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Nguetsa GC, Elanga-Ndille E, Essangui Same EG, Nganso Keptchouang T, Mandeng SE, Ekoko Eyisap W, Binyang JA, Fogang B, Nouage L, Piameu M, Ayong L, Etang J, Wanji S, Eboumbou Moukoko CE. Utility of plasma anti-gSG6-P1 IgG levels in determining changes in Anopheles gambiae bite rates in a rural area of Cameroon. Sci Rep 2024; 14:14294. [PMID: 38906949 PMCID: PMC11192751 DOI: 10.1038/s41598-024-58337-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 03/27/2024] [Indexed: 06/23/2024] Open
Abstract
The applicability of the specific human IgG antibody response to Anopheles gambiae salivary Gland Protein-6 peptide 1 (gSG6-P1 salivary peptide) as a biomarker able to distinguish the level of exposure to mosquito bites according to seasonal variations has not yet been evaluated in Central African regions. The study aimed to provide the first reliable data on the IgG anti-gSG6-P1 response in rural area in Cameroon according to the dry- and rainy-season. Between May and December 2020, dry blood samples were collected from people living in the Bankeng village in the forest area of the Centre region of Cameroon. Malaria infection was determined by thick-blood smear microscopy and multiplex PCR. The level of IgG anti-gSG6-P1 response, was assessed by enzyme-linked immunosorbent assay. Anopheles density and aggressiveness were assessed using human landing catches. The prevalence of malaria infection remains significantly higher in the rainy season than in the dry season (77.57% vs 61.44%; p = 0.0001). The specific anti-gSG6-P1 IgG response could be detected in individuals exposed to few mosquito bites and showed inter-individual heterogeneity even when living in the same exposure area. In both seasons, the level of anti-gSG6-P1 IgG response was not significantly different between Plasmodium infected and non-infected individuals. Mosquito bites were more aggressive in the rainy season compared to the dry season (human biting rate-HBR of 15.05 b/p/n vs 1.5 b/p/n) where mosquito density was very low. Infected mosquitoes were found only during the rainy season (sporozoite rate = 10.63% and entomological inoculation rate-EIR = 1.42 ib/p/n). The level of IgG anti-gSG6-P1 response was significantly higher in the rainy season and correlated with HBR (p ˂ 0.0001). This study highlights the high heterogeneity of individual's exposure to the Anopheles gambiae s.l vector bites depending on the transmission season in the same area. These findings reinforce the usefulness of the anti-gSG6-P1 IgG response as an accurate immunological biomarker for detecting individual exposure to Anopheles gambiae s.l. bites during the low risk period of malaria transmission in rural areas and for the differentiating the level of exposure to mosquitoes.
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Affiliation(s)
- Glwadys Cheteug Nguetsa
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
- Department of Microbiology and Parasitology, Faculty of Sciences, The University of Buea, P.O. Box 63, Buea, Cameroon.
| | - Emmanuel Elanga-Ndille
- Department of Animal Biology, Faculty of Sciences, The University of Dschang, P.O. Box 96, Dschang, Cameroon
- Department of Medical Entomology, Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé, Cameroon
| | - Estelle Géraldine Essangui Same
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon
| | - Tatiana Nganso Keptchouang
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon
| | - Stanilas Elysée Mandeng
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
- 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
| | - Wolfgang Ekoko Eyisap
- 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
| | - Jérome Achille Binyang
- Department of Medical Entomology, Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
| | - Balotin Fogang
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
| | - Lynda Nouage
- Department of Medical Entomology, Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
| | - Micheal Piameu
- 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
- Ecole des Sciences de La Santé, Université Catholique d'Afrique Centrale, P.O. Box 1110, Yaoundé, Cameroon
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
| | - Josiane Etang
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon
- 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
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Sciences, The University of Buea, P.O. Box 63, Buea, Cameroon
| | - Carole Else Eboumbou Moukoko
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon.
- Laboratory of Parasitology, Mycology and Virology, Postgraduate Training Unit for Health Sciences, Postgraduate School for Pure and Applied Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon.
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Carrasco-Tenezaca M, Jawara M, Bradley J, D'Alessandro U, Jeffries D, Knudsen JB, Lindsay SW. The effect of physical barriers under a raised house on mosquito entry: an experimental study in rural Gambia. Malar J 2024; 23:100. [PMID: 38589884 PMCID: PMC11003187 DOI: 10.1186/s12936-024-04889-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 02/21/2024] [Indexed: 04/10/2024] Open
Abstract
BACKGROUND Anopheles gambiae, the major malaria mosquito in sub-Saharan Africa, feed largely indoors at night. Raising a house off the ground with no barriers underneath reduces mosquito-house entry. This experiment tested whether walling off the space under an elevated hut affects mosquito-hut entry. METHODS Four inhabited experimental huts, each of which could be moved up and down, were used in rural Gambia. Nightly collections of mosquitoes were made using light traps and temperature and carbon dioxide levels monitored indoors and outdoors using loggers. Each night, a reference hut was kept at ground level and three huts raised 2 m above the ground; with the space under the hut left open, walled with air-permeable walls or solid walls. Treatments were rotated every four nights using a randomized block design. The experiment was conducted for 32 nights. Primary measurements were mosquito numbers and indoor temperature in each hut. RESULTS A total of 1,259 female Anopheles gambiae sensu lato were collected in the hut at ground level, 655 in the hut with an open ground floor, 981 in the hut with air-permeable walls underneath and 873 in the hut with solid walls underneath. Multivariate analysis, adjusting for confounders, showed that a raised hut open underneath had 53% fewer mosquitoes (95% CI 47-58%), those with air-permeable walls underneath 24% fewer (95% CI 9-36%) and huts with solid walls underneath 31% fewer (95% CI 24-37%) compared with a hut on the ground. Similar results were found for Mansonia spp. and total number of female mosquitoes, but not for Culex mosquitoes where hut entry was unaffected by height or barriers. Indoor temperature and carbon dioxide levels were similar in all huts. CONCLUSION Raising a house 2 m from the ground reduces the entry of An. gambiae and Mansonia mosquitoes, but not Culex species. The protective effect of height is reduced if the space underneath the hut is walled off.
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Affiliation(s)
- Majo Carrasco-Tenezaca
- Department of Biosciences, Durham University, Durham, UK
- Centro de Investigación Para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Musa Jawara
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - John Bradley
- London School of Hygiene & Tropical Medicine, London, UK
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
- London School of Hygiene & Tropical Medicine, London, UK
| | - David Jeffries
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Jakob B Knudsen
- Royal Danish Academy-Architecture, Design and Conservation, Copenhagen, Denmark
| | - Steve W Lindsay
- Department of Biosciences, Durham University, Durham, UK.
- London School of Hygiene & Tropical Medicine, London, UK.
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Ojianwuna CC, Enwemiwe VN, Egwunyenga AO, Agboro A, Owobu E. Sampling efficiency and screening of Aedes albopictus for yellow fever virus in Niger Delta region of Nigeria. Pan Afr Med J 2024; 47:120. [PMID: 38828420 PMCID: PMC11143074 DOI: 10.11604/pamj.2024.47.120.39462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 03/12/2024] [Indexed: 06/05/2024] Open
Abstract
Introduction Aedes albopictus, like Aedes aegypti, is a virulent vector of arboviruses especially the well-documented spread of yellow fever around the world. Although yellow fever is prevalent in Nigeria, there is a paucity of information in the Niger Delta region on the distribution of Aedes mosquito vectors and molecular detection of the virus in infected mosquitoes. This study sampled Aedes mosquitoes around houses associated with farms from four communities (Otolokpo, Ute-Okpu, Umunede, and Ute Alohen) in Ika North-East Local Government Area of Delta State, Nigeria. Methods various sampling methods were used in Aedes mosquito collection to test their efficacy in the survey. Mosquitoes in holding cages were killed by freezing and morphologically identified. A pool of 15 mosquitoes per Eppendorf tube was preserved in RNAi later for yellow fever virus screening. Two samples were molecularly screened for each location. Results seven hundred and twenty-five (725) mosquitoes were obtained from the various traps. The mean abundance of the mosquitoes was highest in m-HLC (42.9) compared to the mosquitoes sampled using other techniques (p<0.0001). The mean abundance of mosquitoes was lowest in Center for Disease Control (CDC) light traps without attractant (0.29). No yellow fever virus strain was detected in all the mosquitoes sampled at the four locations. Conclusion this study suggests that Aedes albopictus are the mosquitoes commonly biting around houses associated with farms. More so, yellow fever virus was not detected in the mosquitoes probably due to the mass vaccination exercise that was carried out the previous year in the study area. More studies are required using the m-HLC to determine the infection rate in this endemic area.
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Affiliation(s)
- Chioma Cynthia Ojianwuna
- Department of Animal and Environmental Biology, Faculty of Science, Delta State University, Abraka, Nigeria
| | - Victor Ngozi Enwemiwe
- Department of Animal and Environmental Biology, Faculty of Science, Delta State University, Abraka, Nigeria
| | - Andy Ogochukwu Egwunyenga
- Department of Animal and Environmental Biology, Faculty of Science, Delta State University, Abraka, Nigeria
| | - Akwilla Agboro
- Department of Animal and Environmental Biology, Faculty of Science, Delta State University, Abraka, Nigeria
| | - Emmanuel Owobu
- Department of Animal and Environmental Biology, Faculty of Science, Delta State University, Abraka, Nigeria
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Ashu FA, Fouet C, Ambadiang MM, Penlap-Beng V, Kamdem C. Adult mosquitoes of the sibling species Anopheles gambiae and Anopheles coluzzii exhibit contrasting patterns of susceptibility to four neonicotinoid insecticides along an urban-to-rural gradient in Yaoundé, Cameroon. Malar J 2024; 23:65. [PMID: 38431623 PMCID: PMC10909279 DOI: 10.1186/s12936-024-04876-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 02/10/2024] [Indexed: 03/05/2024] Open
Abstract
BACKGROUND Neonicotinoids are potential alternatives for controlling pyrethroid-resistant mosquitoes, but their efficacy against malaria vector populations of sub-Saharan Africa has yet to be investigated. The aim of the present study was to test the efficacy of four neonicotinoids against adult populations of the sibling species Anopheles gambiae and Anopheles coluzzii sampled along an urban-to-rural gradient. METHODS The lethal toxicity of three active ingredients for adults of two susceptible Anopheles strains was assessed using concentration-response assays, and their discriminating concentrations were calculated. The discriminating concentrations were then used to test the susceptibility of An. gambiae and An. coluzzii mosquitoes collected from urban, suburban and rural areas of Yaoundé, Cameroon, to acetamiprid, imidacloprid, clothianidin and thiamethoxam. RESULTS Lethal concentrations of neonicotinoids were relatively high suggesting that this class of insecticides has low toxicity against Anopheles mosquitoes. Reduced susceptibility to the four neonicotinoids tested was detected in An. gambiae populations collected from rural and suburban areas. By contrast, adults of An. coluzzii that occurred in urbanized settings were susceptible to neonicotinoids except acetamiprid for which 80% mortality was obtained within 72 h of insecticide exposure. The cytochrome inhibitor, piperonyl butoxide (PBO), significantly enhanced the activity of clothianidin and acetamiprid against An. gambiae mosquitoes. CONCLUSIONS These findings corroborate susceptibility profiles observed in larvae and highlight a significant variation in tolerance to neonicotinoids between An. gambiae and An. coluzzii populations from Yaoundé. Further studies are needed to disentangle the role of exposure to agricultural pesticides and of cross-resistance mechanisms in the development of neonicotinoid resistance in some Anopheles species.
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Affiliation(s)
- Fred A Ashu
- Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé 9, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 11 812, Yaoundé, Cameroon
| | - Caroline Fouet
- Department of Biological Sciences, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX, 79968, USA
| | - Marilene M Ambadiang
- Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé 9, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 11 812, Yaoundé, Cameroon
| | - Véronique Penlap-Beng
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 11 812, Yaoundé, Cameroon
| | - Colince Kamdem
- Department of Biological Sciences, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX, 79968, USA.
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Fouet C, Ashu FA, Ambadiang MM, Tchapga W, Wondji CS, Kamdem C. Clothianidin-resistant Anopheles gambiae adult mosquitoes from Yaoundé, Cameroon, display reduced susceptibility to SumiShield® 50WG, a neonicotinoid formulation for indoor residual spraying. BMC Infect Dis 2024; 24:133. [PMID: 38273227 PMCID: PMC10811947 DOI: 10.1186/s12879-024-09030-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND Chronic exposure of mosquito larvae to pesticide residues and cross-resistance mechanisms are major drivers of tolerance to insecticides used for vector control. This presents a concern for the efficacy of clothianidin, an agricultural neonicotinoid prequalified for Indoor Residual Spraying (IRS). METHODS Using standard bioassays, we tested if reduced susceptibility to clothianidin can affect the efficacy of SumiShield® 50WG, one of four new IRS formulations containing clothianidin. We simultaneously monitored susceptibility to clothianidin and to SumiShield 50WG, testing adults of Anopheles gambiae, An. coluzzii and Culex sp sampled from urban, suburban and agricultural areas of Yaoundé, Cameroon. RESULTS We found that in this geographic area, the level of susceptibility to the active ingredient predicted the efficacy of SumiShield 50WG. This formulation was very potent against populations that reached 100% mortality within 72 h of exposure to a discriminating concentration of clothianidin. By contrast, mortality leveled off at 75.4 ± 3.5% within 7 days of exposure to SumiShield 50WG in An. gambiae adults collected from a farm where the spraying of the two neonicotinoids acetamiprid and imidacloprid for crop protection is likely driving resistance to clothianidin. CONCLUSIONS Despite the relatively small geographic extend of the study, the findings suggest that cross-resistance may impact the efficacy of some new IRS formulations and that alternative compounds could be prioritized in areas where neonicotinoid resistance is emerging.
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Affiliation(s)
- Caroline Fouet
- Department of Biological Sciences, The University of Texas at El Paso, 500 W. University Ave, El Paso, TX, 79968, USA
| | - Fred A Ashu
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Marilene M Ambadiang
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Williams Tchapga
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, L3 5QA, UK
| | - Colince Kamdem
- Department of Biological Sciences, The University of Texas at El Paso, 500 W. University Ave, El Paso, TX, 79968, USA.
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Akuoko OK, Dhikrullahi SB, Hinne IA, Mohammed AR, Owusu-Asenso CM, Coleman S, Dadzie SK, Kyerematen R, Boakye DA, Wilson MD, Afrane YA. Biting behaviour, spatio-temporal dynamics, and the insecticide resistance status of malaria vectors in different ecological zones in Ghana. Parasit Vectors 2024; 17:16. [PMID: 38195546 PMCID: PMC10775458 DOI: 10.1186/s13071-023-06065-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 11/20/2023] [Indexed: 01/11/2024] Open
Abstract
BACKGROUND A significant decrease in malaria morbidity and mortality has been attained using long-lasting insecticide-treated nets and indoor residual spraying. Selective pressure from these control methods influences changes in vector bionomics and behavioural pattern. There is a need to understand how insecticide resistance drives behavioural changes within vector species. This study aimed to determine the spatio-temporal dynamics and biting behaviour of malaria vectors in different ecological zones in Ghana in an era of high insecticide use for public health vector control. METHODS Adult mosquitoes were collected during the dry and rainy seasons in 2017 and 2018 from five study sites in Ghana in different ecological zones. Indoor- and outdoor-biting mosquitoes were collected per hour from 18:00 to 06:00 h employing the human landing catch (HLC) technique. Morphological and molecular species identifications of vectors were done using identification keys and PCR respectively. Genotyping of insecticide-resistant markers was done using the TaqMan SNP genotyping probe-based assays. Detection of Plasmodium falciparum sporozoites was determined using PCR. RESULTS A total of 50,322 mosquitoes belonging to four different genera were collected from all the study sites during the sampling seasons in 2017 and 2018. Among the Anophelines were Anopheles gambiae s.l. 93.2%, (31,055/33,334), An. funestus 2.1%, (690/33,334), An. pharoensis 4.6%, (1545/33,334), and An. rufipes 0.1% (44/33,334). Overall, 76.4%, (25,468/33,334) of Anopheles mosquitoes were collected in the rainy season and 23.6%, (7866/33,334) in the dry season. There was a significant difference (Z = 2.410; P = 0.0160) between indoor-biting (51.1%; 15,866/31,055) and outdoor-biting An. gambiae s.l. (48.9%; 15,189/31,055). The frequency of the Vgsc-1014F mutation was slightly higher in indoor-biting mosquitoes (54.9%) than outdoors (45.1%). Overall, 44 pools of samples were positive for P. falciparum CSP giving an overall sporozoite rate of 0.1%. CONCLUSION Anopheles gambiae s.l. were more abundant indoors across all ecological zones of Ghana. The frequency of G119S was higher indoors than outdoors from all the study sites, but with higher sporozoite rates in outdoor mosquitoes in Dodowa and Kpalsogu. There is, therefore, an urgent need for a supplementary malaria control intervention to control outdoor-biting mosquitoes.
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Affiliation(s)
- Osei K Akuoko
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
- African Regional Post-Graduate Programme in Insect Science, College of Basic and Applied Science, University of Ghana, Legon, Accra, Ghana
| | - Shittu B Dhikrullahi
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Isaac A Hinne
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
- Department of Biochemistry and Molecular Biology, CABNR, University of Nevada, Reno, NV, USA
| | - Abdul R Mohammed
- African Regional Post-Graduate Programme in Insect Science, College of Basic and Applied Science, University of Ghana, Legon, Accra, Ghana
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Christopher M Owusu-Asenso
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Sylvester Coleman
- Department of Clinical Microbiology - Vector Biology Laboratory, School of Medicine and Dentistry (SMD)-College of Health Sciences, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Samuel K Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Rosina Kyerematen
- African Regional Post-Graduate Programme in Insect Science, College of Basic and Applied Science, University of Ghana, Legon, Accra, Ghana
- Department of Animal Biology and Conservation Science, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Daniel A Boakye
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Michael D Wilson
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Yaw A Afrane
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana.
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Moss S, Pretorius E, Ceesay S, Hutchins H, da Silva ET, Ndiath MO, Jones RT, Vasileva H, Phelan J, Acford-Palmer H, Collins E, Rodrigues A, Krishna S, Clark TG, Last A, Campino S. Genomic surveillance of Anopheles mosquitoes on the Bijagós Archipelago using custom targeted amplicon sequencing identifies mutations associated with insecticide resistance. Parasit Vectors 2024; 17:10. [PMID: 38178249 PMCID: PMC10768400 DOI: 10.1186/s13071-023-06085-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 12/06/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND Insecticide resistance is reducing the efficacy of vector control interventions, consequently threatening efforts to control vector-borne diseases, including malaria. Investigating the prevalence of molecular markers of resistance is a useful tool for monitoring the spread of insecticide resistance in disease vectors. The Bijagós Archipelago (Bijagós) in Guinea-Bissau is a region of stable malaria transmission where insecticide-treated nets are the mainstay for malaria control. However, the prevalence of molecular markers of insecticide resistance in malaria vectors is not well understood. METHODS A total of 214 Anopheles mosquitoes were analysed from 13 islands across the Bijagós. These mosquitoes were collected using CDC light traps in November 2019, during the peak malaria transmission season. High-throughput multiplex amplicon sequencing was used to investigate the prevalence of 17 different molecular markers associated with insecticide resistance in four genes: vgsc, rdl, ace1 and gste2. RESULTS Of the 17 screened mutations, four were identified in mosquitoes from the Bijagós: vgsc L995F (12.2%), N1570Y (6.2%) and A1746S (0.7%) and rdl A269G (1.1%). This study is the first to report the L995F knock-down resistance (kdr)-west allele in Anopheles melas on the Archipelago. An additional eight non-synonymous single-nucleotide polymorphisms were identified across the four genes which have not been described previously. The prevalences of the vgsc L995F and N1570Y mutations were higher on Bubaque Island than on the other islands in this study; Bubaque is the most populous island in the archipelago, with the greatest population mobility and connection to continental Guinea-Bissau. CONCLUSIONS This study provides the first surveillance data for genetic markers present in malaria vectors from islands across the Bijagós Archipelago. Overall prevalence of insecticide resistance mutations was found to be low. However, the identification of the vgsc L995F and N1570Y mutations associated with pyrethroid resistance warrants further monitoring. This is particularly important as the mainstay of malaria control on the islands is the use of pyrethroid insecticide-treated nets.
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Affiliation(s)
- Sophie Moss
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | - Elizabeth Pretorius
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Sainey Ceesay
- Medical Research Council, The Gambia (MRCG), Fajara, Gambia
| | - Harry Hutchins
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Eunice Teixeira da Silva
- Ministério de Saúde Pública, Bissau, Guinea-Bissau
- Projecto de Saúde Bandim, Bissau, Guinea-Bissau
| | | | - Robert T Jones
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Hristina Vasileva
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Jody Phelan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Holly Acford-Palmer
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Emma Collins
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Sanjeev Krishna
- Clinical Academic Group, Institute for Infection and Immunity, St. George's University Hospitals NHS Foundation Trust-St. George's University of London, London, UK
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institut Für Tropenmedizin Universitätsklinikum Tübingen, Tübingen, Germany
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
- Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Anna Last
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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8
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Omucheni DL, Kaduki KA, Mukabana WR. Rapid and non-destructive identification of Anopheles gambiae and Anopheles arabiensis mosquito species using Raman spectroscopy via machine learning classification models. Malar J 2023; 22:342. [PMID: 37940964 PMCID: PMC10634188 DOI: 10.1186/s12936-023-04777-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/31/2023] [Indexed: 11/10/2023] Open
Abstract
BACKGROUND Identification of malaria vectors is an important exercise that can result in the deployment of targeted control measures and monitoring the susceptibility of the vectors to control strategies. Although known to possess distinct biting behaviours and habitats, the African malaria vectors Anopheles gambiae and Anopheles arabiensis are morphologically indistinguishable and are known to be discriminated by molecular techniques. In this paper, Raman spectroscopy is proposed to complement the tedious and time-consuming Polymerase Chain Reaction (PCR) method for the rapid screening of mosquito identity. METHODS A dispersive Raman microscope was used to record spectra from the legs (femurs and tibiae) of fresh anaesthetized laboratory-bred mosquitoes. The scattered Raman intensity signal peaks observed were predominantly centered at approximately 1400 cm-1, 1590 cm-1, and 2067 cm-1. These peaks, which are characteristic signatures of melanin pigment found in the insect cuticle, were important in the discrimination of the two mosquito species. Principal Component Analysis (PCA) was used for dimension reduction. Four classification models were built using the following techniques: Linear Discriminant Analysis (LDA), Logistic Regression (LR), Quadratic Discriminant Analysis (QDA), and Quadratic Support Vector Machine (QSVM). RESULTS PCA extracted twenty-one features accounting for 95% of the variation in the data. Using the twenty-one principal components, LDA, LR, QDA, and QSVM discriminated and classified the two cryptic species with 86%, 85%, 89%, and 93% accuracy, respectively on cross-validation and 79%, 82%, 81% and 93% respectively on the test data set. CONCLUSION Raman spectroscopy in combination with machine learning tools is an effective, rapid and non-destructive method for discriminating and classifying two cryptic mosquito species, Anopheles gambiae and Anopheles arabiensis belonging to the Anopheles gambiae complex.
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Affiliation(s)
| | | | - Wolfgang R Mukabana
- Department of Biology, University of Nairobi, Nairobi, Kenya
- Science for Health Society, Nairobi, Kenya
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9
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Gueye A, Ngom EHM, Diagne A, Ndoye BB, Dione ML, Sambe BS, Sokhna C, Diallo M, Niang M, Dia I. Host feeding preferences of malaria vectors in an area of low malaria transmission. Sci Rep 2023; 13:16410. [PMID: 37775717 PMCID: PMC10542387 DOI: 10.1038/s41598-023-43761-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/28/2023] [Indexed: 10/01/2023] Open
Abstract
Studying the behaviour and trophic preferences of mosquitoes is an important step in understanding the exposure of vertebrate hosts to vector-borne diseases. In the case of human malaria, transmission increases when mosquitoes feed more on humans than on other animals. Therefore, understanding the spatio-temporal dynamics of vectors and their feeding preferences is essential for improving vector control measures. In this study, we investigated the feeding behaviour of Anopheles mosquitoes at two sites in the Sudanian areas of Senegal where transmission is low following the implementation of vector control measures. Blood-fed mosquitoes were collected monthly from July to November 2022 by pyrethrum spray catches in sleeping rooms of almost all houses in Dielmo and Ndiop villages, and blood meals were identified as from human, bovine, ovine, equine and chicken by ELISA. Species from the An. gambiae complex were identified by PCR. The types and numbers of potential domestic animal hosts were recorded in each village. The Human Blood Index (HBI) and the Manly Selection Ratio (MSR) were calculated to determine whether hosts were selected in proportion to their abundance. Spatio-temporal variation in HBI was examined using the Moran's index. A total of 1251 endophilic Anopheles females were collected in 115 bedrooms, including 864 blood fed females of 6 species. An. arabiensis and An. funestus were predominant in Dielmo and Ndiop, respectively. Of the 864 blood meals tested, 853 gave a single host positive result mainly on bovine, equine, human, ovine and chicken in decreasing order in both villages. Overall, these hosts were not selected in proportion to their abundance. The human host was under-selected, highlighting a marked zoophily for the vectors. Over time and space, the HBI were low with no obvious trend, with higher and lower values observed in each of the five months at different points in each village. These results highlight the zoophilic and exophagic behaviour of malaria vectors. This behaviour is likely to be a consequence of the distribution and use of LLINs in both villages and may increase risk of residual outdoor transmission. This underlines the need to study the feeding host profile of outdoor resting populations and how domestic animals may influence malaria epidemiology in order to tailor effective malaria vector control strategies in the two villages.
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Affiliation(s)
- Assiyatou Gueye
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - El Hadji Malick Ngom
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Aissatou Diagne
- Pole Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Baye Bado Ndoye
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Mamadou Lamine Dione
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Babacar Souleymane Sambe
- Pole Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Cheikh Sokhna
- UMR Vecteurs Infections Tropicales et Mediterraneennes (VITROME), Campus International UCAD-IRD, Route des Peres Maristes, BP 1386, Dakar, Senegal
| | - Mawlouth Diallo
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Makhtar Niang
- Pole Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Ibrahima Dia
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal.
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Pretorius E, Kristan M, Bradley J, da Silva ET, Hutchins H, Barri F, Cassama A, Ceesay S, Ndiath MO, Rodrigues A, Logan JG, Last A, Jones RT. Validation of a method for the dry preservation and rehydration of Anopheles gambiae sensu lato for parity analysis to assess the impact of vector control measures in the field. Parasit Vectors 2023; 16:236. [PMID: 37454212 PMCID: PMC10349412 DOI: 10.1186/s13071-023-05866-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
BACKGROUND As the control of malaria remains heavily dependent on vector management interventions, it is important to understand the impact of these on mosquito populations. Age-grading is a valuable tool for this; however, logistical challenges in remote, resource-poor areas make current methodologies difficult to incorporate into clinical trials and routine surveillance. Our aim was to validate a methodology that could be easily implemented in such settings. Using dried mosquito specimens instead of freshly killed ones, we validated the commonly used ovarian tracheation technique for assessing population age structure. METHODS Laboratory-reared Anopheles coluzzii mosquitoes with known parity status were dry preserved in silica gel for up to 12 weeks and rehydrated prior to parity assessment. The results were compared to parity results for freshly killed mosquitoes from the same colony. Preserved, field-caught Anopheles gambiae sensu lato (s.l.) from Guinea-Bissau were assessed by three different assessors blinded to each other's scores. An overall index of agreement was calculated using inter-rater reliability of all assessor pairings. The impact of preservation time was investigated using a one-way ANOVA to look for differences in assessor agreement over three time periods. RESULTS The parity status was correctly identified for 90% of dry preserved and rehydrated insectary-reared An. coluzzii and for 98% of freshly killed insectary-reared An. coluzzii. The inter-rater reliability was highest (0.94) for freshly killed An. coluzzii. The results for all time points showed excellent strength of agreement between assessors. For field-caught An. gambiae s.l., the overall index of agreement between all three assessors was 0.86 (95% confidence interval 0.78-0.93), indicating almost perfect agreement. There was no significant difference between assessor agreement between time frames. CONCLUSIONS Dry preserving and rehydrating Anopheles mosquitoes provides an alternative to using freshly killed mosquitoes to assess the efficacy of a control intervention in remote settings where it is logistically difficult to dissect fresh specimens. This method also provides the flexibility required for parity assessment to be done on larger scales over bigger areas.
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Affiliation(s)
- Elizabeth Pretorius
- Department for Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Mojca Kristan
- Department for Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - John Bradley
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Eunice Teixeira da Silva
- Projecto de Saúde Bandim, Bissau, Guinea-Bissau
- Ministério de Saúde Pública, Bissau, Guinea-Bissau
| | - Harry Hutchins
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | | | | | - Sainey Ceesay
- Medical Research Council Unit, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Mamadou Ousmane Ndiath
- Medical Research Council Unit, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Amabelia Rodrigues
- Projecto de Saúde Bandim, Bissau, Guinea-Bissau
- Ministério de Saúde Pública, Bissau, Guinea-Bissau
| | - James G. Logan
- Department for Disease Control, London School of Hygiene and Tropical Medicine, London, UK
- Arctech Innovation, Dagenham, London, UK
| | - Anna Last
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Robert T. Jones
- Department for Disease Control, London School of Hygiene and Tropical Medicine, London, UK
- Arctech Innovation, Dagenham, London, UK
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11
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Hutchins H, Bradley J, Pretorius E, Teixeira da Silva E, Vasileva H, Jones RT, Ndiath MO, Dit Massire Soumare H, Mabey D, Nante EJ, Martins C, Logan JG, Slater H, Drakeley C, D'Alessandro U, Rodrigues A, Last AR. Protocol for a cluster randomised placebo-controlled trial of adjunctive ivermectin mass drug administration for malaria control on the Bijagós Archipelago of Guinea-Bissau: the MATAMAL trial. BMJ Open 2023; 13:e072347. [PMID: 37419638 PMCID: PMC10335573 DOI: 10.1136/bmjopen-2023-072347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 06/20/2023] [Indexed: 07/09/2023] Open
Abstract
INTRODUCTION As malaria declines, innovative tools are required to further reduce transmission and achieve elimination. Mass drug administration (MDA) of artemisinin-based combination therapy (ACT) is capable of reducing malaria transmission where coverage of control interventions is already high, though the impact is short-lived. Combining ACT with ivermectin, an oral endectocide shown to reduce vector survival, may increase its impact, while also treating ivermectin-sensitive co-endemic diseases and minimising the potential impact of ACT resistance in this context. METHODS AND ANALYSIS MATAMAL is a cluster-randomised placebo-controlled trial. The trial is being conducted in 24 clusters on the Bijagós Archipelago, Guinea-Bissau, where the peak prevalence of Plasmodium falciparum (Pf) parasitaemia is approximately 15%. Clusters have been randomly allocated to receive MDA with dihydroartemisinin-piperaquine and either ivermectin or placebo. The primary objective is to determine whether the addition of ivermectin MDA is more effective than dihydroartemisinin-piperaquine MDA alone in reducing the prevalence of P. falciparum parasitaemia, measured during peak transmission season after 2 years of seasonal MDA. Secondary objectives include assessing prevalence after 1 year of MDA; malaria incidence monitored through active and passive surveillance; age-adjusted prevalence of serological markers indicating exposure to P. falciparum and anopheline mosquitoes; vector parous rates, species composition, population density and sporozoite rates; prevalence of vector pyrethroid resistance; prevalence of artemisinin resistance in P. falciparum using genomic markers; ivermectin's impact on co-endemic diseases; coverage estimates; and the safety of combined MDA. ETHICS AND DISSEMINATION The trial has been approved by the London School of Hygiene and Tropical Medicine's Ethics Committee (UK) (19156) and the Comite Nacional de Eticas de Saude (Guinea-Bissau) (084/CNES/INASA/2020). Results will be disseminated in peer-reviewed publications and in discussion with the Bissau-Guinean Ministry of Public Health and participating communities. TRIAL REGISTRATION NUMBER NCT04844905.
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Affiliation(s)
- Harry Hutchins
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - John Bradley
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Elizabeth Pretorius
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Eunice Teixeira da Silva
- Projecto de Saúde Bandim, Bissau, Guinea-Bissau
- Ministério de Saúde Pública, Bissau, Guinea-Bissau
| | - Hristina Vasileva
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Robert T Jones
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | | | | | - David Mabey
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Ernesto Jose Nante
- Programa Nacional de Luta Contra o Paludismo, Ministério de Saúde, Bissau, Guinea-Bissau
| | | | - James G Logan
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
- Arctech Innovation, London, UK
| | | | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Amabelia Rodrigues
- Projecto de Saúde Bandim, Bissau, Guinea-Bissau
- Ministério de Saúde Pública, Bissau, Guinea-Bissau
| | - Anna R Last
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
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Coleman S, Yihdego Y, Gyamfi F, Kolyada L, Tongren JE, Zigirumugabe S, Dery DB, Badu K, Obiri-Danso K, Boakye D, Szumlas D, Armistead JS, Dadzie SK. Estimating malaria transmission risk through surveillance of human-vector interactions in northern Ghana. Parasit Vectors 2023; 16:205. [PMID: 37337221 DOI: 10.1186/s13071-023-05793-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 04/28/2023] [Indexed: 06/21/2023] Open
Abstract
BACKGROUND Vector bionomics are important aspects of vector-borne disease control programs. Mosquito-biting risks are affected by environmental, mosquito behavior and human factors, which are important for assessing exposure risk and intervention impacts. This study estimated malaria transmission risk based on vector-human interactions in northern Ghana, where indoor residual spraying (IRS) and insecticide-treated nets (ITNs) have been deployed. METHODS Indoor and outdoor human biting rates (HBRs) were measured using monthly human landing catches (HLCs) from June 2017 to April 2019. Mosquitoes collected were identified to species level, and Anopheles gambiae sensu lato (An. gambiae s.l.) samples were examined for parity and infectivity. The HBRs were adjusted using mosquito parity and human behavioral observations. RESULTS Anopheles gambiae was the main vector species in the IRS (81%) and control (83%) communities. Indoor and outdoor HBRs were similar in both the IRS intervention (10.6 vs. 11.3 bites per person per night [b/p/n]; z = -0.33, P = 0.745) and control communities (18.8 vs. 16.4 b/p/n; z = 1.57, P = 0.115). The mean proportion of parous An. gambiae s.l. was lower in IRS communities (44.6%) than in control communities (71.7%). After adjusting for human behavior observations and parity, the combined effect of IRS and ITN utilization (IRS: 37.8%; control: 57.3%) on reducing malaria transmission risk was 58% in IRS + ITN communities and 27% in control communities with ITNs alone (z = -4.07, P < 0.001). However, this also revealed that about 41% and 31% of outdoor adjusted bites in IRS and control communities respectively, occurred before bed time (10:00 pm). The mean directly measured annual entomologic inoculation rates (EIRs) during the study were 6.1 infective bites per person per year (ib/p/yr) for IRS communities and 16.3 ib/p/yr for control communities. After considering vector survival and observed human behavior, the estimated EIR for IRS communities was 1.8 ib/p/yr, which represents about a 70% overestimation of risk compared to the directly measured EIR; for control communities, it was 13.6 ib/p/yr (16% overestimation). CONCLUSION Indoor residual spraying significantly impacted entomological indicators of malaria transmission. The results of this study indicate that vector bionomics alone do not provide an accurate assessment of malaria transmission exposure risk. By accounting for human behavior parameters, we found that high coverage of ITNs alone had less impact on malaria transmission indices than combining ITNs with IRS, likely due to observed low net use. Reinforcing effective communication for behavioral change in net use and IRS could further reduce malaria transmission.
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Affiliation(s)
- Sylvester Coleman
- U.S. President's Malaria Initiative VectorLink Project, Accra, Ghana.
- Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Yemane Yihdego
- U.S. President's Malaria Initiative VectorLink Project, Accra, Ghana
| | - Frank Gyamfi
- U.S. President's Malaria Initiative VectorLink Project, Accra, Ghana
| | - Lena Kolyada
- U.S. President's Malaria Initiative VectorLink Project, Accra, Ghana
| | - Jon Eric Tongren
- U.S. President's Malaria Initiative, Malaria Branch, U.S. Centers for Disease Control and Prevention, Accra, Ghana
| | - Sixte Zigirumugabe
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Accra, Ghana
| | - Dominic B Dery
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Accra, Ghana
| | - Kingsley Badu
- Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | | | - Daniel Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Daniel Szumlas
- Armed Forces Pest Management Board, 172 Forney Road, Forest Glen Annex, Silver Spring, MD, 20910, USA
| | - Jennifer S Armistead
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA
| | - Samuel K Dadzie
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
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Fouet C, Ashu F, Ambadiang M, Tchapga W, Wondji C, Kamdem C. Resistance to clothianidin reduces the efficacy of SumiShield ® 50WG, a neonicotinoid formulation for indoor residual spraying, against Anopheles gambiae. RESEARCH SQUARE 2023:rs.3.rs-2847231. [PMID: 37162950 PMCID: PMC10168466 DOI: 10.21203/rs.3.rs-2847231/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Chronic exposure of mosquito larvae to pesticide residues in agricultural areas is often associated with evolution of resistance to insecticides used for vector control. This presents a concern for the efficacy of clothianidin, an agricultural neonicotinoid qualified for Indoor Residual Spraying (IRS). Using standard bioassays, we tested if reduced susceptibility to clothianidin affects the efficacy of SumiShield® 50WG, one of the two newly approved formulations, which contains 50% clothianidin. We simultaneously monitored susceptibility to clothianidin and to SumiShield® 50WG, testing adults of Anopheles gambiae, An. coluzzii and Culex sp collected from urban, suburban and agricultural areas of Yaoundé. We found that the level of susceptibility to the active ingredient predicted the efficacy of SumiShield® 50WG. This formulation was very potent against populations that achieved 100% mortality within 72 h of exposure to a discriminating dose of clothianidin. By contrast, mortality leveled off at 75.4 ± 3.5% within 7 days of exposure to SumiShield® 50WG in An. gambiae adults collected from a farm where spraying of acetamiprid and imidacloprid is driving cross-resistance to clothianidin. These findings indicate that more potent formulations of clothianidin or different insecticides should be prioritized in areas where resistance is emerging.
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Ashu FA, Fouet C, Ambadiang MM, Penlap-Beng V, Kamdem C. Enhancing the efficacy of neonicotinoids against mosquitoes and overcoming resistance issues. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.18.537427. [PMID: 37131663 PMCID: PMC10153211 DOI: 10.1101/2023.04.18.537427] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Background Neonicotinoids are potential alternatives for targeting pyrethroid-resistant mosquitoes, but their efficacy against malaria vector populations of Sub-Saharan Africa has yet to be investigated. Here we tested and compared the efficacy of four neonicotinoids alone or in combination with a synergist against two major vectors of Plasmodium . Results Using standard bioassays, we first assessed the lethal toxicity of three active ingredients against adults of two susceptible Anopheles strains and we determined discriminating doses for monitoring susceptibility in wild populations. We then tested the susceptibility of 5532 Anopheles mosquitoes collected from urban and rural areas of Yaoundé, Cameroon, to discriminating doses of acetamiprid, imidacloprid, clothianidin and thiamethoxam. We found that in comparison with some public health insecticides, neonicotinoids have high lethal concentration, LC 99 , reflecting their low toxicity to Anopheles mosquitoes. In addition to this reduced toxicity, resistance to the four neonicotinoids tested was detected in An. gambiae populations collected from agricultural areas where larvae are intensively exposed to crop-protection neonicotinoids. However, adults of another major vector that occurred in urbanized settings, An. coluzzii , were fully susceptible to neonicotinoids except acetamiprid for which 80% mortality was obtained within 72 h of insecticide exposure. Importantly, the cytochrome inhibitor, piperonyl butoxide (PBO), was very effective in enhancing the activity of clothianidin and acetamiprid providing opportunities to create potent neonicotinoid formulations against Anopheles . Conclusion These findings suggest that to successfully repurpose agricultural neonicotinoids for malaria vector control, it is essential to use formulations containing synergists such as PBO or surfactants to ensure optimal efficacy.
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15
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Fondjo E, Toto JC, Tchouakui M, Eyisap WE, Patchoke S, Menze B, Njeambosay B, Zeukeug F, Ngomdjum RT, Mandeng E, Elanga-Ndille E, Kopya E, Binyang JA, Ndo C, Tene-Fossog B, Tedjou A, Nchoutpouen E, Tchouine F, Achu D, Ambrose K, Hedje J, Kouambeng C, Carlson J, Zohdy S, Chabi J. High vector diversity and malaria transmission dynamics in five sentinel sites in Cameroon. Malar J 2023; 22:123. [PMID: 37055836 PMCID: PMC10100606 DOI: 10.1186/s12936-023-04552-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 04/03/2023] [Indexed: 04/15/2023] Open
Abstract
BACKGROUND Malaria remains one of the main causes of morbidity and mortality in Cameroon. To inform vector control intervention decision making, malaria vector surveillance was conducted monthly from October 2018 to September 2020 in five selected sentinel sites (Gounougou and Simatou in the North, and Bonabéri, Mangoum and Nyabessang in the South). METHODS Human landing catches (HLCs), U.S. Centers for Disease Control and Prevention (CDC) light traps, and pyrethrum spray catches (PSCs) were used to assess vector density, species composition, human biting rate (HBR), endophagic index, indoor resting density (IRD), parity, sporozoite infection rates, entomological inoculation rate (EIR), and Anopheles vectorial capacity. RESULTS A total of 139,322 Anopheles mosquitoes from 18 species (or 21 including identified sub-species) were collected across all sites. Out of the 18 species, 12 were malaria vectors including Anopheles gambiae sensu lato (s.l.), Anopheles funestus s.l.., Anopheles nili, Anopheles moucheti, Anopheles paludis, Anopheles demeilloni, Anopheles. pharoensis, Anopheles ziemanni, Anopheles multicinctus, Anopheles tenebrosus, Anopheles rufipes, and Anopheles marshallii. Anopheles gambiae s.l. remains the major malaria vector (71% of the total Anopheles) collected, though An. moucheti and An. paludis had the highest sporozoite rates in Nyabessang. The mean indoor HBR of Anopheles ranged from 11.0 bites/human/night (b/h/n) in Bonabéri to 104.0 b/h/n in Simatou, while outdoors, it varied from 24.2 b/h/n in Mangoum to 98.7 b/h/n in Simatou. Anopheles gambiae s.l. and An. moucheti were actively biting until at least 8:00 a.m. The mean Anopheles IRD was 17.1 females/room, and the parity rate was 68.9%. The mean EIRs for each site were 55.4 infective bites/human/month (ib/h/m) in Gounougou, 99.0 ib/h/m in Simatou, 51.2 ib/h/m in Mangoum, 24.4 ib/h/m in Nyabessang, and 18.1 ib/h/m in Bonabéri. Anopheles gambiae s.l. was confirmed as the main malaria vector with the highest vectorial capacity in all sites based on sporozoite rate, except in Nyabessang. CONCLUSION These findings highlight the high malaria transmission occurring in Cameroon and will support the National Malaria Control Program to design evidence-based malaria vector control strategies, and deployment of effective and integrated vector control interventions to reduce malaria transmission and burden in Cameroon, where several Anopheles species could potentially maintain year-round transmission.
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Affiliation(s)
- Etienne Fondjo
- U.S. President's Malaria Initiative (PMI) VectorLink Project, Abt Associates, Yaoundé, Cameroon
| | - Jean-Claude Toto
- Central African Organization for Endemic Disease Control (OCEAC), Yaoundé, Cameroon
| | | | - Wolfgang Ekoko Eyisap
- Central African Organization for Endemic Disease Control (OCEAC), Yaoundé, Cameroon
- University of Bamenda, Bamenda, Cameroon
| | - Salomon Patchoke
- The Biotechnology Center (BTC), University of Yaoundé 1, Yaoundé, Cameroon
| | - Benjamin Menze
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Boris Njeambosay
- The Biotechnology Center (BTC), University of Yaoundé 1, Yaoundé, Cameroon
| | - Francis Zeukeug
- The Biotechnology Center (BTC), University of Yaoundé 1, Yaoundé, Cameroon
| | | | - Elysée Mandeng
- Central African Organization for Endemic Disease Control (OCEAC), Yaoundé, Cameroon
| | | | - Edmond Kopya
- Central African Organization for Endemic Disease Control (OCEAC), Yaoundé, Cameroon
| | | | - Cyrille Ndo
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Billy Tene-Fossog
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Armel Tedjou
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Elysée Nchoutpouen
- Central African Organization for Endemic Disease Control (OCEAC), Yaoundé, Cameroon
| | - Frederic Tchouine
- U.S. President's Malaria Initiative (PMI) VectorLink Project, Abt Associates, Yaoundé, Cameroon
| | - Dorothy Achu
- National Malaria Control Programme, Yaoundé, Cameroon
| | - Kelley Ambrose
- U.S. President's Malaria Initiative VectorLink Project, Abt Associates, Rockville, MD, USA
| | - Judith Hedje
- U.S. President's Malaria Initiative, U.S. Centers for Disease Control and Prevention (CDC), Yaoundé, Cameroon
| | - Celestin Kouambeng
- U.S. President's Malaria Initiative U.S. Agency for International Development (USAID), Yaoundé, Cameroon
| | - Jenny Carlson
- U.S. President's Malaria Initiative, USAID, Washington, DC, USA
| | - Sarah Zohdy
- U.S. President's Malaria Initiative, U.S. Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Joseph Chabi
- U.S. President's Malaria Initiative VectorLink Project, Abt Associates, Rockville, MD, USA.
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Carrasco-Tenezaca M, Jawara M, Lee DSH, Holmes MS, Ceesay S, McCall P, Pinder M, D'Alessandro U, Knudsen JB, Lindsay SW, Wilson AL. Effect of passive and active ventilation on malaria mosquito house entry and human comfort: an experimental study in rural Gambia. J R Soc Interface 2023; 20:20220794. [PMID: 37015266 PMCID: PMC10072938 DOI: 10.1098/rsif.2022.0794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023] Open
Abstract
Rural houses in sub-Saharan Africa are typically hot and allow malaria mosquitoes inside. We assessed whether passive or active ventilation can reduce house entry of malaria mosquitoes and cool a bedroom at night in rural Gambia. Two identical experimental houses were used: one ventilated and one unventilated (control). We evaluated the impact of (i) passive ventilation (solar chimney) and (ii) active ventilation (ceiling fan) on the number of mosquitoes collected indoors and environmental parameters (temperature, humidity, CO2, evaporation). Although the solar chimney did not reduce entry of Anopheles gambiae sensu lato, the ceiling fan reduced house entry by 91% compared with the control house. There were no differences in indoor nightly temperature, humidity or CO2 between intervention and control houses in either experiment. The solar chimney did not improve human comfort assessed using psychrometric analysis. While the ceiling fan improved human comfort pre-midnight, in the morning it was too cool compared with the control house, although this could be remedied through provision of blankets. Further improvements to the design of the solar chimney are needed. High air velocity in the ceiling fan house probably reduced mosquito house entry by preventing mosquito flight. Improved ventilation in houses may reduce malaria transmission.
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Affiliation(s)
| | - Musa Jawara
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Daniel Sang-Hoon Lee
- Architecture, Design and Conservation, The Royal Danish Academy, Philip De Langes Allé 10, Copenhagen 1435, Denmark
| | - Matthew S Holmes
- JDDK Architects, Millmount, Ponteland Rd, Cowgate, Newcastle upon Tyne NE5 3AL, England
| | - Sainey Ceesay
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Phillip McCall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Margaret Pinder
- Department of Biosciences, Durham University, Stockton Road, Durham, Durham DH1 3LE, UK
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Jakob B Knudsen
- Architecture, Design and Conservation, The Royal Danish Academy, Philip De Langes Allé 10, Copenhagen 1435, Denmark
| | - Steve W Lindsay
- Department of Biosciences, Durham University, Stockton Road, Durham, Durham DH1 3LE, UK
- London School of Hygiene & Tropical Medicine, Keppel St, Bloomsbury, London WC1E 7HT, UK
| | - Anne L Wilson
- Department of Biosciences, Durham University, Stockton Road, Durham, Durham DH1 3LE, UK
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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17
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Hamid-Adiamoh M, Jabang AMJ, Opondo KO, Ndiath MO, Assogba BS, Amambua-Ngwa A. Distribution of Anopheles gambiae thioester-containing protein 1 alleles along malaria transmission gradients in The Gambia. Malar J 2023; 22:89. [PMID: 36899431 PMCID: PMC9999626 DOI: 10.1186/s12936-023-04518-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/28/2023] [Indexed: 03/12/2023] Open
Abstract
BACKGROUND Thioester-containing protein 1 (TEP1) is a highly polymorphic gene playing an important role in mosquito immunity to parasite development and associated with Anopheles gambiae vectorial competence. Allelic variations in TEP1 could render mosquito either susceptible or resistant to parasite infection. Despite reports of TEP1 genetic variations in An. gambiae, the correlation between TEP1 allelic variants and transmission patterns in malaria endemic settings remains unclear. METHODS TEP1 allelic variants were characterized by PCR from archived genomic DNA of > 1000 An. gambiae mosquitoes collected at 3 time points between 2009 and 2019 from eastern Gambia, where malaria transmission remains moderately high, and western regions with low transmission. RESULTS Eight common TEP1 allelic variants were identified at varying frequencies in An. gambiae from both transmission settings. These comprised the wild type TEP1, homozygous susceptible genotype, TEP1s; homozygous resistance genotypes: TEP1rA and TEP1rB, and the heterozygous resistance genotypes: TEP1srA, TEP1srB, TEP1rArB and TEP1srArB. There was no significant disproportionate distribution of the TEP1 alleles by transmission setting and the temporal distribution of alleles was also consistent across the transmission settings. TEP1s was the most common in all vector species in both settings (allele frequencies: East = 21.4-68.4%. West = 23.5-67.2%). In Anopheles arabiensis, the frequency of wild type TEP1 and susceptible TEP1s was significantly higher in low transmission setting than in high transmission setting (TEP1: Z = - 4.831, P < 0.0001; TEP1s: Z = - 2.073, P = 0.038). CONCLUSIONS The distribution of TEP1 allele variants does not distinctly correlate with malaria endemicity pattern in The Gambia. Further studies are needed to understand the link between genetic variations in vector population and transmission pattern in the study settings. Future studies on the implication for targeting TEP1 gene for vector control strategy such as gene drive systems in this settings is also recommended.
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Affiliation(s)
- Majidah Hamid-Adiamoh
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia.
| | - Abdoulie Mai Janko Jabang
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Kevin Ochieng Opondo
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Mamadou Ousmane Ndiath
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Benoit Sessinou Assogba
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
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18
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Forson AO, Hinne IA, Sraku IK, Afrane YA. Larval habitat stability and productivity in two sites in Southern Ghana. Malar J 2023; 22:74. [PMID: 36864430 PMCID: PMC9983185 DOI: 10.1186/s12936-023-04498-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 02/14/2023] [Indexed: 03/04/2023] Open
Abstract
BACKGROUND Mosquito larval source management (LSM) is a valuable additional tool for malaria vector control. Understanding the characteristics of mosquito larval habitats and its ecology in different land use types can give valuable insight for an effective larval control strategy. This study determined the stability and productivity of potential anopheline larval habitats in two different ecological sites: Anyakpor and Dodowa in southern Ghana. METHODS A total of 59 aquatic habitats positive for anopheline larvae were identified, and sampled every two weeks for a period of 30 weeks using a standard dipping method. Larvae were collected using standard dippers and were raised in the insectary for identification. Sibling species of the Anopheles gambiae sensu lato (s.l.) were further identified by polymerase chain reaction. The presence of larval habitats, their stability and larvae positive habitats were compared between the two sites using Mann-Whitney U and the Kruskal-Wallis test. Factors affecting the presence of An. gambiae larvae and physicochemical properties at the sites were determined using multiple logistic regression analysis and Spearman's correlation. RESULTS Out of a total of 13,681 mosquito immatures collected, 22.6% (3095) were anophelines and 77.38% (10,586) were culicines. Out of the 3095 anophelines collected, An. gambiae s.l. was predominant (99.48%, n = 3079), followed by Anopheles rufipes (0.45%, n = 14), and Anopheles pharoensis (0.064%, n = 2). Sibling species of the An. gambiae consisted of Anopheles coluzzii (71%), followed by An. gambiae s.s. (23%), and Anopheles melas (6%). Anopheles mean larval density was highest in wells [6.44 (95% CI 5.0-8.31) larvae/dip], lowest in furrows [4.18 (95% CI 2.75-6.36) larvae/dip] and man-made ponds [1.20 (95% CI 0.671-2.131) larvae/dip].The results also revealed habitat stability was highly dependent on rainfall intensity, and Anopheles larval densities were also dependent on elevated levels of pH, conductivity and TDS. CONCLUSION The presence of larvae in the habitats was dependent on rainfall intensity and proximity to human settlements. To optimize the vector control measures of malaria interventions in southern Ghana, larval control should be focused on larval habitats that are fed by underground water, as these are more productive habitats.
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Affiliation(s)
- Akua O Forson
- Department of Medical Laboratory Science, School of Biomedical and Allied Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - Isaac A Hinne
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Isaac Kwame Sraku
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Yaw A Afrane
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana.
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19
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Escobar D, Pérez F, Ortiz B, Fontecha G. PCR-RFLP assays for the identification of Anopheles (Diptera: Culicidae) species circulating in Honduras. Malar J 2023; 22:57. [PMID: 36805673 PMCID: PMC9938605 DOI: 10.1186/s12936-023-04494-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/13/2023] [Indexed: 02/20/2023] Open
Abstract
BACKGROUND Vector populations are a key target for malaria control and elimination. In Honduras, there are at least 12 reported anopheline species, however, the definitive number of species remains uncertain. Due to the inherent limitations of morphological identification of Anopheles species, molecular approaches have been developed to provide accurate identification and robust surveillance of local malaria vectors. The aim of this study was to design and assess three PCR-RFLP assays to identify anopheline species known to presently occur in Honduras. METHODS Mosquitoes captured between 2018 and 2022 in seven malaria-endemic and non-endemic departments in Honduras were analysed. The ITS2 ribosomal region and three restriction enzyme-based assays were evaluated in silico and experimentally. RESULTS A total of 132 sequences from 12 anopheline species were analysed. The ITS2 marker showed length polymorphisms that generated products between 388 and 592 bp and no relevant intraspecies polymorphisms were found. Furthermore, the three PCR-RFLP assays were able to differentiate 11 species with sufficient precision and resolution. CONCLUSION The ITS2 region was shown to be a useful molecular marker for identifying local Anopheles species. In addition, the PCR-RFLP assays evaluated here proved to be capable of discriminating most of the anopheline species present in Honduras. These methods provide alternatives to improve entomological surveillance of Anopheles in Honduras and other Mesoamerican countries.
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Affiliation(s)
- Denis Escobar
- grid.10601.360000 0001 2297 2829Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Fernando Pérez
- grid.10601.360000 0001 2297 2829Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Bryan Ortiz
- grid.10601.360000 0001 2297 2829Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Gustavo Fontecha
- Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras.
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20
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Pollegioni P, Persampieri T, Minuz RL, Bucci A, Trusso A, Martino SD, Leo C, Bruttini M, Ciolfi M, Waldvogel A, Tripet F, Simoni A, Crisanti A, Müller R. Introgression of a synthetic sex ratio distortion transgene into different genetic backgrounds of Anopheles coluzzii. INSECT MOLECULAR BIOLOGY 2023; 32:56-68. [PMID: 36251429 PMCID: PMC10092091 DOI: 10.1111/imb.12813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
The development of genetically modified mosquitoes (GMM) and their subsequent field release offers innovative approaches for vector control of malaria. A non-gene drive self-limiting male-bias Ag(PMB)1 strain has been developed in a 47-year-old laboratory G3 strain of Anopheles gambiae s.l. When Ag(PMB)1 males are crossed to wild-type females, expression of the endonuclease I-PpoI during spermatogenesis causes the meiotic cleavage of the X chromosome in sperm cells, leading to fertile offspring with a 95% male bias. However, World Health Organization states that the functionality of the transgene could differ when inserted in different genetic backgrounds of Anopheles coluzzii which is currently a predominant species in several West-African countries and thus a likely recipient for a potential release of self-limiting GMMs. In this study, we introgressed the transgene from the donor Ag(PMB)1 by six serial backcrosses into two recipient colonies of An. coluzzii that had been isolated in Mali and Burkina Faso. Scans of informative Single Nucleotide Polymorphism (SNP) markers and whole-genome sequencing analysis revealed a nearly complete introgression of chromosomes 3 and X, but a remarkable genomic divergence in a large region of chromosome 2 between the later backcrossed (BC6) transgenic offspring and the recipient paternal strains. These findings suggested to extend the backcrossing breeding strategy beyond BC6 generation and increasing the introgression efficiency of critical regions that have ecological and epidemiological implications through the targeted selection of specific markers. Disregarding differential introgression efficiency, we concluded that the phenotype of the sex ratio distorter is stable in the BC6 introgressed An. coluzzii strains.
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Affiliation(s)
- Paola Pollegioni
- Research Institute on Terrestrial EcosystemsNational Research CouncilTerniItaly
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Tania Persampieri
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Roxana L. Minuz
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Alessandro Bucci
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Alessandro Trusso
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Salvatore Di Martino
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Chiara Leo
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Marco Bruttini
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
- Tuscan Centre of Precision Medicine, Department of Medicine, Surgery and NeurosciencesUniversity of SienaSienaItaly
| | - Marco Ciolfi
- Research Institute on Terrestrial EcosystemsNational Research CouncilTerniItaly
| | | | - Frédéric Tripet
- Centre for Applied Entomology and ParasitologyKeele UniversityNewcastle‐under‐LymeUK
| | - Alekos Simoni
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
| | - Andrea Crisanti
- Department of Molecular MedicineUniversity of PadovaPadovaItaly
| | - Ruth Müller
- Genetics and Ecology Research CentrePolo d'Innovazione di Genomica, Genetica e BiologiaTerniItaly
- Unit Entomology, Department of Biomedical SciencesInstitute of Tropical MedicineAntwerpBelgium
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21
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Tondossama N, Coulibaly ZI, Traoré I, Ako BA, Zoh DD, Virgillito C, Guindo-Coulibaly N, Serini P, Assouho FK, Dia I, Touré AO, Adja MA, Caputo B, della Torre A, Pichler V. High Levels of Admixture in Anopheles gambiae Populations from Côte d'Ivoire Revealed by Multilocus Genotyping. INSECTS 2022; 13:1090. [PMID: 36555000 PMCID: PMC9782310 DOI: 10.3390/insects13121090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
Anopheles coluzzii and An. gambiae-the two most recently radiated species of the An. gambiae complex and the major Afrotropical malaria vector species-are identified by markers in the X-centromeric IGS rDNA region. Putative IGS-hybrids are rarely found in the field, except in restricted areas where genomic studies have led to the hypothesis that the observed IGS-patterns are due to cryptic taxa rather than to hybridization between the two species. We investigated the genome-wide levels of admixture in two villages in Côte d'Ivoire where high levels of IGS-hybrids have been detected, confirming unparalleled high frequencies in the coastal village. Genotyping of 24 Ancestry Informative Markers (AIMs) along the three chromosomes produced discordant results between the IGS-marker and the multilocus genotype obtained for AIMs across the whole genome (29%) as well as AIMs on chromosome-X (considered to be fundamental for species reproductive isolation) only (21%). Results highlight a complicated pattern of admixture that deserves deeper genomic analyses to understand better possible underlying causes (from extensive processes of hybridization to the existence of different cryptic taxa), and stress the need of developing advanced diagnostics for An. coluzzii, An. gambiae and putative new taxa, instrumental for assessing taxon-specific epidemiological characters.
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Affiliation(s)
- Naminata Tondossama
- Laboratoire de Biologie et Santé, UFR Biosciences, Université Félix Houphouet Boigny Cocody, Abidjan 01 BP V34, Côte d’Ivoire
- Entomology and Herpetology Unit, Institut Pasteur de Côte d’Ivoire, Abidjan 01 PB 490, Côte d’Ivoire
| | - Zanakoungo I. Coulibaly
- Entomology and Herpetology Unit, Institut Pasteur de Côte d’Ivoire, Abidjan 01 PB 490, Côte d’Ivoire
| | - Issouf Traoré
- Laboratoire de Biologie et Santé, UFR Biosciences, Université Félix Houphouet Boigny Cocody, Abidjan 01 BP V34, Côte d’Ivoire
- Entomology and Herpetology Unit, Institut Pasteur de Côte d’Ivoire, Abidjan 01 PB 490, Côte d’Ivoire
| | - Bérenger A. Ako
- Malaria Unit, Institut Pasteur de Côte d’Ivoire, Abidjan 01 PB 490, Côte d’Ivoire
| | - Danielle D. Zoh
- Laboratoire de Biologie et Santé, UFR Biosciences, Université Félix Houphouet Boigny Cocody, Abidjan 01 BP V34, Côte d’Ivoire
- Institut Pierre Richet/Institut National de Santé Publique, Bouaké 01 BP 1500, Côte d’Ivoire
| | - Chiara Virgillito
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma “La Sapienza,” Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Négnorogo Guindo-Coulibaly
- Laboratoire de Biologie et Santé, UFR Biosciences, Université Félix Houphouet Boigny Cocody, Abidjan 01 BP V34, Côte d’Ivoire
| | - Paola Serini
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma “La Sapienza,” Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Fabrice K. Assouho
- Institut Pierre Richet/Institut National de Santé Publique, Bouaké 01 BP 1500, Côte d’Ivoire
| | - Ibrahima Dia
- Pôle de Zoologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, Dakar BP 220, Senegal
| | - Andre O. Touré
- Malaria Unit, Institut Pasteur de Côte d’Ivoire, Abidjan 01 PB 490, Côte d’Ivoire
| | - Maurice A. Adja
- Laboratoire de Biologie et Santé, UFR Biosciences, Université Félix Houphouet Boigny Cocody, Abidjan 01 BP V34, Côte d’Ivoire
- Institut Pierre Richet/Institut National de Santé Publique, Bouaké 01 BP 1500, Côte d’Ivoire
| | - Beniamino Caputo
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma “La Sapienza,” Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Alessandra della Torre
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma “La Sapienza,” Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Verena Pichler
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma “La Sapienza,” Piazzale Aldo Moro, 5, 00185 Rome, Italy
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22
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Soumare HM, Dabira ED, Camara MM, Jadama L, Gaye PM, Kanteh S, Jawara EA, Njie AK, Sanneh F, Ndiath MO, Lindsay SW, Conteh B, Ceesay S, Mohammed N, Ooko M, Bradley J, Drakeley C, Erhart A, Bousema T, D'Alessandro U. Entomological impact of mass administration of ivermectin and dihydroartemisinin-piperaquine in The Gambia: a cluster-randomized controlled trial. Parasit Vectors 2022; 15:435. [PMID: 36397132 PMCID: PMC9673448 DOI: 10.1186/s13071-022-05557-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/16/2022] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Vector control interventions in sub-Saharan Africa rely on insecticide-treated nets and indoor residual spraying. Insecticide resistance, poor coverage of interventions, poor quality nets and changes in vector behavior threaten the effectiveness of these interventions and, consequently, alternative tools are needed. Mosquitoes die after feeding on humans or animals treated with ivermectin (IVM). Mass drug administration (MDA) with IVM could reduce vector survival and decrease malaria transmission. The entomological impact of MDA of combined IVM and dihydroartemisinin-piperaquine was assessed in a community-based, cluster-randomized trial. METHODS A cluster-randomized trial was implemented in 2018 and 2019 in 32 villages in the Upper River Region, The Gambia. The with the inhabitants of 16 intervention villages eligible to receive three monthly rounds of MDA at the beginning of the malaria transmission season. Entomological surveillance with light traps and human landing catches (HLC) was carried out during a 7- to 14-day period after each round of MDA, and then monthly until the end of the year. The mosquitocidal effect of IVM was determined by direct membrane feeding assays. RESULTS Of the 15,017 mosquitoes collected during the study period, 99.65% (n = 14,965) were Anopheles gambiae sensu lato (An. gambiae s.l.), comprising Anopheles arabiensis (56.2%), Anopheles coluzzii (24.5%), Anopheles gambiae sensu stricto (An. gembiae s.s.; 16.0%) and Anopheles funestus sensu lato (An. funestus s.l.; 0.35%). No effect of the intervention on vector parity was observed. Vector density determined on light trap collections was significantly lower in the intervention villages in 2019 (adjusted incidence rate ratio: 0.39; 95% confidence interval [CI]: 0.20, 0.74; P = 0.005) but not in 2018. However, vector density determined in HLC collections was similar in both the intervention and control villages. The entomological inoculation rate was significantly lower in the intervention villages than in the control villages (odds ratio: 0.36, 95% CI: 0.19, 0.70; P = 0·003). Mosquito mortality was significantly higher when blood fed on IVM-treated individuals up to 21 days post-treatment, particularly in adults and individuals with a higher body mass index. CONCLUSION Mass drug administration with IVM decreased vector density and the entomological inoculation rate while the effect on vector parity was less clear. Survival of mosquitoes fed on blood collected from IVM-treated individuals was significantly lower than that in mosquitoes which fed on controls. The influence of host characteristics on mosquito survivorship indicated that dose optimization could improve IVM efficacy. Future detailed entomological evaluation trials in which IVM is administered as stand-alone intervention may elucidate the contribution of this drug to the observed reduction in transmission.
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Affiliation(s)
- Harouna M Soumare
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia.
| | - Edgard Diniba Dabira
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Muhammed M Camara
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Lamin Jadama
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Pa Modou Gaye
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Sainey Kanteh
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Ebrima A Jawara
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Amie Kolleh Njie
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Fatou Sanneh
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Mamadou Ousman Ndiath
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | | | - Bakary Conteh
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Sainey Ceesay
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Nuredin Mohammed
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Michael Ooko
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris Drakeley
- Faculty of Infectious & Tropical Diseases, The London School of Hygiene and Tropical Medicine, London, UK
| | - Annette Erhart
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Teun Bousema
- Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
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Assogba BS, Sillah S, Opondo KO, Cham ST, Camara MM, Jadama L, Camara L, Ndiaye A, Wathuo M, Jawara M, Diabaté A, Achan J, D'Alessandro U. Anopheles gambiae s.l. swarms trapping as a complementary tool against residual malaria transmission in eastern Gambia. Sci Rep 2022; 12:17057. [PMID: 36224312 PMCID: PMC9556655 DOI: 10.1038/s41598-022-21577-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 09/29/2022] [Indexed: 12/30/2022] Open
Abstract
Malaria remains a major health problem and vector control is an essential approach to decrease its burden, although it is threatened by insecticide resistance. New approaches for vector control are needed. The females of Anopheles gambiae s.l. mate once in their life and in the swarms formed by males. Trapping swarms of Anopheles gambiae s.l. males is a potential new intervention for vector control, alternative to the use of insecticides, as it would disrupt mating . The proof-of-concept pilot study aiming at investigating swarm trapping as a potential vector control intervention, was carried out in 6 villages as in eastern Gambia. Swarms of Anopheles gambiae s.l. were identified and their size, height, and duration determined during the baseline year. Swarm trapping by local volunteers was implemented the following transmission season in 4 villages while the other 2 villages were taken as controls. Entomological outcomes were monitored by Human Landing Catches and Pyrethrum Spray Catches. A cross-sectional survey to determine malaria prevalence was carried out at the peak of the malaria transmission season for two consecutive years. At baseline, 23 swarming sites of Anopheles gambiae s.l. were identified. Before the intervention, mean indoor resting density per house and malaria prevalence were similar between control and intervention villages. Following the intervention, Anopheles gambiae s.l. indoor resting density was 44% lower in intervention than in control villages (adj IRR: 0.0.56; 95% CI 0.47-0.68); the odds of malaria infections were 68% lower in intervention than in control villages (OR: 0.32; 95% CI 0.11-0.97). Swarm trapping seems to be a promising, community-based vector control intervention that could reduce malaria prevalence by reducing vector density. Such results should be further investigated and confirmed by larger cluster-randomized trials.
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Affiliation(s)
- Benoît Sessinou Assogba
- Disease Control and Elimination Theme, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia.
| | - Salimina Sillah
- Disease Control and Elimination Theme, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia
| | - Kevin O Opondo
- Disease Control and Elimination Theme, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia
| | - Sheikh Tijan Cham
- Disease Control and Elimination Theme, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia
| | - Muhammed M Camara
- Disease Control and Elimination Theme, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia
| | - Lamin Jadama
- Disease Control and Elimination Theme, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia
| | - Lamin Camara
- Disease Control and Elimination Theme, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia
| | - Assane Ndiaye
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Miriam Wathuo
- Statistic and Bioinformatic Department, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia
| | - Musa Jawara
- Disease Control and Elimination Theme, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia
| | - Abdoulaye Diabaté
- Institut de Recherche en Science de la Santé/Centre Muraz, BP 545, Bobo-Dioulasso, Burkina Faso
| | - Jane Achan
- Disease Control and Elimination Theme, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia
| | - Umberto D'Alessandro
- Disease Control and Elimination Theme, Medical Research Council, Unit The Gambia at London School of Hygiene and Tropical Medicine, PO Box 273, Banjul, The Gambia.
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Boddé M, Makunin A, Ayala D, Bouafou L, Diabaté A, Ekpo UF, Kientega M, Le Goff G, Makanga BK, Ngangue MF, Omitola OO, Rahola N, Tripet F, Durbin R, Lawniczak MKN. High-resolution species assignment of Anopheles mosquitoes using k-mer distances on targeted sequences. eLife 2022; 11:e78775. [PMID: 36222650 PMCID: PMC9648975 DOI: 10.7554/elife.78775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 10/11/2022] [Indexed: 11/13/2022] Open
Abstract
The ANOSPP amplicon panel is a genus-wide targeted sequencing panel to facilitate large-scale monitoring of Anopheles species diversity. Combining information from the 62 nuclear amplicons present in the ANOSPP panel allows for a more senstive and specific species assignment than single gene (e.g. COI) barcoding, which is desirable in the light of permeable species boundaries. Here, we present NNoVAE, a method using Nearest Neighbours (NN) and Variational Autoencoders (VAE), which we apply to k-mers resulting from the ANOSPP amplicon sequences in order to hierarchically assign species identity. The NN step assigns a sample to a species-group by comparing the k-mers arising from each haplotype's amplicon sequence to a reference database. The VAE step is required to distinguish between closely related species, and also has sufficient resolution to reveal population structure within species. In tests on independent samples with over 80% amplicon coverage, NNoVAE correctly classifies to species level 98% of samples within the An. gambiae complex and 89% of samples outside the complex. We apply NNoVAE to over two thousand new samples from Burkina Faso and Gabon, identifying unexpected species in Gabon. NNoVAE presents an approach that may be of value to other targeted sequencing panels, and is a method that will be used to survey Anopheles species diversity and Plasmodium transmission patterns through space and time on a large scale, with plans to analyse half a million mosquitoes in the next five years.
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Affiliation(s)
- Marilou Boddé
- Department of Genetics, University of CambridgeCambridgeUnited Kingdom
- Wellcome Sanger InstituteHinxtonUnited Kingdom
| | | | - Diego Ayala
- Institut de Recherche pour le Développement, MIVEGEC, Univ. Montpellier, CNRS, IRDMontpellier,France
| | - Lemonde Bouafou
- Institut de Recherche pour le Développement, MIVEGEC, Univ. Montpellier, CNRS, IRDMontpellier,France
| | - Abdoulaye Diabaté
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'OuestBobo-DioulassoBurkina Faso
| | | | - Mahamadi Kientega
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'OuestBobo-DioulassoBurkina Faso
| | - Gilbert Le Goff
- Institut de Recherche pour le Développement, MIVEGEC, Univ. Montpellier, CNRS, IRDMontpellier,France
| | | | - Marc F Ngangue
- Centre International de Recherches Medicales de FrancevilleFrancevilleGabon
| | | | - Nil Rahola
- Institut de Recherche pour le Développement, MIVEGEC, Univ. Montpellier, CNRS, IRDMontpellier,France
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, Keele UniversityNewcastleUnited Kingdom
| | - Richard Durbin
- Department of Genetics, University of CambridgeCambridgeUnited Kingdom
- Wellcome Sanger InstituteHinxtonUnited Kingdom
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Mishra R, Hua G, Bagal UR, Champagne DE, Adang MJ. Anopheles gambiae strain (Ag55) cultured cells originated from Anopheles coluzzii and are phagocytic with hemocyte-like gene expression. INSECT SCIENCE 2022; 29:1346-1360. [PMID: 35358364 DOI: 10.1111/1744-7917.13036] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 02/21/2022] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Anopheles gambiae and Anopheles coluzzii are closely related species that are predominant vectors of malaria in Africa. Recently, A. gambiae form M was renamed A. coluzzii and we now conclude on the basis of a diagnostic PCR-restriction fragment length polymorphism assay that Ag55 cells were derived from A. coluzzii. We established an Ag55 cell transcriptome, and KEGG pathway analysis showed that Ag55 cells are enriched in phagosome pathway transcripts. The Ag55 transcriptome has an abundance of specific transcripts characteristic of mosquito hemocytes. Functional E. coli bioparticle uptake experiments visualized by fluorescence microscopy and confocal microscopy and quantified by flow cytometry establish the phagocytic competence of Ag55 cells. Results from this investigation of Ag55 cell properties will guide researchers in the use and engineering of the Ag55 cell line to better enable investigations of Plasmodium, other microbes, and insecticidal toxins.
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Affiliation(s)
- Ruchir Mishra
- Department of Entomology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA
- Department of Entomology and Nematology, University of Florida, Gainesville, Florida, USA
| | - Gang Hua
- Department of Entomology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA
| | - Ujwal R Bagal
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, USA
| | - Donald E Champagne
- Department of Entomology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA
| | - Michael J Adang
- Department of Entomology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
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26
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Fournet F, Adja AM, Adou KA, Dahoui MMC, Coulibaly B, Assouho KF, Zoh DD, Koné M, Koné A, Niamien KL, Cornelie S, Tia E, Moiroux N. First detection of the malaria vector Anopheles arabiensis in Côte d'Ivoire: urbanization in question. Malar J 2022; 21:275. [PMID: 36171572 PMCID: PMC9520799 DOI: 10.1186/s12936-022-04295-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 09/15/2022] [Indexed: 12/03/2022] Open
Abstract
Background Previous studies have revealed high malaria transmission in Bouaké, Côte d’Ivoire. The sociopolitical crisis in the country and the resulting environmental changes have raised the need to update existing knowledge on mosquito vector species and malaria transmission. Methods Adult mosquitoes were caught using the human landing catch (HLC) sampling method in Bouaké. They were collected in six districts representative of the diversity in urban landscapes. Sampling points were selected along the water network crossing the city and monitored from 2020 to 2021 to detect the presence of anopheline larvae. PCR techniques were used to ascertain the species of the Anopheles gambiae complex, Plasmodium falciparum sporozoite infection in a subset of Anopheles vectors, and insecticide resistance mechanisms in Anopheles arabiensis only. Results A total of 4599 Anopheles mosquitoes were collected and then identified. Anopheles gambiae sensu lato (s.l.) made up the majority of the whole collection (99%) while Anopheles funestus (0.7%), Anopheles ziemanni (0.2%), Anopheles pharoensis (0.2%) represented the remaining proportion of collection. Among the Anopheles gambiae complex, three species were identified namely An. gambiae sensu stricto (45.9%), Anopheles coluzzii (52.2%), and Anopheles arabiensis (1.9%). The first two species had already been collected in Bouaké, however this is the first time that An. arabiensis is reported in Côte d’Ivoire. Anopheles arabiensis was also collected during the larval surveys in a similar proportion (1.1%) in the same areas as the adults. Conclusions This study detected the presence of An. arabiensis for the first time in Côte d’Ivoire. This species was found quite far from its usual geographic area and its expansion could be linked to the urbanization process. Although no An. arabiensis was found to be infected by Plasmodium sp., its role in malaria transmission in Bouaké has to be explored, particularly since its exophagic behaviour raises the issue of control measures and the use of insecticide-impregnated nets. The spread of this species in Côte d'Ivoire should be assessed through further research in additional towns in the country.
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Affiliation(s)
- Florence Fournet
- MIVEGEC (Université de Montpellier, CNRS, IRD), Montpellier, France. .,Centre d'Entomologie Médicale Et Vétérinaire, Bouaké, Côte d'Ivoire. .,Institut Pierre Richet, Institut National de Santé Publique, Bouaké, Côte d'Ivoire.
| | - Akre M Adja
- Institut Pierre Richet, Institut National de Santé Publique, Bouaké, Côte d'Ivoire.,Unité de Formation Et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Kouassi A Adou
- MIVEGEC (Université de Montpellier, CNRS, IRD), Montpellier, France.,Institut Pierre Richet, Institut National de Santé Publique, Bouaké, Côte d'Ivoire.,Institut de Géographie Tropicale, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Milossé M C Dahoui
- MIVEGEC (Université de Montpellier, CNRS, IRD), Montpellier, France.,Institut Pierre Richet, Institut National de Santé Publique, Bouaké, Côte d'Ivoire
| | - Baba Coulibaly
- Institut Pierre Richet, Institut National de Santé Publique, Bouaké, Côte d'Ivoire
| | - Konan F Assouho
- Institut Pierre Richet, Institut National de Santé Publique, Bouaké, Côte d'Ivoire.,Unité de Formation Et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Dounin D Zoh
- Institut Pierre Richet, Institut National de Santé Publique, Bouaké, Côte d'Ivoire.,Unité de Formation Et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Moussa Koné
- Centre d'Entomologie Médicale Et Vétérinaire, Bouaké, Côte d'Ivoire
| | - Aboubacar Koné
- Institut Pierre Richet, Institut National de Santé Publique, Bouaké, Côte d'Ivoire
| | - Koffi L Niamien
- Institut Pierre Richet, Institut National de Santé Publique, Bouaké, Côte d'Ivoire
| | - Sylvie Cornelie
- MIVEGEC (Université de Montpellier, CNRS, IRD), Montpellier, France
| | - Emmanuel Tia
- Centre d'Entomologie Médicale Et Vétérinaire, Bouaké, Côte d'Ivoire
| | - Nicolas Moiroux
- MIVEGEC (Université de Montpellier, CNRS, IRD), Montpellier, France
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Evolution of the Ace-1 and Gste2 Mutations and Their Potential Impact on the Use of Carbamate and Organophosphates in IRS for Controlling Anopheles gambiae s.l., the Major Malaria Mosquito in Senegal. Pathogens 2022; 11:pathogens11091021. [PMID: 36145453 PMCID: PMC9504234 DOI: 10.3390/pathogens11091021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
Widespread of insecticide resistance amongst the species of the Anopheles gambiae complex continues to threaten vector control in Senegal. In this study, we investigated the presence and evolution of the Ace-1 and Gste2 resistance genes in natural populations of Anopheles gambiae s.l., the main malaria vector in Senegal. Using historical samples collected from ten sentinel health districts, this study focused on three different years (2013, 2017, and 2018) marking the periods of shift between the main public health insecticides families (pyrethroids, carbamates, organophosphates) used in IRS to track back the evolutionary history of the resistance mutations on the Ace-1 and Gste2 loci. The results revealed the presence of four members of the Anopheles gambiae complex, with the predominance of An. arabiensis followed by An. gambiae, An. coluzzii, and An. gambiae–coluzzii hybrids. The Ace-1 mutation was only detected in An. gambiae and An. gambiae–coluzzii hybrids at low frequencies varying between 0.006 and 0.02, while the Gste2 mutation was found in all the species with a frequency ranging between 0.02 and 0.25. The Ace-1 and Gste2 genes were highly diversified with twenty-two and thirty-one different haplotypes, respectively. The neutrality tests on each gene indicated a negative Tajima’s D, suggesting the abundance of rare alleles. The presence and spread of the Ace-1 and Gste2 resistance mutations represent a serious threat to of the effectiveness and the sustainability of IRS-based interventions using carbamates or organophosphates to manage the widespread pyrethroids resistance in Senegal. These data are of the highest importance to support the NMCP for evidence-based vector control interventions selection and targeting.
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Forson AO, Hinne IA, Dhikrullahi SB, Sraku IK, Mohammed AR, Attah SK, Afrane YA. The resting behavior of malaria vectors in different ecological zones of Ghana and its implications for vector control. Parasit Vectors 2022; 15:246. [PMID: 35804461 PMCID: PMC9270803 DOI: 10.1186/s13071-022-05355-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 06/10/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND In sub-Saharan Africa there is widespread use of long-lasting insecticidal nets and indoor residual spraying to help control the densities of malaria vectors and decrease the incidence of malaria. This study was carried out to investigate the resting behavior, host preference and infection with Plasmodium falciparum of malaria vectors in Ghana in the context of the increasing insecticide resistance of malaria vectors in sub-Saharan Africa. METHODS Indoor and outdoor resting anopheline mosquitoes were sampled during the dry and rainy seasons in five sites in three ecological zones [Sahel savannah (Kpalsogo, Pagaza, Libga); coastal savannah (Anyakpor); and forest (Konongo)]. Polymerase chain reaction-based molecular diagnostics were used to determine speciation, genotypes for knockdown resistance mutations (L1014S and L1014F) and the G119S ace1 mutation, specific host blood meal origins and sporozoite infection in the field-collected mosquitoes. RESULTS Anopheles gambiae sensu lato (s.l.) predominated (89.95%, n = 1718), followed by Anopheles rufipes (8.48%, n = 162) and Anopheles funestus s.l. (1.57%, n = 30). Sibling species of the Anopheles gambiae s.l. revealed Anopheles coluzzii accounted for 63% (95% confidence interval = 57.10-68.91) and 27% (95% confidence interval = 21.66-32.55) was Anopheles gambiae s. s.. The mean resting density of An. gambiae s.l. was higher outdoors (79.63%; 1368/1718) than indoors (20.37%; 350/1718) (Wilcoxon rank sum test, Z = - 4.815, P < 0.0001). The kdr west L1014F and the ace1 mutation frequencies were higher in indoor resting An. coluzzii and An. gambiae in the Sahel savannah sites than in the forest and coastal savannah sites. Overall, the blood meal analyses revealed that a larger proportion of the malaria vectors preferred feeding on humans (70.2%) than on animals (29.8%) in all of the sites. Sporozoites were only detected in indoor resting An. coluzzii from the Sahel savannah (5.0%) and forest (2.5%) zones. CONCLUSIONS This study reports high outdoor resting densities of An. gambiae and An. coluzzii with high kdr west mutation frequencies, and the presence of malaria vectors indoors despite the use of long-lasting insecticidal nets and indoor residual spraying. Continuous monitoring of changes in the resting behavior of mosquitoes and the implementation of complementary malaria control interventions that target outdoor resting Anopheles mosquitoes are necessary in Ghana.
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Affiliation(s)
- Akua Obeng Forson
- Department of Medical Laboratory Science, School of Biomedical and Allied Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - Isaac A. Hinne
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Shittu B. Dhikrullahi
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Isaac Kwame Sraku
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Abdul Rahim Mohammed
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Simon K. Attah
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Yaw Asare Afrane
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
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Perfect association between spatial swarm segregation and the X-chromosome speciation island in hybridizing Anopheles coluzzii and Anopheles gambiae populations. Sci Rep 2022; 12:10800. [PMID: 35750745 PMCID: PMC9232630 DOI: 10.1038/s41598-022-14865-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 06/14/2022] [Indexed: 11/08/2022] Open
Abstract
The sibling species An. coluzzii and An. gambiae s.s. are major malaria vectors thought to be undergoing sympatric speciation with gene flow. In the absence of intrinsic post-zygotic isolation between the two taxa, speciation is thought possible through the association of assortative mating and genomic regions protected from gene flow by recombination suppression. Such genomic islands of speciation have been described in pericentromeric regions of the X, 2L and 3L chromosomes. Spatial swarm segregation plays a major role in assortative mating between sympatric populations of the two species and, given their importance for speciation, genes responsible for such pre-mating reproductive barriers are expected to be protected within divergence islands. In this study 2063 male and 266 female An. coluzzii and An. gambiae s.s. individuals from natural swarms in Burkina Faso, West Africa were sampled. These were genotyped at 16 speciation island SNPs, and characterized as non-hybrid individuals, F1 hybrids or recombinant F1+n backcrossed individuals. Their genotypes at each speciation island were associated with their participation in An. coluzzii and An. gambiae-like swarms. Despite extensive introgression between the two species, the X-island genotype of non-hybrid individuals (37.6%), F1 hybrids (0.1%) and F1+n recombinants (62.3%) of either sex perfectly associated to each swarm type. Associations between swarm type and the 3L and 2L speciation islands were weakened or broken down by introgression. The functional demonstration of a close association between spatial segregation behaviour and the X speciation island lends further support to sympatric speciation models facilitated by pericentric recombination suppression in this important species complex.
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Chanyalew T, Natea G, Amenu D, Yewhalaw D, Simma EA. Composition of mosquito fauna and insecticide resistance status of Anopheles gambiae sensu lato in Itang special district, Gambella, Southwestern Ethiopia. Malar J 2022; 21:125. [PMID: 35436961 PMCID: PMC9014582 DOI: 10.1186/s12936-022-04150-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 04/04/2022] [Indexed: 11/10/2022] Open
Abstract
Background Anopheles arabiensis, member species of the Anopheles gambiae complex, is the primary vector of malaria and is widely distributed in Ethiopia. Anopheles funestus, Anopheles pharoensis and Anopheles nili are secondary vectors occurring with limited distribution in the country. Indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) are pillars for the interventions against malaria control and elimination efforts in Ethiopia. However, the emergence and widespread of insecticide resistance in An. gambiae sensu lato (s.l.), might compromise the control efforts of the country. The aim of this study was to investigate composition of mosquito fauna and insecticide resistance status of An. gambiae s.l. in Itang special district ( woreda), Gambella, southwestern Ethiopia. Methods Adult mosquitoes were sampled from September 2020 to February 2021 using the CDC light trap and pyrethrum spray catch (PSC). CDC light traps were placed in three selected houses for two consecutive days per month to collect mosquitoes indoor and outdoor from 6:00 P.M. to 06:00 A.M. and PSC was used to collect indoor resting mosquitoes from ten selected houses once in a month from October 2020 to February 2021. Moreover, mosquito larvae were also collected from different breeding sites and reared to adults to assess susceptibility status of populations of An. gambiae s.l. in the study area. Susceptibility tests were conducted on two to three days old non blood fed female An. gambiae s.l. using insecticide impregnated papers with deltamethrin (0.05%), alpha-cypermethrin (0.05%), propoxur (0.1%), pirimiphos-methyl (0.25%) and bendiocarb (0.1%) following World Health Organization (WHO) standard susceptibility test procedure. Molecular diagnostics were done for the identification of member species of An. gambiae s.l. and detection of knockdown resistance (kdr) allele using species specific polymerase chain reaction (PCR) and allele specific PCR. Results In total, 468 adult mosquitoes were collected from different houses. Culex mosquitoes were the most dominant (80.4%) followed by Anopheles mosquitoes. Three species of Anopheles (Anopheles coustani, An. pharoensis, and An. gambiae s.l.) were identified, of which An. coustani was the dominant (8.1%) species. Higher number of mosquitoes (231) were collected outdoor by CDC light traps. Out of 468 adult mosquitoes, 294 were blood fed, 46 were half-gravid and gravid whereas the remaining 128 were unfed. WHO bioassay tests revealed that the populations of An. gambiae s.l. in the study area are resistant against alpha-cypermethrin and deltamethrin, but susceptible to bendiocarb, pirimiphos-methyl and propoxur. Of the total 86 An. gambiae s.l. specimens assayed, 79 (92%) successfully amplified and identified as An. arabiensis. West African kdr (L1014F) mutation was detected with high kdr allele frequency ranging from 67 to 88%. Conclusion The detection of target site mutation, kdr L1014F allele, coupled with the phenotypic resistance against alpha-cypermethrin and deltamethrin call for continuous resistance monitoring.
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Thabet HS, TagEldin RA, Fahmy NT, Diclaro JW, Alaribe AA, Ezedinachi E, Nwachuku NS, Odey FO, Arimoto H. Spatial Distribution of PCR-Identified Species of Anopheles gambiae senu lato (Diptera: Culicidae) Across Three Eco-Vegetational Zones in Cross River State, Nigeria. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:576-584. [PMID: 35064267 DOI: 10.1093/jme/tjab221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Indexed: 06/14/2023]
Abstract
Anopheles gambiae sensu lato complex (An. gambiae s.l.) describes a group of nine morphologically indistinguishable members that vary in their distribution, ability to transmit malaria, and susceptibility to pyrethroids. Here, we recorded the spatial patterns of PCR-identified An. gambiae s.l. complex species collected from four sites in Cross River State, Nigeria that represented three different ecological zones. Trapping was conducted between October 2015 and June 2016. Anopheles gambiae s.l. complex species identification was performed using species-specific primers followed by An. gambiae and An. coluzzii differentiation using the restriction fragment length polymorphism (RFLP) method. Bivariate and multivariate logistic regression models were used to identify ecological and seasonal variables closely associated with An. coluzzii and An. gambiae distribution. Out of 1,388 An. gambiae s.l. successfully amplified, 1,074 (77.4%) were An. coluzzii, 278 (20%) were An. gambiae, and 25 (1.8%) were hybrids (An. coluzzii/An. gambiae). A very small number of An. arabiensis (0.8%, n = 11) were also collected. Statistical analysis indicated that An. coluzzii is predominant in Guinea-savannah and tropical rainforest, and is highly associated with rainy seasons, while, An. gambiae is prevalent in mangrove swamp forest during dry seasons. Only 13 An. gambiae s.l. females were infected with Plasmodium falciparum (P. falciparum). The sporozoite infection rate was higher in mangrove swamp forest (53.8%, n = 7) than in rain forest (38.5%, n = 5) followed by Guinea-savannah (7.7%, n = 1) ecological zones. These results provide important insights for strategic planning of malaria control programs in Nigeria.
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Affiliation(s)
- H S Thabet
- U.S. Naval Medical Research Unit No. 3 (NAMRU-3), Cairo Detachment, Egypt
| | - R A TagEldin
- U.S. Naval Medical Research Unit No. 3 (NAMRU-3), Cairo Detachment, Egypt
| | - N T Fahmy
- U.S. Naval Medical Research Unit No. 3 (NAMRU-3), Cairo Detachment, Egypt
| | - J W Diclaro
- U.S. Naval Medical Research Unit No. 3 (NAMRU-3), Cairo Detachment, Egypt
- Navy Entomology Center of Excellence (NECE), Jacksonville, FL, USA
| | - A A Alaribe
- Calabar Institute of Tropical Diseases Research and Prevention (CITDRP), University of Calabar, Cross River State, Nigeria
| | - E Ezedinachi
- Calabar Institute of Tropical Diseases Research and Prevention (CITDRP), University of Calabar, Cross River State, Nigeria
| | - N S Nwachuku
- Calabar Institute of Tropical Diseases Research and Prevention (CITDRP), University of Calabar, Cross River State, Nigeria
| | - F O Odey
- Calabar Institute of Tropical Diseases Research and Prevention (CITDRP), University of Calabar, Cross River State, Nigeria
| | - H Arimoto
- U.S. Naval Medical Research Unit No. 3 (NAMRU-3), Cairo Detachment, Egypt
- Navy Environmental and Preventive Medicine Unit Five, San Diego, CA, USA
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Williams J, Cowlishaw R, Sanou A, Ranson H, Grigoraki L. In vivo functional validation of the V402L voltage gated sodium channel mutation in the malaria vector An. gambiae. PEST MANAGEMENT SCIENCE 2022; 78:1155-1163. [PMID: 34821465 DOI: 10.1002/ps.6731] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/19/2021] [Accepted: 11/25/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Pyrethroids are the most widely used insecticides for the control of malaria transmitting Anopheles gambiae mosquitoes and rapid increase in resistance to this insecticide class is of major concern. Pyrethroids target the Voltage Gated Sodium Channels (VGSCs), that have a key role in the normal function of the mosquitoes' nervous system. VGSC mutations L995F and L995S have long been associated with pyrethroid resistance and screening for their presence is routine in insecticide resistance management programs. Recently, a VGSC haplotype containing two amino acid substitutions associated with resistance in other species, V402L and I1527T, was identified. These two VGSC mutations are found in tight linkage and are mutually exclusive to the classical L995F/S mutations. RESULTS We identify the presence of the V402L-I1527T haplotype in resistant An. coluzzii colonized strains and in field populations from Burkina Faso, at frequencies higher than previously reported; in some cases almost reaching fixation. Functional validation of V402L in insecticide resistance using a CRISPR/Cas9 genome modified line showed that it confers reduced mortality after exposure to all tested pyrethroids and DDT, but at lower levels compared to L995F. In contrast to L995F however, no fitness costs were identified for mosquitoes carrying V402L under laboratory conditions. CONCLUSION The V402L substitution confers pyrethroid resistance in An. gambiae in the absence of any other VGSC substitution and/or alternative resistance mechanisms. The lower fitness cost associated with this kdr mutation may provide a selective advantage over the classical kdr in some settings and genotyping at this locus should be added in the list of resistant alleles for routine screening.
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Affiliation(s)
- Jessica Williams
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Ruth Cowlishaw
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Antoine Sanou
- Service Scientifique et Technique, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Hilary Ranson
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Linda Grigoraki
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK
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Omotayo AI, Ande AT, Oduola AO, Adelaja OJ, Adesalu O, Jimoh TR, Ghazali AI, Awolola ST. Multiple insecticide resistance mechanisms in urban population of Anopheles coluzzii (Diptera: culicidae) from Lagos, South-West Nigeria. Acta Trop 2022; 227:106291. [PMID: 34958768 DOI: 10.1016/j.actatropica.2021.106291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 12/18/2021] [Accepted: 12/21/2021] [Indexed: 11/01/2022]
Abstract
Malaria is a major public health challenge in Africa with Nigeria accounting for the highest burden of the disease in the world. Vector control has proved to be a highly effective component of malaria control, however, the development and spread of insecticide resistance in major vectors of malaria have been a major challenge. This study assessed resistance mechanisms in Anopheles coluzzii populations from Kosofe, Lagos mainland and Ojo Local Government Areas in Lagos, Nigeria where An. gambiae s.l is resistant to DDT and Permethrin. WHO susceptibility bioassay test was used in determining resistance status of An. coluzzii to discriminating doses of DDT and Permethrin while synergist assay was used to assess the involvement of monooxygenases in resistance development. Sub-species of An. gambiae s.l (An. gambiae and An. coluzzii) were identified using polymerase chain reaction (PCR) and Restriction Fragment Length Polymorphism (PCR-RFLP) while Allele-Specific Polymerase Chain Reaction (AS-PCR) assay was used to detect knockdown mutation (kdr-West; L1014F). Biochemical assays were used in determining the activities of metabolic enzymes. High DDT resistance was recorded in An. coluzzii populations from the three sites. Mortality rate of mosquitoes exposed confirmed Permethrin resistance in Kosofe (50%) and Lagos mainland (48%) but resistance was suspected in Ojo (96%). All specimens tested were confirmed as An. coluzzii with low kdr frequency; 11.6%, 16.4% and 6.7% in Kosofe, Lagos mainland and Ojo respectively. Pre-exposure to synergist (PBO) before exposure to Permethrin led to increased mortality in all populations. Esterase activity was insignificantly overexpressed in Kosofe (p = 0.849) and Lagos mainland (p = 0.229) populations. In contrast, GST activity was significantly lower in populations from Lagos mainland (63.650 ± 9.861; p = 0.007) and Ojo (91.765 ± 4.959; p = 0.042) than Kisumu susceptible strains (120.250 ± 13.972). Monooxygenase activity was higher in Lagos mainland (2.371 ± 0.261) and Ojo (1.361 ± 0.067) populations, albeit significantly in Lagos mainland (p = 0.007) only. Presence of target-site mutation in all populations, increased mortality with pre-exposure to PBO and elevated monooxygenase in Lagos mainland population were confirmed. Multiple resistance mechanisms in some urban populations of An. coluzzii from Lagos, Nigeria calls for appropriate resistance management strategies.
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Hamid-Adiamoh M, Nwakanma D, Sraku I, Amambua-Ngwa A, A. Afrane Y. Is outdoor-resting behaviour in malaria vectors consistent? Short report from northern Ghana. AAS Open Res 2022. [DOI: 10.12688/aasopenres.13317.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Recent studies have observed vectors resting predominantly outdoors in settings where anti-vector tools are extensively deployed, attributed to selection pressure from use of control tools. This present study examined if the outdoor resting behaviour in the vector population is random or indicative of a consistent preference of one resting site over the other. Methods: Mark-release-recapture experiments were conducted with outdoor-resting Anopheles gambiae and An. funestus mosquitoes collected from two villages in northern Ghana during rainy and dry seasons. Mosquitoes were marked with fluorescent dyes and released indoors. The experiments were controlled with indoor-resting mosquitoes, which were marked and released outdoors. Species of all recaptured mosquitoes were identified and assessed for consistency in their resting behaviour. Results: A total of 4,460 outdoor-resting mosquitoes comprising An. gambiae sensu lato (s.l.) (2,636, 59%) and An. funestus complex (1,824, 41%) were marked and released. Overall, 31 (0.7%) mosquitoes were recaptured mostly from outdoor location comprising 25 (81%) An. gambiae s.l. and 6 (19%) An. funestus complex. Only 3 (10%) of the recaptured mosquitoes were found resting indoors where they were released. The majority of the outdoor-recaptured mosquitoes were An. arabiensis (11, 39%), followed by An. coluzzii (7, 25%); whereas all indoor-recaptured mosquitoes were An. coluzzii. For the control experiment, 324 indoor-resting mosquitoes constituting 313 (97%) An. gambiae s.l. and 11 (3%) An. funestus complex were marked and released. However, none of these was recaptured neither indoors nor outdoors. More mosquitoes were captured and recaptured during rainy season, but this was not statistically significant (Z=0.79, P=0.21). Conclusions: These results suggested the tendency for the mosquitoes to retain their outdoor-resting behaviour. Further investigations are required to ascertain if emerging preference for outdoor resting behaviour in malaria vector populations is consistent or a random occurrence.
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Sympatric Populations of the Anopheles gambiae Complex in Southwest Burkina Faso Evolve Multiple Diverse Resistance Mechanisms in Response to Intense Selection Pressure with Pyrethroids. INSECTS 2022; 13:insects13030247. [PMID: 35323544 PMCID: PMC8955173 DOI: 10.3390/insects13030247] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/16/2022] [Accepted: 02/21/2022] [Indexed: 02/01/2023]
Abstract
Simple Summary Targeting mosquitoes with insecticides is one of the most effective methods to prevent malaria transmission. Although numbers of malaria cases have declined substantially this century, this pattern is not universal and Burkina Faso has one of the highest burdens of malaria; it is also a hotspot for the evolution of insecticide resistance in malaria vectors. We have established laboratory colonies from multiple species within the An. gambiae complex, the most efficient group of malaria vectors in the world, from larval collections in southwest Burkina Faso. Using bioassays with different insecticides widely used to control public health pests, we provide a profile of insecticide resistance in each of these colonies and, using molecular tools, reveal the genetic changes underpinning this resistance. We show that, whilst many resistance mechanisms are shared between species, there are some important differences which may affect resistance to current and future insecticide classes. The complexity, and diversity of resistance mechanisms highlights the importance of screening any potential new insecticide intended for use in malaria control against a wide range of populations. These stable laboratory colonies provide a valuable resource for insecticide discovery, and for further studies on the evolution and dispersal of insecticide resistance within and between species. Abstract Pyrethroid resistance in the Anopheles vectors of malaria is driving an urgent search for new insecticides that can be used in proven vector control tools such as insecticide treated nets (ITNs). Screening for potential new insecticides requires access to stable colonies of the predominant vector species that contain the major pyrethroid resistance mechanisms circulating in wild populations. Southwest Burkina Faso is an apparent hotspot for the emergence of pyrethroid resistance in species of the Anopheles gambiae complex. We established stable colonies from larval collections across this region and characterised the resistance phenotype and underpinning genetic mechanisms. Three additional colonies were successfully established (1 An. coluzzii, 1 An. gambiae and 1 An. arabiensis) to add to the 2 An. coluzzii colonies already established from this region; all 5 strains are highly resistant to pyrethroids. Synergism assays found that piperonyl butoxide (PBO) exposure was unable to fully restore susceptibility although exposure to a commercial ITN containing PBO resulted in 100% mortality. All colonies contained resistant alleles of the voltage gated sodium channel but with differing proportions of alternative resistant haplotypes. RNAseq data confirmed the role of P450s, with CYP6P3 and CYP6Z2 elevated in all 5 strains, and identified many other resistance mechanisms, some found across strains, others unique to a particular species. These strains represent an important resource for insecticide discovery and provide further insights into the complex genetic changes driving pyrethroid resistance.
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Etang J, Mandeng SE, Nwane P, Awono-Ambene HP, Bigoga JD, Ekoko WE, Binyang AJ, Piameu M, Mbakop LR, Mvondo N, Tabue R, Mimpfoundi R, Toto JC, Kleinschmidt I, Knox TB, Mnzava AP, Donnelly MJ, Fondjo E. Patterns of Kdr-L995F Allele Emergence Alongside Detoxifying Enzymes Associated with Deltamethrin Resistance in Anopheles gambiae s.l. from North Cameroon. Pathogens 2022; 11:pathogens11020253. [PMID: 35215196 PMCID: PMC8876678 DOI: 10.3390/pathogens11020253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/09/2022] [Accepted: 02/12/2022] [Indexed: 11/16/2022] Open
Abstract
Understanding how multiple insecticide resistance mechanisms occur in malaria vectors is essential for efficient vector control. This study aimed at assessing the evolution of metabolic mechanisms and Kdr L995F/S resistance alleles in Anopheles gambiae s.l. from North Cameroon, following long-lasting insecticidal nets (LLINs) distribution in 2011. Female An. gambiae s.l. emerging from larvae collected in Ouro-Housso/Kanadi, Be-Centre, and Bala in 2011 and 2015, were tested for susceptibility to deltamethrin + piperonyl butoxide (PBO) or SSS-tributyl-phosphoro-thrithioate (DEF) synergists, using the World Health Organization's standard protocol. The Kdr L995F/S alleles were genotyped using Hot Ligation Oligonucleotide Assay. Tested mosquitoes identified using PCR-RFLP were composed of An. arabiensis (68.5%), An. coluzzii (25.5%) and An. gambiae (6%) species. From 2011 to 2015, metabolic resistance increased in Ouro-Housso/Kanadi (up to 89.5% mortality to deltametnrin+synergists in 2015 versus <65% in 2011; p < 0.02), while it decreased in Be-Centre and Bala (>95% mortality in 2011 versus 42-94% in 2015; p < 0.001). Conversely, the Kdr L995F allelic frequencies slightly decreased in Ouro-Housso/Kanadi (from 50% to 46%, p > 0.9), while significantly increasing in Be-Centre and Bala (from 0-13% to 18-36%, p < 0.02). These data revealed two evolutionary trends of deltamethrin resistance mechanisms; non-pyrethroid vector control tools should supplement LLINs in North Cameroon.
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Affiliation(s)
- Josiane Etang
- Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon; (S.E.M.); (P.N.); (H.P.A.-A.); (W.E.E.); (M.P.); (L.R.M.); (J.C.T.)
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 2701, Douala 999108, Cameroon
- Institute for Insect Biotechnology, Justus Liebig University Gießen, 35394 Gießen, Germany
- Correspondence: ; Tel.: +237-677-61-97-79
| | - Stanislas Elysée Mandeng
- Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon; (S.E.M.); (P.N.); (H.P.A.-A.); (W.E.E.); (M.P.); (L.R.M.); (J.C.T.)
- Laboratory of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé 999108, Cameroon; (A.J.B.); (N.M.); (R.M.)
| | - Philippe Nwane
- Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon; (S.E.M.); (P.N.); (H.P.A.-A.); (W.E.E.); (M.P.); (L.R.M.); (J.C.T.)
- Laboratory of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé 999108, Cameroon; (A.J.B.); (N.M.); (R.M.)
| | - Herman Parfait Awono-Ambene
- Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon; (S.E.M.); (P.N.); (H.P.A.-A.); (W.E.E.); (M.P.); (L.R.M.); (J.C.T.)
| | - Jude D. Bigoga
- Laboratory for Vector Biology and Control, National Reference Unit for Vector Control, The Biotechnology Center, Nkolbisson-University of Yaounde I, P.O. Box 3851 Messa, Yaoundé 999108, Cameroon; (J.D.B.); (R.T.)
| | - Wolfgang Eyisap Ekoko
- Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon; (S.E.M.); (P.N.); (H.P.A.-A.); (W.E.E.); (M.P.); (L.R.M.); (J.C.T.)
| | - Achille Jerome Binyang
- Laboratory of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé 999108, Cameroon; (A.J.B.); (N.M.); (R.M.)
| | - Michael Piameu
- Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon; (S.E.M.); (P.N.); (H.P.A.-A.); (W.E.E.); (M.P.); (L.R.M.); (J.C.T.)
- Ecole des Sciences de la Santé, Université Catholique d’Afrique Centrale, P.O. Box 1110, Yaoundé 999108, Cameroon
| | - Lili Ranaise Mbakop
- Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon; (S.E.M.); (P.N.); (H.P.A.-A.); (W.E.E.); (M.P.); (L.R.M.); (J.C.T.)
- Laboratory of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé 999108, Cameroon; (A.J.B.); (N.M.); (R.M.)
| | - Narcisse Mvondo
- Laboratory of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé 999108, Cameroon; (A.J.B.); (N.M.); (R.M.)
| | - Raymond Tabue
- Laboratory for Vector Biology and Control, National Reference Unit for Vector Control, The Biotechnology Center, Nkolbisson-University of Yaounde I, P.O. Box 3851 Messa, Yaoundé 999108, Cameroon; (J.D.B.); (R.T.)
- National Malaria Control Programme, Ministry of Public Health, Yaoundé 999108, Cameroon
| | - Rémy Mimpfoundi
- Laboratory of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé 999108, Cameroon; (A.J.B.); (N.M.); (R.M.)
| | - Jean Claude Toto
- Laboratoire de Recherche sur le Paludisme, Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé 999108, Cameroon; (S.E.M.); (P.N.); (H.P.A.-A.); (W.E.E.); (M.P.); (L.R.M.); (J.C.T.)
| | - Immo Kleinschmidt
- MRC International Statistics and Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel St., London WC1E 7HT, UK;
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2141, South Africa
- Southern African Development Community Malaria Elimination Eight Secretariat, 10 Platinum Street, Erf 490, Prosperita, Windhoek 10005, Namibia
| | - Tessa Bellamy Knox
- World Health Organization Country Liaison Office, Port Vila 99514, Vanuatu;
| | | | - Martin James Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Etienne Fondjo
- ABT ASSOCIATES, PMI VectorLink, Yaoundé 999108, Cameroon;
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Feugère L, Roux O, Gibson G. Behavioural analysis of swarming mosquitoes reveals higher hearing sensitivity than previously measured with electrophysiology methods. J Exp Biol 2022; 225:274290. [PMID: 35132997 DOI: 10.1242/jeb.243535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 02/03/2022] [Indexed: 11/20/2022]
Abstract
Mosquitoes of many species mate in station-keeping swarms. Mating chases ensue as soon as a male detects the flight tones of a female with his auditory organs. Previous studies of hearing thresholds have mainly used electrophysiological methods that prevent the mosquito from flying naturally. The main aim of this study was to quantify behaviourally the sound-level threshold at which males can hear females. Free-flying male Anopheles coluzzii were released in a large arena (∼2 m high x 2 m x 1 m) with a conspicuous object on the ground that stimulates swarming behaviour. Males were exposed to a range of natural and synthetic played-back sounds of female flight. We monitored the responses of males and their distance to the speaker by recording changes in their wingbeat frequency and angular speed. We show that the mean male behavioural threshold of particle-velocity hearing lies between 13-20 dB SVL (95%-CI). A conservative estimate of 20 dB SVL (i.e.,<0.5 µm/s particle velocity) is already 12 to 26 dB lower than most of the published electrophysiological measurements from the Johnston's organ. In addition, we suggest that 1) the first harmonic of female flight-sound is sufficient for males to detect her presence, 2) males respond with a greater amplitude to single-female sounds than to the sound of a group of females and 3) the response of males to the playback of the flight sound of a live female is the same as that of a recorded sound of constant frequency and amplitude.
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Affiliation(s)
- Lionel Feugère
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France.,Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK
| | - Olivier Roux
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France.,Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545 Bobo-Dioulasso 01, Burkina Faso
| | - Gabriella Gibson
- Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK
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Makunin A, Korlević P, Park N, Goodwin S, Waterhouse RM, von Wyschetzki K, Jacob CG, Davies R, Kwiatkowski D, St Laurent B, Ayala D, Lawniczak MKN. A targeted amplicon sequencing panel to simultaneously identify mosquito species and Plasmodium presence across the entire Anopheles genus. Mol Ecol Resour 2022; 22:28-44. [PMID: 34053186 PMCID: PMC7612955 DOI: 10.1111/1755-0998.13436] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 05/19/2021] [Indexed: 01/04/2023]
Abstract
Anopheles is a diverse genus of mosquitoes comprising over 500 described species, including all known human malaria vectors. While a limited number of key vector species have been studied in detail, the goal of malaria elimination calls for surveillance of all potential vector species. Here, we develop a multilocus amplicon sequencing approach that targets 62 highly variable loci in the Anopheles genome and two conserved loci in the Plasmodium mitochondrion, simultaneously revealing both the mosquito species and whether that mosquito carries malaria parasites. We also develop a cheap, nondestructive, and high-throughput DNA extraction workflow that provides template DNA from single mosquitoes for the multiplex PCR, which means specimens producing unexpected results can be returned to for morphological examination. Over 1000 individual mosquitoes can be sequenced in a single MiSeq run, and we demonstrate the panel's power to assign species identity using sequencing data for 40 species from Africa, Southeast Asia, and South America. We also show that the approach can be used to resolve geographic population structure within An. gambiae and An. coluzzii populations, as the population structure determined based on these 62 loci from over 1000 mosquitoes closely mirrors that revealed through whole genome sequencing. The end-to-end approach is quick, inexpensive, robust, and accurate, which makes it a promising technique for very large-scale mosquito genetic surveillance and vector control.
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Affiliation(s)
- Alex Makunin
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | - Petra Korlević
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridge, UK
| | - Naomi Park
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | | | - Robert M Waterhouse
- Department of Ecology and Evolution, University of Lausanne, and Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | | | | | | | | | | | - Diego Ayala
- MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France
- CIRMF, Franceville, Gabon
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Evolution of the Pyrethroids Target-Site Resistance Mechanisms in Senegal: Early Stage of the Vgsc-1014F and Vgsc-1014S Allelic Frequencies Shift. Genes (Basel) 2021; 12:genes12121948. [PMID: 34946897 PMCID: PMC8701854 DOI: 10.3390/genes12121948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/17/2021] [Accepted: 11/30/2021] [Indexed: 11/17/2022] Open
Abstract
The evolution and spread of insecticide resistance mechanisms amongst malaria vectors across the sub-Saharan Africa threaten the effectiveness and sustainability of current insecticide-based vector control interventions. However, a successful insecticide resistance management plan relies strongly on evidence of historical and contemporary mechanisms circulating. This study aims to retrospectively determine the evolution and spread of pyrethroid resistance mechanisms among natural Anopheles gambiae s.l. populations in Senegal. Samples were randomly drawn from an existing mosquito sample, collected in 2013, 2017, and 2018 from 10 sentinel sites monitored by the Senegalese National Malaria Control Programme (NMCP). Molecular species of An. gambiae s.l. and the resistance mutations at the Voltage-gated Sodium Channel 1014 (Vgsc-1014) locus were characterised using PCR-based assays. The genetic diversity of the Vgsc gene was further analyzed by sequencing. The overall species composition revealed the predominance of Anopheles arabiensis (73.08%) followed by An. gambiae s.s. (14.48%), Anopheles coluzzii (10.94%) and Anopheles gambiae-coluzii hybrids (1.48%). Both Vgsc-1014F and Vgsc-1014S mutations were found in all studied populations with a spatial variation of allele frequencies from 3% to 90%; and 7% to 41%, respectively. The two mutations have been detected since 2013 across all the selected health districts, with Vgsc-L1014S frequency increasing over the years while Vgsc-1014F decreasing. At species level, the Vgsc-1014F and Vgsc-1014S alleles were more frequent amongst An. gambiae s.s. (70%) and An. arabiensis (20%). The Vgsc gene was found to be highly diversified with eight different haplotypes shared between Vgsc-1014F and Vgsc-1014S. The observed co-occurrence of Vgsc-1014F and Vgsc-1014S mutations suggest that pyrethroid resistance is becoming a widespread phenomenon amongst malaria vector populations, and the NMCP needs to address this issue to sustain the gain made in controlling malaria.
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Hamid-Adiamoh M, Nwakanma D, Sraku I, Amambua-Ngwa A, A. Afrane Y. Is outdoor-resting behaviour in malaria vectors consistent? Short report from northern Ghana. AAS Open Res 2021. [DOI: 10.12688/aasopenres.13317.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Recent studies have observed vectors resting predominantly outdoors in settings where anti-vector tools are extensively deployed, attributed to selection pressure from use of control tools. This present study examined if the outdoor resting behaviour in the vector population is random or indicative of a consistent preference of one resting site over the other. Methods: Mark-release-recapture experiments were conducted with outdoor-resting Anopheles gambiae and An. funestus mosquitoes collected from two villages in northern Ghana during rainy and dry seasons. Mosquitoes were marked with fluorescent dyes and released indoors. The experiments were controlled with indoor-resting mosquitoes, which were marked and released outdoors. Species of all recaptured mosquitoes were identified and assessed for consistency in their resting behaviour. Results: A total of 4,460 outdoor-resting mosquitoes comprising An. gambiae sensu lato (s.l.) (2,636, 59%) and An. funestus complex (1,824, 41%) were marked and released. Overall, 31 (0.7%) mosquitoes were recaptured mostly from outdoor location comprising 25 (81%) An. gambiae s.l. and 6 (19%) An. funestus complex. Only 3 (10%) of the recaptured mosquitoes were found resting indoors where they were released. The majority of the outdoor-recaptured mosquitoes were An. arabiensis (11, 39%), followed by An. coluzzii (7, 25%); whereas all indoor-recaptured mosquitoes were An. coluzzii. For the control experiment, 324 indoor-resting mosquitoes constituting 313 (97%) An. gambiae s.l. and 11 (3%) An. funestus complex were marked and released. However, none of these was recaptured neither indoors nor outdoors. More mosquitoes were captured and recaptured during rainy season, but this was not statistically significant (Z=0.79, P=0.21). Conclusions: These results suggested the tendency for the mosquitoes to retain their outdoor-resting behaviour. Further investigations are required to ascertain if emerging preference for outdoor resting behaviour in malaria vector populations is consistent or a random occurrence.
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Yaro JB, Tiono AB, Sanou A, Toe HK, Bradley J, Ouedraogo A, Ouedraogo ZA, Guelbeogo MW, Agboraw E, Worrall E, Sagnon N'F, Lindsay SW, Wilson AL. Risk factors associated with house entry of malaria vectors in an area of Burkina Faso with high, persistent malaria transmission and high insecticide resistance. Malar J 2021; 20:397. [PMID: 34629053 PMCID: PMC8504047 DOI: 10.1186/s12936-021-03926-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 09/26/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In rural Burkina Faso, the primary malaria vector Anopheles gambiae sensu lato (s.l.) primarily feeds indoors at night. Identification of factors which influence mosquito house entry could lead to development of novel malaria vector control interventions. A study was therefore carried out to identify risk factors associated with house entry of An. gambiae s.l. in south-west Burkina Faso, an area of high insecticide resistance. METHODS Mosquitoes were sampled monthly during the malaria transmission season using CDC light traps in 252 houses from 10 villages, each house sleeping at least one child aged five to 15 years old. Potential risk factors for house entry of An. gambiae s.l. were measured, including socio-economic status, caregiver's education and occupation, number of people sleeping in the same part of the house as the child, use of anti-mosquito measures, house construction and fittings, proximity of anopheline aquatic habitats and presence of animals near the house. Mosquito counts were compared using a generalized linear mixed-effect model with negative binomial and log link function, adjusting for repeated collections. RESULTS 20,929 mosquitoes were caught, of which 16,270 (77.7%) were An. gambiae s.l. Of the 6691 An. gambiae s.l. identified to species, 4101 (61.3%) were An. gambiae sensu stricto and 2590 (38.7%) Anopheles coluzzii. Having a metal-roof on the child's sleeping space (IRR = 0.55, 95% CI 0.32-0.95, p = 0.03) was associated with fewer malaria vectors inside the home. CONCLUSION This study demonstrated that the rate of An. gambiae s.l. was 45% lower in sleeping spaces with a metal roof, compared to those with thatch roofs. Improvements in house construction, including installation of metal roofs, should be considered in endemic areas of Africa to reduce the burden of malaria.
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Affiliation(s)
- Jean Baptiste Yaro
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso.,Department of Biosciences, Durham University, Durham, UK
| | - Alfred B Tiono
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - Antoine Sanou
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - Hyacinthe K Toe
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Alphonse Ouedraogo
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - Z Amidou Ouedraogo
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - Moussa W Guelbeogo
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - Efundem Agboraw
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Eve Worrall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - N 'Fale Sagnon
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | | | - Anne L Wilson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
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Akorli J, Akorli EA, Tetteh SNA, Amlalo GK, Opoku M, Pwalia R, Adimazoya M, Atibilla D, Pi-Bansa S, Chabi J, Dadzie SK. Microsporidia MB is found predominantly associated with Anopheles gambiae s.s and Anopheles coluzzii in Ghana. Sci Rep 2021; 11:18658. [PMID: 34545153 PMCID: PMC8452686 DOI: 10.1038/s41598-021-98268-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 09/07/2021] [Indexed: 11/16/2022] Open
Abstract
A vertically transmitted microsporidian, Microsporidia MB, with the ability to disrupt Plasmodium development was reported in Anopheles arabiensis from Kenya, East Africa. To demonstrate its range of incidence, archived DNA samples from 7575 Anopheles mosquitoes collected from Ghana were screened. MB prevalence was observed at 1.8%. An. gambiae s.s constituted 87% of positive mosquitoes while the remaining were from An. coluzzii. Both sibling species had similar positivity rates (24% and 19%; p = 0.42) despite the significantly higher number of An. gambiae s.s analysed (An. gambiae s.s = 487; An. coluzzii = 94; p = 0.0005). The microsporidian was also more prevalent in emerged adults from field-collected larvae than field-caught adults (p < 0.0001) suggestive of an efficient vertical transmission and/or horizontal transfer among larvae. This is the first report of Microsporidia MB in Anopheles mosquitoes in West Africa. It indicates possible widespread among malaria vector species and warrants investigations into the symbiont’s diversity across sub-Saharan Africa.
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Affiliation(s)
- Jewelna Akorli
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana.
| | - Esinam Abla Akorli
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Seraphim Naa Afoley Tetteh
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Godwin Kwame Amlalo
- Vestergaard-NMIMR Vector Labs, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Millicent Opoku
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Rebecca Pwalia
- Vestergaard-NMIMR Vector Labs, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Michelle Adimazoya
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Dorcas Atibilla
- Entomology Unit, Department of Clinical Laboratory, Kintampo Health Research Centre, P.O. Box 200, Kintampo, Ghana
| | - Sellase Pi-Bansa
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Joseph Chabi
- Vestergaard-NMIMR Vector Labs, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Samuel Kweku Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
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Akuamoah-Boateng Y, Brenyah RC, Kwarteng SA, Obuam P, Owusu-Frimpong I, Agyapong AK, Badu K. Malaria Transmission, Vector Diversity, and Insecticide Resistance at a Peri-Urban Site in the Forest Zone of Ghana. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.739771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
IntroductionRecent surge of Anopheles resistance to major classes of World Health Organization (WHO)-approved insecticides globally necessitates the need for information about local malaria vector populations. It is believed that insecticide efficacy loss may lead to operational failure of control interventions and an increase in malaria infection transmission. We investigated the susceptibility levels of malaria vectors to all classes of WHO-approved vector control insecticides and described the dynamics of malaria transmission in a peri-urban setting.MethodsFit 3–5-day-old adults that emerged from Anopheles larvae collected from several different sites in the study area were subjected to the WHO bioassay for detecting insecticide resistance. The knockdown resistance gene (kdr) mutations within the vector populations were detected using PCR. Entomological inoculation rates were determined using the human landing catch technique and Plasmodium falciparum circumsporozoite ELISA.ResultsThe malaria vectors from the study area were resistant to all classes of insecticides tested. Out of the 284 Anopheles complex specimen assayed for the resistance study, 265 (93.30%) were identified as Anopheles gambiae s.s. The kdr gene was detected in 90% of the Anopheles gambiae s.s. assayed. In an area where Anopheles coluzzii resistance to insecticides had never been reported, the kdr gene was detected in 78% of the Anopheles coluzzii sampled. The entomological inoculation rate (EIR) for the dry season was 1.44 ib/m/n, whereas the EIR for the rainy season was 2.69 ib/m/n.ConclusionsThis study provides information on the high parasite inoculation rate and insecticide resistance of malaria vectors in a peri-urban community, which is critical in the development of an insecticide resistance management program for the community.
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Coleman S, Yihdego Y, Sherrard-Smith E, Thomas CS, Dengela D, Oxborough RM, Dadzie SK, Boakye D, Gyamfi F, Obiri-Danso K, Johns B, Siems LV, Lucas B, Tongren JE, Zigirumugabe S, Dery D, Fornadel C, George K, Belemvire A, Carlson J, Irish SR, Armistead JS, Seyoum A. Partial indoor residual spraying with pirimiphos-methyl as an effective and cost-saving measure for the control of Anopheles gambiae s.l. in northern Ghana. Sci Rep 2021; 11:18055. [PMID: 34508114 PMCID: PMC8433436 DOI: 10.1038/s41598-021-97138-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 08/19/2021] [Indexed: 11/09/2022] Open
Abstract
The scale up of indoor residual spraying (IRS) and insecticide treated nets have contributed significantly to global reductions in malaria prevalence over the last two decades. However, widespread pyrethroid resistance has necessitated the use of new and more expensive insecticides for IRS. Partial IRS with pirimiphos-methyl in experimental huts and houses in a village-wide trial was evaluated against Anopheles gambiae s.l. in northern Ghana. Four different scenarios in which either only the top or bottom half of the walls of experimental huts were sprayed, with or without also spraying the ceiling were compared. Mortality of An. gambiae s.l. on partially sprayed walls was compared with the standard procedures in which all walls and ceiling surfaces are sprayed. A small-scale trial was then conducted to assess the effectiveness, feasibility, and cost of spraying only the upper walls and ceiling as compared to full IRS and no spraying in northern Ghana. Human landing catches were conducted to estimate entomological indices and determine the effectiveness of partial IRS. An established transmission dynamics model was parameterized by an analysis of the experimental hut data and used to predict the epidemiological impact and cost effectiveness of partial IRS for malaria control in northern Ghana. In the experimental huts, partial IRS of the top (IRR 0.89, p = 0.13) or bottom (IRR 0.90, p = 0.15) half of walls and the ceiling was not significantly less effective than full IRS in terms of mosquito mortality. In the village trial, the annual entomological inoculation rate was higher for the unsprayed control (217 infective bites/person/year (ib/p/yr)) compared with the fully and partially sprayed sites, with 28 and 38 ib/p/yr, respectively. The transmission model predicts that the efficacy of partial IRS against all-age prevalence of malaria after six months would be broadly equivalent to a full IRS campaign in which 40% reduction is expected relative to no spray campaign. At scale, partial IRS in northern Ghana would have resulted in a 33% cost savings ($496,426) that would enable spraying of 36,000 additional rooms. These findings suggest that partial IRS is an effective, feasible, and cost saving approach to IRS that could be adopted to sustain and expand implementation of this key malaria control intervention.
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Affiliation(s)
- Sylvester Coleman
- PMI VectorLink Project, Abt Associates, Plot 11 Waterson Road, Fuo, Tamale, Ghana.
| | - Yemane Yihdego
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Ellie Sherrard-Smith
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Churcher S Thomas
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Dereje Dengela
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Richard M Oxborough
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Samuel K Dadzie
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Daniel Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Frank Gyamfi
- PMI VectorLink Project, Abt Associates, Plot 11 Waterson Road, Fuo, Tamale, Ghana
| | - Kwasi Obiri-Danso
- Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Ben Johns
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Lilly V Siems
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Bradford Lucas
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Jon Eric Tongren
- US. President's Malaria Initiative, U.S. Agency for International Development, Accra, Ghana
| | - Sixte Zigirumugabe
- US. President's Malaria Initiative, U.S. Agency for International Development, Accra, Ghana
| | - Dominic Dery
- US. President's Malaria Initiative, U.S. Agency for International Development, Accra, Ghana
| | - Christen Fornadel
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA
| | - Kristen George
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA
| | - Allison Belemvire
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA
| | - Jenny Carlson
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA
| | - Seth R Irish
- U.S. President's Malaria Initiative, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jennifer S Armistead
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA
| | - Aklilu Seyoum
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
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Sanou A, Nelli L, Guelbéogo WM, Cissé F, Tapsoba M, Ouédraogo P, Sagnon N, Ranson H, Matthiopoulos J, Ferguson HM. Insecticide resistance and behavioural adaptation as a response to long-lasting insecticidal net deployment in malaria vectors in the Cascades region of Burkina Faso. Sci Rep 2021; 11:17569. [PMID: 34475470 PMCID: PMC8413378 DOI: 10.1038/s41598-021-96759-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 08/12/2021] [Indexed: 02/07/2023] Open
Abstract
The decline in malaria across Africa has been largely attributed to vector control using long-lasting insecticidal nets (LLINs). However, this intervention has prompted widespread insecticide resistance (IR) and been associated with changes in mosquito behaviour that reduce their contact with LLINs. The relative importance and rate at which IR and behavioural adaptations emerge are poorly understood. We conducted surveillance of mosquito behaviour and IR at 12 sites in Burkina Faso to assess the magnitude and temporal dynamics of insecticide, biting and resting behaviours in vectors in the 2-year period following mass LLIN distribution. Insecticide resistance was present in all vector populations and increased rapidly over the study period. In contrast, no longitudinal shifts in LLIN-avoidance behaviours (earlier or outdoor biting and resting) were detected. There was a moderate but statistically significant shift in vector species composition from Anopheles coluzzii to Anopheles gambiae which coincided with a reduction in the proportion of bites preventable by LLINs; possibly driven by between-species variation in behaviour. These findings indicate that adaptations based on insecticide resistance arise and intensify more rapidly than behavioural shifts within mosquito vectors. However, longitudinal shifts in mosquito vector species composition were evident within 2 years following a mass LLIN distribution. This ecological shift was characterized by a significant increase in the exophagic species (An. gambiae) and coincided with a predicted decline in the degree of protection expected from LLINs. Although human exposure fell through the study period due to reducing vector densities and infection rates, such ecological shifts in vector species along with insecticide resistance were likely to have eroded the efficacy of LLINs. While both adaptations impact malaria control, the rapid increase of the former indicates this strategy develops more quickly in response to selection from LLINS. However, interventions targeting both resistance strategies will be needed.
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Affiliation(s)
- Antoine Sanou
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK.
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda Yonré, PO Box 2208, Ouagadougou, Burkina Faso.
| | - Luca Nelli
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
| | - W Moussa Guelbéogo
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda Yonré, PO Box 2208, Ouagadougou, Burkina Faso
| | - Fatoumata Cissé
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda Yonré, PO Box 2208, Ouagadougou, Burkina Faso
| | - Madou Tapsoba
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda Yonré, PO Box 2208, Ouagadougou, Burkina Faso
| | - Pierre Ouédraogo
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda Yonré, PO Box 2208, Ouagadougou, Burkina Faso
| | - N'falé Sagnon
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda Yonré, PO Box 2208, Ouagadougou, Burkina Faso
| | - Hilary Ranson
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Jason Matthiopoulos
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
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Niang A, Sawadogo SP, Millogo AA, Akpodiete NO, Dabiré RK, Tripet F, Diabaté A. Entomological baseline data collection and power analyses in preparation of a mosquito swarm-killing intervention in south-western Burkina Faso. Malar J 2021; 20:346. [PMID: 34425839 PMCID: PMC8381508 DOI: 10.1186/s12936-021-03877-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/10/2021] [Indexed: 11/18/2022] Open
Abstract
Background Insecticides are currently the main tools used to reduce the transmission of malaria; therefore, the development of resistance to insecticides in malaria vectors is of major concern for malaria control. The resistance level to pyrethroids is particularly high in the Western region of Burkina Faso and may affect the efficacy of insecticidal bed nets and indoor residual spraying. Adult mosquito swarming and other nocturnal behaviours exhibit spatial and temporal patterns that suggest potential vulnerability to targeted space spraying with effective insecticides. Indeed, targeted space-spraying against adult mosquito swarms has been used to crash mosquito populations and disrupt malaria transmission. Methods Prior to impact assessment of swarm killing, a baseline data collection was conducted from June to November 2016 in 10 villages divided into two areas in western Burkina Faso. The data considered both ecological and demographic characteristics to monitor the key entomological parameters. Results The mean number of swarms observed was 35 per village, ranging from 25 to 70 swarms according to the village. Female density in both areas varied significantly as a function of the village and the period of collection. The human biting rate was significantly affected by the period of collection and depended upon whether the collection was carried out indoors or outdoors. Averages of parity rate were high in both areas for all periods of collection, ranging from 60 to 90%. These values ranged from 80 to 100% for inseminated females. Sporozoite rates ranged between 1.6 and 7.2% depending upon the village. The molecular identification of resting and swarming mosquitoes showed the presence of the three major malaria vectors in Burkina Faso, but in different proportions for each village. Conclusions The distribution of the potential swarm markers and swarms in villages suggested that swarms are clustered across space, making intervention easier. Power simulations showed that the direct sampling of swarms provides the highest statistical power, thereby reducing the number of villages needed for a trial. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03877-x.
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Affiliation(s)
- Abdoulaye Niang
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.
| | - Simon P Sawadogo
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Abdoul A Millogo
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.,Institut des Sciences des Sociétés (INSS), Ouagadougou, Burkina Faso
| | - Nwamaka O Akpodiete
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Roch K Dabiré
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Abdoulaye Diabaté
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
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Longo-Pendy NM, Tene-Fossog B, Tawedi RE, Akone-Ella O, Toty C, Rahola N, Braun JJ, Berthet N, Kengne P, Costantini C, Ayala D. Ecological plasticity to ions concentration determines genetic response and dominance of Anopheles coluzzii larvae in urban coastal habitats of Central Africa. Sci Rep 2021; 11:15781. [PMID: 34349141 PMCID: PMC8338965 DOI: 10.1038/s41598-021-94258-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 06/29/2021] [Indexed: 02/07/2023] Open
Abstract
In Central Africa, the malaria vector Anopheles coluzzii is predominant in urban and coastal habitats. However, little is known about the environmental factors that may be involved in this process. Here, we performed an analysis of 28 physicochemical characteristics of 59 breeding sites across 5 urban and rural sites in coastal areas of Central Africa. We then modelled the relative frequency of An. coluzzii larvae to these physicochemical parameters in order to investigate environmental patterns. Then, we assessed the expression variation of 10 candidate genes in An. coluzzii, previously incriminated with insecticide resistance and osmoregulation in urban settings. Our results confirmed the ecological plasticity of An. coluzzii larvae to breed in a large range of aquatic conditions and its predominance in breeding sites rich in ions. Gene expression patterns were comparable between urban and rural habitats, suggesting a broad response to ions concentrations of whatever origin. Altogether, An. coluzzii exhibits a plastic response to occupy both coastal and urban habitats. This entails important consequences for malaria control in the context of the rapid urban expansion in Africa in the coming years.
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Affiliation(s)
| | | | - Robert E. Tawedi
- grid.473396.cInstitut de Recherches Géologiques Et Minières / Centre de Recherches Hydrologiques, Yaoundé, Cameroon
| | | | - Celine Toty
- grid.462603.50000 0004 0382 3424MIVEGEC, Univ Montpellier, CNRS, IRD, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France
| | - Nil Rahola
- grid.462603.50000 0004 0382 3424MIVEGEC, Univ Montpellier, CNRS, IRD, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France
| | - Jean-Jacques Braun
- grid.473396.cInstitut de Recherches Géologiques Et Minières / Centre de Recherches Hydrologiques, Yaoundé, Cameroon ,grid.462928.30000 0000 9033 1612Géosciences Environnement Toulouse, Université de Toulouse, CNRS, IRD, Toulouse, France ,International Joint Laboratory DYCOFAC, IRGM-UY1-IRD, BP 1857, Yaoundé, Cameroon
| | - Nicolas Berthet
- grid.418115.80000 0004 1808 058XCIRMF, Franceville, Gabon ,grid.428999.70000 0001 2353 6535Institut Pasteur, Unité Environnement Et Risque Infectieux, Cellule D’Intervention Biologique D’Urgence, Paris, France
| | - Pierre Kengne
- grid.418115.80000 0004 1808 058XCIRMF, Franceville, Gabon ,grid.462603.50000 0004 0382 3424MIVEGEC, Univ Montpellier, CNRS, IRD, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France
| | - Carlo Costantini
- grid.462603.50000 0004 0382 3424MIVEGEC, Univ Montpellier, CNRS, IRD, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France
| | - Diego Ayala
- grid.418115.80000 0004 1808 058XCIRMF, Franceville, Gabon ,grid.462603.50000 0004 0382 3424MIVEGEC, Univ Montpellier, CNRS, IRD, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France
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48
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Ngom EHM, Virgillito C, Manica M, Rosà R, Pichler V, Sarleti N, Kassé I, Diallo M, della Torre A, Dia I, Caputo B. Entomological Survey Confirms Changes in Mosquito Composition and Abundance in Senegal and Reveals Discrepancies among Results by Different Host-Seeking Female Traps. INSECTS 2021; 12:692. [PMID: 34442258 PMCID: PMC8396443 DOI: 10.3390/insects12080692] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 11/16/2022]
Abstract
Mosquitoes-borne diseases are major public health issues particularly in Africa. Vector control interventions and human-made environmental/climatic changes significantly affect the distribution and abundance of vector species. We carried out an entomological survey targeting host-seeking mosquitos in two different ecological contexts-coastal and inland-in Senegal, by CDC-light and BG-sentinel traps. Results show high predominance of Culex quinquefasciatus (90%) and of Anopheles arabiensis within malaria vectors (46%), with mean numbers of females/trap/nights =8 and <1, respectively, reinforcing previous evidence of changes in species composition and abundance, highlighting thus increasing risk of transmission of filariasis and emerging arboviruses in the Senegambia region. From the methodological perspective, results show a higher specificity of BG traps for Cx. quinquefasciatus and of CDC traps for An. gambiae s.l. and highlight that, despite both traps target the host-seeking fraction of the population, they provide different patterns of species abundance, temporal dynamics and host-seeking activity, leading to possible misinterpretation of the species bionomics. This draws attention to the need of taking into account trapping performance, in order to provide realistic quantification of the number of mosquitoes per units of space and time, the crucial parameter for evaluating vector-human contact, and estimating risk of pathogen transmission.
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Affiliation(s)
- El Hadji Malick Ngom
- Medical Zoology Pole, Institut Pasteur de Dakar, Dakar 12500, Senegal; (E.H.M.N.); (I.K.); (M.D.)
| | - Chiara Virgillito
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (C.V.); (V.P.); (N.S.); (A.d.T.)
- Department of Biodiversity and Molecular Ecology, Edmund Mach Foundation, 38098 San Michele all’Adige, Italy; (M.M.); (R.R.)
| | - Mattia Manica
- Department of Biodiversity and Molecular Ecology, Edmund Mach Foundation, 38098 San Michele all’Adige, Italy; (M.M.); (R.R.)
- Center for Health Emergencies, Bruno Kessler Foundation, 380123 Trento, Italy
| | - Roberto Rosà
- Department of Biodiversity and Molecular Ecology, Edmund Mach Foundation, 38098 San Michele all’Adige, Italy; (M.M.); (R.R.)
- Center Agriculture Food Environment, University of Trento, 38098 San Michele all’Adige, Italy
| | - Verena Pichler
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (C.V.); (V.P.); (N.S.); (A.d.T.)
| | - Noemi Sarleti
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (C.V.); (V.P.); (N.S.); (A.d.T.)
| | - Isseu Kassé
- Medical Zoology Pole, Institut Pasteur de Dakar, Dakar 12500, Senegal; (E.H.M.N.); (I.K.); (M.D.)
| | - Mawlouth Diallo
- Medical Zoology Pole, Institut Pasteur de Dakar, Dakar 12500, Senegal; (E.H.M.N.); (I.K.); (M.D.)
| | - Alessandra della Torre
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (C.V.); (V.P.); (N.S.); (A.d.T.)
| | - Ibrahima Dia
- Medical Zoology Pole, Institut Pasteur de Dakar, Dakar 12500, Senegal; (E.H.M.N.); (I.K.); (M.D.)
| | - Beniamino Caputo
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (C.V.); (V.P.); (N.S.); (A.d.T.)
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49
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Bang WJ, Won MH, Cho ST, Ryu J, Choi KS. A multiplex PCR assay for six Aedini species, including Aedes albopictus. Parasit Vectors 2021; 14:380. [PMID: 34321059 PMCID: PMC8317425 DOI: 10.1186/s13071-021-04871-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 07/05/2021] [Indexed: 11/22/2022] Open
Abstract
Background Mosquitoes, as vectors of various human pathogens, are significant drivers of serious human illness. In particular, those species in the Aedini tribe, which typically transmit dengue virus, Chikungunya fever virus, and Zika virus, are increasing their range because of climate change and international commerce. In order to evaluate the risk of disease transmission, accurate mosquito species identification and monitoring are needed. The goal of this work was to develop a rapid and simple molecular diagnostic method for six morphologically similar Aedini species (Aedes flavopictus, Aedes albopictus, Ochlerotatus koreicus, Ochlerotatus japonicus, Ochlerotatus togoi and Ochlerotatus hatorii) in Korea. Methods A total of 109 samples were assayed in this study. The internal transcribed spacer 2 (ITS2) regions from all six species were amplified, sequenced and analyzed using Mega 6. Following the identification of regions that were consistently different in terms of sequence between all six species, multiplex primers were designed to amplify these regions to generate species-specific fragments distinguishable by their size. Results Uniquely sized fragments were generated in Ae. flavopictus (495 bp), Ae. albopictus (438 bp), Oc. koreicus (361 bp), Oc. togoi (283 bp), Oc. hatorii (220 bp) and Oc. japonicus (160 bp). Pairwise distance analysis showed that the difference was 35.0 ± 1.5% between Aedes spp. and Ochlerotatus spp., 17.4 ± 0.2% between Ae. albopictus and Ae. flavopictus and 11.1 ± 0.3% between Oc. koreicus and Oc. japonicus. Conclusions In this study, a multiplex PCR assay for six species of the Aedini tribe was developed. This assay is more accurate than morphological identification and will be useful for monitoring and controlling these vector mosquitoes. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04871-7.
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Affiliation(s)
- Woo Jun Bang
- School of Life Sciences, Kyungpook National University, Biology building 226, Daehak-ro 80, Daegu, Korea.,Research Institute for Dokdo and Ulleungdo Island, Kyungpook National University, Daegu, Korea
| | - Min Hyeok Won
- School of Life Sciences, Kyungpook National University, Biology building 226, Daehak-ro 80, Daegu, Korea.,Research Institute for Dokdo and Ulleungdo Island, Kyungpook National University, Daegu, Korea
| | - Seong Tae Cho
- School of Life Sciences, Kyungpook National University, Biology building 226, Daehak-ro 80, Daegu, Korea
| | - Jihun Ryu
- School of Life Sciences, Kyungpook National University, Biology building 226, Daehak-ro 80, Daegu, Korea.,Research Institute for Dokdo and Ulleungdo Island, Kyungpook National University, Daegu, Korea
| | - Kwang Shik Choi
- School of Life Sciences, Kyungpook National University, Biology building 226, Daehak-ro 80, Daegu, Korea. .,Research Institute for Dokdo and Ulleungdo Island, Kyungpook National University, Daegu, Korea. .,Research Institute for Phylogenomics and Evolution, Kyungpook National University, Daegu, Korea.
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50
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Mosquito species identification using convolutional neural networks with a multitiered ensemble model for novel species detection. Sci Rep 2021; 11:13656. [PMID: 34211009 PMCID: PMC8249627 DOI: 10.1038/s41598-021-92891-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/16/2021] [Indexed: 11/17/2022] Open
Abstract
With over 3500 mosquito species described, accurate species identification of the few implicated in disease transmission is critical to mosquito borne disease mitigation. Yet this task is hindered by limited global taxonomic expertise and specimen damage consistent across common capture methods. Convolutional neural networks (CNNs) are promising with limited sets of species, but image database requirements restrict practical implementation. Using an image database of 2696 specimens from 67 mosquito species, we address the practical open-set problem with a detection algorithm for novel species. Closed-set classification of 16 known species achieved 97.04 ± 0.87% accuracy independently, and 89.07 ± 5.58% when cascaded with novelty detection. Closed-set classification of 39 species produces a macro F1-score of 86.07 ± 1.81%. This demonstrates an accurate, scalable, and practical computer vision solution to identify wild-caught mosquitoes for implementation in biosurveillance and targeted vector control programs, without the need for extensive image database development for each new target region.
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