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Agboka KM, Wamalwa M, Mutunga JM, Tonnang HEZ. A mathematical model for mapping the insecticide resistance trend in the Anopheles gambiae mosquito population under climate variability in Africa. Sci Rep 2024; 14:9850. [PMID: 38684842 PMCID: PMC11059405 DOI: 10.1038/s41598-024-60555-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 04/24/2024] [Indexed: 05/02/2024] Open
Abstract
The control of arthropod disease vectors using chemical insecticides is vital in combating malaria, however the increasing insecticide resistance (IR) poses a challenge. Furthermore, climate variability affects mosquito population dynamics and subsequently IR propagation. We present a mathematical model to decipher the relationship between IR in Anopheles gambiae populations and climate variability. By adapting the susceptible-infected-resistant (SIR) framework and integrating temperature and rainfall data, our model examines the connection between mosquito dynamics, IR, and climate. Model validation using field data achieved 92% accuracy, and the sensitivity of model parameters on the transmission potential of IR was elucidated (e.g. μPRCC = 0.85958, p-value < 0.001). In this study, the integration of high-resolution covariates with the SIR model had a significant impact on the spatial and temporal variation of IR among mosquito populations across Africa. Importantly, we demonstrated a clear association between climatic variability and increased IR (width = [0-3.78], α = 0.05). Regions with high IR variability, such as western Africa, also had high malaria incidences thereby corroborating the World Health Organization Malaria Report 2021. More importantly, this study seeks to bolster global malaria combat strategies by highlighting potential IR 'hotspots' for targeted intervention by National malria control programmes.
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Affiliation(s)
- Komi Mensah Agboka
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772 00100, Nairobi, Kenya.
| | - Mark Wamalwa
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772 00100, Nairobi, Kenya
| | - James Mutuku Mutunga
- School of Engineering Design and Innovation Pennsylvania State University, University Park, PA, 16802, USA
| | - Henri E Z Tonnang
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772 00100, Nairobi, Kenya.
- School of Agricultural, Earth, and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, 3209, South Africa.
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Gómez M, Martínez D, Páez-Triana L, Luna N, Ramírez A, Medina J, Cruz-Saavedra L, Hernández C, Castañeda S, Bohórquez Melo R, Suarez LA, Palma-Cuero M, Murcia LM, González Páez L, Estrada Bustos L, Medina MA, Ariza Campo K, Padilla HD, Zamora Flórez A, De las Salas JL, Muñoz M, Ramírez JD. Influence of dengue virus serotypes on the abundance of Aedes aegypti insect-specific viruses (ISVs). J Virol 2024; 98:e0150723. [PMID: 38095414 PMCID: PMC10804971 DOI: 10.1128/jvi.01507-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/13/2023] [Indexed: 01/24/2024] Open
Abstract
A comprehensive understanding of the virome in mosquito vectors is crucial for assessing the potential transmission of viral agents, designing effective vector control strategies, and advancing our knowledge of insect-specific viruses (ISVs). In this study, we utilized Oxford Nanopore Technologies metagenomics to characterize the virome of Aedes aegypti mosquitoes collected in various regions of Colombia, a country hyperendemic for dengue virus (DENV). Analyses were conducted on groups of insects with previous natural DENV infection (DENV-1 and DENV-2 serotypes), as well as mosquito samples that tested negative for virus infection (DENV-negative). Our findings indicate that the Ae. aegypti virome exhibits a similar viral composition at the ISV family and species levels in both DENV-positive and DENV-negative samples across all study sites. However, differences were observed in the relative abundance of viral families such as Phenuiviridae, Partitiviridae, Flaviviridae, Rhabdoviridae, Picornaviridae, Bromoviridae, and Virgaviridae, depending on the serotype of DENV-1 and DENV-2. In addition, ISVs are frequently found in the core virome of Ae. aegypti, such as Phasi Charoen-like phasivirus (PCLV), which was the most prevalent and showed variable abundance in relation to the presence of specific DENV serotypes. Phylogenetic analyses of the L, M, and S segments of the PCLV genome are associated with sequences from different regions of the world but show close clustering with sequences from Brazil and Guadeloupe, indicating a shared evolutionary relationship. The profiling of the Ae. aegypti virome in Colombia presented here improves our understanding of viral diversity within mosquito vectors and provides information that opens the way to possible connections between ISVs and arboviruses. Future studies aimed at deepening our understanding of the mechanisms underlying the interactions between ISVs and DENV serotypes in Ae. aegypti could provide valuable information for the design of effective vector-borne viral disease control and prevention strategies.IMPORTANCEIn this study, we employed a metagenomic approach to characterize the virome of Aedes aegypti mosquitoes, with and without natural DENV infection, in several regions of Colombia. Our findings indicate that the mosquito virome is predominantly composed of insect-specific viruses (ISVs) and that infection with different DENV serotypes (DENV-1 and DENV-2) could lead to alterations in the relative abundance of viral families and species constituting the core virome in Aedes spp. The study also sheds light on the identification of the genome and evolutionary relationships of the Phasi Charoen-like phasivirus in Ae. aegypti in Colombia, a widespread ISV in areas with high DENV incidence.
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Affiliation(s)
- Marcela Gómez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
- Grupo de Investigación en Ciencias Básicas (NÚCLEO), Facultad de Ciencias e Ingeniería, Universidad de Boyacá, Tunja, Colombia
| | - David Martínez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
| | - Luisa Páez-Triana
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
| | - Nicolás Luna
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
| | - Angie Ramírez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
| | - Julián Medina
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
| | - Lissa Cruz-Saavedra
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
| | - Carolina Hernández
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
- Centro de Tecnología en Salud (CETESA), Innovaseq SAS, Bogotá, Colombia
| | - Sergio Castañeda
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
| | - Ramiro Bohórquez Melo
- Grupo de Estudios en Salud Pública de la Amazonía, Laboratorio de Salud Pública de Amazonas, Leticia, Colombia
| | - Luis Alejandro Suarez
- Grupo de Estudios en Salud Pública de la Amazonía, Laboratorio de Salud Pública de Amazonas, Leticia, Colombia
| | - Mónica Palma-Cuero
- Grupo de Estudios en Salud Pública de la Amazonía, Laboratorio de Salud Pública de Amazonas, Leticia, Colombia
| | - Luz Mila Murcia
- Grupo de Estudios en Salud Pública de la Amazonía, Laboratorio de Salud Pública de Amazonas, Leticia, Colombia
| | | | | | | | | | | | | | | | - Marina Muñoz
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
| | - Juan David Ramírez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
- Department of Pathology, Molecular and Cell-Based Medicine, Molecular Microbiology Laboratory, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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Chimfwembe K, Shirley H, Baker N, Wamai R. Zambia: A Narrative Review of Success and Challenges in Lymphatic Filariasis Elimination. Trop Med Infect Dis 2024; 9:21. [PMID: 38251218 PMCID: PMC10820422 DOI: 10.3390/tropicalmed9010021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 12/28/2023] [Accepted: 01/05/2024] [Indexed: 01/23/2024] Open
Abstract
The establishment of the Global Programme to Eliminate Lymphatic Filariasis (GPELF) to stop the transmission of infection has significantly reduced the incidence of lymphatic filariasis, a debilitating mosquito-borne neglected tropical disease. The primary strategies that have been employed include mass drug administration (MDA) of anthelminthics and morbidity management and disability prevention (MMDP). While some countries have been able to reach elimination status in Africa, there is still active transmission of LF in Zambia. The nematode responsible for the disease is Wuchereria bancrofti, which is transmitted by Anopheles mosquitoes. To alleviate the suffering of those infected by the disease, the Zambian Ministry of Health launched a program to eliminate LF as a public health problem in 2003. This project reviewed the efforts to achieve the elimination of LF in Zambia, past and present government policies, and the anticipated challenges. MDAs have been conducted since 2014 and coverage has been between 87% and 92%. Zambia has now moved towards pre-transmission assessment surveys (PRETAS) and transmission assessment surveys (TAS). MMDP is a major priority and planned to be conducted between 2022 and 2026. COVID-19 presented a new challenge in the control of LF, while climate change, immigration, co-infections, and funding limitations will complicate further progress.
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Affiliation(s)
- Kingford Chimfwembe
- Department of Research and Postgraduate Studies, Chreso University, Lusaka 37178, Zambia;
- Ministry of Health, Lusaka 10101, Zambia
| | - Hugh Shirley
- Program in Medical Education, Harvard Medical School, Boston, MA 02115, USA
- African Center for Community Investment in Health, Nginyang P.O. Box 48-30404, Kenya;
| | - Natalie Baker
- Program in Medical Education, Harvard Medical School, Boston, MA 02115, USA
| | - Richard Wamai
- African Center for Community Investment in Health, Nginyang P.O. Box 48-30404, Kenya;
- Integrate Initiative for Global Health, Department of Cultures, Societies and Global Studies, College of Social Sciences and Humanities, Northeastern University, Boston, MA 02115, USA
- Department of Global and Public Health, University of Nairobi, Nairobi 00100, Kenya
- Nigerian Institute of Medical Research, Federal Ministry of Health, Lagos 101212, Nigeria
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Abbott AJ, Matope A, Jones J, Voloshin V, Towers CE, Towers D, McCall PJ. Insecticidal roof barriers mounted on untreated bed nets can be as effective against Anopheles gambiae as regular insecticide-treated bed nets. Sci Rep 2023; 13:22080. [PMID: 38086842 PMCID: PMC10716170 DOI: 10.1038/s41598-023-48499-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Barrier bednets (BBnets), regular bednets with a vertical insecticidal panel to target mosquitoes above the bednet roof, where they are most active, have the potential to improve existing Insecticidal Treated Bednets (ITNs), by reducing the quantity of insecticide required per net, reducing the toxic risks to those using the net, potentially increasing insecticide choice. We evaluated the performance of PermaNet 3.0 (P3) and untreated (Ut) bed nets with and without pyrethroid and piperonyl butoxide roof barriers in killing pyrethroid-resistant and susceptible Anopheles gambiae, simultaneously video-recording mosquito flight tracks. Bioassay results showed that treated roof barriers, particularly the longitudinal P3 barrier (P3L) could be an effective addition to a bed net: P3 + P3L were consistently significantly more effective than the reference P3 bednet while performance of untreated nets could be raised to equal that of the reference P3 following the addition of a P3 barrier. The BBnet's potential to augment existing bednets and enhance their performance is considered.
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Affiliation(s)
- Anthony J Abbott
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Agnes Matope
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Jeff Jones
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Vitaly Voloshin
- Optical Engineering Group, School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | - Catherine E Towers
- Optical Engineering Group, School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | - David Towers
- Optical Engineering Group, School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | - Philip J McCall
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK.
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Okafor MA, Ekpo ND, Opara KN, Udoidung NI, Ataya FS, Yaro CA, Batiha GES, Alexiou A, Papadakis M. Pyrethroid insecticides susceptibility profiles and evaluation of L1014F kdr mutant alleles in Culex quinquefasciatus from lymphatic filariasis endemic communities. Sci Rep 2023; 13:18716. [PMID: 37907533 PMCID: PMC10618241 DOI: 10.1038/s41598-023-44962-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 10/13/2023] [Indexed: 11/02/2023] Open
Abstract
This study investigated the dynamics in pyrethriod resistance and the presence/frequencies of L1014F knockdown resistance mutant allelles in Culex quinquefasciatus vector populations from Uruan Local Government Area of AkwaIbom State, Southern Nigeria between the months of March and November, 2021. Uruan LGA is among the endemic LGAs for lymphatic filariasis in AkwaIbomState. Female Anopheles mosquitoes from Eman Uruan, Ituk Mbang and Idu Uruan were exposed to permethrin, deltamethrin and alphacypermethrin in CDC insecticide coated bottles for susceptibility bioassay following standard protocols. The mosquitoes were obtained as aquatic forms from the study sites and reared under laboratory conditions to adults. The adult mosquitoes were used for this study. All the mosquitoes used for the insecticide susceptibility bioassay were morphologically identified. Standard Polymerase chain reaction (PCR) was used for authenticating the Culex quinquefasciatus species. A portion of the vgsc (917 bp) gene spanning the entire intron and the exon containing the L1014F mutation associated with knockdown resistance (kdr) in the vectorswere amplified using Allele-SPECIFIC POLYMERASE CHAIN REACTION (AS-PCR) in order to detect target site insensitivity in the vectors from the study sites. Results obtained revealed that vectors from all the study sites were resistant to permethrin insecticide (mortality rate: 18-23%). Suspected resistance (mortality rate: 90-93%) to deltamethrin and low resistance (mortality rate: 82-85%) to alphacypermethrin insecticides were detected. knockdown was more rapid with deltamethrin and alphacypermethrin than with permethrin across the study sites considering their KDT50 and KDT95. The frequency of the resistant phenotypes ranged from 35.14 to 55.3% across the study sites with a net of 45.1% resistant phenotype recorded in this study. The 1014F allelic frequency calculated from Hardy-Weinberg principle for vector populations across the study sites ranged from 0.500 (50.00%) to 0.7763 (77.63%). All populations witnessed significant (p < 0.05) deviations from Hardy-Weinberg equilibrium in the distribution of these alleles. The findings of this study show that there is a tendency to record an entire population of resistant vectors in this study area over time due to natural selection. The public health implication of these findings is that the use of pyrethroid based aerosols, coils, sprays, LLITNs and others for the purpose of controlling vectors of lymphatic filariasis and other diseases may be effort in futility.
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Affiliation(s)
- Martina Anurika Okafor
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Ndifreke Daniel Ekpo
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria.
| | - Kenneth Nnamdi Opara
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Nsima Ibanga Udoidung
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Farid S Ataya
- Department of Biochemistry, College of Science, King Saud University, PO Box 2455, 11451, Riyadh, Saudi Arabia.
| | - Clement Ameh Yaro
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria.
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, AlBeheira, 22511, Egypt
| | - Athanasios Alexiou
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham, NSW, 2770, Australia
- AFNP Med, 1030, Wien, Austria
| | - Marios Papadakis
- Department of Surgery II, University Hospital Witten-Herdecke, University of Witten-Herdecke, Heusnerstrasse 40, 42283, Wuppertal, Germany.
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Yüksel E, Yıldırım A, İmren M, Canhilal R, Dababat AA. Xenorhabdus and Photorhabdus Bacteria as Potential Candidates for the Control of Culex pipiens L. (Diptera: Culicidae), the Principal Vector of West Nile Virus and Lymphatic Filariasis. Pathogens 2023; 12:1095. [PMID: 37764903 PMCID: PMC10537861 DOI: 10.3390/pathogens12091095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/27/2023] [Accepted: 08/05/2023] [Indexed: 09/29/2023] Open
Abstract
Vector-borne diseases pose a severe threat to human and animal health. Culex pipiens L. (Diptera: Culicidae) is a widespread mosquito species and serves as a vector for the transmission of infectious diseases such as West Nile disease and Lymphatic Filariasis. Synthetic insecticides have been the prime control method for many years to suppress Cx. pipiens populations. However, recently, the use of insecticides has begun to be questioned due to the detrimental impact on human health and the natural environment. Therefore, many authorities urge the development of eco-friendly control methods that are nontoxic to humans. The bacterial associates [Xenorhabdus and Photorhabdus spp. (Enterobacterales: Morganellaceae)] of entomopathogenic nematodes (EPNs) (Sterinernema spp. and Heterorhabditis spp.) (Rhabditida: Heterorhabditidae and Steinernematidae) are one of the green approaches to combat a variety of insect pests. In the present study, the mosquitocidal activity of the cell-free supernatants and cell suspension (4 × 107 cells mL-1) of four different symbiotic bacteria (Xenorhabdus nematophila, X. bovienii, X. budapestensis, and P. luminescens subsp. kayaii) was assessed against different development stages of Cx. pipiens (The 1st/2nd and 3rd/4th instar larvae and pupa) under laboratory conditions. The bacterial symbionts were able to kill all the development stages with varying levels of mortality. The 1st/2nd instar larvae exhibited the highest susceptibility to the cell-free supernatants and cell suspensions of symbiotic bacteria and the efficacy of the cell-free supernatants and cell suspensions gradually declined with increasing phases of growth. The highest effectiveness was achieved by the X. bovienii KCS-4S strain inducing 95% mortality to the 1st/2nd instar larvae. The results indicate that tested bacterial symbionts have great potential as an eco-friendly alternative to insecticides.
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Affiliation(s)
- Ebubekir Yüksel
- Department of Plant Protection, Faculty of Agriculture, Kayseri Erciyes University, Kayseri 38030, Türkiye;
| | - Alparslan Yıldırım
- Department of Parasitology, Faculty of Veterinary Medicine, Erciyes University, Kayseri 38280, Türkiye;
| | - Mustafa İmren
- Department of Plant Protection, Faculty of Agriculture, Abant Izzet Baysal University, Bolu 14030, Türkiye;
| | - Ramazan Canhilal
- Department of Plant Protection, Faculty of Agriculture, Kayseri Erciyes University, Kayseri 38030, Türkiye;
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Pelletier J, Dawit M, Ghaninia M, Marois E, Ignell R. A mosquito-specific antennal protein is critical for the attraction to human odor in the malaria vector Anopheles gambiae. Insect Biochem Mol Biol 2023; 159:103988. [PMID: 37437853 DOI: 10.1016/j.ibmb.2023.103988] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/21/2023] [Accepted: 07/08/2023] [Indexed: 07/14/2023]
Abstract
Mosquitoes rely mainly on the sense of smell to decipher their environment and locate suitable food sources, hosts for blood feeding and oviposition sites. The molecular bases of olfaction involve multigenic families of olfactory proteins that have evolved to interact with a narrow set of odorants that are critical for survival. Understanding the complex interplay between diversified repertoires of olfactory proteins and ecologically-relevant odorant signals, which elicit important behaviors, is fundamental for the design of novel control strategies targeting the sense of smell of disease vector mosquitoes. Previously, large multigene families of odorant receptor and ionotropic receptor proteins, as well as a subset of odorant-binding proteins have been shown to mediate the selectivity and sensitivity of the mosquito olfactory system. In this study, we identify a mosquito-specific antennal protein (MSAP) gene as a novel molecular actor of odorant reception. MSAP is highly conserved across mosquito species and is transcribed at an extremely high level in female antennae. In order to understand its role in the mosquito olfactory system, we generated knockout mutant lines in Anopheles gambiae, and performed comparative analysis of behavioral and physiological responses to human-associated odorants. We found that MSAP promotes female mosquito attraction to human odor and enhances the sensitivity of the antennae to a variety of odorants. These findings suggest that MSAP is an important component of the mosquito olfactory system, which until now has gone completely unnoticed.
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Affiliation(s)
- Julien Pelletier
- Disease Vector Group, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden.
| | - Mengistu Dawit
- Disease Vector Group, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | | | - Eric Marois
- INSERM U1257, CNRS UPR9022, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France
| | - Rickard Ignell
- Disease Vector Group, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden
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Namountougou M, Kientega M, Kaboré PDA, Soma DD, Pare Toe L, Sawadogo JME, Birba WJ, Gnankiné O, Dabiré KR, Okumu F, Diabaté A. Residual Malaria Transmission: magnitude and drivers of persistent Plasmodium infections despite high coverage of control interventions in Burkina Faso, West Africa. Acta Trop 2023; 242:106913. [PMID: 36997012 DOI: 10.1016/j.actatropica.2023.106913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/04/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023]
Abstract
This study collected baseline data on malaria vectors to characterize the drivers and the factors of persistent malaria transmission in two villages in the western part of Burkina Faso. Mosquitoes were collected in each village using the Human landing catch and pyrethrum spray catch and identified using the morphological keys. Molecular analyses were performed for the identification of An. gambiae complex species, the detection of Plasmodium infection and kdr-995F mutation. Anopheles mosquito larvae were also collected in the same villages, reared to adult's stage for the WHO tube and cone tests performing. The physical integrity of the LLINs already used by people in each village was assessed using the proportional hole index (pHI). An. gambiae s.l. was the main malaria vector accounting for 79.82% (5560/6965) of all collected mosquitoes. The biting pattern of An. gambiae s.l. was almost constant during the survey with an early aggressiveness before 8 p.m. and later biting activity after 6 a.m. The EIR varied from 0.13 to 2.55 infected bites per human per night (average: 1.03 infected bites per human per night). An. gambiae s.l. populations were full susceptible to Chlorpyrifos-methyl (0.4%) and Malathion (5%) with high kdr-995F mutation frequencies (>0.8). The physical integrity assessment showed high proportion of good nets in Santidougou compared to those collected in Kimidougou. This study highlighted a persistence of malaria transmission despite the intense use of vector control tools as LLINs and IRS by correlating mosquito biting time and human behavior. It provided a baseline guide for the monitoring of the residual malaria transmission in sub-Saharan Africa and encouraging the development of new alternative strategies to support the current malaria control tools.
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9
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Milesi P, Claret JL, Unal S, Weill M, Labbé P. Evolutionary trade-offs associated with copy number variations in resistance alleles in Culex pipiens mosquitoes. Parasit Vectors 2022; 15:484. [PMID: 36550589 PMCID: PMC9783466 DOI: 10.1186/s13071-022-05599-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022] Open
Abstract
Organophosphate and carbamate insecticides have largely been used worldwide to control mosquito populations. As a response, the same amino acid substitution in the ace-1 gene (G119S), conferring resistance to both insecticides, has been selected independently in many mosquito species. In Anopheles gambiae, it has recently been shown that the G119S mutation is actually part of homogeneous duplications that associate multiple resistance copies of the ace-1 gene. In this study, we showed that duplications of resistance copies of the ace-1 gene also exist in the Culex pipiens species complex. The number of copies is variable, and different numbers of copies are associated with different phenotypic trade-offs: we used a combination of bioassays and competition in population cages to show that having more resistance copies conferred higher resistance levels, but was also associated with higher selective disadvantage (or cost) in the absence of insecticide. These results further show the versatility of the genetic architecture of resistance to organophosphate and carbamate insecticides around the ace-1 locus and its role in fine-tuned adaptation to insecticide treatment variations.
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Affiliation(s)
- Pascal Milesi
- grid.8993.b0000 0004 1936 9457Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen, 18D, SE-752 36, Uppsala, Sweden ,grid.452834.c0000 0004 5911 2402Science for Life Laboratory (SciLifeLab), Uppsala, Sweden
| | - Jean-Loup Claret
- grid.121334.60000 0001 2097 0141Institut Des Sciences de L’Évolution de Montpellier (UMR 5554, CNRS-UM-IRD- EPHE), Université de Montpellier, Cedex 05, Montpellier, France
| | - Sandra Unal
- grid.121334.60000 0001 2097 0141Institut Des Sciences de L’Évolution de Montpellier (UMR 5554, CNRS-UM-IRD- EPHE), Université de Montpellier, Cedex 05, Montpellier, France
| | - Mylène Weill
- grid.121334.60000 0001 2097 0141Institut Des Sciences de L’Évolution de Montpellier (UMR 5554, CNRS-UM-IRD- EPHE), Université de Montpellier, Cedex 05, Montpellier, France
| | - Pierrick Labbé
- grid.121334.60000 0001 2097 0141Institut Des Sciences de L’Évolution de Montpellier (UMR 5554, CNRS-UM-IRD- EPHE), Université de Montpellier, Cedex 05, Montpellier, France ,grid.440891.00000 0001 1931 4817Institut Universitaire de France, 1 Rue Descartes Cedex 05, 75231 Paris, France
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Kientega M, Kranjc N, Traoré N, Kaboré H, Soma DD, Morianou I, Namountougou M, Belem AMG, Diabaté A. Analysis of the Genetic Variation of the Fruitless Gene within the Anopheles gambiae ( Diptera: Culicidae) Complex Populations in Africa. Insects 2022; 13:1048. [PMID: 36421951 PMCID: PMC9699577 DOI: 10.3390/insects13111048] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/06/2022] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
Targeting genes involved in sexual determinism, for vector or pest control purposes, requires a better understanding of their polymorphism in natural populations in order to ensure a rapid spread of the construct. By using genomic data from An. gambiae s.l., we analyzed the genetic variation and the conservation score of the fru gene in 18 natural populations across Africa. A total of 34,339 SNPs were identified, including 3.11% non-synonymous segregating sites. Overall, the nucleotide diversity was low, and the Tajima’s D neutrality test was negative, indicating an excess of low frequency SNPs in the fru gene. The allelic frequencies of the non-synonymous SNPs were low (freq < 0.26), except for two SNPs identified at high frequencies (freq > 0.8) in the zinc-finger A and B protein domains. The conservation score was variable throughout the fru gene, with maximum values in the exonic regions compared to the intronic regions. These results showed a low genetic variation overall in the exonic regions, especially the male sex-specific exon and the BTB-exon 1 of the fru gene. These findings will facilitate the development of an effective gene drive construct targeting the fru gene that can rapidly spread without encountering resistance in wild populations.
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Affiliation(s)
- Mahamadi Kientega
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso 01 BP 545, Burkina Faso
- Laboratoire de Santé Animale Tropicale, Institut du Développement Rural, Université Nazi Boni, Bobo-Dioulasso 01 BP 1091, Burkina Faso
| | - Nace Kranjc
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Nouhoun Traoré
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso 01 BP 545, Burkina Faso
- Laboratoire de Santé Animale Tropicale, Institut du Développement Rural, Université Nazi Boni, Bobo-Dioulasso 01 BP 1091, Burkina Faso
| | - Honorine Kaboré
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso 01 BP 545, Burkina Faso
- Laboratoire de Santé Animale Tropicale, Institut du Développement Rural, Université Nazi Boni, Bobo-Dioulasso 01 BP 1091, Burkina Faso
| | - Dieudonné Diloma Soma
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso 01 BP 545, Burkina Faso
- Laboratoire de Santé Animale Tropicale, Institut du Développement Rural, Université Nazi Boni, Bobo-Dioulasso 01 BP 1091, Burkina Faso
| | - Ioanna Morianou
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Moussa Namountougou
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso 01 BP 545, Burkina Faso
- Laboratoire de Santé Animale Tropicale, Institut du Développement Rural, Université Nazi Boni, Bobo-Dioulasso 01 BP 1091, Burkina Faso
| | - Adrien Marie Gaston Belem
- Laboratoire de Santé Animale Tropicale, Institut du Développement Rural, Université Nazi Boni, Bobo-Dioulasso 01 BP 1091, Burkina Faso
| | - Abdoulaye Diabaté
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso 01 BP 545, Burkina Faso
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11
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Adageba SK, Kanmiki EW, Asoala V, Oduro AR, Baidoo PK. Bio-efficacy, physical integrity, use and attrition of long-lasting insecticidal nets under operational conditions for malaria prevention in Ghana. PLoS One 2022; 17:e0275825. [PMID: 36240161 DOI: 10.1371/journal.pone.0275825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 09/23/2022] [Indexed: 11/05/2022] Open
Abstract
Background Malaria remains a public health challenge in endemic countries of the world. The use of Long-lasting Insecticidal Nets (LLINs) is one of the major ways of malaria vector control. Recent evidence however suggests some LLINs are unable to maintain their effectiveness over their useful life span. This study assessed the bio-efficacy, physical integrity, use and attrition at 6 and 12-months post-distribution of LLINs (LifeNet). Methods Following a mass distribution of LLINs in the West Mamprusi District of the North-East region of Ghana in 2018, a total of 147 LLINs were sampled for physical integrity and attrition assessment using hole size and the number of holes as a measure of the proportionate hole index (pHI). Bioassays were conducted on sixty randomly selected LLINs using the WHO guidelines for bio-efficacy testing (cone tests), (20 each at baseline, midline and endline) over a one-year study period. Bed net ownership and use as well as malaria vector resistance status were also assessed. Results Findings indicate high bio-efficacy of approximately 100% average mortalities of mosquitoes at baseline, 6-months and 12-months post-distribution. A small proportion of LLINs (0.8% and 5.6% at the 6 and 12-months surveys respectively) were damaged beyond maintenance while 62.4% and 62.7% of LLINs were used the night before the survey for 6 and 12-months post-distribution respectively. Households with electricity were less likely to use LLINs compared to those without electricity (P-value = 0.016, OR = 0.39). There were 20 fewer LLINs recovered at the 12-months relative to the 6-months resulting in 14.3% attrition rate. Susceptibility testing showed high pyrethroid and organochlorine resistance (18%, 67.5% and 3.8%) to local malaria vectors respectively), whereas organophosphates and carbamates recorded vector susceptibility of 100% for pirimiphos-methyl and 98.7% for bendiocarb. Conclusion Biological efficacy, physical integrity and net attrition during the study period were in conformity with respect to the WHOPES one year net use. LLINs remained effective after one-year of usage. Net ownership was high in the study households. There should be continuous and regular distribution campaigns to maintain high coverage.
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12
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Gómez M, Martinez D, Muñoz M, Ramírez JD. Aedes aegypti and Ae. albopictus microbiome/virome: new strategies for controlling arboviral transmission? Parasit Vectors 2022; 15:287. [PMID: 35945559 PMCID: PMC9364528 DOI: 10.1186/s13071-022-05401-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/14/2022] [Indexed: 02/07/2023] Open
Abstract
Aedes aegypti and Aedes albopictus are the main vectors of highly pathogenic viruses for humans, such as dengue (DENV), chikungunya (CHIKV), and Zika (ZIKV), which cause febrile, hemorrhagic, and neurological diseases and remain a major threat to global public health. The high ecological plasticity, opportunistic feeding patterns, and versatility in the use of urban and natural breeding sites of these vectors have favored their dispersal and adaptation in tropical, subtropical, and even temperate zones. Due to the lack of available treatments and vaccines, mosquito population control is the most effective way to prevent arboviral diseases. Resident microorganisms play a crucial role in host fitness by preventing or enhancing its vectorial ability to transmit viral pathogens. High-throughput sequencing and metagenomic analyses have advanced our understanding of the composition and functionality of the microbiota of Aedes spp. Interestingly, shotgun metagenomics studies have established that mosquito vectors harbor a highly conserved virome composed of insect-specific viruses (ISV). Although ISVs are not infectious to vertebrates, they can alter different phases of the arboviral cycle, interfering with transmission to the human host. Therefore, this review focuses on the description of Ae. aegypti and Ae. albopictus as vectors susceptible to infection by viral pathogens, highlighting the role of the microbiota-virome in vectorial competence and its potential in control strategies for new emerging and re-emerging arboviruses.
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Affiliation(s)
- Marcela Gómez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia.,Grupo de Investigación en Ciencias Básicas (NÚCLEO) Facultad de Ciencias e Ingeniería, Universidad de Boyacá, Tunja, Colombia
| | - David Martinez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Marina Muñoz
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Juan David Ramírez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia. .,Molecular Microbiology Laboratory, Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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13
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Sanei-Dehkordi A, Agholi M, Shafiei M, Osanloo M. Promising Larvicidal Efficacy of Solid Lipid Nanoparticles Containing Mentha longifolia L., Mentha pulegium L., and Zataria multiflora Boiss. Essential Oils Against the Main Malaria Vector, Anopheles stephensi Liston. Acta Parasitol 2022; 67:1265-1272. [PMID: 35704149 DOI: 10.1007/s11686-022-00580-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 05/20/2022] [Indexed: 11/26/2022]
Abstract
PURPOSE An attempt was made in the current study to develop a natural mosquito larvicide using nanotechnology. METHODS Solid lipid nanoparticles (SLNs) containing three essential oils were first prepared using the high-pressure homogenizer. Larvicidal effects of essential oils and the SLNs against Anopheles stephensi were then compared. RESULTS The size of SLN containing Mentha longifolia, Mentha pulegium, Zataria multiflora essential oil was obtained as 105 ± 7, 210 ± 4, and 137 ± 8 nm. Their zeta potentials were - 7.8, - 4.7, and - 9.7 mV. Besides, their efficacy with LC50 values of 24.79, 5.11, and 9.19 µg/mL was significantly more potent than that of their un-formulated essential oils with LC50 values of 36.2, 27.55, and 33.33 µg/mL. CONCLUSION SLNs containing M. pulegium with the best efficacy (P < 0.05) could be considered as potent larvicides against other important species of mosquitoes and field trials.
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Affiliation(s)
- Alireza Sanei-Dehkordi
- Department of Medical Entomology and Vector Control, School of Health, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
- Infectious and Tropical Diseases Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Mahmoud Agholi
- Department of Medical Parasitology and Mycology, School of Medicine, Fasa University of Medical Sciences, Fasa, Iran
| | - Mahsa Shafiei
- Noncommunicable Disease Research Center, Fasa University of Medical Sciences, Fasa, Iran
| | - Mahmoud Osanloo
- Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Fasa University of Medical Sciences, Fasa, Iran.
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Musiba RM, Tarimo BB, Monroe A, Msaky D, Ngowo H, Mihayo K, Limwagu A, Chilla GT, Shubis GK, Ibrahim A, Greer G, Mcha JH, Haji KA, Abbas FB, Ali A, Okumu FO, Kiware SS. Outdoor biting and pyrethroid resistance as potential drivers of persistent malaria transmission in Zanzibar. Malar J 2022; 21:172. [PMID: 35672768 PMCID: PMC9171934 DOI: 10.1186/s12936-022-04200-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 05/24/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Low-level of malaria transmission persist in Zanzibar despite high coverage of core vector control interventions. This study was carried out in hot-spot sites to better understand entomological factors that may contribute to residual malaria transmission in Zanzibar. METHODS A total of 135 households were randomly selected from six sites and consented to participate with 20-25 households per site. Mosquito vector surveillance was carried out indoors and outdoors from 6:00 pm-7:00 am using miniaturized double net trap (DN-Mini™). Additional collections were done indoors using mouth aspirators to retrieve resting mosquitoes from wall and ceiling surfaces, and outdoors using resting bucket and pit traps. All collected mosquitoes were morphologically and genetically (PCR) analysed in the laboratory. All collected anopheline and blood-fed mosquitoes were analysed for sporozoite infection and blood meal host preferences by Circumsporozoite Protein ELISA and blood meal ELISA, respectively. The differences between indoor and outdoor mosquito biting rates were analysed using generalized linear mixed models. Levels of resistance to commonly used insecticides were quantified by WHO susceptibility tests. RESULTS Out of 704 malaria vectors collected across 135 households, PCR analysis shows that 98.60% were Anopheles arabiensis, 0.6% Anopheles merus and 0.6% Anopheles gambiae sensu stricto. Sporozoite ELISA analysis indicates that all mosquitoes were negative for the malaria parasite. The results show that more An. arabiensis were collected outdoor (~ 85%) compared to indoor (~ 15%). Furthermore, large numbers of An. arabiensis were caught in outdoor resting sites, where the pit trap (67.2%) collected more mosquitoes compared to the outdoor DN-Mini trap (32.8%). Nearly two-thirds (60.7%) of blood-fed mosquitoes had obtained blood meals from non-human hosts. Mosquitoes displayed non-uniform susceptibility status and resistance intensity among the tested insecticides across the study sites to all WHO recommended insecticides across the study sites. CONCLUSION This study suggests that in contexts such as Zanzibar, testing of novel techniques to complement indoor protection and targeting outdoor biting and/or resting mosquitoes, may be warranted to complement existing interventions and contribute to malaria elimination efforts. The study highlights the need to implement novel interventions and/or adaptations of strategies that can target outdoors biting mosquitoes.
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Affiliation(s)
| | | | - April Monroe
- PMI VectorWorks Project, Johns Hopkins Center for Communication Programs, Baltimore, MD, USA
| | | | - Halfan Ngowo
- Ifakara Health Institute, Dar es Salaam, Tanzania
| | | | - Alex Limwagu
- Ifakara Health Institute, Dar es Salaam, Tanzania
| | | | | | | | - George Greer
- US President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, Tanzania
| | - Juma H Mcha
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | - Khamis A Haji
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | - Faiza B Abbas
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | | | - Samson S Kiware
- Ifakara Health Institute, Dar es Salaam, Tanzania
- Pan African Mosquito Control Association (PAMCA), Nairobi, Kenya
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15
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Nolden M, Brockmann A, Ebbinghaus-Kintscher U, Brueggen KU, Horstmann S, Paine MJI, Nauen R. Towards understanding transfluthrin efficacy in a pyrethroid-resistant strain of the malaria vector Anopheles funestus with special reference to cytochrome P450-mediated detoxification. Curr Res Parasitol Vector Borne Dis 2022; 1:100041. [PMID: 35284893 PMCID: PMC8906121 DOI: 10.1016/j.crpvbd.2021.100041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/23/2021] [Accepted: 07/13/2021] [Indexed: 11/17/2022]
Abstract
Malaria vector control interventions rely heavily on the application of insecticides against anopheline mosquitoes, in particular the fast-acting pyrethroids that target insect voltage-gated sodium channels (VGSC). Frequent applications of pyrethroids have resulted in resistance development in the major malaria vectors including Anopheles funestus, where resistance is primarily metabolic and driven by the overexpression of microsomal cytochrome P450 monooxygenases (P450s). Here we examined the pattern of cross-resistance of the pyrethroid-resistant An. funestus strain FUMOZ-R towards transfluthrin and multi-halogenated benzyl derivatives, permethrin, cypermethrin and deltamethrin in comparison to the susceptible reference strain FANG. Transfluthrin and two multi-fluorinated derivatives exhibited micromolar potency - comparable to permethrin - to functionally expressed dipteran VGSC in a cell-based cation influx assay. The activity of transfluthrin and its derivatives on VGSC was strongly correlated with their contact efficacy against strain FUMOZ-R, although no such correlation was obtained for the other pyrethroids due to their rapid detoxification by the resistant strain. The low resistance levels for transfluthrin and derivatives in strain FUMOZ-R were only weakly synergized by known P450 inhibitors such as piperonyl butoxide (PBO), triflumizole and 1-aminobenzotriazole (1-ABT). In contrast, deltamethrin toxicity in FUMOZ-R was synergized > 100-fold by all three P450 inhibitors. The biochemical profiling of a range of fluorescent resorufin and coumarin compounds against FANG and FUMOZ-R microsomes identified 7-benzyloxymethoxy-4-trifluoromethylcoumarin (BOMFC) as a highly sensitive probe substrate for P450 activity. BOMFC was used to develop a fluorescence-based high-throughput screening assay to measure the P450 inhibitory action of potential synergists. Azole fungicides prochloraz and triflumizole were identified as extremely potent nanomolar inhibitors of microsomal P450s, strongly synergizing deltamethrin toxicity in An. funestus. Overall, the present study contributed to the understanding of transfluthrin efficacy at the molecular and organismal level and identified azole compounds with potential to synergize pyrethroid efficacy in malaria vectors. Transfluthrin and derivatives lack cross-resistance in resistant Anopheles funestus. Pyrethroid resistance in An. funestus is strongly synergized by azole fungicides. BOMFC is a highly active fluorescent probe substrate for microsomal cytochrome P450 monooxygenases in An. funestus. Azole fungicides are nanomolar inhibitors of microsomal cytochrome P450 monooxygenases in An. funestus.
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Affiliation(s)
- Melanie Nolden
- Bayer AG, Crop Science Division, Alfred Nobel Str. 50, D-40789, Monheim am Rhein, Germany.,Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Andreas Brockmann
- Bayer AG, Crop Science Division, Alfred Nobel Str. 50, D-40789, Monheim am Rhein, Germany.,Rheinische Friedrich-Wilhelms-Universität Bonn, D-53113, Bonn, Germany
| | | | - Kai-Uwe Brueggen
- Bayer AG, Crop Science Division, Alfred Nobel Str. 50, D-40789, Monheim am Rhein, Germany
| | - Sebastian Horstmann
- Bayer AG, Crop Science Division, Alfred Nobel Str. 50, D-40789, Monheim am Rhein, Germany
| | - Mark J I Paine
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Ralf Nauen
- Bayer AG, Crop Science Division, Alfred Nobel Str. 50, D-40789, Monheim am Rhein, Germany
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García GA, Fuseini G, Mba Nlang JA, Nsue Maye VO, Bela NR, Wofford RN, Weppelmann TA, Matulis G, Efiri PB, Smith JM, Rivas MR, Phiri WP, von Fricken ME. Evaluation of a Multi-Season, Community-Based Larval Source Management Program on Bioko Island, Equatorial Guinea. Front Trop Dis 2022. [DOI: 10.3389/fitd.2022.846955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BackgroundIn 2015 and 2016, the Bioko Island Malaria Control Project (BIMCP) introduced a pilot larvicide program, which recruited local volunteers to assess the sustainability and effectiveness of community-led larval source management. This study evaluates the effectiveness of the community-led LSM program to determine if this type of intervention could be used as a sustainable malaria control method on Bioko Island.MethodsThe pilot program was split into two phases, both taking place between February and December, with phase I in 2015 and phase II in 2016. During phase I, the BIMCP team assisted in identifying and treating Anopheles species mosquito breeding habitats. During phase II, community volunteers, with supervision from designated community leaders, identified and treated breeding habitats. Larval source management took place at thirteen locations around the Island during both phases. Human landing catches were conducted at seven sentinel sites once every month for the duration of the study period to determine average nightly biting rates.ResultsDuring phase I, 1,033 breeding sites were identified with a 100% treatment coverage rate. Only 970 breeding sites were identified in phase II with a 75% treatment coverage rate, a significant decrease from phase I (p<0.001). Between phase I and phase II, larvicide usage also decreased by 45% (95% CI: 32, 59%, p=0.003). However, excluding the sentinel site Balboa, vector density showed a nonsignificant (p=0.272) relationship between phase I and phase II.ConclusionOverall, community-based larval source management can be effective with strong operational management and oversight. However, repeated training and evaluation will be necessary to monitor the effectiveness and sustainability of such interventions.
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Jung H, An H, Lee M, Lee J, Tak JH. Comparative Efficacy of Commercial Liquid and Mat-Type Electric Vaporizer Insecticides Against Asian Tiger Mosquito (Diptera: Culicidae). J Med Entomol 2021; 58:2274-2283. [PMID: 34021566 DOI: 10.1093/jme/tjab087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Indexed: 06/12/2023]
Abstract
Mat and liquid-type electric insecticide vaporizers continuously emit insecticides into the surrounding air. Because both the target insects, mostly mosquitoes, and humans are exposed to those insecticides, it is crucial to understand and monitor their deposition and spatial distribution in treated areas. In the current study, we examined the evaporation of insecticides from seven commercial liquid and mat vaporizers and measured their knock-down and insecticidal activity against the adult females of the Asian tiger mosquito, Aedes albopictus (Skuse). Electric vaporizers from three manufactures had differences in their heaters and active ingredients. Most had continued evaporation during hourly and daily monitoring; however, some liquid vaporizers failed to continue emission to their designated end periods. Overall, mosquitoes located at the upper position in a Peet-Grady chamber and in a field-simulation room exhibited faster knock-down activity than did mosquitoes in other areas, indicating that the insecticides accumulated on the ceiling area. Although most of mat and liquid vaporizers had <60 min of average KT90 values when tested in the Peet-Grady chamber (1.8 × 1.8 × 1.8 m), they failed to have any knock-down in 2 h of observation in the field-simulation room (6.8 × 3.4 × 2.7 m) but showed 72. 8 ± 11.7% and 56. 7 ± 7.3% knock-down in the mat and liquid vaporizers, respectively, in 3 h of operation. Further study will be required to examine whether this relatively limited efficacy can be compensated by other physiological and behavioral effects, including disruption in host-seeking or blood-sucking activities.
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Affiliation(s)
- Hun Jung
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, South Korea
| | - Huijun An
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, South Korea
| | - Minjin Lee
- Consumer Product & Environment Business Division, KOTITI Testing & Research Institute, Seongnam, Gyeonggi 13202, South Korea
| | - Jieun Lee
- Consumer Product & Environment Business Division, KOTITI Testing & Research Institute, Seongnam, Gyeonggi 13202, South Korea
| | - Jun-Hyung Tak
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, South Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, South Korea
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Rohaizat Hassan M, Atika Azit N, Mohd Fadzil S, Abd Ghani SR, Ahmad N, Mohammed Nawi A. Insecticide resistance of Dengue vectors in South East Asia: a systematic review. Afr Health Sci 2021; 21:1124-1140. [PMID: 35222575 PMCID: PMC8843301 DOI: 10.4314/ahs.v21i3.21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The insecticides used widely has led to resistance in the vector and impose a challenge to vector control operation. OBJECTIVES This review aims to analyse the distribution of insecticide resistance of dengue vectors in South East Asia and to describe the mechanism of insecticide resistance. METHODS Literature search for articles published on 2015 to 2019 from PubMed, Scopus and ProQuest was performed. Total of 37 studies included in the final review from the initial 420 studies. RESULTS Pyrethroid resistance was concentrated on the west coast of Peninsular Malaysia and Northern Thailand and scattered at Java Island, Indonesia while organophosphate resistance was seen across the Java Island (Indonesia), West Sumatera and North Peninsular Malaysia. Organochlorine resistance was seen in Sabah, Malaysia and scattered distribution in Nusa Tenggara, Indonesia. V1016G, S989P, F1269C gene mutation in Aedes Aegypti were associated with Pyrethroid resistance in Singapore and Indonesia. In Malaysia, over-expressed with monooxygenase P450 genes (CYP9J27, CYP6CB1, CYP9J26 and CYP9M4) Glutathione S-transferases, carboxylesterases commonly associated with pyrethroids resistance in Aedes Aegypti and CYP612 overexpressed in Aedes Albopictus. The genetic mutation in A302S in Aedes Albopictus was associated with organochlorine resistance in Malaysia. CONCLUSIONS Rotation of insecticide, integration with synergist and routine assessment of resistance profile are recommended strategies in insecticide resistance management.
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Arich S, Assaid N, Taki H, Weill M, Labbé P, Sarih M. Distribution of insecticide resistance and molecular mechanisms involved in the West Nile vector Culex pipiens in Morocco. Pest Manag Sci 2021; 77:1178-1186. [PMID: 33009878 DOI: 10.1002/ps.6127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 09/03/2020] [Accepted: 10/03/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Mosquitoes of the Culex pipiens complex are the vectors of several arboviruses and are thus subjected to insecticide control worldwide. However, overuse of insecticides selects for resistance. While assessing the resistance status of the vectors is required for effective and sustainable disease control, resistance has so far only been sparsely studied in Morocco. In this study, we establish a first countrywide assessment of the levels of resistance to various insecticides and the potential responsible mechanisms involved. Cx. pipiens larvae were collected from natural populations of five regions of Morocco, and their taxonomic status was determined (molecular forms). The level of their susceptibility to insecticides was assessed by single-diagnostic-dose bioassays. Molecular identification of known resistance alleles was investigated to determine the frequency of target-site mutations. RESULTS This study confirms that Moroccan populations are an interbreeding mix of pipiens and molestus forms, with large gene flow for the resistance alleles. We also found that Cx. pipiens mosquitoes are resistant to all insecticide families, all over Morocco: resistance is high for insecticides used in mosquito control, but also present for other pesticides. Resistance alleles are similarly more frequent for mosquito control insecticides. However, their distribution is heterogeneous in the five regions, with significant genetic differentiation between populations, revealing the crucial role of local insecticide treatment practices. CONCLUSION This study provides reference countrywide data that highlight the need for further research to refine the distribution of resistance in Morocco and to understand the role of agriculture/urban residuals in its spread. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Soukaina Arich
- Laboratory of Biology and Health, Faculty of Sciences Ben M'Sik, URAC 34, Hassan II University-Casablanca, Casablanca, Morocco
- Laboratoire des Maladies Vectorielles (LMV), Institut Pasteur du Maroc, Casablanca, Morocco
| | - Najlaa Assaid
- Laboratoire des Maladies Vectorielles (LMV), Institut Pasteur du Maroc, Casablanca, Morocco
| | - Hassan Taki
- Laboratory of Biology and Health, Faculty of Sciences Ben M'Sik, URAC 34, Hassan II University-Casablanca, Casablanca, Morocco
| | - Mylène Weill
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Montpellier, CEDEX 5, France
| | - Pierrick Labbé
- Institut des Sciences de l'Evolution de Montpellier (UMR 5554, CNRS-UM-IRD-EPHE), Université de Montpellier, Montpellier, CEDEX 5, France
| | - M'hammed Sarih
- Laboratoire des Maladies Vectorielles (LMV), Institut Pasteur du Maroc, Casablanca, Morocco
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Bokore GE, Ouma P, Onyango PO, Bukhari T, Fillinger U. A cross-sectional observational study investigating the association between sedges (swamp grasses, Cyperaceae) and the prevalence of immature malaria vectors in aquatic habitats along the shore of Lake Victoria, western Kenya. F1000Res 2020; 9:1032. [PMID: 33093949 PMCID: PMC7551511 DOI: 10.12688/f1000research.25673.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/24/2020] [Indexed: 12/01/2022] Open
Abstract
Background: Strategies that involve manipulations of the odour-orientation of gravid malaria vectors could lead to novel attract-and-kill interventions. Recent work has highlighted the potential involvement of graminoid plants in luring vectors to oviposition sites. This study aimed to analyse the association between water-indicating graminoid plants (Cyperaceae, sedges), other abiotic and biotic factors and the presence and abundance of early instar
Anopheles larvae in aquatic habitats as a proxy indicator for oviposition. Methods: A cross-sectional survey of 110 aquatic habitats along the shores of Lake Victoria was done during the rainy season. Habitats were sampled for mosquito larvae using the sweep-net method and habitat characteristics recorded. Results:
Anopheles arabiensis was the dominant species identified from aquatic habitats. Larvae of the secondary malaria vectors such as
Anopheles coustani, An. rufipes and
An. maculipalpis were found only in habitats covered with graminoids, whereas
An. arabiensis, An. ziemanni and
An. pharoensis were found in both habitats with and without graminoid plants. The hypothesis that sedges might be positively associated with the presence and abundance of early instar
Anopheles larvae could not be confirmed. The dominant graminoid plants in the habitats were
Panicum repens,
Cynodon dactylon in the Poaceae family and
Cyperus rotundus in the Cyperaceae family. All of these habitats supported abundant immature vector populations. The presence of early instar larvae was significantly and positively associated with swamp habitat types (OR=22, 95% CI=6-86, P<0.001) and abundance of late
Anopheles larvae (OR=359, CI=33-3941, P<0.001), and negatively associated with the presence of tadpoles (OR=0.1, CI=0.0.01-0.5, P=0.008). Conclusions: Early instar malaria vectors were abundant in habitats densely vegetated with graminoid plants in the study area but no specific preference could be detected for any species or family. In search for oviposition cues, it might be useful to screen for chemical volatiles released from all dominant plant species.
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Affiliation(s)
- Getachew E Bokore
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.,School of Physical and Biological Sciences, Department of Zoology, Maseno University, P.O. Box 333 - 40105, Maseno, Kenya.,Public Health Entomology Team, Ethiopian Public Health Institute, P.O. Box 1242, Addis Ababa, Ethiopia
| | - Paul Ouma
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Patrick O Onyango
- School of Physical and Biological Sciences, Department of Zoology, Maseno University, P.O. Box 333 - 40105, Maseno, Kenya
| | - Tullu Bukhari
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.,School of Physical and Biological Sciences, Department of Zoology, Maseno University, P.O. Box 333 - 40105, Maseno, Kenya
| | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
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Moyes CL, Athinya DK, Seethaler T, Battle KE, Sinka M, Hadi MP, Hemingway J, Coleman M, Hancock PA. Evaluating insecticide resistance across African districts to aid malaria control decisions. Proc Natl Acad Sci U S A 2020; 117:22042-50. [PMID: 32843339 DOI: 10.1073/pnas.2006781117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Malaria control in Africa largely relies on the use of insecticides to prevent mosquitoes from transmitting the malaria parasite to humans; however, these mosquitoes have evolved resistance to these insecticides. To manage this threat to malaria control, it is vital that we map locations where the prevalence of resistance exceeds thresholds defined by insecticide resistance management plans. A geospatial model and data from Africa are used to predict locations where thresholds of resistance linked to specific recommended actions are exceeded. This model is shown to provide more accurate next-year predictions than two simpler approaches. The model is used to generate maps that aid insecticide resistance management planning and that allow targeted deployment of interventions that counter specific mechanisms of resistance. Malaria vector control may be compromised by resistance to insecticides in vector populations. Actions to mitigate against resistance rely on surveillance using standard susceptibility tests, but there are large gaps in the monitoring data across Africa. Using a published geostatistical ensemble model, we have generated maps that bridge these gaps and consider the likelihood that resistance exceeds recommended thresholds. Our results show that this model provides more accurate next-year predictions than two simpler approaches. We have used the model to generate district-level maps for the probability that pyrethroid resistance in Anopheles gambiae s.l. exceeds the World Health Organization thresholds for susceptibility and confirmed resistance. In addition, we have mapped the three criteria for the deployment of piperonyl butoxide-treated nets that mitigate against the effects of metabolic resistance to pyrethroids. This includes a critical review of the evidence for presence of cytochrome P450-mediated metabolic resistance mechanisms across Africa. The maps for pyrethroid resistance are available on the IR Mapper website, where they can be viewed alongside the latest survey data.
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22
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Fernando HSD, Saavedra-Rodriguez K, Perera R, Black WC, De Silva BGDNK. Resistance to commonly used insecticides and underlying mechanisms of resistance in Aedes aegypti (L.) from Sri Lanka. Parasit Vectors 2020; 13:407. [PMID: 32778147 PMCID: PMC7418196 DOI: 10.1186/s13071-020-04284-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 08/03/2020] [Indexed: 11/28/2022] Open
Abstract
Background Drastic increases of dengue fever (DF) over the past few years have prompted studies on the development of resistance to insecticides in the mosquito vector, Aedes aegypti (Linnaeus). In Sri Lanka control of the vector population is essentially achieved using larvicides (temephos) and adulticides (principally pyrethroids). The present study investigates resistance to commonly used insecticides and underlying mechanisms of Ae. aegypti in selected sites in Sri Lanka. Methods In this study, susceptibility to three commonly used adulticides (malathion, permethrin and deltamethrin) and the larvicide temephos were tested for Ae. aegypti sampled from five localities in Sri Lanka using WHO dose diagnostics tests. In addition, we performed dose-response tests for permethrin to determine lethal concentrations (LCs) with CDC bottle bioassays. An assessment of the activity of metabolic detoxifying enzymes (multifunction oxidases (MFOs), glutathione S-transferases (GSTs) and esterases) and determination of frequency of the kdr mutations (F1534C, V1016G and S989P) were also carried out to ascertain the associated resistance mechanisms. Kdr genotype frequencies were compared with samples collected from the same sites in 2015 to determine the change of allele frequencies over the years. Results The present study revealed resistance in all Ae. aegypti populations studied, with low mortality percentages for both permethrin (10–89%) and deltamethrin (40–92%). Dose response tests revealed highest resistance ratios (RR) for permethrin and temephos from Colombo district whereas Puttalum district exhibited the lowest. High frequencies of the 1534C allele (0.052–0.802) were found in the study sites in 2017. Comparison with samples collected in 2015 revealed a substantial increase in this allele. The activity of MFOs and p-nitro phenyl-acetate esterase was significantly greater in most Sri Lankan populations in comparison to that of the New Orleans (NO) susceptible strain. In contrast, the activity of α-esterase and β-esterase was similar or lower than that in the NO strain. Conclusions Aedes aegypti from Sri Lanka is resistant to pyrethroid insecticides showing rapid selection for kdr mutations and varying metabolic mechanisms. Continued monitoring of vector populations is crucial to mitigate the development of resistance to commonly used insecticides and in turn, controlling the vector population.![]()
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Affiliation(s)
- H Sachini D Fernando
- Center for Biotechnology, Department of Zoology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
| | - Karla Saavedra-Rodriguez
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Rushika Perera
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523, USA
| | - William C Black
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523, USA
| | - B G D Nissanka Kolitha De Silva
- Center for Biotechnology, Department of Zoology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka.
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Hancock PA, Hendriks CJM, Tangena JA, Gibson H, Hemingway J, Coleman M, Gething PW, Cameron E, Bhatt S, Moyes CL. Mapping trends in insecticide resistance phenotypes in African malaria vectors. PLoS Biol 2020; 18:e3000633. [PMID: 32584814 PMCID: PMC7316233 DOI: 10.1371/journal.pbio.3000633] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 05/11/2020] [Indexed: 11/25/2022] Open
Abstract
Mitigating the threat of insecticide resistance in African malaria vector populations requires comprehensive information about where resistance occurs, to what degree, and how this has changed over time. Estimating these trends is complicated by the sparse, heterogeneous distribution of observations of resistance phenotypes in field populations. We use 6,423 observations of the prevalence of resistance to the most important vector control insecticides to inform a Bayesian geostatistical ensemble modelling approach, generating fine-scale predictive maps of resistance phenotypes in mosquitoes from the Anopheles gambiae complex across Africa. Our models are informed by a suite of 111 predictor variables describing potential drivers of selection for resistance. Our maps show alarming increases in the prevalence of resistance to pyrethroids and DDT across sub-Saharan Africa from 2005 to 2017, with mean mortality following insecticide exposure declining from almost 100% to less than 30% in some areas, as well as substantial spatial variation in resistance trends.
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Affiliation(s)
| | | | - Julie-Anne Tangena
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Harry Gibson
- Big Data Institute, University of Oxford, Oxford, United Kingdom
| | - Janet Hemingway
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Michael Coleman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Peter W. Gething
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
- Curtin University, Bentley, Perth, Australia
| | - Ewan Cameron
- Big Data Institute, University of Oxford, Oxford, United Kingdom
| | - Samir Bhatt
- Department of Infectious Disease Epidemiology, Imperial College, St Mary’s Hospital, London, United Kingdom
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24
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Diouf I, Rodriguez Fonseca B, Caminade C, Thiaw WM, Deme A, Morse AP, Ndione JA, Gaye AT, Diaw A, Ndiaye MKN. Climate Variability and Malaria over West Africa. Am J Trop Med Hyg 2020; 102:1037-1047. [PMID: 32189612 PMCID: PMC7204584 DOI: 10.4269/ajtmh.19-0062] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 02/01/2020] [Indexed: 01/24/2023] Open
Abstract
Malaria is a major public health problem in West Africa. Previous studies have shown that climate variability significantly affects malaria transmission. The lack of continuous observed weather station data and the absence of surveillance data for malaria over long periods have led to the use of reanalysis data to drive malaria models. In this study, we use the Liverpool Malaria Model (LMM) to simulate spatiotemporal variability of malaria in West Africa using daily rainfall and temperature from the following: Twentieth Century Reanalysis (20th CR), National Center for Environmental Prediction (NCEP), European Centre for Medium-Range Weather Forecasts (ECMWF) Atmospheric Reanalysis of the Twentieth Century (ERA20C), and interim ECMWF Re-Analysis (ERA-Interim). Malaria case data from the national surveillance program in Senegal are used for model validation between 2001 and 2016. The warm temperatures found over the Sahelian fringe of West Africa can lead to high malaria transmission during wet years. The rainfall season peaks in July to September over West Africa and Senegal, and the malaria season lasts from September to November, about 1-2 months after the rainfall peak. The long-term trends exhibit interannual and decadal variabilities. The LMM shows acceptable performance in simulating the spatial distribution of malaria incidence. However, some discrepancies are found. These results are useful for decision-makers who plan public health and control measures in affected West African countries. The study would have substantial implications for directing malaria surveillance activities and health policy. In addition, this malaria modeling framework could lead to the development of an early warning system for malaria in West Africa.
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Affiliation(s)
- Ibrahima Diouf
- NOAA Center for Weather and Climate Prediction, College Park, Maryland
- Laboratoire de Physique de L’Atmosphère et de L’Océan-Siméon Fongang, Ecole Supérieure Polytechnique de L’Université Cheikh Anta Diop, Dakar, Sénégal
| | - Belén Rodriguez Fonseca
- Department of Geophysics and Meteorology, Universidad Complutense de Madrid, Madrid, Spain
- Instituto de Geociencias IGEO, CSIC-UCM, Agencia Estatal del Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Cyril Caminade
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
- National Institute for Health Research [M1] (NIHR), Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, United Kingdom
| | - Wassila M. Thiaw
- NOAA Center for Weather and Climate Prediction, College Park, Maryland
| | - Abdoulaye Deme
- Unité de Formation et de Recherche de Sciences Appliquées et de Technologie, Université Gaston Berger, Saint Louis, Sénégal
| | - Andrew P. Morse
- National Institute for Health Research [M1] (NIHR), Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, United Kingdom
- Department of Geography and Planning, School of Environmental Sciences, University of Liverpool, Liverpool, United Kingdom
| | | | - Amadou Thierno Gaye
- Laboratoire de Physique de L’Atmosphère et de L’Océan-Siméon Fongang, Ecole Supérieure Polytechnique de L’Université Cheikh Anta Diop, Dakar, Sénégal
| | - Anta Diaw
- General Direction of Public Health, Ministry of Health and Social Action, Dakar, Senegal
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25
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Tangena JAA, Hendriks CMJ, Devine M, Tammaro M, Trett AE, Williams I, DePina AJ, Sisay A, Herizo R, Kafy HT, Chizema E, Were A, Rozier J, Coleman M, Moyes CL. Indoor residual spraying for malaria control in sub-Saharan Africa 1997 to 2017: an adjusted retrospective analysis. Malar J 2020; 19:150. [PMID: 32276585 PMCID: PMC7149868 DOI: 10.1186/s12936-020-03216-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 03/30/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Indoor residual spraying (IRS) is a key tool for controlling and eliminating malaria by targeting vectors. To support the development of effective intervention strategies it is important to understand the impact of vector control tools on malaria incidence and on the spread of insecticide resistance. In 2006, the World Health Organization (WHO) stated that countries should report on coverage and impact of IRS, yet IRS coverage data are still sparse and unspecific. Here, the subnational coverage of IRS across sub-Saharan Africa for the four main insecticide classes from 1997 to 2017 were estimated. METHODS Data on IRS deployment were collated from a variety of sources, including the President's Malaria Initiative spray reports and National Malaria Control Programme reports, for all 46 malaria-endemic countries in sub-Saharan Africa from 1997 to 2017. The data were mapped to the applicable administrative divisions and the proportion of households sprayed for each of the four main insecticide classes; carbamates, organochlorines, organophosphates and pyrethroids was calculated. RESULTS The number of countries implementing IRS increased considerably over time, although the focal nature of deployment means the number of people protected remains low. From 1997 to 2010, DDT and pyrethroids were commonly used, then partly replaced by carbamates from 2011 and by organophosphates from 2013. IRS deployment since the publication of resistance management guidelines has typically avoided overlap between pyrethroid IRS and ITN use. However, annual rotations of insecticide classes with differing modes of action are not routinely used. CONCLUSION This study highlights the gaps between policy and practice, emphasizing the continuing potential of IRS to drive resistance. The data presented here can improve studies on the impact of IRS on malaria incidence and help to guide future malaria control efforts.
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Affiliation(s)
- Julie-Anne A Tangena
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.
| | - Chantal M J Hendriks
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Maria Devine
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Meghan Tammaro
- President's Malaria Initiative Africa Indoor Residual Spraying Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Anna E Trett
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Ignatius Williams
- Monitoring, & Evaluation Department, AngloGold Ashanti Malaria Limited, AO0540595 Obuasi Mine Road, P. O. Box 10, Obuasi, Ghana
| | - Adilson José DePina
- Malaria Pre-Elimination Program, CCS-SIDA/MSSS, Avenida Cidade Lisboa, "Prédio Bô Casa" 1º Andar, CP, 855, Praia, Cabo Verde
- Ecole Doctorale Des Sciences de La Vie, de la Santé et de l´Environnement (ED‑SEV), Université Cheikh Anta Diop (UCAD) de Dakar, BP 1386, Dakar, Sénégal
| | | | - Ramandimbiarijaona Herizo
- Programme national de lutte contre le paludisme, Androhibe en face ENAM, BP 101, Antananarivo, Madagascar
| | - Hmooda Toto Kafy
- Integrated Vector Management Department, Federal Ministry of Health, Khartoum, Sudan
| | - Elizabeth Chizema
- National Malaria Elimination Centre, Chainama Hills Hospital Grounds, Lusaka, Zambia
| | - Allan Were
- President's Malaria Initiative Africa Indoor Residual Spraying Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Jennifer Rozier
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Michael Coleman
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Catherine L Moyes
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK.
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Grossman MK, Oliver SV, Brooke BD, Thomas MB. Use of alternative bioassays to explore the impact of pyrethroid resistance on LLIN efficacy. Parasit Vectors 2020; 13:179. [PMID: 32264935 PMCID: PMC7140572 DOI: 10.1186/s13071-020-04055-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/30/2020] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND There is substantial concern that the spread of insecticide resistance will render long-lasting insecticide-treated nets (LLINs) ineffective. However, there is limited evidence supporting a clear association between insecticide resistance and malaria incidence or prevalence in the field. We suggest that one reason for this disconnect is that the standard WHO assays used in surveillance to classify mosquito populations as resistant are not designed to determine how resistance might impact LLIN efficacy. The standard assays expose young, unfed female mosquitoes to a diagnostic insecticide dose in a single, forced exposure, whereas in the field, mosquitoes vary in their age, blood-feeding status, and the frequency or intensity of LLIN exposure. These more realistic conditions could ultimately impact the capacity of "resistant" mosquitoes to transmit malaria. METHODS Here, we test this hypothesis using two different assays that allow female mosquitoes to contact a LLIN as they host-seek and blood-feed. We quantified mortality after both single and multiple exposures, using seven different strains of Anopheles ranging in pyrethroid resistance intensity. RESULTS We found that strains classified as 1×-resistant to the pyrethroid insecticide deltamethrin in the standard WHO assay exhibited > 90% mortality over 24 h following more realistic LLIN contact. Mosquitoes that were able to blood-feed had increased survival compared to their unfed counterparts, but none of the 1×-resistant strains survived for 12 days post-exposure (the typical period for malaria parasite development within the mosquito). Mosquitoes that were 5×- and 10×-resistant (i.e. moderate or high intensity resistance based on the WHO assays) survived a single LLIN exposure well. However, only about 2-3% of these mosquitoes survived multiple exposures over the course of 12 days and successfully blood-fed during the last exposure. CONCLUSIONS These results suggest that the standard assays provide limited insight into how resistance might impact LLIN efficacy. In our laboratory setting, there appears little functional consequence of 1×-resistance and even mosquitoes with moderate (5×) or high (10×) intensity resistance can suffer substantial reduction in transmission potential. Monitoring efforts should focus on better characterizing intensity of resistance to inform resistance management strategies and prioritize deployment of next generation vector control products.
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Affiliation(s)
- Marissa K. Grossman
- Department of Entomology, Pennsylvania State University, University Park, PA USA
| | - Shüné V. Oliver
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Basil D. Brooke
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - Matthew B. Thomas
- Department of Entomology, Pennsylvania State University, University Park, PA USA
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Fotakis EA, Giantsis IA, Castells Sierra J, Tanti F, Balaska S, Mavridis K, Kourtidis S, Vontas J, Chaskopoulou A. Population dynamics, pathogen detection and insecticide resistance of mosquito and sand fly in refugee camps, Greece. Infect Dis Poverty 2020; 9:30. [PMID: 32183909 PMCID: PMC7079361 DOI: 10.1186/s40249-020-0635-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 02/03/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As of 2015 thousands of refugees are being hosted in temporary refugee camps in Greece. Displaced populations, travelling and living under poor conditions with limited access to healthcare are at a high risk of exposure to vector borne disease (VBD). This study sought to evaluate the risk for VBD transmission within refugee camps in Greece by analyzing the mosquito and sand fly populations present, in light of designing effective and efficient context specific vector and disease control programs. METHODS A vector/pathogen surveillance network targeting mosquitoes and sand flies was deployed in four temporary refugee camps in Greece. Sample collections were conducted bi-weekly during June-September 2017 with the use of Centers for Disease Control (CDC) light traps and oviposition traps. Using conventional and molecular diagnostic tools we investigated the mosquito/sand fly species composition, population dynamics, pathogen infection rates, and insecticide resistance status in the major vector species. RESULTS Important disease vectors including Anopheles sacharovi, Culex pipiens, Aedes albopictus and the Leishmania vectors Phlebotomus neglectus, P. perfiliewi and P. tobbi were recorded in the study refugee camps. No mosquito pathogens (Plasmodium parasites, flaviviruses) were detected in the analysed samples yet high sand fly Leishmania infection rates are reported. Culex pipiens mosquitoes displayed relatively high knock down resistance (kdr) mutation allelic frequencies (ranging from 41.0 to 63.3%) while kdr mutations were also detected in Ae. albopictus populations, but not in Anopheles and sand fly specimens. No diflubenzuron (DFB) mutations were detected in any of the mosquito species analysed. CONCLUSIONS Important disease vectors and pathogens in vectors (Leishmania spp.) were recorded in the refugee camps indicating a situational risk factor for disease transmission. The Cx. pipiens and Ae. albopictus kdr mutation frequencies recorded pose a potential threat against the effectiveness of pyrethroid insecticides in these settings. In contrast, pyrethroids appear suitable for the control of Anopheles mosquitoes and sand flies and DFB for Cx. pipiens and Ae. albopictus larvicide applications. Targeted actions ensuring adequate living conditions and the establishment of integrated vector-borne disease surveillance programs in refugee settlements are essential for protecting refugee populations against VBDs.
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Affiliation(s)
- Emmanouil Alexandros Fotakis
- Department of Crop Science, Pesticide Science Lab, Agricultural University of Athens, Athens, Greece. .,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece.
| | | | | | - Filianna Tanti
- Department of Crop Science, Pesticide Science Lab, Agricultural University of Athens, Athens, Greece
| | - Sofia Balaska
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece.,Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Konstantinos Mavridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
| | - Sofoklis Kourtidis
- General Directorate of Public Health and Social Welfare, Region of Central Macedonia, Thessaloniki, Greece
| | - John Vontas
- Department of Crop Science, Pesticide Science Lab, Agricultural University of Athens, Athens, Greece.,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
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Tedrow RE, Ratovonjato J, Walker ED, Ratsimbasoa AC, Zimmerman PA. A Novel Assay for Simultaneous Assessment of Mammalian Host Blood, Mosquito Species, and Plasmodium spp. in the Medically Important Anopheles Mosquitoes of Madagascar. Am J Trop Med Hyg 2020; 100:544-551. [PMID: 30675844 DOI: 10.4269/ajtmh.18-0782] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Anopheles mosquitoes vary in habitat preference, feeding pattern, and susceptibility to various measures of vector control. Consequently, it is important that we identify reservoirs of disease, identify vectors, and characterize feeding patterns to effectively implement targeted control measures. Using 467 anopheline mosquito abdomen squashes captured in Madagascar, we designed a novel ligase detection reaction and fluorescent microsphere assay, dubbed Bloodmeal Detection Assay for Regional Transmission (BLOODART), to query the bloodmeal content, identify five Anopheles mosquito species, and detect Plasmodium infection. Validation of mammalian bloodspots was achieved by preparation and analysis of known hosts (singular and mixed), sensitivity to degradation and storage method were assessed through mosquito feeding experiments, and quantification was explored by altering ratios of two mammal hosts. BLOODART identifications were validated by comparison with mosquito samples identified by sequenced portions of the internal transcribed spacer 2. BLOODART identification of control mammal bloodspots was 100% concordant for singular and mixed mammalian blood. BLOODART was able to detect hosts up to 42 hours after digestion when mosquito samples were stored in ethanol. A mammalian host was identified in every field-collected, blood-fed female Anopheles mosquito by BLOODART. The predominant mosquito host was cow (n = 451), followed by pig (n = 26) and human (n = 25). Mixed species bloodmeals were commonly observed (n = 33). A BLOODART molecular identification was successful for 318/467 mosquitoes, with an overall concordance of 60% with all field-captured, morphologically identified Anopheles specimens. BLOODART enables characterization of large samples and simultaneous pathogen detection to monitor and incriminate disease vectors in Madagascar.
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Affiliation(s)
- Riley E Tedrow
- Department of Biology, Case Western Reserve University, Cleveland, Ohio.,The Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Jocelyn Ratovonjato
- Direction de Lutte contre le Paludisme/National Malaria Control Program Madagascar, Antananarivo, Madagascar
| | - Edward D Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Arsene C Ratsimbasoa
- Faculty of Medicine and Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar.,Direction de Lutte contre le Paludisme/National Malaria Control Program Madagascar, Antananarivo, Madagascar
| | - Peter A Zimmerman
- The Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio.,Department of Biology, Case Western Reserve University, Cleveland, Ohio
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Hendriks CMJ, Gibson HS, Trett A, Python A, Weiss DJ, Vrieling A, Coleman M, Gething PW, Hancock PA, Moyes CL. Mapping Geospatial Processes Affecting the Environmental Fate of Agricultural Pesticides in Africa. Int J Environ Res Public Health 2019; 16:E3523. [PMID: 31547208 PMCID: PMC6801543 DOI: 10.3390/ijerph16193523] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/15/2019] [Accepted: 09/16/2019] [Indexed: 11/16/2022]
Abstract
The application of agricultural pesticides in Africa can have negative effects on human health and the environment. The aim of this study was to identify African environments that are vulnerable to the accumulation of pesticides by mapping geospatial processes affecting pesticide fate. The study modelled processes associated with the environmental fate of agricultural pesticides using publicly available geospatial datasets. Key geospatial processes affecting the environmental fate of agricultural pesticides were selected after a review of pesticide fate models and maps for leaching, surface runoff, sedimentation, soil storage and filtering capacity, and volatilization were created. The potential and limitations of these maps are discussed. We then compiled a database of studies that measured pesticide residues in Africa. The database contains 10,076 observations, but only a limited number of observations remained when a standard dataset for one compound was extracted for validation. Despite the need for more in-situ data on pesticide residues and application, this study provides a first spatial overview of key processes affecting pesticide fate that can be used to identify areas potentially vulnerable to pesticide accumulation.
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Affiliation(s)
- Chantal M J Hendriks
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford OX3 7LF, UK.
- Team Sustainable Soil Use, Wageningen Environmental Research, P.O. Box 47, 6700 AA Wageningen, The Netherlands.
| | - Harry S Gibson
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford OX3 7LF, UK.
| | - Anna Trett
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK.
| | - André Python
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford OX3 7LF, UK.
| | - Daniel J Weiss
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford OX3 7LF, UK.
| | - Anton Vrieling
- Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Michael Coleman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK.
| | - Peter W Gething
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford OX3 7LF, UK.
| | - Penny A Hancock
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford OX3 7LF, UK.
| | - Catherine L Moyes
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford OX3 7LF, UK.
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30
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Canavesi R, Miggiano R, Stella M, Galli U, Rossi F, Rizzi M, Del Grosso E. Study of Anopheles gambiae 3-hydroxykynurenine transaminase activity and inhibition by LC-MS/MS method. J Pharm Biomed Anal 2019; 173:154-61. [DOI: 10.1016/j.jpba.2019.05.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 05/08/2019] [Accepted: 05/12/2019] [Indexed: 12/17/2022]
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Fuseini G, Phiri WP, von Fricken ME, Smith J, Garcia GA. Evaluation of the residual effectiveness of Fludora™ fusion WP-SB, a combination of clothianidin and deltamethrin, for the control of pyrethroid-resistant malaria vectors on Bioko Island, Equatorial Guinea. Acta Trop 2019; 196:42-47. [PMID: 31077641 DOI: 10.1016/j.actatropica.2019.05.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 05/07/2019] [Accepted: 05/07/2019] [Indexed: 10/26/2022]
Abstract
Over the past decade, insecticide resistance to malaria vectors has been identified in 71 malaria endemic countries. This has posed a major global health challenge in the fight against malaria, with declining rates of indoor residual spraying coverage attributed to pyrethroid-resistance. As part of its vector control monitoring strategies, the Bioko Island Malaria Control Project (BIMCP) in Equatorial Guinea conducted routine insecticide resistance bioassays using the WHO's standard susceptibility tests from 2013 to 2018. During the same period, the frequency of the target-site knockdown resistance allele (kdr) in the local vector population was also determined via PCR for detection of the L1014 F mutation. Biochemical analysis for metabolic resistance was also conducted in 2015. From 2016-2017, Fludora™ fusion, a formulated combination of clothianidin (a neonicotinoid) and deltamethrin (a pyrethroid) was evaluated for 9 months on Bioko Island, using the WHO's standard test procedure for determining residual effectiveness of insecticides on sprayed surfaces. In 2016, the mortality rate of the vectors on 0.05% deltamethrin was as low as 38%. The frequency of the West African form of knockdown resistance allele, L1014 F, in the vector population was as high as 80%, and metabolic resistance analysis indicated high upregulated cytochrome P450 s. However, the residual effectiveness of Fludora™ fusion recorded mortalities above 80% after 72 h of exposure for 8 months. Although both target-site knockdown resistance and metabolic resistance to pyrethroids were implicated in the local malaria vector population, Fludora™ fusion was effective under field conditions in controlling the resistant vectors for a period of 8 months on wooden surfaces on Bioko Island and represents a valuable addition to IRS programs, especially in regions with high levels of pyrethroid resistance.
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Moyes CL, Wiebe A, Gleave K, Trett A, Hancock PA, Padonou GG, Chouaïbou MS, Sovi A, Abuelmaali SA, Ochomo E, Antonio-Nkondjio C, Dengela D, Kawada H, Dabire RK, Donnelly MJ, Mbogo C, Fornadel C, Coleman M. Analysis-ready datasets for insecticide resistance phenotype and genotype frequency in African malaria vectors. Sci Data 2019; 6:121. [PMID: 31308378 PMCID: PMC6629700 DOI: 10.1038/s41597-019-0134-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 06/19/2019] [Indexed: 12/19/2022] Open
Abstract
The impact of insecticide resistance in malaria vectors is poorly understood and quantified. Here a series of geospatial datasets for insecticide resistance in malaria vectors are provided, so that trends in resistance in time and space can be quantified, and the impact of resistance found in wild populations on malaria transmission in Africa can be assessed. Specifically, data have been collated and geopositioned for the prevalence of insecticide resistance, as measured by standard bioassays, in representative samples of individual species or species complexes. Data are provided for the Anopheles gambiae species complex, the Anopheles funestus subgroup, and for nine individual vector species. Data are also given for common genetic markers of resistance to support analyses of whether these markers can improve the ability to monitor resistance in low resource settings. Allele frequencies for known resistance-associated markers in the Voltage-gated sodium channel (Vgsc) are provided. In total, eight analysis-ready, standardised, geopositioned datasets encompassing over 20,000 African mosquito collections between 1957 and 2017 are released.
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Affiliation(s)
- Catherine L Moyes
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX1 7LF, UK.
| | - Antoinette Wiebe
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX1 7LF, UK
| | - Katherine Gleave
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L1, UK
| | - Anna Trett
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L1, UK
| | - Penelope A Hancock
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX1 7LF, UK
| | - Germain Gil Padonou
- Centre de Recherche Entomologique de Cotonou (CREC), 06BP2604, Cotonou, Benin
| | - Mouhamadou S Chouaïbou
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01BP1303, Abj 01, Abidjan, Côte d'Ivoire
| | - Arthur Sovi
- Centre de Recherche Entomologique de Cotonou (CREC), 06BP2604, Cotonou, Benin
- Faculty of Agronomy, University of Parakou, BP123, Parakou, Benin
| | - Sara A Abuelmaali
- Department of Medical Entomology, National Public Health Laboratory, Federal Ministry of Health, Khartoum, Sudan
| | - Eric Ochomo
- Kenya Medical Research Institute, Center for Global Health Research, Kisumu, Kenya
| | - Christophe Antonio-Nkondjio
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Dereje Dengela
- U.S. PMI VectorLink Project, Abt Associates, 6130 Executive Boulevard, Rockville, MD, 20852, USA
| | - Hitoshi Kawada
- Department of Vector Ecology and Environment, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Roch K Dabire
- Department of Medical Biology and Public Health, Institut de Recherche en Science de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L1, UK
| | - Charles Mbogo
- KEMRI Centre for Geographic Medicine Research-Coast, P.O Box 230-80108, Kilifi, Kenya
- KEMRI-Wellcome Trust Research Program, P.O Box 43640-00100, Nairobi, Kenya
| | - Christen Fornadel
- US President's Malaria Initiative, US Agency for International Development, Washington, DC, USA
| | - Michael Coleman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L1, UK
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Nelli L, Ferguson HM, Matthiopoulos J. Achieving explanatory depth and spatial breadth in infectious disease modelling: Integrating active and passive case surveillance. Stat Methods Med Res 2019; 29:1273-1287. [PMID: 31213191 DOI: 10.1177/0962280219856380] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ideally, the data used for robust spatial prediction of disease distribution should be both high-resolution and spatially expansive. However, such in-depth and geographically broad data are rarely available in practice. Instead, researchers usually acquire either detailed epidemiological data with high resolution at a small number of active sampling sites, or more broad-ranging but less precise data from passive case surveillance. We propose a novel inferential framework, capable of simultaneously drawing insights from both passive and active data types. We developed a Bayesian latent point process approach, combining active data collection in a limited set of points, where in-depth covariates are measured, with passive case detection, where error-prone, large-scale disease data are accompanied only by coarse or remotely-sensed covariate layers. Using the example of malaria, we tested our method's efficiency under several hypothetical scenarios of reported incidence in different combinations of imperfect detection and spatial complexity of the environmental variables. We provide a simple solution to a widespread problem in spatial epidemiology, combining latent process modelling and spatially autoregressive modelling. By using active sampling and passive case detection in a complementary way, we achieved the best-of-both-worlds, in effect, a formal calibration of spatially extensive, error-prone data by localised, high-quality data.
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Affiliation(s)
- Luca Nelli
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Heather M Ferguson
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Jason Matthiopoulos
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
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Silva Martins WF, Silva Pereira BN, Vieira Alves AT, Murphy A, Silva Martins PG, Weetman D, Wilding CS, Donnelly MJ. Development and application of a tri-allelic PCR assay for screening Vgsc-L1014F kdr mutations associated with pyrethroid and organochlorine resistance in the mosquito Culex quinquefasciatus. Parasit Vectors 2019; 12:232. [PMID: 31088572 PMCID: PMC6518802 DOI: 10.1186/s13071-019-3490-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/06/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Culex quinquefasciatus has a widespread distribution across tropical and sub-tropical regions, and plays an important role in the transmission of vector-borne diseases of public health importance, including lymphatic filariasis (LF) and multiple arboviruses. Increased resistance to insecticides threatens the efficacy and sustainability of insecticide-based anti-vector interventions which mitigate the burden of mosquito transmitted diseases in endemic regions. In C. quinquefasciatus two non-synonymous voltage gated sodium channel (Vgsc) variants, both resulting in a leucine to phenylalanine change at codon 1014, are associated with resistance to pyrethroids and DDT. This tri-allelic variation has compromised the ability to perform high-throughput single-assay screening. To facilitate the detection and monitoring of the Vgsc-1014 locus in field-caught mosquitoes, an Engineered-Tail Allele-Specific-PCR (ETAS-PCR) diagnostic assay was developed and applied to wild mosquitoes from Brazil, Tanzania and Uganda. RESULTS This new cost-effective, single-tube assay was compared to two, well-established, genotyping approaches, pyrosequencing and TaqMan. The ETAS-PCR assay showed high specificity for discriminating the three alleles at Vgsc-L1014F, with genotyping results strongly correlated with pyrosequencing and TaqMan results (98.64% and 100% respectively). CONCLUSIONS Our results support the utility of the ETAS-PCR/Vgsc-1014 diagnostic assay, which stands as an effective alternative for genotyping tri-allelic variants.
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Affiliation(s)
- Walter Fabricio Silva Martins
- Laboratório de Entomologia Médica e Molecular, Departamento de Biologia, CCBS, Universidade Estadual da Paraíba, Campina Grande, Paraíba, Brasil
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | | | - Ana Thayse Vieira Alves
- Laboratório de Entomologia Médica e Molecular, Departamento de Biologia, CCBS, Universidade Estadual da Paraíba, Campina Grande, Paraíba, Brasil
- Departamento de Farmácia, CCBS, Universidade Estadual da Paraíba, Campina Grande, Paraíba, Brasil
| | - Annabel Murphy
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Paulo Geovani Silva Martins
- Laboratório de Interações Insetos-Tóxicos, Departamento de Agronomia e Fitossanidade, Universidade Federal Rural de Pernambuco, Recife, Brasil
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Craig Stephen Wilding
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - Martin James Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
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Si FL, Qiao L, He QY, Zhou Y, Yan ZT, Chen B. HSP superfamily of genes in the malaria vector Anopheles sinensis: diversity, phylogenetics and association with pyrethroid resistance. Malar J 2019; 18:132. [PMID: 30975215 PMCID: PMC6460852 DOI: 10.1186/s12936-019-2770-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/06/2019] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Heat shock proteins (HSPs) are molecular chaperones that are involved in many normal cellular processes and various kinds of environmental stress. There is still no report regarding the diversity and phylogenetics research of HSP superfamily of genes at whole genome level in insects, and the HSP gene association with pyrethroid resistance is also not well known. The present study investigated the diversity, classification, scaffold location, characteristics, and phylogenetics of the superfamily of genes in Anopheles sinensis genome, and the HSP genes associated with pyrethroid resistance. METHODS The present study identified the HSP genes in the An. sinensis genome, analysed their characteristics, and deduced phylogenetic relationships of all HSPs in An. sinensis, Anopheles gambiae, Culex quinquefasciatus and Aedes aegypti by bioinformatic methods. Importantly, the present study screened the HSPs associated with pyrethroid resistance using three field pyrethroid-resistant populations with RNA-seq and RT-qPCR, and looked over the HSP gene expression pattern for the first time in An. sinensis on the time-scale post insecticide treatment with RT-qPCR. RESULTS There are 72 HSP genes in An. sinensis genome, and they are classified into five families and 11 subfamilies based on their molecular weight, homology and phylogenetics. Both RNA-seq and qPCR analysis revealed that the expression of AsHSP90AB, AsHSP70-2 and AsHSP21.7 are significantly upregulated in at least one field pyrethroid-resistant population. Eleven genes are significantly upregulated in different period after pyrethroid exposure. The HSP90, sHSP and HSP70 families are proposed to be involved in pyrethroid stress response based in expression analyses of three field pyrethroid-resistant populations, and expression pattern on the time scale post insecticide treatment. The AsHSP90AB gene is proposed to be the essential HSP gene for pyrethroid stress response in An. sinensis. CONCLUSIONS This study provides the information frame for HSP superfamily of genes, and lays an important basis for the better understanding and further research of HSP function in insect adaptability to diverse environments.
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Affiliation(s)
- Feng-Ling Si
- School of Life Sciences, Chongqing University, Chongqing, 401331, China
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, Chongqing Normal University, Chongqing, 401331, China
| | - Liang Qiao
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, Chongqing Normal University, Chongqing, 401331, China
| | - Qi-Yi He
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, Chongqing Normal University, Chongqing, 401331, China
| | - Yong Zhou
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, Chongqing Normal University, Chongqing, 401331, China
| | - Zhen-Tian Yan
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, Chongqing Normal University, Chongqing, 401331, China
| | - Bin Chen
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, Chongqing Normal University, Chongqing, 401331, China.
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Mackenzie-Impoinvil L, Weedall GD, Lol JC, Pinto J, Vizcaino L, Dzuris N, Riveron J, Padilla N, Wondji C, Lenhart A. Contrasting patterns of gene expression indicate differing pyrethroid resistance mechanisms across the range of the New World malaria vector Anopheles albimanus. PLoS One 2019; 14:e0210586. [PMID: 30699158 PMCID: PMC6353143 DOI: 10.1371/journal.pone.0210586] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 12/25/2018] [Indexed: 11/18/2022] Open
Abstract
Decades of unmanaged insecticide use and routine exposure to agrochemicals have left many populations of malaria vectors in the Americas resistant to multiple classes of insecticides, including pyrethroids. The molecular basis of pyrethroid resistance is relatively uncharacterised in American malaria vectors, preventing the design of suitable resistance management strategies. Using whole transcriptome sequencing, we characterized the mechanisms of pyrethroid resistance in Anopheles albimanus from Peru and Guatemala. An. albimanus were phenotyped as either deltamethrin or alpha-cypermethrin resistant. RNA from 1) resistant, 2) unexposed, and 3) a susceptible laboratory strain of An. albimanus was sequenced and analyzed using RNA-Seq. Expression profiles of the three groups were compared based on the current annotation of the An. albimanus reference genome. Several candidate genes associated with pyrethroid resistance in other malaria vectors were found to be overexpressed in resistant An. albimanus. In addition, gene ontology terms related to serine-type endopeptidase activity, extracellular activity and chitin metabolic process were also commonly overexpressed in the field caught resistant and unexposed samples from both Peru and Guatemala when compared to the susceptible strain. The cytochrome P450 CYP9K1 was overexpressed 14x in deltamethrin and 8x in alpha-cypermethrin-resistant samples from Peru and 2x in deltamethrin-resistant samples from Guatemala, relative to the susceptible laboratory strain. CYP6P5 was overexpressed 68x in deltamethrin-resistant samples from Peru but not in deltamethrin-resistant samples from Guatemala. When comparing overexpressed genes between deltamethrin-resistant and alpha-cypermethrin-resistant samples from Peru, a single P450 gene, CYP4C26, was overexpressed 9.8x (p<0.05) in alpha-cypermethrin-resistant samples. In Peruvian deltamethrin-resistant samples, the knockdown resistance mutation (kdr) variant alleles at position 1014 were rare, with approximately 5% frequency, but in the alpha-cypermethrin-resistant samples, the frequency of these alleles was approximately 15-30%. Functional validation of the candidate genes and the kdr mutation as a resistance marker for alpha-cypermethrin will confirm the role of these mechanisms in conferring pyrethroid resistance.
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Affiliation(s)
- Lucy Mackenzie-Impoinvil
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Gareth D. Weedall
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, United Kingdom
| | - Juan C. Lol
- Centro de Estudios en Salud, Universidad del Valle de Guatemala, Guatemala
| | - Jesús Pinto
- Instituto Nacional de Salud Lima, Lima, Peru
| | - Lucrecia Vizcaino
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Nicole Dzuris
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Jacob Riveron
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Norma Padilla
- Centro de Estudios en Salud, Universidad del Valle de Guatemala, Guatemala
| | - Charles Wondji
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Audrey Lenhart
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail:
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Vajravijayan S, Pletnev S, Pletnev VZ, Nandhagopal N, Gunasekaran K. Crystal structure of a novel Kunitz type inhibitor, alocasin with anti-Aedes aegypti activity targeting midgut proteases. Pest Manag Sci 2018; 74:2761-2772. [PMID: 29737039 DOI: 10.1002/ps.5063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/13/2018] [Accepted: 04/30/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND The pesticidal properties of many Kunitz-type inhibitors have been reported previously; however, the mechanism of action is not well established. In this study, the activity of alocasin against Aedes aegypti is demonstrated and the structure-activity relationship of this Kunitz-type inhibitor is explained through X-ray structure analyses. RESULTS Alocasin was purified from mature rhizomes of Alocasia as a single polypeptide chain of ∼ 20 kDa. The structure at 2.5 Å resolution revealed a Kunitz-type fold, but variation in the loop regions makes this structure unique; one loop with a single disulfide bridge is replaced by a long loop with two bridges. Alignment of homologous sequences revealed that this long loop contains a conserved Arg residue and modeling studies showed interaction with the catalytic Ser residue of trypsin-like enzymes. The anti-Aedes aegypti activity of alocasin is examined and discussed in detail. The in vitro activity of alocasin against midgut proteases of Aedes aegypti showed profound inhibition. Further, morphological changes in larvae upon treatment with alocasin revealed its activity against Ae. aegypti. Docking studies of alocasin with trypsin (5G1), a midgut protease involved in the development cycle and blood meal digestion, illustrated its insecticidal activity. CONCLUSION The three-dimensional structure of alocasin was determined and its structure-function relationship established for its anti Ae. aegypti activity. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Senthilvadivel Vajravijayan
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, India
| | - Sergei Pletnev
- Macromolecular Crystallography Laboratory, National Cancer Institute, and Basic Science Program, Leidos Biomedical Research Inc., Argonne, IL, USA
| | - Vladimir Z Pletnev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Narayanasamy Nandhagopal
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, India
| | - Krishnasamy Gunasekaran
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, India
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Janko MM, Churcher TS, Emch ME, Meshnick SR. 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 DOI: 10.1038/s41598-018-35353-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Xu J, Su X, Bonizzoni M, Zhong D, Li Y, Zhou G, Nguyen H, Tong S, Yan G, Chen XG. Comparative transcriptome analysis and RNA interference reveal CYP6A8 and SNPs related to pyrethroid resistance in Aedes albopictus. PLoS Negl Trop Dis 2018; 12:e0006828. [PMID: 30418967 PMCID: PMC6258463 DOI: 10.1371/journal.pntd.0006828] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 11/26/2018] [Accepted: 09/11/2018] [Indexed: 11/19/2022] Open
Abstract
Wide and improper application of pyrethroid insecticides for mosquito control has resulted in widespread resistance in Aedes albopictus mosquitoes, an important dengue vector. Therefore, understanding the molecular regulation of insecticide resistance is urgently needed to provide a basis for developing novel resistance diagnostic methods and vector control approaches. We investigated the transcriptional profiles of deltamethrin-resistant and -susceptible Ae. albopictus by performing paired-end sequencing for RNA expression analysis. The analysis used 24 independent libraries constructed from 12 wild-caught resistant and 12 susceptible Ae. albopictus female adults. A total of 674,503,592 and 612,512,034 reads were obtained, mapped to the Ae. albopictus genome and assembled into 20,091 Ae. albopictus transcripts. A total of 1,130 significantly differentially expressed genes included 874 up-regulated genes and 256 down-regulated genes in the deltamethrin-resistant individuals. These differentially expressed genes code for cytochrome P450s, cuticle proteins, glutathione S-transferase, serine proteases, heat shock proteins, esterase, and others. We selected three highly differentially expressed candidate genes, CYP6A8 and two genes of unknown function (CCG013931 and CCG000656), to test the association between these 3 genes and deltamethrin resistance using RNAi through microinjection in adult mosquitoes and oral feeding in larval mosquitoes. We found that expression knockdown of these three genes caused significant changes in resistance. Further, we detected 1,162 single nucleotide polymorphisms (SNPs) with a frequency difference of more than 50%. Among them, 5 SNPs in 4 cytochrome P450 gene families were found to be significantly associated with resistance in a genotype-phenotype association study using independent field-collected mosquitoes of known resistance phenotypes. Altogether, a combination of novel individually based transcriptome profiling, RNAi, and genetic association study identified both differentially expressed genes and SNPs associated with pyrethroid resistance in Ae. albopictus mosquitoes, and laid a useful foundation for further studies on insecticide resistance mechanisms.
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Affiliation(s)
- Jiabao Xu
- Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Xinghua Su
- Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
| | | | - Daibin Zhong
- Program in Public Health, University of California, Irvine, Irvine, CA, United States of America
| | - Yiji Li
- Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
- Key Laboratory of Translational Medicine Tropical Diseases of Ministry of Education and Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan, China
| | - Guofa Zhou
- Program in Public Health, University of California, Irvine, Irvine, CA, United States of America
| | - Hoan Nguyen
- Program in Public Health, University of California, Irvine, Irvine, CA, United States of America
| | - Sarah Tong
- Program in Public Health, University of California, Irvine, Irvine, CA, United States of America
| | - Guiyun Yan
- Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
- Program in Public Health, University of California, Irvine, Irvine, CA, United States of America
| | - Xiao-Guang Chen
- Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
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Implications of Insecticide Resistance Consortium. Implications of insecticide resistance for malaria vector control with long-lasting insecticidal nets: trends in pyrethroid resistance during a WHO-coordinated multi-country prospective study. Parasit Vectors 2018; 11:550. [PMID: 30348209 DOI: 10.1186/s13071-018-3101-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 09/06/2018] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Increasing pyrethroid resistance has been an undesirable correlate of the rapid increase in coverage of insecticide-treated nets (ITNs) since 2000. Whilst monitoring of resistance levels has increased markedly over this period, longitudinal monitoring is still lacking, meaning the temporal and spatial dynamics of phenotypic resistance in the context of increasing ITN coverage are unclear. METHODS As part of a large WHO-co-ordinated epidemiological study investigating the impact of resistance on malaria infection, longitudinal monitoring of phenotypic resistance to pyrethroids was undertaken in 290 clusters across Benin, Cameroon, India, Kenya and Sudan. Mortality in response to pyrethroids in the major anopheline vectors in each location was recorded during consecutive years using standard WHO test procedures. Trends in mosquito mortality were examined using generalised linear mixed-effect models. RESULTS Insecticide resistance (using the WHO definition of mortality < 90%) was detected in clusters in all countries across the study period. The highest mosquito mortality (lowest resistance frequency) was consistently reported from India, in an area where ITNs had only recently been introduced. Substantial temporal and spatial variation was evident in mortality measures in all countries. Overall, a trend of decreasing mosquito mortality (increasing resistance frequency) was recorded (Odds Ratio per year: 0.79 per year (95% CI: 0.79-0.81, P < 0.001). There was also evidence that higher net usage was associated with lower mosquito mortality in some countries. DISCUSSION Pyrethroid resistance increased over the study duration in four out of five countries. Insecticide-based vector control may be compromised as a result of ever higher resistance frequencies.
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Gorouhi MA, Oshaghi MA, Vatandoost H, Enayati AA, Raeisi A, Abai MR, Salim-Abadie Y, Hanafi-Bojd AA, Paksa A, Nikpoor F. Biochemical Basis of Cyfluthrin and DDT Resistance in Anopheles stephensi (Diptera: Culicidae) in Malarious Area of Iran. J Arthropod Borne Dis 2018; 12:310-320. [PMID: 30584554 PMCID: PMC6297723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 09/24/2018] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Anopheles stephensi is a key urban malaria vector in the Indian subcontinent and Middle East including south and southeast of Iran. Wide application of insecticides resulted in resistance of this species to various insecticides in these regions. This study was conducted to reveal the role of metabolic mechanisms in the development of resistance in An. stephensi to DDT and cyfluthrin. METHODS Field mosquito specimens were collected from Chabahar Seaport, southeast corner of Iran, in 2015. Insecticide susceptibility and enzyme assays were conducted as recommended by WHO. RESULTS Mean enzyme ratios were 3.95 and 3.04 for α- esterases and 2.40 and 1.97 for β- esterases in the DDT and cyfluthrin- resistant populations correspondingly compared with the susceptible strain. The GSTs enzyme mean activity ratios were 5.07 and 2.55 in the DDT and cyfluthrin- resistant populations compared with the susceptible beech strain. The cytochrome p450s enzyme ratios were 1.11 and 1.28 in the DDT and cyfluthrin- resistant populations respectively compared with the susceptible beech strain. CONCLUSION Metabolic mechanisms play a crucial role in the development of DDT and cyfluthrin resistance in An. stephensi, therefore, further evaluation of the mechanisms involved as well as implementation of proper insecticide resistance management strategies are recommended.
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Affiliation(s)
- Mohammad Amin Gorouhi
- Department of Vector Biology and Control, School of Health, Kerman University of Medical Sciences, Kerman, Iran,Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ali Oshaghi
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran,Corresponding authors: Dr Mohammad Ali Oshaghi, E-mail: , Dr Hassan Vatandoost, E-mail: ,
| | - Hassan Vatandoost
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran,Dept. of Chemical Pollutants and Pesticides, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran,Corresponding authors: Dr Mohammad Ali Oshaghi, E-mail: , Dr Hassan Vatandoost, E-mail: ,
| | | | - Ahmad Raeisi
- National Programme Manager for Malaria Control, Ministry of Health, Tehran, Iran
| | - Mohamad Reza Abai
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran,Dept. of Chemical Pollutants and Pesticides, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Yaser Salim-Abadie
- Department of Health Service and Health Promotion, School of Health, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Ahmad Ali Hanafi-Bojd
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran,Dept. of Chemical Pollutants and Pesticides, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Azim Paksa
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Nikpoor
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran,Dept. of Chemical Pollutants and Pesticides, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran
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Hancock PA, Wiebe A, Gleave KA, Bhatt S, Cameron E, Trett A, Weetman D, Smith DL, Hemingway J, Coleman M, Gething PW, Moyes CL. Associated patterns of insecticide resistance in field populations of malaria vectors across Africa. Proc Natl Acad Sci U S A 2018; 115:5938-5943. [PMID: 29784773 PMCID: PMC6003363 DOI: 10.1073/pnas.1801826115] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The development of insecticide resistance in African malaria vectors threatens the continued efficacy of important vector control methods that rely on a limited set of insecticides. To understand the operational significance of resistance we require quantitative information about levels of resistance in field populations to the suite of vector control insecticides. Estimation of resistance is complicated by the sparsity of observations in field populations, variation in resistance over time and space at local and regional scales, and cross-resistance between different insecticide types. Using observations of the prevalence of resistance in mosquito species from the Anopheles gambiae complex sampled from 1,183 locations throughout Africa, we applied Bayesian geostatistical models to quantify patterns of covariation in resistance phenotypes across different insecticides. For resistance to the three pyrethroids tested, deltamethrin, permethrin, and λ-cyhalothrin, we found consistent forms of covariation across sub-Saharan Africa and covariation between resistance to these pyrethroids and resistance to DDT. We found no evidence of resistance interactions between carbamate and organophosphate insecticides or between these insecticides and those from other classes. For pyrethroids and DDT we found significant associations between predicted mean resistance and the observed frequency of kdr mutations in the Vgsc gene in field mosquito samples, with DDT showing the strongest association. These results improve our capacity to understand and predict resistance patterns throughout Africa and can guide the development of monitoring strategies.
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Affiliation(s)
- Penelope A Hancock
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, OX3 7LF Oxford, United Kingdom;
| | - Antoinette Wiebe
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, OX3 7LF Oxford, United Kingdom
| | - Katherine A Gleave
- Department of Vector Biology, Liverpool School of Tropical Medicine, L3 5QA Liverpool, United Kingdom
| | - Samir Bhatt
- Department of Infectious Disease Epidemiology, St Mary's Hospital, Imperial College, W2 1NY London, United Kingdom
| | - Ewan Cameron
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, OX3 7LF Oxford, United Kingdom
| | - Anna Trett
- Department of Vector Biology, Liverpool School of Tropical Medicine, L3 5QA Liverpool, United Kingdom
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, L3 5QA Liverpool, United Kingdom
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA 98121
| | - Janet Hemingway
- Department of Vector Biology, Liverpool School of Tropical Medicine, L3 5QA Liverpool, United Kingdom;
| | - Michael Coleman
- Department of Vector Biology, Liverpool School of Tropical Medicine, L3 5QA Liverpool, United Kingdom
| | - Peter W Gething
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, OX3 7LF Oxford, United Kingdom
| | - Catherine L Moyes
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, OX3 7LF Oxford, United Kingdom;
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Huijben S, Paaijmans KP. Putting evolution in elimination: Winning our ongoing battle with evolving malaria mosquitoes and parasites. Evol Appl 2018; 11:415-430. [PMID: 29636796 PMCID: PMC5891050 DOI: 10.1111/eva.12530] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/01/2017] [Indexed: 12/17/2022] Open
Abstract
Since 2000, the world has made significant progress in reducing malaria morbidity and mortality, and several countries in Africa, South America and South-East Asia are working hard to eliminate the disease. These elimination efforts continue to rely heavily on antimalarial drugs and insecticide-based interventions, which remain the cornerstones of malaria treatment and prevention. However, resistance has emerged against nearly every antimalarial drug and insecticide that is available. In this review we discuss the evolutionary consequences of the way we currently implement antimalarial interventions, which is leading to resistance and may ultimately lead to control failure, but also how evolutionary principles can be applied to extend the lifespan of current and novel interventions. A greater understanding of the general evolutionary principles that are at the core of emerging resistance is urgently needed if we are to develop improved resistance management strategies with the ultimate goal to achieve a malaria-free world.
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Affiliation(s)
- Silvie Huijben
- ISGlobalBarcelona Ctr. Int. Health Res. (CRESIB)Hospital Clínic ‐ Universitat de BarcelonaBarcelonaSpain
| | - Krijn P. Paaijmans
- ISGlobalBarcelona Ctr. Int. Health Res. (CRESIB)Hospital Clínic ‐ Universitat de BarcelonaBarcelonaSpain
- Centro de Investigação em Saúde de ManhiçaMaputoMozambique
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Briand D, Roux E, Desconnets JC, Gervet C, Barcellos C. From global action against malaria to local issues: state of the art and perspectives of web platforms dealing with malaria information. Malar J 2018; 17:122. [PMID: 29562918 PMCID: PMC5863370 DOI: 10.1186/s12936-018-2270-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 03/13/2018] [Indexed: 11/30/2022] Open
Abstract
Background Since prehistory to present times and despite a rough combat against it, malaria remains a concern for human beings. While evolutions of science and technology through times allowed for some infectious diseases eradication in the 20th century, malaria resists. Objectives This review aims at assessing how Internet and web technologies are used in fighting malaria. Precisely, how do malaria fighting actors profit from these developments, how do they deal with ensuing phenomena, such as the increase of data volume, and did these technologies bring new opportunities for fighting malaria? Methods Eleven web platforms linked to spatio-temporal malaria information are reviewed, focusing on data, metadata, web services and categories of users. Results Though the web platforms are highly heterogeneous the review reveals that the latest advances in web technologies are underused. Information are rarely updated dynamically, metadata catalogues are absent, web services are more and more used, but rarely standardized, and websites are mainly dedicated to scientific communities, essentially researchers. Conclusion Improvement of systems interoperability, through standardization, is an opportunity to be seized in order to allow real time information exchange and online multisource data analysis. To facilitate multidisciplinary/multiscale studies, the web of linked data and the semantic web innovations can be used in order to formalize the different view points of actors involved in the combat against malaria. By doing so, new malaria fighting strategies could take place, to tackle the bottlenecks listed in the United Nation Millennium Development Goals reports, but also specific issues highlighted by the World Health Organization such as malaria elimination in international borders. Electronic supplementary material The online version of this article (10.1186/s12936-018-2270-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dominique Briand
- FIOCRUZ, LIS Laboratory, Avenida Brasil, 4365, Pavilhão Haity Moussatché, Rio de Janeiro, Brazil. .,IRD, UMR ESPACE-DEV, Maison de la télédétection, 500 rue Jean François Breton, 34090, Montpelllier, France.
| | - Emmanuel Roux
- IRD, UMR ESPACE-DEV, Maison de la télédétection, 500 rue Jean François Breton, 34090, Montpelllier, France
| | - Jean Christophe Desconnets
- IRD, UMR ESPACE-DEV, Maison de la télédétection, 500 rue Jean François Breton, 34090, Montpelllier, France
| | - Carmen Gervet
- Université de Montpellier, UMR ESPACE-DEV, Maison de la télédétection, 500 rue Jean François Breton, 34090, Montpellier, France
| | - Christovam Barcellos
- FIOCRUZ, LIS Laboratory, Avenida Brasil, 4365, Pavilhão Haity Moussatché, Rio de Janeiro, Brazil
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Abstract
Our planet is an increasingly urbanized landscape, with over half of the human population residing in cities. Despite advances in urban ecology, we do not adequately understand how urbanization affects the evolution of organisms, nor how this evolution may affect ecosystems and human health. Here, we review evidence for the effects of urbanization on the evolution of microbes, plants, and animals that inhabit cities. Urbanization affects adaptive and nonadaptive evolutionary processes that shape the genetic diversity within and between populations. Rapid adaptation has facilitated the success of some native species in urban areas, but it has also allowed human pests and disease to spread more rapidly. The nascent field of urban evolution brings together efforts to understand evolution in response to environmental change while developing new hypotheses concerning adaptation to urban infrastructure and human socioeconomic activity. The next generation of research on urban evolution will provide critical insight into the importance of evolution for sustainable interactions between humans and our city environments.
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Affiliation(s)
- Marc T J Johnson
- Department of Biology and Center for Urban Environments, University of Toronto Mississauga, Mississauga, Ontario, Canada. .,Department of Ecology and Evolutionary Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Jason Munshi-South
- Department of Biological Sciences and Louis Calder Center, Fordham University, Armonk, NY, USA.
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Pinilla YT, C P Lopes S, S Sampaio V, Andrade FS, Melo GC, Orfanó AS, Secundino NFC, Guerra MGVB, Lacerda MVG, Kobylinski KC, Escobedo-Vargas KS, López-Sifuentes VM, Stoops CA, Baldeviano GC, Tarning J, Vasquez GM, Pimenta PFP, Monteiro WM. Promising approach to reducing Malaria transmission by ivermectin: Sporontocidal effect against Plasmodium vivax in the South American vectors Anopheles aquasalis and Anopheles darlingi. PLoS Negl Trop Dis 2018; 12:e0006221. [PMID: 29444080 DOI: 10.1371/journal.pntd.0006221] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 02/27/2018] [Accepted: 01/08/2018] [Indexed: 12/20/2022] Open
Abstract
Background The mosquito resistance to the insecticides threatens malaria control efforts, potentially becoming a major public health issue. Alternative methods like ivermectin (IVM) administration to humans has been suggested as a possible vector control to reduce Plasmodium transmission. Anopheles aquasalis and Anopheles darlingi are competent vectors for Plasmodium vivax, and they have been responsible for various malaria outbreaks in the coast of Brazil and the Amazon Region of South America. Methods To determine the IVM susceptibility against P. vivax in An. aquasalis and An. darlingi, ivermectin were mixed in P. vivax infected blood: (1) Powdered IVM at four concentrations (0, 5, 10, 20 or 40 ng/mL). (2) Plasma (0 hours, 4 hours, 1 day, 5, 10 and 14 days) was collected from healthy volunteers after to administer a single oral dose of IVM (200 μg/kg) (3) Mosquitoes infected with P. vivax and after 4 days was provided with IVM plasma collected 4 hours post-treatment (4) P. vivax-infected patients were treated with various combinations of IVM, chloroquine, and primaquine and plasma or whole blood was collected at 4 hours. Seven days after the infective blood meal, mosquitoes were dissected to evaluate oocyst presence. Additionally, the ex vivo effects of IVM against asexual blood-stage P. vivax was evaluated. Results IVM significantly reduced the prevalence of An. aquasalis that developed oocysts in 10 to 40 ng/mL pIVM concentrations and plasma 4 hours, 1 day and 5 days. In An. darlingi to 4 hours and 1 day. The An. aquasalis mortality was expressively increased in pIVM (40ng/mL) and plasma 4 hours, 1, 5 10 and 14 days post-intake drug and in An. darlingi only to 4 hours and 1 day. The double fed meal with mIVM by the mosquitoes has a considerable impact on the proportion of infected mosquitoes for 7 days post-feeding. The oocyst infection prevalence and intensity were notably reduced when mosquitoes ingested blood from P. vivax patients that ingested IVM+CQ, PQ+CQ and IVM+PQ+CQ. P. vivax asexual development was considerably inhibited by mIVM at four-fold dilutions. Conclusion In conclusion, whole blood spiked with IVM reduced the infection rate of P. vivax in An. aquasalis and An. darlingi, and increased the mortality of mosquitoes. Plasma from healthy volunteers after IVM administration affect asexual P. vivax development. These findings support that ivermectin may be used to decrease P. vivax transmission. Malaria is one of the most important infectious diseases in the world with hundreds of millions of new cases every year. The disease is caused by parasites of the genus Plasmodium where Plasmodium vivax represent most of the cases in the Americas. Current strategies to combat malaria transmission are being implemented; however, widespread insecticide resistance in vectors threatens the effectiveness of vector control programs. Ivermectin (IVM) has arisen as a new potential tool to be added to these programs as it has mosquito-lethal and sporontocidal properties making it a promising transmission reduction drug. Plasmodium vivax was drawn from patients, mixed with powdered IVM and metabolized IVM in plasma collected from healthy volunteers receiving IVM, and fed to mosquitoes via membrane feeding. Powdered and metabolized IVM interrupt P. vivax transmission, reducing oocyst infection and intensity rate of two South American malaria vectors An. aquasalis and An. darlingi. We also demonstrate the effect of IVM on asexual stages development of P. vivax, providing evidence that IVM may affect different parasite life cycle stages. Our findings place IVM as a strong candidate for malaria transmission reducing interventions.
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Abstract
PURPOSE OF REVIEW Malaria remains a global burden contributing to morbidity and mortality especially in children under 5 years of age. Despite the progress achieved towards malaria burden reduction, achieving elimination in more countries remains a challenge. This article aims to review the prevention and control strategies for malaria, to assess their impact towards reducing the disease burden and to highlight the best practices observed. RECENT FINDINGS Use of long-lasting insecticide-treated nets and indoor residual spraying has resulted a decline in the incidence and prevalence of malaria in Sub-Saharan Africa. Other strategies such as larval source management have been shown to reduce mosquito density but require further evaluation. New methods under development such as house improvement have demonstrated to minimize disease burden but require further evidence on efficacy. Development of the RTS,S/AS01 malaria vaccine that provides protection in under-five children has provided further progress in efforts of malaria control. SUMMARY There has been a tremendous reduction in malaria burden in the past decade; however, more work is required to fill the necessary gaps to eliminate malaria.
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Affiliation(s)
- Tinashe A. Tizifa
- Training and Research Unit of Excellence (TRUE), Public Health Department, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Alinune N. Kabaghe
- Training and Research Unit of Excellence (TRUE), Public Health Department, College of Medicine, University of Malawi, Blantyre, Malawi
- Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Robert S. McCann
- Training and Research Unit of Excellence (TRUE), Public Health Department, College of Medicine, University of Malawi, Blantyre, Malawi
- Wageningen University and Research Center, Wageningen, Netherlands
| | | | - Michele Van Vugt
- Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Kamija S. Phiri
- Training and Research Unit of Excellence (TRUE), Public Health Department, College of Medicine, University of Malawi, Blantyre, Malawi
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48
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Prosser C, Meyer W, Ellis J, Lee R. Evolutionary ARMS Race: Antimalarial Resistance Molecular Surveillance. Trends Parasitol 2018; 34:322-334. [PMID: 29396203 DOI: 10.1016/j.pt.2018.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/02/2018] [Accepted: 01/03/2018] [Indexed: 01/13/2023]
Abstract
Molecular surveillance of antimalarial drug resistance markers has become an important part of resistance detection and containment. In the current climate of multidrug resistance, including resistance to the global front-line drug artemisinin, there is a consensus to upscale molecular surveillance. The most salient limitation to current surveillance efforts is that skill and infrastructure requirements preclude many regions. This includes sub-Saharan Africa, where Plasmodium falciparum is responsible for most of the global malaria disease burden. New molecular and data technologies have emerged with an emphasis on accessibility. These may allow surveillance to be conducted in broad settings where it is most needed, including at the primary healthcare level in endemic countries, and extending to the village health worker.
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Affiliation(s)
- Christiane Prosser
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Westmead Clinical School-Sydney Medical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia; Westmead Institute for Medical Research, Westmead, NSW, Australia.
| | - Wieland Meyer
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Westmead Clinical School-Sydney Medical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia; Westmead Institute for Medical Research, Westmead, NSW, Australia
| | - John Ellis
- School of Life Sciences, University of Technology Sydney, NSW, Australia
| | - Rogan Lee
- Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology & Medical Research, Westmead Hospital, Westmead, NSW, Australia
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49
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Nsakashalo-Senkwe M, Mwase E, Chizema-Kawesha E, Mukonka V, Songolo P, Masaninga F, Rebollo M, Thomas B, Bockarie M, Betts H, Stothard J, Kelly-Hope L. Significant decline in lymphatic filariasis associated with nationwide scale-up of insecticide-treated nets in Zambia. Parasite Epidemiol Control 2017; 2:7-14. [PMID: 29774291 PMCID: PMC5952671 DOI: 10.1016/j.parepi.2017.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/25/2017] [Accepted: 08/26/2017] [Indexed: 11/29/2022] Open
Abstract
Lymphatic filariasis (LF) is a mosquito-borne disease, broadly endemic in Zambia, and is targeted for elimination by mass drug administration (MDA) of albendazole and diethylcarbamazine citrate (DEC) to at-risk populations. Anopheline mosquitoes are primary vectors of LF in Africa, and it is possible that the significant scale-up of malaria vector control over the past decade may have also impacted LF transmission, and contributed to a decrease in prevalence in Zambia. We therefore aimed to examine the putative association between decreasing LF prevalence and increasing coverage of insecticide-treated mosquito nets (ITNs) for malaria vector control, by comparing LF mapping data collected between 2003-2005 and 2009-2011 to LF sentinel site prevalence data collected between 2012 and 2014, before any anti-LF MDA was started. The coverage of ITNs for malaria was quantified and compared for each site in relation to the dynamics of LF. We found a significant decrease in LF prevalence from the years 2003-2005 (11.5% CI95 6.6; 16.4) to 2012-2014 (0.6% CI95 0.03; 1.1); at the same time, there was a significant scale-up of ITNs across the country from 0.2% (CI95 0.0; 0.3) to 76.1% (CI95 71.4; 80.7) respectively. The creation and comparison of two linear models demonstrated that the geographical and temporal variation in ITN coverage was a better predictor of LF prevalence than year alone. Whilst a causal relationship between LF prevalence and ITN coverage cannot be proved, we propose that the scale-up of ITNs has helped to control Anopheles mosquito populations, which have in turn impacted on LF transmission significantly before the scale-up of MDA. This putative synergy with vector control has helped to put Zambia on track to meet national and global goals of LF elimination by 2020.
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Affiliation(s)
- M. Nsakashalo-Senkwe
- Ministry of Health, P.O. Box 30205, Lusaka, Zambia
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - E. Mwase
- School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, Zambia
| | | | - V. Mukonka
- Ministry of Health, P.O. Box 30205, Lusaka, Zambia
| | - P. Songolo
- WHO Country Office, World Health Organisation, P.O. Box 32346, Ridgeway, Lusaka, Zambia
| | - F. Masaninga
- WHO Country Office, World Health Organisation, P.O. Box 32346, Ridgeway, Lusaka, Zambia
| | - M.P. Rebollo
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - B. Thomas
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - M.J. Bockarie
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - H. Betts
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - J.R. Stothard
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - L.A. Kelly-Hope
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
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50
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Kyalo D, Amratia P, Mundia CW, Mbogo CM, Coetzee M, Snow RW. A geo-coded inventory of anophelines in the Afrotropical Region south of the Sahara: 1898-2016. Wellcome Open Res 2017; 2:57. [PMID: 28884158 PMCID: PMC5558104 DOI: 10.12688/wellcomeopenres.12187.1] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2017] [Indexed: 11/20/2022] Open
Abstract
Background: Understanding the distribution of anopheline vectors of malaria is an important prelude to the design of national malaria control and elimination programmes. A single, geo-coded continental inventory of anophelines using all available published and unpublished data has not been undertaken since the 1960s. Methods: We have searched African, European and World Health Organization archives to identify unpublished reports on anopheline surveys in 48 sub-Saharan Africa countries. This search was supplemented by identification of reports that formed part of post-graduate theses, conference abstracts, regional insecticide resistance databases and more traditional bibliographic searches of peer-reviewed literature. Finally, a check was made against two recent repositories of dominant malaria vector species locations ( circa 2,500). Each report was used to extract information on the survey dates, village locations (geo-coded to provide a longitude and latitude), sampling methods, species identification methods and all anopheline species found present during the survey. Survey records were collapsed to a single site over time. Results: The search strategy took years and resulted in 13,331 unique, geo-coded survey locations of anopheline vector occurrence between 1898 and 2016. A total of 12,204 (92%) sites reported the presence of 10 dominant vector species/sibling species; 4,473 (37%) of these sites were sampled since 2005. 4,442 (33%) sites reported at least one of 13 possible secondary vector species; 1,107 (25%) of these sites were sampled since 2005. Distributions of dominant and secondary vectors conform to previous descriptions of the ecological ranges of these vectors. Conclusion: We have assembled the largest ever geo-coded database of anophelines in Africa, representing a legacy dataset for future updating and identification of knowledge gaps at national levels. The geo-coded database is available on Harvard Dataverse as a reference source for African national malaria control programmes planning their future control and elimination strategies.
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Affiliation(s)
- David Kyalo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Punam Amratia
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Clara W Mundia
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Charles M Mbogo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Maureen Coetzee
- Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa.,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Robert W Snow
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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