
- National HIV Reference Laboratory, Malawi Ministry of Health, Lilongwe, Malawi
| | - Bernard Mvula
- National HIV Reference Laboratory, Malawi Ministry of Health, Lilongwe, Malawi
| | - Gerald Tegha
- University of North Carolina Project-Malawi, Lilongwe, Malawi
| | - Tisungane Mvalo
- University of North Carolina Project-Malawi, Lilongwe, Malawi.,Department of Pediatrics, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Jessie K Edwards
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA
| | - Michael Emch
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA.,Department of Geography, University of North Carolina, Chapel Hill, NC, USA
| | - Audrey Pettifor
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA.,Carolina Population Center, University of North Carolina, Chapel Hill, NC, USA
| | - Jennifer S Smith
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA
| | - Irving Hoffman
- University of North Carolina Project-Malawi, Lilongwe, Malawi.,Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, NC, USA
| | - Steven R Meshnick
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, 27510, USA
| | - Jonathan J Juliano
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
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Wotodjo AN, Doucoure S, Diagne N, Sarr FD, Parola P, Gaudart J, Sokhna C. The Impact of Renewing Long-Lasting Insecticide-Treated Nets in the Event of Malaria Resurgence: Lessons from 10 Years of Net Use in Dielmo, Senegal. Am J Trop Med Hyg 2020; 104:255-262. [PMID: 33078700 DOI: 10.4269/ajtmh.20-0127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The occurrence of malaria resurgences could threaten progress toward elimination of the disease. This study investigated the impact of repeated renewal of long-lasting insecticide-treated net (LLIN) universal coverage on malaria resurgence over a period of 10 years of net implementation in Dielmo (Senegal). A longitudinal study was carried out in Dielmo between August 2007 and July 2018. In July 2008, LLINs were offered to all villagers through universal campaign distribution which was renewed in July 2011, August 2014, and May 2016. Malaria cases were treated with artemisinin-based combination therapy. Two resurgences of malaria occurred during the 10 years in which LLINs have been in use. Since the third renewal of the nets, malaria decreased significantly compared with the first year the nets were implemented (adjusted incidence rate ratio) (95% CI) = 0.35 (0.15-0.85), during the ninth year after net implementation). During the tenth year of net implementation, no cases of malaria were observed among the study population. The use of nets increased significantly after the third time the nets were renewed when compared with the year after the first and the second times the nets were renewed (P < 0.001). The third renewal of nets, which took place after 2 years instead of 3 years together with a higher use of LLINs especially among the young, probably prevented the occurrence of a third malaria upsurge in this village.
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Affiliation(s)
| | | | | | - Fatoumata Diene Sarr
- 2Unité d'Épidémiologie des Maladies Infectieuses, Institut Pasteur de Dakar, Dakar, Senegal
| | - Philippe Parola
- 3IRD, AP-HM, SSA, IHU-Méditerranée Infection, VITROME, Aix-Marseille University, Marseille, France
| | - Jean Gaudart
- 4APHM, INSERM, IRD, SESSTIM, Hop Timone, BioSTIC, Biostatistic and ICT, Aix Marseille University, Marseille, France.,5Malaria Research and Training Center - Ogobara K Doumbo (MRTC-OKD), FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Cheikh Sokhna
- 1VITROME, UMR 257 IRD, Campus UCAD-IRD, Dakar, Senegal
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20
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Hamid-Adiamoh M, Amambua-Ngwa A, Nwakanma D, D'Alessandro U, Awandare GA, Afrane YA. Insecticide resistance in indoor and outdoor-resting Anopheles gambiae in Northern Ghana. Malar J 2020; 19:314. [PMID: 32867769 PMCID: PMC7460795 DOI: 10.1186/s12936-020-03388-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 08/25/2020] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Selection pressure from continued exposure to insecticides drives development of insecticide resistance and changes in resting behaviour of malaria vectors. There is need to understand how resistance drives changes in resting behaviour within vector species. The association between insecticide resistance and resting behaviour of Anopheles gambiae sensu lato (s.l.) in Northern Ghana was examined. METHODS F1 progenies from adult mosquitoes collected indoors and outdoors were exposed to DDT, deltamethrin, malathion and bendiocarb using WHO insecticide susceptibility tests. Insecticide resistance markers including voltage-gated sodium channel (Vgsc)-1014F, Vgsc-1014S, Vgsc-1575Y, glutathione-S-transferase epsilon 2 (GSTe2)-114T and acetylcholinesterase (Ace1)-119S, as well as blood meal sources were investigated using PCR methods. Activities of metabolic enzymes, acetylcholine esterase (AChE), non-specific β-esterases, glutathione-S-transferase (GST) and monooxygenases were measured from unexposed F1 progenies using microplate assays. RESULTS Susceptibility of Anopheles coluzzii to deltamethrin 24 h post-exposure was significantly higher in indoor (mortality = 5%) than outdoor (mortality = 2.5%) populations (P = 0.02). Mosquitoes were fully susceptible to malathion (mortality: indoor = 98%, outdoor = 100%). Susceptibility to DDT was significantly higher in outdoor (mortality = 9%) than indoor (mortality = 0%) mosquitoes (P = 0.006). Mosquitoes were also found with suspected resistance to bendiocarb but mortality was not statistically different (mortality: indoor = 90%, outdoor = 95%. P = 0.30). Frequencies of all resistance alleles were higher in F1 outdoor (0.11-0.85) than indoor (0.04-0.65) mosquito populations, while Vgsc-1014F in F0 An. gambiae sensu stricto (s.s) was significantly associated with outdoor-resting behaviour (P = 0.01). Activities of non-specific β-esterase enzymes were significantly higher in outdoor than indoor mosquitoes (Mean enzyme activity: Outdoor = : 1.70/mg protein; Indoor = 1.35/mg protein. P < 0.0001). AChE activity was also more elevated in outdoor (0.62/mg protein) than indoor (0.57/mg protein) mosquitoes but this was not significant (P = 0.08). Human blood index (HBI) was predominantly detected in indoor (18%) than outdoor mosquito populations (3%). CONCLUSIONS The overall results did not establish that there was a significant preference of resistant malaria vectors to solely rest indoors or outdoors, but varied depending on the resistant alleles present. Phenotypic resistance was higher in indoor than outdoor-resting mosquitoes, but genotypic and metabolic resistance levels were higher in outdoor than the indoor populations. Continued monitoring of changes in resting behaviour within An. gambiae s.l. populations is recommended.
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Affiliation(s)
- Majidah Hamid-Adiamoh
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) and Department of Biochemistry, Cell and Molecular, University of Ghana, Legon, Ghana
- Medical Research Council Unit, The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Alfred Amambua-Ngwa
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) and Department of Biochemistry, Cell and Molecular, University of Ghana, Legon, Ghana
- Medical Research Council Unit, The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Davis Nwakanma
- Medical Research Council Unit, The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit, The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) and Department of Biochemistry, Cell and Molecular, University of Ghana, Legon, Ghana
| | - Yaw A Afrane
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) and Department of Biochemistry, Cell and Molecular, University of Ghana, Legon, Ghana.
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
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21
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Choi R, Michaels SA, Onu EC, Hulverson MA, Saha A, Coker ME, Weeks JC, Van Voorhis WC, Ojo KK. Taming the Boys for Global Good: Contraceptive Strategy to Stop Malaria Transmission. Molecules 2020; 25:molecules25122773. [PMID: 32560085 PMCID: PMC7356879 DOI: 10.3390/molecules25122773] [Citation(s) in RCA: 4] [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: 04/20/2020] [Revised: 06/10/2020] [Accepted: 06/14/2020] [Indexed: 12/21/2022] Open
Abstract
Transmission of human malaria parasites (Plasmodium spp.) by Anopheles mosquitoes is a continuous process that presents a formidable challenge for effective control of the disease. Infectious gametocytes continue to circulate in humans for up to four weeks after antimalarial drug treatment, permitting prolonged transmission to mosquitoes even after clinical cure. Almost all reported malaria cases are transmitted to humans by mosquitoes, and therefore decreasing the rate of Plasmodium transmission from humans to mosquitoes with novel transmission-blocking remedies would be an important complement to other interventions in reducing malaria incidence.
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Affiliation(s)
- Ryan Choi
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
| | - Samantha A. Michaels
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
| | - Emmanuel C. Onu
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria; (E.C.O.); (M.E.C.)
| | - Matthew A. Hulverson
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
| | - Aparajita Saha
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
| | - Morenike E. Coker
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria; (E.C.O.); (M.E.C.)
| | - Janis C. Weeks
- Department of Biology, University of Oregon, Eugene, OR 97403, USA;
| | - Wesley C. Van Voorhis
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
| | - Kayode K. Ojo
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109, USA; (R.C.); (S.A.M.); (M.A.H.); (A.S.); (W.C.V.V.)
- Correspondence: ; Tel.: +1-206-543-0821
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Sougoufara S, Ottih EC, Tripet F. The need for new vector control approaches targeting outdoor biting Anopheline malaria vector communities. Parasit Vectors 2020; 13:295. [PMID: 32522290 PMCID: PMC7285743 DOI: 10.1186/s13071-020-04170-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/04/2020] [Indexed: 12/13/2022] Open
Abstract
Since the implementation of Roll Back Malaria, the widespread use of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) is thought to have played a major part in the decrease in mortality and morbidity achieved in malaria-endemic regions. In the past decade, resistance to major classes of insecticides recommended for public health has spread across many malaria vector populations. Increasingly, malaria vectors are also showing changes in vector behaviour in response to current indoor chemical vector control interventions. Changes in the time of biting and proportion of indoor biting of major vectors, as well as changes in the species composition of mosquito communities threaten the progress made to control malaria transmission. Outdoor biting mosquito populations contribute to malaria transmission in many parts of sub-Saharan Africa and pose new challenges as they cannot be reliably monitored or controlled using conventional tools. Here, we review existing and novel approaches that may be used to target outdoor communities of malaria vectors. We conclude that scalable tools designed specifically for the control and monitoring of outdoor biting and resting malaria vectors with increasingly complex and dynamic responses to intensifying malaria control interventions are urgently needed. These are crucial for integrated vector management programmes designed to challenge current and future vector populations.
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Affiliation(s)
- Seynabou Sougoufara
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Emmanuel Chinweuba Ottih
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Frederic Tripet
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
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Nguela RL, Bigoga JD, Armel TN, Esther T, Line D, Boris NA, Frederic T, Kazi R, Williams P, Mbacham WF, Leke RGF. The effect of improved housing on indoor mosquito density and exposure to malaria in the rural community of Minkoameyos, Centre Region of Cameroon. Malar J 2020; 19:172. [PMID: 32362282 PMCID: PMC7197188 DOI: 10.1186/s12936-020-03232-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 04/09/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND This study evaluated the effectiveness of improved housing on indoor residual mosquito density and exposure to infected Anophelines in Minkoameyos, a rural community in southern forested Cameroon. METHODS Following the identification of housing factors affecting malaria prevalence in 2013, 218 houses were improved by screening the doors and windows, installing plywood ceilings on open eaves and closing holes on walls and doors. Monthly entomological surveys were conducted in a sample of 21 improved and 21 non-improved houses from November 2014 to October 2015. Mosquitoes sampled from night collections on human volunteers were identified morphologically and their parity status determined. Mosquito infectivity was verified through Plasmodium falciparum CSP ELISA and the average entomological inoculation rates determined. A Reduction Factor (RF), defined as the ratio of the values for mosquitoes collected outdoor to those collected indoor was calculated in improved houses (RFI) and non-improved houses (RFN). An Intervention Effect (IE = RFI/RFN) measured the true effect of the intervention. Chi square test was used to determine variable significance. The threshold for statistical significance was set at P < 0.05. RESULTS A total of 1113 mosquitoes were collected comprising Anopheles sp (58.6%), Culex sp (36.4%), Aedes sp (2.5%), Mansonia sp (2.4%) and Coquillettidia sp (0.2%). Amongst the Anophelines were Anopheles gambiae sensu lato (s.l.) (95.2%), Anopheles funestus (2.9%), Anopheles ziemanni (0.2%), Anopheles brohieri (1.2%) and Anopheles paludis (0.5%). Anopheles gambiae sensu stricto (s.s.) was the only An. gambiae sibling species found. The intervention reduced the indoor Anopheles density by 1.8-fold (RFI = 3.99; RFN = 2.21; P = 0.001). The indoor density of parous Anopheles was reduced by 1.7-fold (RFI = 3.99; RFN = 2.21; P = 0.04) and that of infected Anopheles by 1.8-fold (RFI = 3.26; RFN = 1.78; P = 0.04). Indoor peak biting rates were observed between 02 a.m. to 04 a.m. in non-improved houses and from 02 a.m. to 06 a.m. in improved houses. CONCLUSION Housing improvement contributed to reducing indoor residual anopheline density and malaria transmission. This highlights the need for policy specialists to further evaluate and promote aspects of house design as a complementary control tool that could reduce indoor human-vector contact and malaria transmission in similar epidemiological settings.
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Affiliation(s)
- Rachel L Nguela
- Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon.
- Department of Public Health, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon.
- National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon.
| | - Jude D Bigoga
- National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Tedjou N Armel
- National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
| | - Tallah Esther
- Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon
| | - Dongmo Line
- Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon
| | - Njeambosay A Boris
- National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
| | - Tchouine Frederic
- Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon
| | - Riksum Kazi
- Architecture for Health in Vulnerable Environments (ARCHIVE Global), New York, USA
| | - Peter Williams
- Architecture for Health in Vulnerable Environments (ARCHIVE Global), New York, USA
| | - Wilfred F Mbacham
- Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon
- National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Rose G F Leke
- Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon.
- National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, Yaoundé, Cameroon.
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Dahmana H, Mediannikov O. Mosquito-Borne Diseases Emergence/Resurgence and How to Effectively Control It Biologically. Pathogens 2020; 9:E310. [PMID: 32340230 PMCID: PMC7238209 DOI: 10.3390/pathogens9040310] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 12/28/2022] Open
Abstract
Deadly pathogens and parasites are transmitted by vectors and the mosquito is considered the most threatening vector in public health, transmitting these pathogens to humans and animals. We are currently witnessing the emergence/resurgence in new regions/populations of the most important mosquito-borne diseases, such as arboviruses and malaria. This resurgence may be the consequence of numerous complex parameters, but the major cause remains the mismanagement of insecticide use and the emergence of resistance. Biological control programmes have rendered promising results but several highly effective techniques, such as genetic manipulation, remain insufficiently considered as a control mechanism. Currently, new strategies based on attractive toxic sugar baits and new agents, such as Wolbachia and Asaia, are being intensively studied for potential use as alternatives to chemicals. Research into new insecticides, Insect Growth Regulators, and repellent compounds is pressing, and the improvement of biological strategies may provide key solutions to prevent outbreaks, decrease the danger to at-risk populations, and mitigate resistance.
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Affiliation(s)
- Handi Dahmana
- Aix Marseille Univ, IRD, AP-HM, MEPHI, 13005 Marseille, France;
- IHU-Méditerranée Infection, 13005 Marseille, France
| | - Oleg Mediannikov
- Aix Marseille Univ, IRD, AP-HM, MEPHI, 13005 Marseille, France;
- IHU-Méditerranée Infection, 13005 Marseille, France
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Varela ML, Koffi D, White M, Niang M, Mbengue B, Diene Sarr F, Touré AO, Perraut R. Practical example of multiple antibody screening for evaluation of malaria control strategies. Malar J 2020; 19:117. [PMID: 32192514 PMCID: PMC7082935 DOI: 10.1186/s12936-020-03186-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 03/09/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ongoing efforts to fight Plasmodium falciparum malaria has reduced malaria in many areas, but new tools are needed to monitor further progress, including indicators of decreasing exposure to parasite infection. Sero-surveillance is considered promising to monitor exposure, transmission and immunity. METHODS IgG responses to three antigen biomarkers were evaluated in a retrospective study involving: (i) surveys of 798 asymptomatic villagers from 2 Senegalese endemic settings conducted before 2002 and after the 2013 intensification of control measures, and (ii) in 105 symptomatic individuals from different settings in Côte d'Ivoire. Response to up to eight P. falciparum antigens, including recombinant MSP1p9 antigen and LSA141 peptide, were analysed using multiplex technology and responses to whole P. falciparum schizont extract (SE, local strain adapted to culture) were measured by ELISA. RESULTS MSP1p9 and LSA141 IgG responses were shown to be relevant indicators monitoring immune status in the different study sites both from Côte d'Ivoire and Senegal. Between 2002 and 2013, individuals participating in both studies showed higher decline of sero-positivity in young (< 15 years: range 12% to 50%) than older (> 15 years: no decline to 15%) individuals from Dielmo and Ndiop. A mathematical sero-catalytic model from the complete Dielmo/Ndiop survey was used to reconstruct declining levels of sero-positivity in more detail, demonstrating that anti-SE seroprevalence levels most accurately reflected malaria exposure in the two villages. CONCLUSION For standard screening of population immune status at sites envisaging elimination, the use of ELISA-based assays targeting selected antigens can contribute to provide important epidemiologic surveillance data to aid malaria control programmes.
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Affiliation(s)
| | - David Koffi
- Unité de Paludologie, Institut Pasteur de Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Michael White
- Malaria Unit, Parasites and hosts, Institut Pasteur, Paris, France
| | - Makhtar Niang
- Unité d'Immunologie, Institut Pasteur de Dakar, Dakar, Senegal
| | - Babacar Mbengue
- Unité d'Immunogénétique, Institut Pasteur de Dakar, Dakar, Senegal.,Service d'Immunologie FMPO, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | | | | | - Ronald Perraut
- Unité d'Immunologie, Institut Pasteur de Dakar, Dakar, Senegal. .,Unité d'Immunogénétique, Institut Pasteur de Dakar, Dakar, Senegal. .,Centre Pasteur du Cameroun, Annexe de Garoua, Garoua, Cameroun.
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Krezanoski PJ, Santorino D, Agaba A, Dorsey G, Bangsberg DR, Carroll RW. How Are Insecticide-Treated Bednets Used in Ugandan Households? A Comprehensive Characterization of Bednet Adherence Using a Remote Monitor. Am J Trop Med Hyg 2020; 101:404-411. [PMID: 31287045 DOI: 10.4269/ajtmh.19-0032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Long-lasting insecticide-treated bednets are widely used and promoted for malaria control. Limitations in measurement methods have resulted in a poor understanding of how bednets are used in practice. We deployed a novel remote monitoring tool in Uganda to obtain, for the first time, a comprehensive characterization of bednet use in households at risk for malaria. Ten households each used one SmartNet adherence monitor over a commonly used sleeping area for 6 weeks. SmartNet continuously measures and records bednet use every 15 minutes. Bednet use was monitored for a total of 9,258 hours overall, with an average of 42 nights per household (SD: 3.5). Average duration of bednet use was 9 hours 49 minutes per night (SD: 1 hour 56 minutes), and adherence was 85-90% from 2100 to 0600. Bednets were not used at all on 4.5% (19/418) of observation nights. Overall, the average clock time that bednets were unfurled was 2034 (SD: 1 hour 25 minutes) and they were folded up at 0743 (SD: 43 minutes). The rate of interruptions per night observed in all households was 0.23 (86/369), with an average duration of 48 minutes (SD: 49 minutes). There was substantial heterogeneity between households, and some households had consistently poorer adherence relative to others. Variations in bednet use behaviors are a potentially important, and under-researched, component of long-lasting insecticide-treated bednet effectiveness. Remote bednet use monitors can provide novel insights into how bednets are used in practice, helping identify both households at risk of malaria due to poor adherence and also potentially novel targets for improving malaria prevention.
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Affiliation(s)
| | - Data Santorino
- Consortium for Affordable Medical Technologies, Mbarara, Uganda.,Mbarara University of Science and Technology, Mbarara, Uganda
| | - Alfred Agaba
- Mbarara University of Science and Technology, Mbarara, Uganda
| | - Grant Dorsey
- University of California, San Francisco, San Francisco, California
| | - David R Bangsberg
- Oregon Health and Science University-Portland State University School of Public Health, Portland, Oregon
| | - Ryan W Carroll
- Harvard Medical School, Boston, Massachusetts.,Massachusetts General Hospital, Boston, Massachusetts
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Machani MG, Ochomo E, Amimo F, Kosgei J, Munga S, Zhou G, Githeko AK, Yan G, Afrane YA. Resting behaviour of malaria vectors in highland and lowland sites of western Kenya: Implication on malaria vector control measures. PLoS One 2020; 15:e0224718. [PMID: 32097407 PMCID: PMC7041793 DOI: 10.1371/journal.pone.0224718] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 02/04/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Understanding the interactions between increased insecticide resistance and resting behaviour patterns of malaria mosquitoes is important for planning of adequate vector control. This study was designed to investigate the resting behavior, host preference and rates of Plasmodium falciparum infection in relation to insecticide resistance of malaria vectors in different ecologies of western Kenya. METHODS Anopheles mosquito collections were carried out during the dry and rainy seasons in Kisian (lowland site) and Bungoma (highland site), both in western Kenya using pyrethrum spray catches (PSC), mechanical aspiration (Prokopack) for indoor collections, clay pots, pit shelter and Prokopack for outdoor collections. WHO tube bioassay was used to determine levels of phenotypic resistance of indoor and outdoor collected mosquitoes to deltamethrin. PCR-based molecular diagnostics were used for mosquito speciation, genotype for knockdown resistance mutations (1014S and 1014F) and to determine specific host blood meal origins. Enzyme-linked Immunosorbent Assay (ELISA) was used to determine mosquito sporozoite infections. RESULTS Anopheles gambiae s.l. was the most predominant species (75%, n = 2706) followed by An. funestus s.l. (25%, n = 860). An. gambiae s.s hereafter (An. gambiae) accounted for 91% (95% CI: 89-93) and An. arabiensis 8% (95% CI: 6-9) in Bungoma, while in Kisian, An. arabiensis composition was 60% (95% CI: 55-66) and An. gambiae 39% (95% CI: 34-44). The resting densities of An. gambiae s.l and An. funestus were higher indoors than outdoor in both sites (An. gambiae s.l; F1, 655 = 41.928, p < 0.0001, An. funestus; F1, 655 = 36.555, p < 0.0001). The mortality rate for indoor and outdoor resting An. gambiae s.l F1 progeny was 37% (95% CI: 34-39) vs 67% (95% CI: 62-69) respectively in Bungoma. In Kisian, the mortality rate was 67% (95% CI: 61-73) vs 76% (95% CI: 71-80) respectively. The mortality rate for F1 progeny of An. funestus resting indoors in Bungoma was 32% (95% CI: 28-35). The 1014S mutation was only detected in indoor resitng An. arabiensis. Similarly, the 1014F mutation was present only in indoor resting An. gambiae. The sporozoite rates were highest in An. funestus followed by An. gambiae, and An. arabiensis resting indoors at 11% (34/311), 8% (47/618) and 4% (1/27) respectively in Bungoma. Overall, in Bungoma, the sporozoite rate for indoor resting mosquitoes was 9% (82/956) and 4% (8/190) for outdoors. In Kisian, the sporozoite rate was 1% (1/112) for indoor resting An. gambiae. None of the outdoor collected mosquitoes in Kisian tested positive for sporozoite infections (n = 73). CONCLUSION The study reports high indoor resting densities of An. gambiae and An. funestus, insecticide resistance, and persistence of malaria transmission indoors regardless of the use of long-lasting insecticidal nets (LLINs). These findings underline the difficulties of controlling malaria vectors resting and biting indoors using the current interventions. Supplemental vector control tools and implementation of sustainable insecticide resistance management strategies are needed in western Kenya.
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Affiliation(s)
- Maxwell G. Machani
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- School of Health Sciences, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya
| | - Eric Ochomo
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Fred Amimo
- School of Health Sciences, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya
| | - Jackline Kosgei
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California, Irvine, California, United States of America
| | - Andrew K. Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California, Irvine, California, United States of America
| | - Yaw A. Afrane
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Accra, Ghana
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Kudom AA. Entomological surveillance to assess potential outbreak of Aedes-borne arboviruses and insecticide resistance status of Aedes aegypti from Cape Coast, Ghana. Acta Trop 2020; 202:105257. [PMID: 31682813 DOI: 10.1016/j.actatropica.2019.105257] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 10/29/2019] [Accepted: 10/31/2019] [Indexed: 11/26/2022]
Abstract
This study was conducted in Cape Coast, a major tourist destination in Ghana to assess the risk of an outbreak of Aedes-borne arboviruses based on entomological indicators and determine their susceptibility to pyrethroid insecticides. A larval survey was conducted in 414 houses between April and July 2017. Larvae collected were reared to adult for WHO susceptibility bioassay against four pyrethroid insecticides (Deltamethrin 0.05%, Permethrin 0.75%, Cyfluthrin 0.15%, Etofenprox 0.5%) and three different brands of mosquito coil; Heaven® (Dimefluthrin 0.03%), Sasso® (Esbiothrin 0.25%), and Fastkit® (D-allethrin 0.25%) as well as four enzyme-activities and F1534C kdr-mutation. Some physicochemical parameters were also measured in Aedes breeding sites. Three larval indices and water quality index (WQI) were calculated. The estimated larval indices were: House index - 68%, Container index - 44%, and Breteau index - 2.4. The level of resistance of the vector to the different pyrethroid insecticides and mosquito coils varied. F1534C kdr-mutation with an allele frequency of 35% and metabolic detoxifying enzyme activities are suspected to be the cause of resistance. Ae. aegypti breeding sites were found to contain organic and other anthropogenic pollutants. Based on the larval indices estimated, the population density of Ae. aegypti in Cape Coast was found to be sufficient to promote an outbreak of arboviruses. Pyrethroid resistance in the vector population could compromise the effectiveness of pyrethroid-based control strategies as was seen with the reduced efficacy of mosquito coils. With large number of international travellers to the city, there is a need to put in place a regular Aedes surveillance program for early response to any potential outbreaks.
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Pesticides and the evolution of the genetic structure of Anopheles coluzzii populations in some localities in Benin (West Africa). Malar J 2019; 18:407. [PMID: 31805939 PMCID: PMC6896764 DOI: 10.1186/s12936-019-3036-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 11/26/2019] [Indexed: 01/25/2023] Open
Abstract
Background Changes in the natural habitats of insect groups are determined the genetic polymorphisms between individuals. The objective of this study was to establish the genetic structure of the Anopheles coluzzii populations in four localities of Benin. Methods Insecticide surveys and larval sampling were conducted on 4 study localities, including Cotonou, Ketou, Zagnanado, and Sô-Ava. Molecular characterizations were performed on the Anopheles mosquitoes collected with the allelic and genotypic frequencies of kdr gene determined. The multiple comparison Chi square test for proportions was performed with R version 3.3.3. Next, the observed heterozygosity, expected heterozygosity, and indices of fixation, and genetic differentiation were estimated. Finally, the Hardy–Weinberg equilibrium (EHW) was determined to assess whether panmixia exists in the different populations of mosquitoes of the agroecological zones under study. Results Carbamates, pyrethroids, organophosphorus and organochlorines use have been reported in all localities except Sô-Ava. Anopheles coluzzii was strongly represented across all study localities. The L1014F allele was observed in the localities of Kétou, Cotonou and Zagnanado. Likewise, insecticide selection pressure of homozygous resistant individuals (L1014F/L1014F) was significantly higher in Kétou, Cotonou and Zagnanado (p value < 0.05). Surprisingly in Sô-Ava, a relatively high frequency of the L1014F allele despite the reported absence of pesticide use was observed. All mosquito populations were found to be deficient in heterozygosity across the study sites (FIS< 0). No genetic differentiation (FST< 0) was observed in the localities of Zagnanado and Kétou. Conclusion The survey on the use of insecticides showed that insecticide selection pressures differ across the investigated localities. It would be desirable to rotate or apply formulations of combined products with different modes of action. Doing so would enable a better management of resistant homozygous individuals, and mitigate the resistance effect of commonly used insecticides.
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Lovett B, Bilgo E, Diabate A, St Leger R. A review of progress toward field application of transgenic mosquitocidal entomopathogenic fungi. PEST MANAGEMENT SCIENCE 2019; 75:2316-2324. [PMID: 30801913 DOI: 10.1002/ps.5385] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/02/2019] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
In Africa, adult mosquito populations are primarily controlled with insecticide-impregnated bed nets and residual insecticide sprays. This coupled with widespread applications of pesticides in agriculture has led to increasing insecticide resistance in mosquito populations. We have developed multiple alternative strategies for exploiting transgenic Metarhizium spp. directed at: (i) shortening the lifespan of adult mosquitoes; (ii) reducing transmission potential of Plasmodium spp.; (iii) reducing vector competence via pre-lethal effects. The present challenge is to convert this promising strategy into a validated public health intervention by resolving outstanding issues related to the release of genetically modified organisms. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Brian Lovett
- Department of Entomology, University of Maryland, College Park, MD, USA
| | - Etienne Bilgo
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Raymond St Leger
- Department of Entomology, University of Maryland, College Park, MD, USA
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Muhindo MK, Jagannathan P, Kakuru A, Opira B, Olwoch P, Okiring J, Nalugo N, Clark TD, Ruel T, Charlebois E, Feeney ME, Havlir DV, Dorsey G, Kamya MR. Intermittent preventive treatment with dihydroartemisinin-piperaquine and risk of malaria following cessation in young Ugandan children: a double-blind, randomised, controlled trial. THE LANCET. INFECTIOUS DISEASES 2019; 19:962-972. [PMID: 31307883 DOI: 10.1016/s1473-3099(19)30299-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/21/2019] [Accepted: 04/24/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Intermittent preventive treatment (IPT) of malaria with dihydroartemisinin-piperaquine is a promising strategy for malaria prevention in young African children. However, the optimal dosing strategy is unclear and conflicting evidence exists regarding the risk of malaria after cessation of chemoprevention. We aimed to compare two dosing strategies of IPT with dihydroartemisinin-piperaquine in young Ugandan children, and to evaluate the risk of malaria after cessation of IPT. METHODS In this double-blind, randomised controlled phase 2 trial, women and their unborn children were recruited at Tororo District Hospital (Tororo, Uganda). Eligible participants were HIV-negative women aged 16 years or older with a viable pregnancy (gestational age 12-20 weeks). Women and their unborn children were randomly assigned (1:1:1:1) to one of four treatment groups, all receiving dihydroartemisinin-piperaquine, on the basis of the IPT intervention received by the woman during pregnancy: women every 8 weeks, children every 4 weeks; women every 4 weeks, children every 4 weeks; women every 8 weeks, children every 12 weeks; and women every 4 weeks, children every 12 weeks. Block randomisation was done by an independent investigator using a computer-generated randomisation list (permuted block sizes of six and 12). We analysed children on the basis of their random assignment to receive dihydroartemisinin-piperaquine (20 mg/160 mg tablets) once daily for 3 consecutive days every 4 weeks or 12 weeks. Children received study drugs from age 8 weeks to 24 months and were followed-up to age 36 months. Participants and investigators were masked to treatment allocation. The primary outcome was the incidence of symptomatic malaria during the intervention and following cessation of the intervention, adjusted for potential confounders. The primary outcome and safety were assessed in the modified intention-to-treat population, which included all children who reached 8 weeks of age and received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, number NCT02163447. FINDINGS Between Oct 21, 2014, and May 18, 2015, 191 children were born, of whom 183 reached 8 weeks of age and received at least one dose of study drug and thus were included in the primary analysis (96 children in the 4-week group and 87 in the 12-week group). During the intervention, the incidence of symptomatic malaria was significantly lower among children treated every 4 weeks than children treated every 12 weeks; three episodes occurred among children treated every 4 weeks (incidence 0·018 episodes per person-year) compared with 61 episodes among children treated every 12 weeks (incidence 0·39 episodes per person-year; adjusted incidence rate ratio [aIRR] 0·041, 95% CI 0·012-0·150, p<0·0001). After cessation of IPT, children who had previously received dihydroartemisinin-piperaquine every 4 weeks had a lower incidence of symptomatic malaria than children who were treated every 12 weeks; 62 episodes occurred among children previously treated every 4 weeks (incidence 0·73 episodes per person-year) compared with 83 episodes among children treated every 12 weeks (incidence 1·1 episodes per person-year; aIRR 0·62, 0·40-0·95, p=0·028). In the 4-week group, 94 (98%) of 96 children had adverse events versus 87 (100%) of 87 children in the 12-week group. The most commonly reported adverse event was cough in both treatment groups (94 [98%] in the 4-week group vs 87 [100%] in the 12-week group). 16 children had severe adverse events (seven [7%] children in the 4-week group vs nine [10%] children in the 12-week group). No severe adverse events were thought to be related to study drug administration. One death occurred during the intervention (age 8 weeks to 24 months), which was due to respiratory failure unrelated to malaria. INTERPRETATION IPT with dihydroartemisinin-piperaquine given every 4 weeks was superior to treatment every 12 weeks for the prevention of malaria during childhood, and this protection was extended for up to 1 year after cessation of IPT. FUNDING Eunice Kennedy Shriver National Institute of Child Health and Human Development.
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Affiliation(s)
- Mary K Muhindo
- Infectious Diseases Research Collaboration, Kampala, Uganda.
| | | | - Abel Kakuru
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Bishop Opira
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Peter Olwoch
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Jaffer Okiring
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Noeline Nalugo
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Tamara D Clark
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Theodore Ruel
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Edwin Charlebois
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Margaret E Feeney
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA; Department of Pediatrics, University of California, San Francisco, San Francisco, CA, USA
| | - Diane V Havlir
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda; School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
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Cappelli A, Valzano M, Cecarini V, Bozic J, Rossi P, Mensah P, Amantini C, Favia G, Ricci I. Killer yeasts exert anti-plasmodial activities against the malaria parasite Plasmodium berghei in the vector mosquito Anopheles stephensi and in mice. Parasit Vectors 2019; 12:329. [PMID: 31266522 PMCID: PMC6604151 DOI: 10.1186/s13071-019-3587-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 06/27/2019] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Wickerhamomyces anomalus is a yeast associated with different insects including mosquitoes, where it is proposed to be involved in symbiotic relationships with hosts. Different symbiotic strains of W. anomalus display a killer phenotype mediated by protein toxins with broad-spectrum antimicrobial activities. In particular, a killer toxin purified from a W. anomalus strain (WaF17.12), previously isolated from the malaria vector mosquito Anopheles stephensi, has shown strong in vitro anti-plasmodial activity against early sporogonic stages of the murine malaria parasite Plasmodium berghei. RESULTS Here, we provide evidence that WaF17.12 cultures, properly stimulated to induce the expression of the killer toxin, can directly affect in vitro P. berghei early sporogonic stages, causing membrane damage and parasite death. Moreover, we demonstrated by in vivo studies that mosquito dietary supplementation with activated WaF17.12 cells interfere with ookinete development in the midgut of An. stephensi. Besides the anti-sporogonic action of WaF17.12, an inhibitory effect of purified WaF17.12-killer toxin was observed on erythrocytic stages of P. berghei, with a consequent reduction of parasitaemia in mice. The preliminary safety tests on murine cell lines showed no side effects. CONCLUSIONS Our findings demonstrate the anti-plasmodial activity of WaF17.12 against different developmental stages of P. berghei. New studies on P. falciparum are needed to evaluate the use of killer yeasts as innovative tools in the symbiotic control of malaria.
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Affiliation(s)
- Alessia Cappelli
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Matteo Valzano
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Valentina Cecarini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Jovana Bozic
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, FL, USA
| | - Paolo Rossi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Priscilla Mensah
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Consuelo Amantini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Guido Favia
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Irene Ricci
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy.
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Wang Y, Li Y, Shang D, Efferth T. Interactions between artemisinin derivatives and P-glycoprotein. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2019; 60:152998. [PMID: 31301971 DOI: 10.1016/j.phymed.2019.152998] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 06/24/2019] [Accepted: 06/26/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Artemisinin was isolated and identified in 1972, which was the starting point for a new era in antimalarial drug therapy. Furthermore, numerous studies have demonstrated that artemisinin and its derivatives exhibit considerable anticancer activity both in vitro, in vivo, and even in clinical Phase I/II trials. P-glycoprotein (P-gp) mediated multi-drug resistance (MDR) is one of the most serious causes of chemotherapy failure in cancer treatment. Interestingly, many artemisinin derivatives exhibit excellent ability to overcome P-gp mediated MDR and even show collateral sensitivity against MDR cancer cells. Furthermore, some artemisinin derivatives show P-gp-mediated MDR reversal activity. Therefore, the interaction between P-gp and artemisinin derivatives is important to develop novel combination treatment protocols with artemisinin derivatives and established anticancer drugs that are P-gp substrates. PURPOSE This systematic review provides an updated overview on the interaction between artemisinin derivatives and P-gp and the effect of artemisinin derivatives on the P-gp expression level. RESULTS Artemisinin derivatives exhibit multi-specific interactions with P-gp. The currently used artemisinin derivatives are not transported by P-gp. However, some of novel synthetized artemisinin derivatives exhibit P-gp substrate properties. Furthermore, many artemisinin derivatives act as P-gp inhibitors, which exhibit the potential to reverse MDR towards clinically used anticancer drugs. CONCLUSION Therefore, studies on the interaction between artemisinin derivatives and P-gp provide important information for the development of novel anti-cancer artemisinin derivatives to reverse P-gp mediated MDR and for the design of rational artemisinin-based combination therapies against cancer.
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Affiliation(s)
- Yulin Wang
- College of Pharmacy, Dalian Medical University, Dalian 116044, China
| | - Yongjie Li
- Department of Chinese Medicine, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, China
| | - Dong Shang
- Clinical Laboratory of Integrative Medicine, First Affiliated Hospital of Dalian Medical University, Dalian China; College of Integrative Medicine, Dalian Medical University, Dalian, China.
| | - Thomas Efferth
- Department of Pharmaceutical Biology, Institute of Pharmacy, Johannes Gutenberg University 55128 Mainz, Germany.
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Apinjoh TO, Ouattara A, Titanji VPK, Djimde A, Amambua-Ngwa A. Genetic diversity and drug resistance surveillance of Plasmodium falciparum for malaria elimination: is there an ideal tool for resource-limited sub-Saharan Africa? Malar J 2019; 18:217. [PMID: 31242921 PMCID: PMC6595576 DOI: 10.1186/s12936-019-2844-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 06/18/2019] [Indexed: 12/20/2022] Open
Abstract
The intensification of malaria control interventions has resulted in its global decline, but it remains a significant public health burden especially in sub-Saharan Africa (sSA). Knowledge on the parasite diversity, its transmission dynamics, mechanisms of adaptation to environmental and interventional pressures could help refine or develop new control and elimination strategies. Critical to this is the accurate assessment of the parasite’s genetic diversity and monitoring of genetic markers of anti-malarial resistance across all susceptible populations. Such wide molecular surveillance will require selected tools and approaches from a variety of ever evolving advancements in technology and the changing epidemiology of malaria. The choice of an effective approach for specific endemic settings remains challenging, particularly for countries in sSA with limited access to advanced technologies. This article examines the current strategies and tools for Plasmodium falciparum genetic diversity typing and resistance monitoring and proposes how the different tools could be employed in resource-poor settings. Advanced approaches enabling targeted deep sequencing is valued as a sensitive method for assessing drug resistance and parasite diversity but remains out of the reach of most laboratories in sSA due to the high cost of development and maintenance. It is, however, feasible to equip a limited number of laboratories as Centres of Excellence in Africa (CEA), which will receive and process samples from a network of peripheral laboratories in the continent. Cheaper, sensitive and portable real-time PCR methods can be used in peripheral laboratories to pre-screen and select samples for targeted deep sequence or genome wide analyses at these CEAs.
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Affiliation(s)
- Tobias O Apinjoh
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, Cameroon
| | - Amed Ouattara
- School of Medicine, University of Maryland, College Park, Baltimore, USA
| | - Vincent P K Titanji
- Faculty of Science, Engineering and Technology, Cameroon Christian University, Bali, Cameroon
| | - Abdoulaye Djimde
- Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
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Opondo KO, Jawara M, Cham S, Jatta E, Jarju L, Camara M, Sanneh F, Gaye PM, Jadama L, Ceesay S, Njie E, Assogba BS, Kandeh B, D'Alessandro U. Status of insecticide resistance in Anopheles gambiae (s.l.) of The Gambia. Parasit Vectors 2019; 12:287. [PMID: 31164149 PMCID: PMC6549352 DOI: 10.1186/s13071-019-3538-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 05/27/2019] [Indexed: 11/10/2022] Open
Abstract
Background Vector control activities, namely long-lasting insecticidal nets (LLIN) and indoor residual spraying (IRS), have contributed significantly to the decreasing malaria burden observed in The Gambia since 2008. Nevertheless, insecticide resistance may threaten such success; it is important to regularly assess the susceptibility of local malaria vectors to available insecticides. Methods In the transmission seasons of 2016 and 2017, Anopheles gambiae (s.l.) larvae were sampled in or around the nine vector surveillance sentinel sites of the Gambia National Malaria Control Programme (GNMCP) and in a few additional sampling points. Using WHO susceptibility bioassays, female adult mosquitoes were exposed to insecticide-impregnated papers. Molecular identification of sibling species and insecticide resistance molecular markers was done on a subset of 2000 female mosquitoes. Results A total of 4666 wild-caught female adult mosquitoes were exposed to either permethrin (n = 665), deltamethrin (n = 744), DDT (n = 1021), bendiocarb (n = 990) or pirimiphos-methyl (n = 630) insecticide-impregnated papers and control papers (n = 616). Among the 2000 anophelines, 1511 (80.7%) were Anopheles arabiensis, 204 (10.9%) Anopheles coluzzii, 75 (4%) Anopheles gambiae (s.s.), and 83 (4.4%) An. gambiae (s.s.) and An. coluzzii hybrids. There was a significant variation in the composition and species distribution by regions and year, P = 0.009. Deltamethrin, permethrin and DDT resistance was found in An. arabiensis, especially in the coastal region, and was mediated by Vgsc-1014F/S mutations (odds ratio = 34, P = 0.014). There was suspected resistance to pirimiphos-methyl (actellic 300CS) in the North Bank Region although only one survivor had the Ace-1-119S mutation. Conclusions As no confirmed resistance to bendiocarb and actellic 300CS was detected, the national malaria control programme can continue using these insecticides for IRS. Nevertheless, the detection of Ace-1 119S mutation warrants extensive monitoring. The source of insecticide pressure driving insecticide resistance to pyrethroids and DDT detected at the coastal region should be further investigated in order to properly manage the spread of resistance in The Gambia. Electronic supplementary material The online version of this article (10.1186/s13071-019-3538-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kevin Ochieng' Opondo
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia.
| | - Musa Jawara
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Saihou Cham
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia.,School of Arts and Sciences, University of Gambia, Banjul, The Gambia
| | - Ebrima Jatta
- Ministry of Health, The Gambia National Malaria Control Programme, Banjul, The Gambia
| | - Lamin Jarju
- Ministry of Health, The Gambia National Malaria Control Programme, Banjul, The Gambia
| | - Muhammed Camara
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Fatou Sanneh
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Pa Modou Gaye
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Lamin Jadama
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Sainey Ceesay
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Ebrima Njie
- School of Arts and Sciences, University of Gambia, Banjul, The Gambia
| | - Benoit Sessinou Assogba
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Balla Kandeh
- Ministry of Health, The Gambia National Malaria Control Programme, Banjul, The Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
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Guerra Mendoza Y, Garric E, Leach A, Lievens M, Ofori-Anyinam O, Pirçon JY, Stegmann JU, Vandoolaeghe P, Otieno L, Otieno W, Owusu-Agyei S, Sacarlal J, Masoud NS, Sorgho H, Tanner M, Tinto H, Valea I, Mtoro AT, Njuguna P, Oneko M, Otieno GA, Otieno K, Gesase S, Hamel MJ, Hoffman I, Kaali S, Kamthunzi P, Kremsner P, Lanaspa M, Lell B, Lusingu J, Malabeja A, Aide P, Akoo P, Ansong D, Asante KP, Berkley JA, Adjei S, Agbenyega T, Agnandji ST, Schuerman L. Safety profile of the RTS,S/AS01 malaria vaccine in infants and children: additional data from a phase III randomized controlled trial in sub-Saharan Africa. Hum Vaccin Immunother 2019; 15:2386-2398. [PMID: 31012786 PMCID: PMC6816384 DOI: 10.1080/21645515.2019.1586040] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A phase III, double-blind, randomized, controlled trial (NCT00866619) in sub-Saharan Africa showed RTS,S/AS01 vaccine efficacy against malaria. We now present in-depth safety results from this study. 8922 children (enrolled at 5–17 months) and 6537 infants (enrolled at 6–12 weeks) were 1:1:1-randomized to receive 4 doses of RTS,S/AS01 (R3R) or non-malaria control vaccine (C3C), or 3 RTS,S/AS01 doses plus control (R3C). Aggregate safety data were reviewed by a multi-functional team. Severe malaria with Blantyre Coma Score ≤2 (cerebral malaria [CM]) and gender-specific mortality were assessed post-hoc. Serious adverse event (SAE) and fatal SAE incidences throughout the study were 24.2%–28.4% and 1.5%–2.5%, respectively across groups; 0.0%–0.3% of participants reported vaccination-related SAEs. The incidence of febrile convulsions in children was higher during the first 2–3 days post-vaccination with RTS,S/AS01 than with control vaccine, consistent with the time window of post-vaccination febrile reactions in this study (mostly the day after vaccination). A statistically significant numerical imbalance was observed for meningitis cases in children (R3R: 11, R3C: 10, C3C: 1) but not in infants. CM cases were more frequent in RTS,S/AS01-vaccinated children (R3R: 19, R3C: 24, C3C: 10) but not in infants. All-cause mortality was higher in RTS,S/AS01-vaccinated versus control girls (2.4% vs 1.3%, all ages) in our setting with low overall mortality. The observed meningitis and CM signals are considered likely chance findings, that – given their severity – warrant further evaluation in phase IV studies and WHO-led pilot implementation programs to establish the RTS,S/AS01 benefit-risk profile in real-life settings.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Seth Owusu-Agyei
- Kintampo Health Research Center , Kintampo , Ghana.,Diseases Control Department, London School of Hygiene and Tropical Medicine , London , UK
| | - Jahit Sacarlal
- Centro de Investigação em Saúde de Manhiça , Manhiça , Mozambique.,Faculdade de Medicina, Universidade Eduardo Mondlane (UEM) , Maputo , Mozambique
| | - Nahya Salim Masoud
- Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam and Ifakara Health Institute , Bagamoyo , Tanzania
| | - Hermann Sorgho
- Institut de Recherche en Science de la Santé , Nanoro , Burkina Faso
| | - Marcel Tanner
- Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam and Ifakara Health Institute , Bagamoyo , Tanzania.,Swiss Tropical and Public Health Institute , Basel , Switzerland.,Epidemiology and Medical Parasitology department, University of Basel , Basel , Switzerland
| | - Halidou Tinto
- Institut de Recherche en Science de la Santé , Nanoro , Burkina Faso
| | - Innocent Valea
- Institut de Recherche en Science de la Santé , Nanoro , Burkina Faso
| | - Ali Takadir Mtoro
- Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam and Ifakara Health Institute , Bagamoyo , Tanzania
| | - Patricia Njuguna
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research , Kilifi , Kenya.,Pwani University , Kilifi , Kenya.,University of Oxford , Oxford , UK
| | - Martina Oneko
- Kenya Medical Research Institute, Centre for Global Health Research , Kisumu , Kenya
| | | | - Kephas Otieno
- Kenya Medical Research Institute, Centre for Global Health Research , Kisumu , Kenya
| | - Samwel Gesase
- National Institute for Medical Research , Korogwe , Tanzania
| | - Mary J Hamel
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention , Atlanta , GA , USA
| | - Irving Hoffman
- University of North Carolina Project , Lilongwe , Malawi
| | - Seyram Kaali
- Kintampo Health Research Center , Kintampo , Ghana
| | | | - Peter Kremsner
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen , Tübingen , Germany
| | - Miguel Lanaspa
- Centro de Investigação em Saúde de Manhiça , Manhiça , Mozambique.,Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona , Barcelona , Spain
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen , Tübingen , Germany
| | - John Lusingu
- National Institute for Medical Research , Korogwe , Tanzania
| | | | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça , Manhiça , Mozambique.,National Institute of Health, Ministry of Health , Maputo , Mozambique
| | - Pauline Akoo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research , Kilifi , Kenya
| | - Daniel Ansong
- Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | | | - James A Berkley
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research , Kilifi , Kenya.,University of Oxford , Oxford , UK
| | - Samuel Adjei
- Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | - Tsiri Agbenyega
- Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen , Tübingen , Germany
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Debalke S, Habtewold T, Duchateau L, Christophides GK. The effect of silencing immunity related genes on longevity in a naturally occurring Anopheles arabiensis mosquito population from southwest Ethiopia. Parasit Vectors 2019; 12:174. [PMID: 30992084 PMCID: PMC6469062 DOI: 10.1186/s13071-019-3414-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 03/27/2019] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Vector control remains the most important tool to prevent malaria transmission. However, it is now severely constrained by the appearance of physiological and behavioral insecticide resistance. Therefore, the development of new vector control tools is warranted. Such tools could include immunization of blood hosts of vector mosquitoes with mosquito proteins involved in midgut homeostasis (anti-mosquito vaccines) or genetic engineering of mosquitoes that can drive population-wide knockout of genes producing such proteins to reduce mosquito lifespan and malaria transmission probability. METHODS To achieve this, candidate genes related to midgut homeostasis regulation need to be assessed for their effect on mosquito survival. Here, different such candidate genes were silenced through dsRNA injection in the naturally occurring Anopheles arabiensis mosquitoes and the effect on mosquito survival was evaluated. RESULTS Significantly higher mortality rates were observed in the mosquitoes silenced for FN3D1 (AARA003032), FN3D3 (AARA007751) and GPRGr9 (AARA003963) genes as compared to the control group injected with dsRNA against a non-related bacterial gene (LacZ). This observed difference in mortality rate between the candidate genes and the control disappeared when gene-silenced mosquitoes were treated with antibiotic mixtures, suggesting that gut microbiota play a key role in the observed reduction of mosquito survival. CONCLUSIONS We demonstrated that interference with the expression of the FN3D1, FN3D3 or GPRGr9 genes causes a significant reduction of the longevity of An. arabiensis mosquito in the wild.
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Affiliation(s)
- Serkadis Debalke
- Department of Medical Laboratory Science & Pathology, Jimma University, Jimma, Ethiopia
- Biometrics Research Group, Ghent University, Ghent, Belgium
| | - Tibebu Habtewold
- Biometrics Research Group, Ghent University, Ghent, Belgium
- Department of Life Sciences, Imperial College London, London, UK
| | - Luc Duchateau
- Biometrics Research Group, Ghent University, Ghent, Belgium
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Witvorapong N, Yakubu KY. Effectiveness of antimalarial interventions in Nigeria: Evidence from facility-level longitudinal data. Health Serv Res 2019; 54:669-677. [PMID: 30740696 DOI: 10.1111/1475-6773.13122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE To evaluate the effectiveness of a program of antimalarial interventions implemented in 2010-2013 in Niger State, Nigeria. DATA SOURCES Utilization reports from 99 intervention and 51 non-intervention health facilities from the Niger State Malaria Elimination Program, supplemented by data on facility-level characteristics from the Niger State Primary Health Care Development Agency and Local Government Malaria Control units. STUDY DESIGN Estimated with mixed-effects negative binomial modeling, a difference-in-differences method was used to quantify the impact of the program on the number of febrile illness cases and confirmed malaria cases. Potential confounding factors, non-stationarity, seasonality, and autocorrelation were explicitly accounted for. DATA EXTRACTION METHODS Data were retrieved from hard copies of utilization reports and manually inputted to create a panel of 5550 facility-month observations. PRINCIPAL FINDINGS The program was implemented in two phases. The first phase (August 2010-June 2012) involved the provision of free artemisinin-based combination therapies, long-lasting insecticidal nets, and intermittent preventive treatments. In the second phase (July 2012-March 2013), the program introduced an additional intervention: free parasite-based rapid diagnostic tests. Compared to the pre-intervention period, the average number of monthly febrile illness and malaria cases increased by 20.876 (P < 0.01) and 22.835 (P < 0.01) in the first phase, and by 19.007 (P < 0.05) and 19.681 (P < 0.05) in the second phase, respectively. The results are consistent across different evaluation methods. CONCLUSIONS This study suggests that user-fee removal leads to increased utilization of antimalarial services. It motivates future studies to cautiously select their investigative methods.
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Affiliation(s)
- Nopphol Witvorapong
- Center for Health Economics, Faculty of Economics, Chulalongkorn University, Pathumwan, Bangkok, Thailand
| | - Kolo Yaro Yakubu
- Strengthening Accountability and Quality Improvement for Maternal, Newborn and Child Health Project, Pact Nigeria, Gombe, Nigeria
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Abstract
Vector control has significantly reduced malaria morbidity in many regions of the world where the disease was endemic and is now moving toward malaria elimination. Among the tools available for vector control, the use of long-lasting insecticidal bed nets (LLINs) and indoor residual spraying (IRS) has proved most effective. However, Anopheles mosquitoes are becoming increasingly resistant to insecticides. In this chapter, we describe the main aspects of vector control-with a particular focus on insecticidal products commonly used in vector control as well as on mechanisms of insecticide resistance. We also discuss the impact of insecticide resistance on malaria transmission.
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Strengthening long-lasting insecticidal nets effectiveness monitoring using retrospective analysis of cross-sectional, population-based surveys across sub-Saharan Africa. Sci Rep 2018; 8:17110. [PMID: 30459359 PMCID: PMC6244007 DOI: 10.1038/s41598-018-35353-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 10/25/2018] [Indexed: 02/01/2023] Open
Abstract
Bed nets averted 68% of malaria cases in Africa between 2000 and 2015. However, concerns over insecticide resistance, bed net durability and the effectiveness of long-lasting insecticidal nets (LLIN) are growing. To assess the effectiveness of LLINs of different ages and insecticides against malaria, we conducted a population-based, cross-sectional study using data from 162,963 children younger than 5 years of age participating in 33 Demographic and Health and Malaria Indicator Surveys conducted in 21 countries between 2009 and 2016. We used Bayesian logistic regression to estimate associations between LLIN age, insecticide type, and malaria. Children sleeping under LLINs the previous night experienced 21% lower odds of malaria infection than children who did not (odds ratio [OR] 0.79; 95% Uncertainty Interval [UI] 0.76-0.82). Nets less than one year of age exhibited the strongest protective effect (OR 0.75; 95% UI 0.72-0.79), and protection weakened as net age increased. LLINs containing different insecticides exhibited similar protection (ORdeltamethrin 0.78 [0.75-0.82]; ORpermethrin 0.79 [0.75-0.83]; ORalphacypermethrin 0.85 [0.76-0.94]). Freely-available, population-based surveys can enhance and guide current entomological monitoring amid concerns of insecticide resistance and bed net durability, and be used with locally-collected data to support decisions on LLIN redistribution campaign timing which insecticide to use.
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Niang EHA, Bassene H, Makoundou P, Fenollar F, Weill M, Mediannikov O. First report of natural Wolbachia infection in wild Anopheles funestus population in Senegal. Malar J 2018; 17:408. [PMID: 30400987 PMCID: PMC6219158 DOI: 10.1186/s12936-018-2559-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/30/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Until very recently, Anopheles were considered naturally unable to host Wolbachia, an intracellular bacterium regarded as a potential biological control tool. Their detection in field populations of Anopheles gambiae sensu lato, suggests that they may also be present in many more anopheline species than previously thought. RESULTS Here, is reported the first discovery of natural Wolbachia infections in Anopheles funestus populations from Senegal, the second main malaria vector in Africa. Molecular phylogeny analysis based on the 16S rRNA gene revealed at least two Wolbachia genotypes which were named wAnfu-A and wAnfu-B, according to their close relatedness to the A and B supergroups. Furthermore, both wAnfu genotypes displayed high proximity with wAnga sequences previously described from the An. gambiae complex, with only few nucleotide differences. However, the low prevalence of infection, together with the difficulties encountered for detection, whatever method used, highlights the need to develop an effective and sensitive Wolbachia screening method dedicated to anopheline. CONCLUSIONS The discovery of natural Wolbachia infection in An. funestus, another major malaria vector, may overcome the main limitation of using a Wolbachia-based approach to control malaria through population suppression and/or replacement.
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Affiliation(s)
- El Hadji Amadou Niang
- Aix Marseille Univ, IRD, AP-HM, MEPHI, IHU-Méditerranée Infection, Marseille, France.
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal.
- VITROME, Campus International, UCAD-IRD, Dakar, Senegal.
| | - Hubert Bassene
- VITROME, Campus International, UCAD-IRD, Dakar, Senegal
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, IHU-Méditerranée Infection, Marseille, France
| | - Patrick Makoundou
- Institut des Sciences de l'Evolution (ISEM), CNRS-Université de Montpellier-IRD-EPHE, Montpellier, France
| | - Florence Fenollar
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, IHU-Méditerranée Infection, Marseille, France
| | - Mylène Weill
- Institut des Sciences de l'Evolution (ISEM), CNRS-Université de Montpellier-IRD-EPHE, Montpellier, France
| | - Oleg Mediannikov
- Aix Marseille Univ, IRD, AP-HM, MEPHI, IHU-Méditerranée Infection, Marseille, France
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Moshi IR, Manderson L, Ngowo HS, Mlacha YP, Okumu FO, Mnyone LL. Outdoor malaria transmission risks and social life: a qualitative study in South-Eastern Tanzania. Malar J 2018; 17:397. [PMID: 30373574 PMCID: PMC6206631 DOI: 10.1186/s12936-018-2550-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 10/25/2018] [Indexed: 12/03/2022] Open
Abstract
Background Behaviour changes in mosquitoes from indoor to outdoor biting result in continuing risk of malaria from outdoor activities, including routine household activities and occasional social and cultural practices and gatherings. This study aimed to identify the range of social and cultural gatherings conducted outdoors and their associated risks for mosquito bites. Methods A cross-sectional study was conducted in four villages in the Kilombero Valley from November 2015 to March 2016. Observations, focus group discussions, and key informant interviews were conducted. The recorded data were transcribed and translated from Swahili to English. Thematic content analysis was used to identify perspectives on the importance of various social and cultural gatherings that incidentally expose people to mosquito bites and malaria infection. Results Religious, cultural and social gatherings involving the wider community are conducted outdoors at night till dawn. Celebrations include life course events, religious and cultural ceremonies, such as Holy Communion, weddings, gatherings at Easter and Christmas, male circumcision, and rituals conducted to please the gods and to remember the dead. These celebrations, at which there is minimal use of interventions to prevent bites, contribute to individual satisfaction and social capital, helping to maintain a cohesive society. Bed net use while sleeping outdoors during mourning is unacceptable, and there is minimal use of other interventions, such as topical repellents. Long sleeve clothes are used for protection from mosquito bites but provide less protection. Conclusion Gatherings and celebrations expose people to mosquito bites. Approaches to prevent risks of mosquito bites and disease management need to take into account social, cultural and environmental factors. Area specific interventions may be expensive, yet may be the best approach to reduce risk of infection as endemic countries work towards elimination. Focusing on single interventions will not yield the best outcomes for malaria prevention as social contexts and vector behaviour vary.
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Affiliation(s)
- Irene R Moshi
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Kiko Avenue, Mikocheni, PO Box 78373, Dar es Salaam, United Republic of Tanzania. .,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Johannesburg, South Africa.
| | - Lenore Manderson
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Johannesburg, South Africa
| | - Halfan S Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Kiko Avenue, Mikocheni, PO Box 78373, Dar es Salaam, United Republic of Tanzania
| | - Yeromin P Mlacha
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Kiko Avenue, Mikocheni, PO Box 78373, Dar es Salaam, United Republic of Tanzania.,Swiss Tropical and Public Health Institute (Swiss TPH), Basel, Switzerland.,University of Basel, Basel, Switzerland.,Sokoine University of Agriculture, Pest Management Centre, P.O. Box 3110, Morogoro, Tanzania
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Kiko Avenue, Mikocheni, PO Box 78373, Dar es Salaam, United Republic of Tanzania.,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Johannesburg, South Africa.,Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Ladislaus L Mnyone
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Kiko Avenue, Mikocheni, PO Box 78373, Dar es Salaam, United Republic of Tanzania.,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Johannesburg, South Africa.,Sokoine University of Agriculture, Pest Management Centre, P.O. Box 3110, Morogoro, Tanzania
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Wotodjo AN, Doucoure S, Diagne N, Sarr FD, Parola P, Gaudart J, Sokhna C. Another challenge in malaria elimination efforts: the increase of malaria among adults after the implementation of long-lasting insecticide-treated nets (LLINs) in Dielmo, Senegal. Malar J 2018; 17:384. [PMID: 30359255 PMCID: PMC6203273 DOI: 10.1186/s12936-018-2536-6] [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] [Received: 05/23/2018] [Accepted: 10/20/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The widespread use of artemisinin-based combination therapy (ACT) and long-lasting insecticide-treated nets (LLINs) has led to an impressive decrease of malaria burden these recent years in Africa. However, some new challenges about the future of malaria control and elimination efforts have appeared. Among these challenges, the loss and-or-the only partial acquisition of anti-Plasmodium immunity among exposed populations lead to an increase of the age at risk of malaria. Indeed, older children and adults may become more vulnerable to malaria. Studies about malaria among adults seemed, therefore, important. This study investigated the evolution of malaria morbidity in adults of Dielmo (Senegal) before and after the implementation of LLINs. METHODS From August 2007 to July 2015, a longitudinal study involving adults above 15 years old was carried out in Dielmo, where ACT was introduced in June 2006 and LLINs in July 2008. In July 2011 and August 2014, all LLINs were renewed. The presence of each person in the village was monitored daily. Thick smears associated lately with rapid diagnosis test (RDT) and quantitative polymerase chain reaction methods were performed for all cases of fever. To assess malaria prevalence, thick smears and RDT were performed quarterly in all individuals. Malaria risks factors were assessed using negative binomial regression mixed-model based on person-trimester observations. RESULTS Malaria morbidity among adults has decreased significantly since the implementation of LLINs in Dielmo. However, malaria resurgences have occurred twice during the 7 years of LLINs use. During these malaria resurgences, the overall incidence of malaria among adults was similar to the incidence during the year before the implementation of LLINs (adjusted incidence rate ratio [95% CI] aIRR = 1.04 [0.66-1.64], p = 0.88 and aIRR = 1.16 [0.74-1.80], p = 0.52 during the first and the second malaria resurgence period, respectively). Younger adults were most vulnerable during these malaria upsurges as the incidence of malaria increased significantly among them (χ2 = 5.2; p = 0.02). CONCLUSION Malaria among adults especially younger adults should deserve more attention in the areas where malaria was previously endemic as they became vulnerable probably because of the partial acquisition and-or-the loss of anti-Plasmodium relative immunity and the non regular use of LLINs.
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Affiliation(s)
- Amélé N Wotodjo
- UMR VITROME (Vecteurs-Infections Tropicales et Méditerranéennes) Campus International IRD-UCAD, Dakar, Senegal.
| | - Souleymane Doucoure
- UMR VITROME (Vecteurs-Infections Tropicales et Méditerranéennes) Campus International IRD-UCAD, Dakar, Senegal
| | - Nafissatou Diagne
- UMR VITROME (Vecteurs-Infections Tropicales et Méditerranéennes) Campus International IRD-UCAD, Dakar, Senegal
| | - Fatoumata Diene Sarr
- Unité d'Épidémiologie des maladies Infectieuses, Institut Pasteur de Dakar, Dakar, Senegal
| | - Philipe Parola
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, IHU-Méditerranée Infection, Marseille, France
| | - Jean Gaudart
- Aix Marseille Univ, IRD, INSERM, AP-HM, SESSTIM, BioSTIC, Marseille, France
| | - Cheikh Sokhna
- UMR VITROME (Vecteurs-Infections Tropicales et Méditerranéennes) Campus International IRD-UCAD, Dakar, Senegal.,Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, IHU-Méditerranée Infection, Marseille, France
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Evidence of Insecticide Resistance to Pyrethroids and Bendiocarb in Anopheles funestus from Tsararano, Marovoay District, Madagascar. BIOMED RESEARCH INTERNATIONAL 2018; 2018:5806179. [PMID: 30402485 PMCID: PMC6196927 DOI: 10.1155/2018/5806179] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/17/2018] [Accepted: 09/20/2018] [Indexed: 12/12/2022]
Abstract
Introduction In Madagascar, malaria control relies on the countrywide use of long lasting insecticide treated bed nets (LLINs) and on indoor residual spraying (IRS) in the central highland area as well as a small area on the eastern coast. We tested insecticide resistance mechanisms of Anopheles funestus from Tsararano, a malaria endemic village in the coastal health district of Marovoay. Methods Insecticide susceptibility bioassays were done in July 2017 on first-generation Anopheles funestus (F1) to assess (i) the susceptibility to permethrin (0.05%), deltamethrin (0.05%), DDT (4%), malathion (5%), fenitrothion (1%), and bendiocarb (0.1%); (ii) the effect of preexposure to the piperonyl butoxide (PBO) synergist; and (iii) the enzymatic activities of cytochrome P450, esterases, and glutathione S-transferases (GST). Results Our results demonstrated that An. funestus was phenotypically resistant to pyrethroids and bendiocarb, with a mortality rate (MR) of 33.6% (95%CI: 24.5-43.7%) and 86% (95%CI: 77.6-92.1%), respectively. In contrast, An. funestus were 100% susceptible to DDT and organophosphates (malathion and fenitrothion). Preexposure of An. funestus to PBO synergist significantly restored the susceptibility to bendiocarb (MR=100%) and increased the MR in the pyrethroid group, from 96% (95%CI: 90.0-98.9%) to 100% for deltamethrin and permethrin, respectively (χ2 = 43, df = 3, P< 0.0001). Enzymatic activities of cytochrome P450 and α-esterases were significantly elevated among An. funestus compared with the IPM reference strain (Mann-Whitney U= 30, P<0.0001; U = 145.5, P <0.0001, respectively). No significant differences of β-esterases activities compared to the IPM reference strain were observed (Mann-Whitney U = 392.5, P = 0.08). Conclusion In Tsararano, despite the absence of an IRS programme, there is evidence of high levels of insecticide resistance to pyrethroids and bendiocarb in An.
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Hemingway J. Resistance: A problem without an easy solution. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2018; 151:73-75. [PMID: 30704716 DOI: 10.1016/j.pestbp.2018.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/10/2018] [Indexed: 06/09/2023]
Abstract
Insecticide resistance can no longer be ignored if we are to retain our ability to control many insect borne diseases. We need new public health insecticides, but these must be embedded in real resistance management strategies. Calls for Integrated Vector Management will continue to fail unless the evidence for the use of different interventions is dramatically improved. The donor community will also need to be prepared for the increased cost of effective long-term vector control. This will not happen without advocacy based on solid economic evaluation, which needs to happen before the opportunity to manage resistance becomes impossible.
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Affiliation(s)
- Janet Hemingway
- London School of Hygiene & Tropical Medicine, United Kingdom Pembroke Place, Liverpool L3 5QA, UK.
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Redox state affects fecundity and insecticide susceptibility in Anopheles gambiae. Sci Rep 2018; 8:13054. [PMID: 30158658 PMCID: PMC6115382 DOI: 10.1038/s41598-018-31360-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 08/19/2018] [Indexed: 01/02/2023] Open
Abstract
Redox reactions play a central role in the metabolism of an organism. It is vital to maintain redox homeostasis in response to the fluctuation of redox shift in various biological contexts. NADPH-dependent reducing capacity is one of the key factors contributing to the redox homeostasis. To understand the redox capacity and its impact on mosquito fecundity and susceptibility to insecticides in Anopheles gambiae, we examined the dynamics of elevated oxidative state via induction by paraquat (PQ) and the inhibition of NADPH regeneration by 6-aminonicotinamide (6AN). In naïve conditions, inherent oxidative capacity varies between individuals, as measured by GSSG/GSH ratio. The high GSSG/GSH ratio was negatively correlated with fecundity. Both PQ and 6AN feeding increased GSSG/GSH ratio and elevated protein carbonylation, a marker of oxidative damage. Both pro-oxidants lowered egg production. Co-feeding the pro-oxidants with antioxidant lycopene attenuated the adverse effects on fecundity, implying that oxidative stress was the cause of this phenotype. Pre-feeding with 6AN increased insecticide susceptibility in DDT resistant mosquitoes. These results indicate that oxidative state is delicate in mosquitoes, manipulation of NADPH pool may adversely affect fecundity and insecticide detoxification capacity. This knowledge can be exploited to develop novel vector control strategies targeting fecundity and insecticide resistance.
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Kapesa A, Kweka EJ, Atieli H, Afrane YA, Kamugisha E, Lee MC, Zhou G, Githeko AK, Yan G. The current malaria morbidity and mortality in different transmission settings in Western Kenya. PLoS One 2018; 13:e0202031. [PMID: 30092043 PMCID: PMC6084967 DOI: 10.1371/journal.pone.0202031] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 07/26/2018] [Indexed: 01/17/2023] Open
Abstract
Background Passive surveillance of malaria in health facilities remains vital for implementation of control and elimination programs. It is therefore essential understanding current age profile of clinical malaria morbidity, mortality and presentations in areas with variant infection susceptibility. This study aimed at understanding the current malaria morbidity and mortality in Western Kenya. Methods Surveillance of clinical and asymptomatic parasitological positivity rates of all malaria suspected patients and school children were respectively determined from June 2015 to August 2016. From 2014 to 2016, register books in hospitals were referred and the confirmed malaria cases in conjunction with total number of monthly outpatient visits (OPD) counted. All registered malaria admissions were counted together with other causes of admissions. Moreover, outcome of malaria admissions in terms of discharge or death was recorded using inpatient charts within the same time frame. Prospective surveillance of severe malaria collected information on clinical features of the disease. Giemsa stained blood slides confirmed existence of malaria parasitemia. Chi-square and analysis of variance tests were used, respectively, to compute proportions and means; then a comparison was made between different age groups, periods, and study areas. Results During the survey of asymptomatic infections among school children, overall blood slide positivity ranged from 6.4% at the epidemic prone site to 38.3% at the hyperendemic site. During the clinical malaria survey, school age children (5–14) presented with overall the highest (45%) blood slide positivity rate among those suspected to have the infection at the epidemic prone study site. The survey of all malaria confirmed and registered cases at OPD found 17% to 27% of all consultations among <5 children and 9.9% to 20.7% of all OPD visits among the ≥5 patients were due to malaria. Moreover, survey of all registered causes of admission in hospitals found 47% of admissions were due to malaria. The disease was a major cause of admission in epidemic prone setting where 63.4% of the <5 children and 62.8% of the ≥5 patients were admitted due to malaria (p>0.05) and 40% of all malaria admissions were school age children. Malaria related death rate was highest among <5 years at the hyperendemic site, that is 60.9 death per 1000 malaria <5 admissions. Conversely, the epidemic prone setting experienced highest malaria related death among ≥15 years (18.6 death per 1000 admissions) than the < 15 years (5.7 death per 1000 admissions of the <15 years) (p< 0.001). Surveillance of severe form of the disease found that hyperpyrexia, hyperparastemia, prostration and convulsions as common presentations of severe disease. Conclusion Malaria is still the major cause of hospital consultations in Western Kenya with an alarming number of severe forms of the disease among the school aged children at the epidemic prone setting. Mortalities were higher among <5 children years in high infection transmission setting and among ≥15 years in low and moderate transmission settings. Surveillance of asymptomatic and symptomatic malaria along with evaluation of current interventions in different age groups should be implemented in Kenya.
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Affiliation(s)
- Anthony Kapesa
- Climate and Health Laboratory, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- Department of Community Medicine, School of Public Health, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
- * E-mail: (AK); (GY)
| | - Eliningaya J. Kweka
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
- Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, Arusha, Tanzania
| | - Harrysone Atieli
- Climate and Health Laboratory, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Yaw A. Afrane
- Climate and Health Laboratory, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Erasmus Kamugisha
- Department of Biochemistry and Molecular Biology, School of Medicine, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Ming-Chieh Lee
- Program in Public Health, University of California, Irvine, CA, United States of America
| | - Guofa Zhou
- Program in Public Health, University of California, Irvine, CA, United States of America
| | - Andrew K. Githeko
- Climate and Health Laboratory, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, United States of America
- * E-mail: (AK); (GY)
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Lawrence N, Dennis ASM, Lehane AM, Ehmann A, Harvey PJ, Benfield AH, Cheneval O, Henriques ST, Craik DJ, McMorran BJ. Defense Peptides Engineered from Human Platelet Factor 4 Kill Plasmodium by Selective Membrane Disruption. Cell Chem Biol 2018; 25:1140-1150.e5. [PMID: 30033131 DOI: 10.1016/j.chembiol.2018.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 06/01/2018] [Accepted: 06/25/2018] [Indexed: 11/29/2022]
Abstract
Malaria is a serious threat to human health and additional classes of antimalarial drugs are greatly needed. The human defense protein, platelet factor 4 (PF4), has intrinsic antiplasmodial activity but also undesirable chemokine properties. We engineered a peptide containing the isolated PF4 antiplasmodial domain, which through cyclization, retained the critical structure of the parent protein. The peptide, cPF4PD, killed cultured blood-stage Plasmodium falciparum with low micromolar potency by specific disruption of the parasite digestive vacuole. Its mechanism of action involved selective penetration and accumulation inside the intraerythrocytic parasite without damaging the host cell or parasite membranes; it did not accumulate in uninfected cells. This selective activity was accounted for by observations of the peptide's specific binding and penetration of membranes with exposed negatively charged phospholipid headgroups. Our findings highlight the tremendous potential of the cPF4PD scaffold for developing antimalarial peptide drugs with a distinct and selective mechanism of action.
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Affiliation(s)
- Nicole Lawrence
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Adelaide S M Dennis
- Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
| | - Adele M Lehane
- Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
| | - Anna Ehmann
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia
| | - Peta J Harvey
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Aurélie H Benfield
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Olivier Cheneval
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Brendan J McMorran
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia.
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Ridley DB, Moe JL, Hamon N. A Voucher System To Speed Review Could Promote A New Generation Of Insecticides To Fight Vector-Borne Diseases. Health Aff (Millwood) 2018; 36:1461-1468. [PMID: 28784739 DOI: 10.1377/hlthaff.2016.1640] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Many in the scientific community are concerned about the potential increase in prevalence of insect-borne diseases such as Chagas disease, Chikungunya, dengue fever, malaria, and Zika in the United States and around the world. Beyond vaccines and drugs to prevent and treat these diseases, a comprehensive approach to fighting these diseases should include control of disease-carrying vectors, such as mosquitoes. Vector-control methods, such as using insecticides to treat bed nets and spray the walls of homes, have prevented millions of deaths from malaria. However, mosquitoes are becoming resistant to insecticides, and no new class of insecticides for vector control has been introduced in decades. We recommend the creation of a new type of incentive for the development and commercialization of safe new insecticides: a Vector Expedited Review Voucher, to be awarded to a sponsor that introduces a novel insecticide for public health use. The voucher could be redeemed to expedite registration of a second, more profitable, product by the US Environmental Protection Agency.
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Affiliation(s)
- David B Ridley
- David B. Ridley is faculty director of health sector management at the Fuqua School of Business, Duke University, in Durham, North Carolina
| | - Jeffrey L Moe
- Jeffrey L. Moe is a professor of the practice of global health at the Duke Global Health Institute, in Durham
| | - Nick Hamon
- Nick Hamon is CEO of the Innovative Vector Control Consortium, in Liverpool, United Kingdom
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Laroche M, Bérenger JM, Delaunay P, Charrel R, Pradines B, Berger F, Ranque S, Bitam I, Davoust B, Raoult D, Parola P. Medical Entomology: A Reemerging Field of Research to Better Understand Vector-Borne Infectious Diseases. Clin Infect Dis 2018; 65:S30-S38. [PMID: 28859353 DOI: 10.1093/cid/cix463] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In the last decade, the Chikungunya and Zika virus outbreaks have turned public attention to the possibility of the expansion of vector-borne infectious diseases worldwide. Medical entomology is focused on the study of arthropods involved in human health. We review here some of the research approaches taken by the medical entomology team of the University Hospital Institute (UHI) Méditerranée Infection of Marseille, France, with the support of recent or representative studies. We propose our approaches to technical innovations in arthropod identification and the detection of microorganisms in arthropods, the use of arthropods as epidemiological or diagnostic tools, entomological investigations around clinical cases or within specific populations, and how we have developed experimental models to decipher the interactions between arthropods, microorganisms, and humans.
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Affiliation(s)
- Maureen Laroche
- Aix Marseille Université, CNRS 7278, IRD 198 (Dakar, Sénégal), Inserm 1095, Assistance Publique-Hôpitaux de Marseille (AP-HM), Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), IHU Méditerranée Infection, Marseille
| | - Jean-Michel Bérenger
- Aix Marseille Université, CNRS 7278, IRD 198 (Dakar, Sénégal), Inserm 1095, Assistance Publique-Hôpitaux de Marseille (AP-HM), Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), IHU Méditerranée Infection, Marseille
| | - Pascal Delaunay
- Service de Parasitologie-Mycologie, Hôpital de l'Archet, Centre Hospitalier Universitaire de Nice, Inserm U1065, Centre Méditerranéen de Médecine Moléculaire, Université de Nice-Sophia Antipolis
| | - Remi Charrel
- UMR "Emergence des Pathologies Virales" (EPV: Aix-Marseille Université, IRD 190, Inserm 1207, EHESP), AP-HM, IHU Méditerranée Infection
| | - Bruno Pradines
- Aix Marseille Université, CNRS 7278, IRD 198 (Dakar, Sénégal), Inserm 1095, Assistance Publique-Hôpitaux de Marseille ( AP-HM), Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), IHU Méditerranée Infection, Marseille.,Unité Parasitologie et Entomologie, Institut de Recherche Biomédicale des Armées.,Centre National de Référence du Paludisme
| | - Franck Berger
- GSBDD Marseille-Aubagne, Centre d'épidémiologie et de santé publique des armées, Marseille, France
| | - Stéphane Ranque
- Aix Marseille Université, CNRS 7278, IRD 198 (Dakar, Sénégal), Inserm 1095, Assistance Publique-Hôpitaux de Marseille (AP-HM), Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), IHU Méditerranée Infection, Marseille
| | - Idir Bitam
- Laboratoire Biodiversité et Environnement: Interactions Génomes, Faculté des Sciences Biologiques Université des Sciences et de la Technologie Houari Boumediene, Bab Ezzouar, Algeria
| | - Bernard Davoust
- Aix Marseille Université, CNRS 7278, IRD 198 (Dakar, Sénégal), Inserm 1095, Assistance Publique-Hôpitaux de Marseille (AP-HM), Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), IHU Méditerranée Infection, Marseille
| | - Didier Raoult
- Aix Marseille Université, CNRS 7278, IRD 198 (Dakar, Sénégal), Inserm 1095, Assistance Publique-Hôpitaux de Marseille (AP-HM), Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), IHU Méditerranée Infection, Marseille
| | - Philippe Parola
- Aix Marseille Université, CNRS 7278, IRD 198 (Dakar, Sénégal), Inserm 1095, Assistance Publique-Hôpitaux de Marseille (AP-HM), Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), IHU Méditerranée Infection, Marseille
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