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Fadel AN, Ibrahim SS, Sandeu MM, Tatsinkou CGM, Menze BD, Irving H, Hearn J, Nagi SC, Weedall GD, Terence E, Tchapga W, Wanji S, Wondji CS. Exploring the molecular mechanisms of increased intensity of pyrethroid resistance in Central African population of a major malaria vector Anopheles coluzzii. Evol Appl 2024; 17:e13641. [PMID: 38410533 PMCID: PMC10895554 DOI: 10.1111/eva.13641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/14/2023] [Accepted: 01/01/2024] [Indexed: 02/28/2024] Open
Abstract
Molecular mechanisms driving the escalation of pyrethroid resistance in the major malaria mosquitoes of Central Africa remain largely uncharacterized, hindering effective management strategies. Here, resistance intensity and the molecular mechanisms driving it were investigated in a population of Anopheles coluzzii from northern Cameroon. High levels of pyrethroid and organochloride resistance were observed in An. coluzzii population, with no mortality for 1× permethrin; only 11% and 33% mortalities for 5× and 10× permethrin diagnostic concentrations, and <2% mortalities for deltamethrin and DDT, respectively. Moderate bendiocarb resistance (88% mortality) and full susceptibility to malathion were observed. Synergist bioassays with piperonyl butoxide recovered permethrin susceptibility, with mortalities increasing to 53.39%, and 87.30% for 5× and 10× permethrin, respectively, implicating P450 monooxygenases. Synergist bioassays with diethyl maleate (DEM) recovered permethrin and DDT susceptibilities (mortalities increasing to 34.75% and 14.88%, respectively), implicating glutathione S-transferases. RNA-seq-based genome-wide transcriptional analyses supported by quantitative PCR identified glutathione S-transferase, GSTe2 (RNA-seqFC = 2.93 and qRT-PCRFC = 8.4, p < 0.0043) and CYP450, CYP6Z2 (RNA-seqFC = 2.39 and qRT-PCRFC = 11.7, p < 0.0177) as the most overexpressed detoxification genes in the pyrethroid-resistant mosquitoes, compared to mosquitoes of the susceptible Ngousso colony. Other overexpressed genes include P450s, CYP6M2 (FC = 1.68, p < 0.0114), CYP4G16 (FC = 2.02, p < 0.0005), and CYP4G17 (FC = 1.86, p < 0.0276). While high frequency of the 1014F kdr mutation (50%) and low frequencies of 1014S (6.61%) and 1575Y (10.29%) were observed, no ace-1 mutation was detected in bendiocarb-resistant populations, suggesting the preeminent role of metabolic mechanism. Overexpression of metabolic resistance genes (including GSTe2 and CYP6Z2 known to confer resistance to multiple insecticides) in An. coluzzii from the Sudan Savannah of Cameroon highlights the need for alternative management strategies to reduce malaria burden in northern Cameroon.
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Affiliation(s)
- Amen N. Fadel
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Sulaiman S. Ibrahim
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of BiochemistryBayero UniversityKanoNigeria
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Maurice M. Sandeu
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of Microbiology and Infectious DiseasesSchool of Veterinary Medicine and SciencesUniversity of NgaoundéréNgaoundéréCameroon
| | | | | | - Helen Irving
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Jack Hearn
- Centre of Epidemiology and Planetary HealthNorth FacultyVeterinary & Animal ScienceScotland's Rural CollegeInvernessUK
| | - Sanjay C. Nagi
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Gareth D. Weedall
- School of Biological and Environmental SciencesLiverpool John Moores UniversityLiverpoolUK
| | - Ebai Terence
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
| | - Williams Tchapga
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
| | - Samuel Wanji
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Charles S. Wondji
- Center for Research in Infectious Diseases (CRID)YaoundéCameroon
- Vector Biology DepartmentLiverpool School of Tropical Medicine (LSTM)LiverpoolUK
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Ibrahim SS, Muhammad A, Hearn J, Weedall GD, Nagi SC, Mukhtar MM, Fadel AN, Mugenzi LJ, Patterson EI, Irving H, Wondji CS. Molecular drivers of insecticide resistance in the Sahelo-Sudanian populations of a major malaria vector Anopheles coluzzii. BMC Biol 2023; 21:125. [PMID: 37226196 DOI: 10.1186/s12915-023-01610-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/03/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Information on common markers of metabolic resistance in malaria vectors from countries sharing similar eco-climatic characteristics can facilitate coordination of malaria control. Here, we characterized populations of the major malaria vector Anopheles coluzzii from Sahel region, spanning four sub-Saharan African countries: Nigeria, Niger, Chad and Cameroon. RESULTS Genome-wide transcriptional analysis identified major genes previously implicated in pyrethroid and/or cross-resistance to other insecticides, overexpressed across the Sahel, including CYP450s, glutathione S-transferases, carboxylesterases and cuticular proteins. Several, well-known markers of insecticide resistance were found in high frequencies-including in the voltage-gated sodium channel (V402L, I940T, L995F, I1527T and N1570Y), the acetylcholinesterase-1 gene (G280S) and the CYP4J5-L43F (which is fixed). High frequencies of the epidemiologically important chromosomal inversion polymorphisms, 2La, 2Rb and 2Rc, were observed (~80% for 2Rb and 2Rc). The 2La alternative arrangement is fixed across the Sahel. Low frequencies of these inversions (<10%) were observed in the fully insecticide susceptible laboratory colony of An. coluzzii (Ngoussou). Several of the most commonly overexpressed metabolic resistance genes sit in these three inversions. Two commonly overexpressed genes, GSTe2 and CYP6Z2, were functionally validated. Transgenic Drosophila melanogaster flies expressing GSTe2 exhibited extremely high DDT and permethrin resistance (mortalities <10% in 24h). Serial deletion of the 5' intergenic region, to identify putative nucleotide(s) associated with GSTe2 overexpression, revealed that simultaneous insertion of adenine nucleotide and a transition (T->C), between Forkhead box L1 and c-EST putative binding sites, were responsible for the high overexpression of GSTe2 in the resistant mosquitoes. Transgenic flies expressing CYP6Z2 exhibited marginal resistance towards 3-phenoxybenzylalcohol (a primary product of pyrethroid hydrolysis by carboxylesterases) and a type II pyrethroid, α-cypermethrin. However, significantly higher mortalities were observed in CYP6Z2 transgenic flies compared with controls, on exposure to the neonicotinoid, clothianidin. This suggests a possible bioactivation of clothianidin into a toxic intermediate, which may make it an ideal insecticide against populations of An. coluzzii overexpressing this P450. CONCLUSIONS These findings will facilitate regional collaborations within the Sahel region and refine implementation strategies through re-focusing interventions, improving evidence-based, cross-border policies towards local and regional malaria pre-elimination.
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Affiliation(s)
- Sulaiman S Ibrahim
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, L3 5QA, UK.
- Department of Biochemistry, Bayero University, PMB 3011, Kano, Nigeria.
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon.
| | - Abdullahi Muhammad
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, L3 5QA, UK
- Centre for Biotechnology Research, Bayero University, PMB 3011, Kano, Nigeria
| | - Jack Hearn
- Centre of Epidemiology and Planetary Health, Veterinary & Animal Science, Scotland's Rural College, Inverness, IV2 5NA, UK
| | - Gareth D Weedall
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Sanjay C Nagi
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, L3 5QA, UK
| | | | - Amen N Fadel
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Leon J Mugenzi
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Edward I Patterson
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
| | - Helen Irving
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, L3 5QA, UK
| | - Charles S Wondji
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, L3 5QA, UK
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
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Tchouakui M, Oruni A, Assatse T, Manyaka CR, Tchoupo M, Kayondo J, Wondji CS. Fitness cost of target-site and metabolic resistance to pyrethroids drives restoration of susceptibility in a highly resistant Anopheles gambiae population from Uganda. PLoS One 2022; 17:e0271347. [PMID: 35881658 PMCID: PMC9321773 DOI: 10.1371/journal.pone.0271347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 06/28/2022] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Insecticide resistance threatens the effectiveness of malaria vector control, calling for an urgent need to design suitable resistance management strategies. Here, we established the resistance profiling of an Ugandan Anopheles gambiae population to insecticides using WHO procedures and assessed the potential restoration of susceptibility in the hybrid line Mayuge/KISUMU in an insecticide-free environment for eighteen (18) generations. RESULTS This An gambiae population exhibited a very high intensity of resistance to permethrin, deltamethrin, and alphacypermethrin with a consistent loss of efficacy of all long-lasting insecticidal nets (LLINs) tested including PBO-based and new generation nets Interceptor G2 (IG2) and Royal guard. Molecular analysis revealed a fixation of the L1014S-kdr mutation together with the overexpression of some P450 metabolic genes (CYP6Z1, CYP9K1, CYP6P1, 3 & 4) besides the cuticular resistance-related genes (CYP4G16) and sensorial appendage proteins (SAP1, SAP2, and SAP3) but no GSTe2 overexpression. In the absence of selection pressure, the mortality rate after exposure to insecticides increased significantly over generations, and restoration of susceptibility was observed for most of the insecticides in less than 10 generations. Accordingly, a significant reduction in the frequency of KdrE was observed after 13 generations coupled with reduced expression of most metabolic resistance genes. CONCLUSIONS The results of this study show that the high intensity of pyrethroid resistance observed in An gambiae from Uganda associated with the loss of efficacy of LLINs could compromise vector control efforts. The study also highlights that an early rotation of insecticides could help manage resistance to insecticides by restoring the susceptibility. However, the persistence of Kdr mutation together with overexpression of some metabolic genes after many generations in the absence of selection pressure indicates the potential implication of modifiers alleviating the cost of resistance which needs to be further investigated.
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Affiliation(s)
| | - Ambrose Oruni
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Entomology Department, Uganda Virus Research Institute (UVRI), Entebbe, Uganda
| | - Tatiane Assatse
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Claudine R Manyaka
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Micareme Tchoupo
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Jonathan Kayondo
- Entomology Department, Uganda Virus Research Institute (UVRI), Entebbe, Uganda
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- International Institute of Tropical Agriculture (IITA), Yaoundé, Cameroon
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Ngangue-Siewe IN, Ndjeunia-Mbiakop P, Kala-Chouakeu NA, Bamou R, Talipouo A, Djamouko-Djonkam L, Vontas J, Mavridis K, Tombi J, Tchuinkam T, Mbida-Mbida JA, Antonio-Nkondjio C. Bendiocarb and Malathion Resistance in Two Major Malaria Vector Populations in Cameroon Is Associated with High Frequency of the G119S Mutation (Ace-1) and Overexpression of Detoxification Genes. Pathogens 2022; 11:pathogens11080824. [PMID: 35894047 PMCID: PMC9330212 DOI: 10.3390/pathogens11080824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 12/10/2022] Open
Abstract
The spread of pyrethroid resistance in malaria vectors is a major threat affecting the performance of current control measures. However, there is still not enough information on the resistance profile of mosquitoes to carbamates and organophosphates which could be used as alternatives. The present study assessed the resistance profile of Anopheles gambiae s.l. to bendiocarb and malathion, at the phenotypic and molecular levels, in different eco-epidemiological settings in Cameroon. Anopheles gambiae s.l. mosquitoes were collected from four eco-epidemiological settings across the country and their susceptibility level to bendiocarb and malathion was determined using WHO tubes bioassays. The ace-1 target site G119S mutation was screened by PCR. Reverse Transcription quantitative PCR 3-plex TaqMan assays were used to quantify the level of expression of eight genes associated with metabolic resistance. Resistance to malathion and/or bendiocarb was recorded in all study sites except in mosquitoes collected in Kaélé and Njombé. The Ace-1 (G119S) mutation was detected in high frequencies (>40%) in Kékem and Santchou. Both An. gambiae and An. coluzzii were detected carrying this mutation. The cytochrome P450s gene Cyp6p3 associated with carbamate resistance and the glutathione S-transferase gene Gste2 associated with organophosphate resistance were found to be overexpressed. Genes associated with pyrethroid (Cyp6m2, Cyp9k1, Cyp6p3) and organochlorine (Gste2, Cyp6z1, Cyp6m2) and cuticle resistance (Cyp4g16) were also overexpressed. The rapid spread of resistance to organophosphates and carbamates could seriously compromise future control strategies based on IRS. It is therefore becoming important to assess the magnitude of bendiocarb and malathion resistance countrywide.
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Affiliation(s)
- Idriss Nasser Ngangue-Siewe
- Laboratory of Animal Biology and Physiology, University of Douala, Douala P.O. Box 24157, Cameroon; (I.N.N.-S.); (J.A.M.-M.)
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé P.O. Box 288, Cameroon; (P.N.-M.); (N.A.K.-C.); (R.B.); (A.T.); (L.D.-D.)
| | - Paulette Ndjeunia-Mbiakop
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé P.O. Box 288, Cameroon; (P.N.-M.); (N.A.K.-C.); (R.B.); (A.T.); (L.D.-D.)
- Faculty of Sciences, University of Yaoundé I, Yaoundé P.O. Box 812, Cameroon;
| | - Nelly Armanda Kala-Chouakeu
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé P.O. Box 288, Cameroon; (P.N.-M.); (N.A.K.-C.); (R.B.); (A.T.); (L.D.-D.)
- Vector-Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang P.O. Box 067, Cameroon;
| | - Roland Bamou
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé P.O. Box 288, Cameroon; (P.N.-M.); (N.A.K.-C.); (R.B.); (A.T.); (L.D.-D.)
- Vector-Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang P.O. Box 067, Cameroon;
| | - Abdou Talipouo
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé P.O. Box 288, Cameroon; (P.N.-M.); (N.A.K.-C.); (R.B.); (A.T.); (L.D.-D.)
- Faculty of Sciences, University of Yaoundé I, Yaoundé P.O. Box 812, Cameroon;
| | - Landre Djamouko-Djonkam
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé P.O. Box 288, Cameroon; (P.N.-M.); (N.A.K.-C.); (R.B.); (A.T.); (L.D.-D.)
- Vector-Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang P.O. Box 067, Cameroon;
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Greece; (J.V.); (K.M.)
- Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, 11855 Athens, Greece
| | - Konstantinos Mavridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Greece; (J.V.); (K.M.)
| | - Jeannette Tombi
- Faculty of Sciences, University of Yaoundé I, Yaoundé P.O. Box 812, Cameroon;
| | - Timoléon Tchuinkam
- Vector-Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang P.O. Box 067, Cameroon;
| | - Jean Arthur Mbida-Mbida
- Laboratory of Animal Biology and Physiology, University of Douala, Douala P.O. Box 24157, Cameroon; (I.N.N.-S.); (J.A.M.-M.)
| | - Christophe Antonio-Nkondjio
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé P.O. Box 288, Cameroon; (P.N.-M.); (N.A.K.-C.); (R.B.); (A.T.); (L.D.-D.)
- Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Correspondence: ; Tel.: +237-699-53-86-56
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Tepa A, Kengne-Ouafo JA, Djova VS, Tchouakui M, Mugenzi LMJ, Djouaka R, Pieme CA, Wondji CS. Molecular Drivers of Multiple and Elevated Resistance to Insecticides in a Population of the Malaria Vector Anopheles gambiae in Agriculture Hotspot of West Cameroon. Genes (Basel) 2022; 13:1206. [PMID: 35885989 PMCID: PMC9316901 DOI: 10.3390/genes13071206] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 11/17/2022] Open
Abstract
(1) Background: Malaria remains a global public health problem. Unfortunately, the resistance of malaria vectors to commonly used insecticides threatens disease control and elimination efforts. Field mosquitoes have been shown to survive upon exposure to high insecticide concentrations. The molecular mechanisms driving this pronounced resistance remain poorly understood. Here, we elucidated the pattern of resistance escalation in the main malaria vector Anopheles gambiae in a pesticide-driven agricultural hotspot in Cameroon and its impact on vector control tools; (2) Methods: Larval stages and indoor blood-fed female mosquitoes (F0) were collected in Mangoum in May and November and forced to lay eggs; the emerged mosquitoes were used for WHO tube, synergist and cone tests. Molecular identification was performed using SINE PCR, whereas TaqMan-based PCR was used for genotyping of L1014F/S and N1575Y kdr and the G119S-ACE1 resistance markers. The transcription profile of candidate resistance genes was performed using qRT-PCR methods. Characterization of the breeding water and soil from Mangoum was achieved using the HPLC technique; (3) Results: An. gambiae s.s. was the only species in Mangoum with 4.10% infection with Plasmodium. These mosquitoes were resistant to all the four classes of insecticides with mortality rates <7% for pyrethroids and DDT and <54% for carbamates and organophophates. This population also exhibited high resistance intensity to pyrethroids (permethrin, alpha-cypermethrin and deltamethrin) after exposure to 5× and 10× discriminating doses. Synergist assays with PBO revealed only a partial recovery of susceptibility to permethrin, alpha-cypermethrin and deltamethrin. Only PBO-based nets (Olyset plus and permaNet 3.0) and Royal Guard showed an optimal efficacy. A high amount of alpha-cypermethrin was detected in breeding sites (5.16-fold LOD) suggesting ongoing selection from agricultural pesticides. The 1014F-kdr allele was fixed (100%) whereas the 1575Y-kdr (37.5%) and the 119S Ace-1R (51.1%) were moderately present. Elevated expression of P450s, respectively, in permethrin and deltamethrin resistant mosquitoes [CYP6M2 (10 and 34-fold), CYP6Z1(17 and 29-fold), CYP6Z2 (13 and 65-fold), CYP9K1 (13 and 87-fold)] supports their role in the observed resistance besides other mechanisms including chemosensory genes as SAP1 (28 and 13-fold), SAP2 (5 and 5-fold), SAP3 (24 and 8-fold) and cuticular genes as CYP4G16 (6 and 8-fold) and CYP4G17 (5 and 27-fold). However, these candidate genes were not associated with resistance escalation as the expression levels did not differ significantly between 1×, 5× and 10× surviving mosquitoes; (4) Conclusions: Intensive and multiple resistance is being selected in malaria vectors from a pesticide-based agricultural hotspot of Cameroon leading to loss in the efficacy of pyrethroid-only nets. Further studies are needed to decipher the molecular basis underlying such resistance escalation to better assess its impact on control interventions.
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Affiliation(s)
- Arnaud Tepa
- Medical Entomology Department, Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (J.A.K.-O.); (V.S.D.); (M.T.); (L.M.J.M.)
- Department of Biochemistry, Faculty of Medicine and Biomedical Sciences, University of Yaounde 1, Yaoundé P.O. Box 1364, Cameroon;
| | - Jonas A. Kengne-Ouafo
- Medical Entomology Department, Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (J.A.K.-O.); (V.S.D.); (M.T.); (L.M.J.M.)
| | - Valdi S. Djova
- Medical Entomology Department, Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (J.A.K.-O.); (V.S.D.); (M.T.); (L.M.J.M.)
- Department of Biochemistry, University of Bamenda, Bambili P.O. Box 39, Cameroon
| | - Magellan Tchouakui
- Medical Entomology Department, Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (J.A.K.-O.); (V.S.D.); (M.T.); (L.M.J.M.)
| | - Leon M. J. Mugenzi
- Medical Entomology Department, Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (J.A.K.-O.); (V.S.D.); (M.T.); (L.M.J.M.)
| | - Rousseau Djouaka
- International Institute of Tropical Agriculture, Cotonou P.O. Box 0932, Benin;
| | - Constant A. Pieme
- Department of Biochemistry, Faculty of Medicine and Biomedical Sciences, University of Yaounde 1, Yaoundé P.O. Box 1364, Cameroon;
| | - Charles S. Wondji
- Medical Entomology Department, Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (J.A.K.-O.); (V.S.D.); (M.T.); (L.M.J.M.)
- International Institute of Tropical Agriculture, Yaoundé P.O. Box 2008, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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6
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Binyang AJ, Elanga-Ndille E, Tene-Fossog B, Ndo C, Nouage L, Assatse T, Fotso-Toguem Y, Tabue R, Zeukeng F, Nguiffo DN, Etang J, Njiokou F, Wondji CS. Distribution of acetylcholinesterase (Ace-1 R) target-site G119S mutation and resistance to carbamates and organophosphates in Anopheles gambiae sensu lato populations from Cameroon. Parasit Vectors 2022; 15:53. [PMID: 35164852 PMCID: PMC8842952 DOI: 10.1186/s13071-022-05174-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/22/2022] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Cameroon is considering the implementation of indoor residual spraying (IRS) as a complementary measure to control malaria in the context of high pyrethroid resistance in major malaria vectors. Non-pyrethroid insecticide classes such as organophosphates and carbamates may be utilized in IRS due to widespread pyrethroid resistance. However, the success of this strategy depends on good knowledge of the resistance status of malaria vectors to carbamates and organophosphates. Here, we assessed the susceptibility profile of Anopheles gambiae sensu lato with respect to carbamates and organophosphate and the distribution of the molecular mechanism underlying resistance to these insecticides. METHODS Anopheles gambiae s.l. mosquitoes were collected from nine settings across the country and bio-assayed with bendiocarb, propoxur and pirimiphos-methyl. The Ace-1 target-site G119S mutation was genotyped using a TaqMan assay. To investigate the polymorphism in the Ace-1 gene, a region of 924 base pairs in a sequence of the gene was amplified from both live and dead females of An. gambiae exposed to bendiocarb. RESULTS Pirimiphos-methyl induced full mortality in An. gambiae s.l. from all study sites, whereas for carbamates, resistance was observed in four localities, with the lowest mortality rate recorded in Mangoum (17.78 ± 5.02% for bendiocarb and 18.61 ± 3.86% for propoxur) in the southern part of Cameroon. Anopheles coluzzii was found to be the predominant species in the northern tropical part of the country where it is sympatric with Anopheles arabiensis. In the localities situated in southern equatorial regions, this species was predominant in urban settings, while An. gambiae was the most abundant species in rural areas. The G119S Ace-1 target-site mutation was detected only in An. gambiae and only in the sites located in southern Cameroon. Phylogenetic analyses showed a clustering according to the phenotype. CONCLUSION The occurrence of the Ace-1 target-site substitution G119S in An. gambiae s.l. populations highlights the challenge associated with the impending deployment of IRS in Cameroon using carbamates or organophosphates. It is therefore important to think about a resistance management plan including the use of other insecticide classes such as neonicotinoids or pyrrole to guarantee the implementation of IRS in Cameroon.
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Affiliation(s)
- Achille Jerome Binyang
- Department of Medical Entomology, Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Emmanuel Elanga-Ndille
- Department of Medical Entomology, Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
- Vector Borne Diseases Laboratory of the Biology and Applied Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon
| | - Billy Tene-Fossog
- Department of Medical Entomology, Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
| | - Cyrille Ndo
- Department of Parasitology and Microbiology, Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
- Department of Biological Science, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 24157, Douala, Cameroon
| | - Lynda Nouage
- Department of Medical Entomology, Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Tatiane Assatse
- Department of Medical Entomology, Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Yvan Fotso-Toguem
- Department of Medical Entomology, Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Raymond Tabue
- Ministry of Public Health, National Malaria Control Programme, P.O. Box 14386, Yaoundé, Cameroon
| | - Francis Zeukeng
- National Reference Unit for Vector Control, The Biotechnology Centre, University of Yaoundé I, P.O. Box, 3851-Messa, Yaoundé, Cameroon
| | - Daniel Nguete Nguiffo
- Department of Parasitology and Microbiology, Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
| | - Josiane Etang
- Department of Biological Science, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 24157, Douala, Cameroon
- Organisation de Coordination Pour La Lutte Contre Les Endémies en Afrique Centrale, BP 288, Yaoundé, Cameroun
| | - Flobert Njiokou
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Charles S. Wondji
- Department of Medical Entomology, Centre for Research in Infectious Diseases (CRID), P.O. BOX 13591, Yaoundé, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA UK
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7
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Doumbe-Belisse P, Kopya E, Ngadjeu CS, Sonhafouo-Chiana N, Talipouo A, Djamouko-Djonkam L, Awono-Ambene HP, Wondji CS, Njiokou F, Antonio-Nkondjio C. Urban malaria in sub-Saharan Africa: dynamic of the vectorial system and the entomological inoculation rate. Malar J 2021; 20:364. [PMID: 34493280 PMCID: PMC8424958 DOI: 10.1186/s12936-021-03891-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/20/2021] [Indexed: 12/11/2022] Open
Abstract
Sub-Saharan Africa is registering one of the highest urban population growth across the world. It is estimated that over 75% of the population in this region will be living in urban settings by 2050. However, it is not known how this rapid urbanization will affect vector populations and disease transmission. The present study summarizes findings from studies conducted in urban settings between the 1970s and 2020 to assess the effects of urbanization on the entomological inoculation rate pattern and anopheline species distribution. Different online databases such as PubMed, ResearchGate, Google Scholar, Google were screened. A total of 90 publications were selected out of 1527. Besides, over 200 additional publications were consulted to collate information on anopheline breeding habitats and species distribution in urban settings. The study confirms high malaria transmission in rural compared to urban settings. The study also suggests that there had been an increase in malaria transmission in most cities after 2003, which could also be associated with an increase in sampling, resources and reporting. Species of the Anopheles gambiae complex were the predominant vectors in most urban settings. Anopheline larvae were reported to have adapted to different aquatic habitats. The study provides updated information on the distribution of the vector population and the dynamic of malaria transmission in urban settings. The study also highlights the need for implementing integrated control strategies in urban settings.
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Affiliation(s)
- P Doumbe-Belisse
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - E Kopya
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - C S Ngadjeu
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - N Sonhafouo-Chiana
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun.,Faculty of Health Sciences, University of Buea, Cameroon, P.O. Box 63, Buea, Cameroon
| | - A Talipouo
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - L Djamouko-Djonkam
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun.,Faculty of Sciences, University of Dschang Cameroon, P.O. Box 67, Dschang, Cameroon
| | - H P Awono-Ambene
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun
| | - C S Wondji
- Vector Group Liverpool School of Tropical Medicine Pembroke Place, Liverpool, L3 5QA, UK
| | - F Njiokou
- Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - C Antonio-Nkondjio
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun. .,Vector Group Liverpool School of Tropical Medicine Pembroke Place, Liverpool, L3 5QA, UK.
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8
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Namias A, Jobe NB, Paaijmans KP, Huijben S. The need for practical insecticide-resistance guidelines to effectively inform mosquito-borne disease control programs. eLife 2021; 10:e65655. [PMID: 34355693 PMCID: PMC8346280 DOI: 10.7554/elife.65655] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 07/26/2021] [Indexed: 11/13/2022] Open
Abstract
Monitoring local mosquito populations for insecticide resistance is critical for effective vector-borne disease control. However, widely used phenotypic assays, which are designed to monitor the emergence and spread of insecticide resistance (technical resistance), do not translate well to the efficacy of vector control products to suppress mosquito numbers in the field (practical resistance). This is because standard testing conditions such as environmental conditions, exposure dose, and type of substrate differ dramatically from those experienced by mosquitoes under field conditions. In addition, field mosquitoes have considerably different physiological characteristics such as age and blood-feeding status. Beyond this, indirect impacts of insecticide resistance and/or exposure on mosquito longevity, pathogen development, host-seeking behavior, and blood-feeding success impact disease transmission. Given the limited number of active ingredients currently available and the observed discordance between resistance and disease transmission, we conclude that additional testing guidelines are needed to determine practical resistance-the efficacy of vector control tools under relevant local conditions- in order to obtain programmatic impact.
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Affiliation(s)
- Alice Namias
- Département de Biologie, Ecole Normale Supérieure, PSL Research University, Paris, France
- Institut des Sciences de l'Evolution de Montpellier (ISEM), Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Ndey Bassin Jobe
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Life Sciences C, Tempe, United States
| | - Krijn Petrus Paaijmans
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Life Sciences C, Tempe, United States
- The Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Biodesign Institute, Tempe, United States
- ISGlobal, Carrer del Rosselló, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Distrito da Manhiça, Mozambique
| | - Silvie Huijben
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Life Sciences C, Tempe, United States
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9
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2La Paracentric Chromosomal Inversion and Overexpressed Metabolic Genes Enhance Thermotolerance and Pyrethroid Resistance in the Major Malaria Vector Anopheles gambiae. BIOLOGY 2021; 10:biology10060518. [PMID: 34200806 PMCID: PMC8230517 DOI: 10.3390/biology10060518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/05/2021] [Accepted: 06/07/2021] [Indexed: 01/31/2023]
Abstract
Changes in global temperature are impacting the spread/intensity of vector-borne diseases, including malaria, and accelerating evolutionary/adaptive changes in vector species. These changes, including chromosomal inversions and overexpression and/or changes in allele frequencies of thermotolerance-associated genes, may facilitate insecticide resistance through pleiotropy. This study investigated the impact of thermotolerance on pyrethroid resistance in four populations of the malaria vector An. gambiae s.l., from the savanna/sub-Sahel of northern Nigeria. Anopheles coluzzii and An. gambiae s.s. were the only malaria vectors found, sympatric in all the sites, with the former species predominant. High thermotolerance was observed, with no mortality at 38 °C, and LT50 of ~44 °C. Significantly high permethrin resistance was observed (mortality < 50%) in 44 °C heat-hardened (exposure to an intermediately high temperature provides protection to a more severe temperature or insecticide) larvae from two sites, BUK and Pantami, compared with the control, and heat-hardened adult females from Auyo (mortality = 3.00% ± 1.20, χ2 = 5.83, p < 0.01) compared with the control (12.00% ± 4.65). The 2La chromosomal inversion was detected at ~50% in subset of larvae and 58% in subset of adult females genotyped. A significant association was observed (OR = 7.2, p < 0.03) between permethrin resistance and the 2La/+a rearrangement compared with 2L+a/+a, in BUK larvae. For all sites, permethrin resistance correlated with 2La/a homozygosity in adult females (R = 5.02, p = 0.01). qRT-PCR identified six genes commonly induced/overexpressed, including the heat shock protein 70 (AGAP004581) which was 2468× and 5× overexpressed in heat-hardened and permethrin-resistant females, respectively; trehalose-6-phosphate synthase (AGAP008227); and the ionotropic glutamate receptor genes, IR25a (AGAP010272) and IR21a (AGAP008511). This study highlights challenges associated with insecticide-based malaria vector control, and the epidemiological significance of taking climate variables into account for the design/choice of control measures.
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10
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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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11
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Black WC, Snell TK, Saavedra-Rodriguez K, Kading RC, Campbell CL. From Global to Local-New Insights into Features of Pyrethroid Detoxification in Vector Mosquitoes. INSECTS 2021; 12:insects12040276. [PMID: 33804964 PMCID: PMC8063960 DOI: 10.3390/insects12040276] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/18/2021] [Accepted: 03/20/2021] [Indexed: 02/04/2023]
Abstract
The threat of mosquito-borne diseases continues to be a problem for public health in subtropical and tropical regions of the world; in response, there has been increased use of adulticidal insecticides, such as pyrethroids, in human habitation areas over the last thirty years. As a result, the prevalence of pyrethroid-resistant genetic markers in natural mosquito populations has increased at an alarming rate. This review details recent advances in the understanding of specific mechanisms associated with pyrethroid resistance, with emphasis on features of insecticide detoxification and the interdependence of multiple cellular pathways. Together, these advances add important context to the understanding of the processes that are selected in resistant mosquitoes. Specifically, before pyrethroids bind to their targets on motoneurons, they must first permeate the outer cuticle and diffuse to inner tissues. Resistant mosquitoes have evolved detoxification mechanisms that rely on cytochrome P450s (CYP), esterases, carboxyesterases, and other oxidation/reduction (redox) components to effectively detoxify pyrethroids to nontoxic breakdown products that are then excreted. Enhanced resistance mechanisms have evolved to include alteration of gene copy number, transcriptional and post-transcriptional regulation of gene expression, as well as changes to cellular signaling mechanisms. Here, we outline the variety of ways in which detoxification has been selected in various mosquito populations, as well as key gene categories involved. Pathways associated with potential new genes of interest are proposed. Consideration of multiple cellular pathways could provide opportunities for development of new insecticides.
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12
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Muhammad A, Ibrahim SS, Mukhtar MM, Irving H, Abajue MC, Edith NMA, Da’u SS, Paine MJI, Wondji CS. High pyrethroid/DDT resistance in major malaria vector Anopheles coluzzii from Niger-Delta of Nigeria is probably driven by metabolic resistance mechanisms. PLoS One 2021; 16:e0247944. [PMID: 33705436 PMCID: PMC7951933 DOI: 10.1371/journal.pone.0247944] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/17/2021] [Indexed: 11/18/2022] Open
Abstract
Entomological surveillance of local malaria vector populations is an important component of vector control and resistance management. In this study, the resistance profile and its possible mechanisms was characterised in a field population of the major malaria vector Anopheles coluzzii from Port Harcourt, the capital of Rivers state, in the Niger-Delta Region of Nigeria. Larvae collected in Port-Harcourt, were reared to adulthood and used for WHO bioassays. The population exhibited high resistance to permethrin, deltamethrin and DDT with mortalities of 6.7% ± 2.4, 37.5% ± 3.2 and 6.3% ± 4.1, respectively, but were fully susceptible to bendiocarb and malathion. Synergist bioassays with piperonylbutoxide (PBO) partially recovered susceptibility, with mortalities increasing to 53% ± 4, indicating probable role of CYP450s in permethrin resistance (χ2 = 29.48, P < 0.0001). Transcriptional profiling revealed five major resistance-associated genes overexpressed in the field samples compared to the fully susceptible laboratory colony, Ngoussou. Highest fold change (FC) was observed with GSTe2 (FC = 3.3 in permethrin exposed and 6.2 in unexposed) and CYP6Z3 (FC = 1.4 in exposed and 4.6 in unexposed). TaqMan genotyping of 32 F0 females detected the 1014F and 1575Y knockdown resistance (kdr) mutations with frequencies of 0.84 and 0.1, respectively, while 1014S mutation was not detected. Sequencing of a fragment of the voltage-gated sodium channel, spanning exon 20 from 13 deltamethrin-resistant and 9 susceptible females revealed only 2 distinct haplotypes with a low haplotype diversity of 0.33. The findings of high pyrethroid resistance but with a significant degree of recovery after PBO synergist assay suggests the need to move to PBO-based nets. This could be complemented with carbamate- or organophosphate-based indoor residual spraying in this area.
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Affiliation(s)
- Abdullahi Muhammad
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, United Kingdom
- Centre for Biotechnology Research, Bayero University, Kano, Nigeria
| | - Sulaiman S. Ibrahim
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, United Kingdom
- Department of Biochemistry, Bayero University, Kano, Nigeria
- LSTM Research Unit, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | | | - Helen Irving
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, United Kingdom
| | - Maduamaka C. Abajue
- Department of Animal and Environmental Biology, University of Port Harcourt, Port Harcourt, Nigeria
| | - Noutcha M. A. Edith
- Department of Animal and Environmental Biology, University of Port Harcourt, Port Harcourt, Nigeria
| | - Sabitu S. Da’u
- Department of Science, School of Continuing Education, Bayero University, Kano, Nigeria
| | - Mark J. I. Paine
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, United Kingdom
| | - Charles S. Wondji
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool, United Kingdom
- LSTM Research Unit, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
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