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Pyrethroid Resistance Aggravation in Ugandan Malaria Vectors Is Reducing Bednet Efficacy. Pathogens 2021; 10:pathogens10040415. [PMID: 33915866 PMCID: PMC8065452 DOI: 10.3390/pathogens10040415] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 01/04/2023] Open
Abstract
Monitoring cases of insecticide resistance aggravation and the effect on the efficacy of control tools is crucial for successful malaria control. In this study, the resistance intensity of major malaria vectors from Uganda was characterised and its impact on the performance of various insecticide-treated nets elucidated. High intensity of resistance to the discriminating concentration (DC), 5× DC, and 10× DC of pyrethroids was observed in both Anopheles funestus and Anopheles gambiae in Mayuge and Busia leading to significant reduced performance of long-lasting insecticidal nets (LLINs) including the piperonyl butoxide (PBO)-based nets (Olyset Plus). Molecular analysis revealed significant over-expression of cytochrome P450 genes (CYP9K1 and CYP6P9a/b). However, the expression of these genes was not associated with resistance escalation as no difference was observed in the level of expression in mosquitoes resistant to 5× DC and 10× DC compared to 1× DC suggesting that other resistance mechanisms are involved. Such high intensity of pyrethroid resistance in Uganda could have terrible consequences on the effectiveness of insecticide-based interventions and urgent action should be taken to prevent the spread of super-resistance in malaria vectors.
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Nkemngo FN, Mugenzi LMJ, Terence E, Niang A, Wondji MJ, Tchoupo M, Nguete ND, Tchapga W, Irving H, Ntabi JDM, Agonhossou R, Boussougou-Sambe TS, Akoton RB, Koukouikila-Koussounda F, Pinilla YT, Ntoumi F, Djogbenou LS, Ghogomu SM, Ndo C, Adegnika AA, Borrmann S, Wondji CS. Multiple insecticide resistance and Plasmodium infection in the principal malaria vectors Anopheles funestus and Anopheles gambiae in a forested locality close to the Yaoundé airport, Cameroon. Wellcome Open Res 2020; 5:146. [PMID: 33204845 PMCID: PMC7667521 DOI: 10.12688/wellcomeopenres.15818.2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2020] [Indexed: 11/20/2022] Open
Abstract
Background: Reducing the burden of malaria requires better understanding of vector populations, particularly in forested regions where the incidence remains elevated. Here, we characterized malaria vectors in a locality near the Yaoundé international airport, Cameroon, including species composition, abundance, Plasmodium infection rate, insecticide resistance profiles and underlying resistance mechanisms. Methods: Blood-fed adult mosquitoes resting indoors were aspirated from houses in April 2019 at Elende, a locality situated 2 km from the Yaoundé-Nsimalen airport. Female mosquitoes were forced to lay eggs to generate F 1 adults. Bioassays were performed to assess resistance profile to the four insecticides classes. The threshold of insecticide susceptibility was defined above 98% mortality rate and mortality rates below 90% were indicative of confirmed insecticide resistance. Furthermore, the molecular basis of resistance and Plasmodium infection rates were investigated. Results: Anopheles funestus s.s. was the most abundant species in Elende (85%) followed by Anopheles gambiae s.s. (15%) with both having similar sporozoite rate. Both species exhibited high levels of resistance to the pyrethroids, permethrin and deltamethrin (<40% mortality). An. gambiae s.s. was resistant to DDT (9.9% mortality) and bendiocarb (54% mortality) while susceptible to organophosphate. An. funestus s.s. was resistant to dieldrin (1% mortality), DDT (86% mortality) but susceptible to carbamates and organophosphates. The L119F-GSTe2 resistance allele (8%) and G119S ace-1 resistance allele (15%) were detected in An. funestus s.s. and An. gambiae s.s., respectively . Furthermore, the high pyrethroid/DDT resistances in An. gambiae corresponded with an increase frequency of 1014F kdr allele (95%). Transcriptional profiling of candidate cytochrome P450 genes reveals the over-expression of CYP6P5, CYP6P9a and CYP6P9b. Conclusion: The resistance to multiple insecticide classes observed in these vector populations alongside the significant Plasmodium sporozoite rate highlights the challenges that vector control programs encounter in sustaining the regular benefits of contemporary insecticide-based control interventions in forested areas.
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Affiliation(s)
- Francis N. Nkemngo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Microbiology and Parasitology, University of Buea, Buea, South West, 237, Cameroon
| | - Leon M. J. Mugenzi
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, South West, 237, Cameroon
| | - Ebai Terence
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Abdoulaye Niang
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Murielle J. Wondji
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Micareme Tchoupo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Nguiffo D. Nguete
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Williams Tchapga
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Helen Irving
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Jacques D. M. Ntabi
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
| | - Romuald Agonhossou
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Terence S. Boussougou-Sambe
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Romaric B. Akoton
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Felix Koukouikila-Koussounda
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
| | - Yudi T. Pinilla
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Francine Ntoumi
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Luc S. Djogbenou
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Stephen M. Ghogomu
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, South West, 237, Cameroon
| | - Cyrille Ndo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Ayola A. Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
- Eberhard Karls Universität Tübingen,, Tübingen, Germany
- German Center for Infection Research (DZIF), Tübingen, Germany
| | - Steffen Borrmann
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Tübingen, Germany
| | - Charles S. Wondji
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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Nkemngo FN, Mugenzi LMJ, Terence E, Niang A, Wondji MJ, Tchoupo M, Nguete ND, Tchapga W, Irving H, Ntabi JDM, Agonhossou R, Boussougou-Sambe TS, Akoton RB, Koukouikila-Koussounda F, Pinilla YT, Ntoumi F, Djogbenou LS, Ghogomu SM, Ndo C, Adegnika AA, Borrmann S, Wondji CS. Elevated Plasmodium sporozoite infection and multiple insecticide resistance in the principal malaria vectors Anopheles funestus and Anopheles gambiae in a forested locality close to the Yaoundé airport, Cameroon. Wellcome Open Res 2020; 5:146. [PMID: 33204845 PMCID: PMC7667521 DOI: 10.12688/wellcomeopenres.15818.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2020] [Indexed: 11/13/2023] Open
Abstract
Background: Reducing the burden of malaria requires better understanding of vector populations, particularly in forested regions where the incidence remains elevated. Here, we characterized malaria vectors in a locality near the Yaoundé international airport, Cameroon, including species composition, abundance, Plasmodium infection rate, insecticide resistance profiles and underlying resistance mechanisms. Methods: Blood-fed adult mosquitoes resting indoors were aspirated from houses in April 2019 at Elende, a village located 2 km from the Yaoundé-Nsimalen airport. Female mosquitoes were forced to lay eggs to generate F 1 adult progeny. Bioassays were performed to assess resistance profile to insecticides. The threshold of insecticide susceptibility was defined above 98% mortality rate and mortality rates below 90% were indicative of confirmed insecticide resistance. Furthermore, the molecular basis of resistance and Plasmodium infection rates were investigated. Results: Anopheles funestus s.s. was most abundant species in Elende (85%) followed by Anopheles gambiae s.s. (15%) with both having a similar sporozoite rate. Both species exhibited high levels of resistance to pyrethroids (<40% mortality). An. gambiae s.s. was also resistant to DDT (9.9% mortality) and bendiocarb (54% mortality) while susceptible to organophosphate. An. funestus s.s. was resistant to dieldrin (1% mortality), DDT (86% mortality) but susceptible to carbamates and organophosphates. The L119F-GSTe2 resistance allele (8%) and G119S ace-1 resistance allele (15%) were detected in An. funestus s.s. and An. gambiae s.s., respectively . Furthermore, the high pyrethroid/DDT resistances in An. gambiae s.s. corresponded with an increase frequency of 1014F kdr allele (95%). Transcriptional profiling of candidate cytochrome P450 genes reveals the over-expression of CYP6P5, CYP6P9a and CYP6P9b. Conclusion: The resistance to multiple insecticide classes observed in these vector populations alongside the high Plasmodium sporozoite rate highlights the challenges that vector control programs encounter in sustaining the regular benefits of contemporary insecticide-based control interventions in forested areas.
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Affiliation(s)
- Francis N. Nkemngo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Microbiology and Parasitology, University of Buea, Buea, South West, 237, Cameroon
| | - Leon M. J. Mugenzi
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, South West, 237, Cameroon
| | - Ebai Terence
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Abdoulaye Niang
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Murielle J. Wondji
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Micareme Tchoupo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Nguiffo D. Nguete
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Williams Tchapga
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
| | - Helen Irving
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Jacques D. M. Ntabi
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
| | - Romuald Agonhossou
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Terence S. Boussougou-Sambe
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Romaric B. Akoton
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Felix Koukouikila-Koussounda
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
| | - Yudi T. Pinilla
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Francine Ntoumi
- Fondation Congolaise pour la Recherche Medicale (FCRM), Brazzaville, Congo
- Université Marien Ngouabi, Brazzaville, Congo
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Luc S. Djogbenou
- Institut Régional de Santé Publique, Université d'Abomey-Calavi, Cotonou, Benin
| | - Stephen M. Ghogomu
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, South West, 237, Cameroon
| | - Cyrille Ndo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Ayola A. Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
- Eberhard Karls Universität Tübingen,, Tübingen, Germany
- German Center for Infection Research (DZIF), Tübingen, Germany
| | - Steffen Borrmann
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Tübingen, Germany
| | - Charles S. Wondji
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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Tchouakui M, Fossog BT, Ngannang BV, Djonabaye D, Tchapga W, Njiokou F, Wondji CS. Investigation of the influence of a glutathione S-transferase metabolic resistance to pyrethroids/DDT on mating competitiveness in males Anopheles funestus, African malaria vector. Wellcome Open Res 2019; 4:13. [PMID: 31069259 PMCID: PMC6480967 DOI: 10.12688/wellcomeopenres.15013.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2019] [Indexed: 10/12/2023] Open
Abstract
Background: Metabolic resistance is a serious challenge to current insecticide-based interventions. The extent to which it affects natural populations of mosquitoes including their reproduction ability remains uncharacterised. Here, we investigated the potential impact of the glutathione S-transferase L119F-GSTe2 resistance on the mating competitiveness of male Anopheles funestus, in Cameroon. Methods: Swarms and indoor resting collections took place in March, 2018 in Tibati, Cameroon. WHO tube and cone assays were performed on F 1 mosquitoes from indoor collected females to assess the susceptibility profile of malaria vectors. Mosquitoes mated and unmated males collected in the swarms were genotyped for the L119F metabolic marker to assess its association with mating male competitiveness. Results: Susceptibility and synergist assays, showed that this population was multiple resistant to pyrethroids, DDT and carbamates, likely driven by metabolic resistance mechanisms. Cone assays revealed a reduced efficacy of standard pyrethroid-nets (Olyset and PermaNet 2.0) with low mortality (<25%) whereas synergist PBO-Nets (Olyset Plus and PermaNet 3.0) retained greater efficacy with higher mortality (>80%). The L119F-GSTe2 mutation, conferring pyrethroid/DDT resistance, was detected in this An.funestus population at a frequency of 28.8%. In addition, a total of 15 mating swarms were identified and 21 An. funestus couples were isolated from those swarms. A comparative genotyping of the L119F-GSTe2 mutation between mated and unmated males revealed that heterozygote males 119L/F-RS were less able to mate than homozygote susceptible (OR=7.2, P<0.0001). Surprisingly, heterozygote mosquitoes were also less able to mate than homozygote resistant (OR=4.2, P=0.010) suggesting the presence of a heterozygote disadvantage effect. Overall, mosquitoes bearing the L119-S susceptible allele were significantly more able to mate than those with 119F-R resistant allele (OR=2.1, P=0.03). Conclusion: This study provides preliminary evidences that metabolic resistance potentially exerts a fitness cost on mating competiveness in resistant mosquitoes.
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Affiliation(s)
- Magellan Tchouakui
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
| | - Billy Tene Fossog
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
| | - Brigitte Vanessa Ngannang
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
- Department of Biochemistry, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
| | - Doumani Djonabaye
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
- Department of Biochemistry, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
| | - Williams Tchapga
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
| | - Flobert Njiokou
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, P.O. Box 812, Cameroon
| | - Charles S. Wondji
- Department of Medical Entomology, Centre for Research in Infectious Diseases, Younde, 13591, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine,, Pembroke Place, L35QA, Liverpool, UK, UK
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