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Mayi MPA, Antonio-Nkondjio C, Bamou R, Damiani C, Cappelli A, Djiappi-Tchamen B, Djamouko-Djonkam L, Ilbeigi Khamseh Nejad M, Pichler V, Ricci I, Favia G. First detection of kdr L1014F allele in Anopheles ziemanni and Anopheles pharoensis in Cameroon and distribution of the allele in members of the Anopheles gambiae complex. Parasit Vectors 2024; 17:363. [PMID: 39192348 DOI: 10.1186/s13071-024-06420-4] [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: 04/22/2024] [Accepted: 07/24/2024] [Indexed: 08/29/2024] Open
Abstract
BACKGROUND Knockdown resistance (kdr) is one of the primary resistance mechanisms present in anopheline species. Although this mutation is largely spread across the Anopheles gambiae s.l. members, its prevalence in other species is still not well documented. METHODS The present study investigated the distribution and allelic frequencies of kdr in An. gambiae s.l., An. pharoensis, and An. ziemanni samples collected in 2022 and 2023 in nine sites spread across five ecogeographical settings in Cameroon. Members of the An. gambiae complex were identified molecularly by polymerase chain reaction (PCR). kdr L1014F and L1014S alleles were screened by PCR and confirmed by sequencing. RESULTS An. gambiae (49.9%), An. coluzzii (36.5%), and An. arabiensis (13%) were identified, and the frequency of the kdr L1014F was high in both An. gambiae and An. coluzzii in all sites. The kdr L1014F allele was detected for the first time in 8 out of 14 An. ziemanni samples examined and in 5 out of 22 An. pharoensis samples examined. The kdr L1014S allele was scarce and found only in the heterozygote "RS" state in An. arabiensis and An. gambiae in Yangah and Santchou. CONCLUSIONS The present study sheds light on the rapid expansion of the kdr L1014F allele in malaria vectors in Cameroon and stresses the need for surveillance activities also targeting secondary malaria vectors to improve the control of malaria transmission.
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Affiliation(s)
- Marie Paul Audrey Mayi
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy
| | - Christophe 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, Cameroon
- Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Roland Bamou
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- Vector Borne Diseases Laboratory of the Research Unit for Biology and Applied Ecology (VBID-RUBAE), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon
- Laboratory of Malaria and Vector Research-LMVR, Rockville National Institute of Health /NIAID, Rockville, USA
| | - Claudia Damiani
- School of Biosciences and Veterinary Medicine, University of Camerino, CIRM Italian Malaria Network, Via Gentile III da Varano, 62032, Camerino, Italy
| | - Alessia Cappelli
- School of Biosciences and Veterinary Medicine, University of Camerino, CIRM Italian Malaria Network, Via Gentile III da Varano, 62032, Camerino, Italy
| | - Borel Djiappi-Tchamen
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- Vector Borne Diseases Laboratory of the Research Unit for Biology and Applied Ecology (VBID-RUBAE), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon
| | - Landre 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, Cameroon
- Vector Borne Diseases Laboratory of the Research Unit for Biology and Applied Ecology (VBID-RUBAE), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon
| | - Mahdokht Ilbeigi Khamseh Nejad
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy
| | - Verena Pichler
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Irene Ricci
- School of Biosciences and Veterinary Medicine, University of Camerino, CIRM Italian Malaria Network, Via Gentile III da Varano, 62032, Camerino, Italy
| | - Guido Favia
- School of Biosciences and Veterinary Medicine, University of Camerino, CIRM Italian Malaria Network, Via Gentile III da Varano, 62032, Camerino, Italy.
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Nkahe DL, Sonhafouo-Chiana N, Ndjeunia Mbiakop P, Kekeunou S, Mimpfoundi R, Awono-Ambene P, Wondji CS, Antonio-Nkondjio C. Can the use of larviciding with biological compounds contribute in increasing Anopheles gambiae s.l. susceptibility to pyrethroid in a population expressing high resistance intensity? PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 195:105569. [PMID: 37666599 DOI: 10.1016/j.pestbp.2023.105569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/05/2023] [Indexed: 09/06/2023]
Abstract
BACKGROUND Larviciding using non-insecticide compounds is considered appropriate for controlling outdoor biting mosquitoes and for managing insecticide resistance. However, there is still not enough information on the influence of larviciding in managing pyrethroid resistance. In the present study, we checked whether the introduction of larviciding using the biolarvicide VectoMax G in the city of Yaoundé is contributing in restoring the susceptibility of An. coluzzii populations to pyrethroids. METHODOLOGY The susceptibility status of field An. coluzzii population was evaluated at different time points before and during larviciding treatments. In addition, An. coluzzii larvae collected in the city of Yaoundé, were split into four groups and exposed to different selection regimes for many generations as follow; (i): deltamethrin 0.05%_only, (ii): Vectomax_only, (iii): Vectomax+deltamethrin 0.05%, (iv): VectoMax+deltamethrin 0.05% + susceptible. Life traits parameters were measured in the progeny and compared between colonies. The control was the susceptible laboratory strain "Ngousso". Kdr allele frequency and the profile of expression of different detoxification genes and oxidative stress genes was checked using qPCR analysis. Gene's expression was compared between the first and the last generation of each colony and in field populations collected before and during larviciding. RESULTS An increase in mosquito susceptibility to deltamethrin and permethrin was recorded for the field populations after larviciding implementation. Resistance intensity to deltamethrin was found to decrease from high to low in field populations. Only the colony vectomax+deltamethrin+susceptible presented a high susceptibility to deltamethrin after 21 generations. The kdr gene frequency was found to be unchanged in the field population and laboratory colonies. A significant decrease in the overexpression profile of Gste2 was detected in field population after larviciding implementation. Other genes showing a similar pattern though not significant were Cyp6z1, Cyp6p1 and Cyp6g16. Concerning fitness only the colony vectomax+deltamethrin+susceptible was found to display a fitness profile similar to the susceptible colony with high fecundity, high hatching rate, short development time and long adult survival rate. CONCLUSION The profile of the field population supported reversal of phenotypic resistance to pyrethroids however no reduction in the frequency of the kdr allele was recorded. Some detoxification genes were detected less overexpressed. The study suggest that reversal may take longer to achieve in a population expressing a very high resistance profile and under continuous insecticide selection pressure.
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Affiliation(s)
- Diane Leslie Nkahe
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon; Department of Animal Physiology and Biology, Faculty of Science, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Nadege 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, Cameroon; Faculty of Science, University of Buea, Buea, P.O. Box 63, Cameroon
| | - Paulette Ndjeunia Mbiakop
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon; Department of Animal Physiology and Biology, Faculty of Science, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Sévilor Kekeunou
- Department of Animal Physiology and Biology, Faculty of Science, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Rémy Mimpfoundi
- Department of Animal Physiology and Biology, Faculty of Science, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Parfait 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, Cameroon
| | - Charles Sinclair Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon; Vector Biology Liverpool School of Tropical medicine Pembroke Place, Liverpool L3 5QA, UK.
| | - Christophe 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, Cameroon; Faculty of Medicine Paris-Sud, 63 rue Gabriel Peri, 94276, Le Kremlin-Bicêtre, Paris, France..
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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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Kala-Chouakeu NA, Ndjeunia-Mbiakop P, Ngangue-Siewe IN, Mavridis K, Balabanidou V, Bamou R, Maxim Bindamu M, Talipouo A, Djamouko-Djonkam L, Mbida-Mbida JA, Tombi J, Vontas J, Tchuinkam T, Antonio-Nkondjio C. Pyrethroid Resistance Situation across Different Eco-Epidemiological Settings in Cameroon. Molecules 2022; 27:molecules27196343. [PMID: 36234887 PMCID: PMC9573433 DOI: 10.3390/molecules27196343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/19/2022] [Accepted: 09/19/2022] [Indexed: 11/17/2022] Open
Abstract
Rapid emergence and spread of pyrethroid resistance in Anopheles gambiae populations is among the main factors affecting malaria vector control in Cameroon, but there is still not enough data on the exact pyrethroid resistance status across Cameroon. The present study assessed pyrethroid resistance profile in different eco-epidemiological settings in Cameroon. Susceptibility bioassay tests were performed with F0 An. gambiae females aged three to five days. Mosquito susceptibility to both permethrin and deltamethrin was assessed. Species of the An. gambiae s.l. complex were identified using molecular diagnostic tools. Target site mutations conferring resistance were detected using Taqman assays. Quantitative reverse transcription-real-time PCR (qRT-PCR) 3-plex TaqMan® assays were used for the quantification of detoxification genes implicated in pyrethroid resistance. An. gambiae, An. coluzzii and An. arabiensis were identified in the different settings. An. gambiae was dominant in Santchou, Kékem, Bélabo, Bertoua and Njombé, while An. coluzzii was abundant in Tibati and Kaélé. High frequencies of the kdr L1014F allele ranging from 43% to 100% were recorded in almost all sites. The L1014S kdr allele was detected at low frequency (4.10–10%) only in mosquito populations from Njombé and Tibati. The N1575Y mutation was recorded in Kaélé, Santchou, Tibati and Bertoua with a frequency varying from 2.10% to 11.70%. Six Cytochrome P450 genes (Cyp6p3, Cyp6m2, Cyp9k1, Cyp6p4, Cyp6z1, and Cyp4g16) were found to be overexpressed in at least one population. Analysis of cuticular hydrocarbon lipids indicated a significant increase in CHC content in mosquito populations from Kaélé and Njombé compared to Kékem, Bélabo and Bertoua populations. The study indicated high pyrethroid resistance across different ecological settings in Cameroon with different profile of resistance across the country. The present situation calls for further actions in order to mitigate the impact of insecticide resistance on vector control measures.
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Affiliation(s)
- Nelly Armanda Kala-Chouakeu
- 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
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé B.P. 288, Cameroon
| | - Paulette Ndjeunia-Mbiakop
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé B.P. 288, Cameroon
- Faculty of Sciences, University of Yaoundé I, Yaoundé P.O. Box 337, Cameroon
| | - Idriss Nasser Ngangue-Siewe
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé B.P. 288, Cameroon
- Laboratory of Animal Biology and Physiology, University of Douala, Douala P.O. Box 24157, Cameroon
| | - Konstantinos Mavridis
- Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, 11855 Athens, Greece
| | - Vasileia Balabanidou
- Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, 11855 Athens, Greece
| | - Roland Bamou
- 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
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé B.P. 288, Cameroon
| | - Mabu Maxim Bindamu
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé B.P. 288, Cameroon
- Research Laboratory of Biochemestry of University of Bamenda, Bambili P.O. Box 39, Cameroon
| | - Abdou Talipouo
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé B.P. 288, Cameroon
- Faculty of Sciences, University of Yaoundé I, Yaoundé P.O. Box 337, Cameroon
| | - Landre Djamouko-Djonkam
- 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
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé B.P. 288, Cameroon
| | - Jean Arthur Mbida-Mbida
- Laboratory of Animal Biology and Physiology, University of Douala, Douala P.O. Box 24157, Cameroon
| | - Jeanette Tombi
- Faculty of Sciences, University of Yaoundé I, Yaoundé P.O. Box 337, Cameroon
| | - John Vontas
- Research Laboratory of Biochemestry of University of Bamenda, Bambili P.O. Box 39, Cameroon
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Greece
| | - 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
| | - Christophe Antonio-Nkondjio
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé B.P. 288, Cameroon
- Correspondence:
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DDT Resistance in Anopheles pharoensis from Northern Cameroon Associated with High Cuticular Hydrocarbon Production. Genes (Basel) 2022; 13:genes13101723. [PMID: 36292608 PMCID: PMC9601446 DOI: 10.3390/genes13101723] [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: 08/15/2022] [Revised: 09/05/2022] [Accepted: 09/21/2022] [Indexed: 11/26/2022] Open
Abstract
Despite the contribution of secondary vectors to malaria transmission, there is still not enough information on their susceptibility status to insecticides. The present study assesses the resistance profile of Anopheles pharoensis to DDT. WHO tube tests were used to screen mosquito populations collected from the far-north region of Cameroon for susceptibility to 4% DDT. High DDT resistance in An. pharoensis populations from Maga, Simatou and Yangah with mortality rates ranging from 62.79% to 80% was recorded. Direct sequencing (Sanger) of the VGSC gene was undertaken to search for kdr L1014F/S mutations. However, no kdr allele was detected in the resistant samples. We then looked for cuticle alterations and CHC identification and quantitation were undertaken using GC-MS and GC-FID. High production of cuticular hydrocarbon was recorded in the populations of Yangah and Simatou, with 2420.9 ± 265 and 2372.5 ± 225 ng CHCs/mg dry weight, respectively. The present findings are the first ever describing the development of cuticle resistance in An. pharoensis. The data suggest the need to expand surveillance activities on other vector species.
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Djoufounna J, Bamou R, Mayi MPA, Kala-Chouakeu NA, Tabue R, Awono-Ambene P, Achu-Fosah D, Antonio-Nkondjio C, Tchuinkam T. Population knowledge, attitudes and practices towards malaria prevention in the locality of Makenene, Centre-Cameroon. Malar J 2022; 21:234. [PMID: 35932025 PMCID: PMC9356395 DOI: 10.1186/s12936-022-04253-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 07/30/2022] [Indexed: 11/14/2022] Open
Abstract
Background To contribute to the mission of the National Malaria Control Programme (NMCP) and guide future interventions in Cameroon in general, and in Makenene in particular, this study assessed the knowledge, attitudes and practices of the population of Makenene towards the fight against malaria. Methods Using a semi-structured questionnaire, a descriptive cross-sectional household community survey was carried out in randomly selected households in Makenene, a locality situated between forest and savannah ecotypes. Results Out of the 413 households surveyed, all (100%) claimed to have heard of malaria with over 94% (n = 391) associating disease transmission with mosquito bites. The main mosquito control tools used in the area were mosquito nets (92.25%). The majority of participants had good knowledge (55.93%; n = 231), good practices (71.67%, n = 296) but moderate attitudes (47.94%; n = 198) towards malaria control and fight. Good knowledge and practices were recorded mostly in educated persons including public servants and students. Good attitudes were adopted mostly by public servants and students of secondary and higher levels of education. Conclusion In Makenene, the population exhibits good knowledge and practices towards malaria and its control. However, despite high LLINs ownership and use, people still complain about malaria in the area. Control tools should be monitored, repaired or replaced when necessary to support the achievement of the NMCP mission. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04253-z.
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Affiliation(s)
- Joel Djoufounna
- Vector Borne Diseases Laboratory of the Research Unit of Biology and Applied Ecology (VBID-RUBAE), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon
| | - Roland Bamou
- Vector Borne Diseases Laboratory of the Research Unit of Biology and Applied Ecology (VBID-RUBAE), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon. .,Organisation de Coordination Pour La Lutte Contre Les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon. .,Aix Marseille Université, IRD, SSA, AP-HM, UMR Vecteurs-Infections Tropicales Et Méditerranéennes (VITROME), Marseille, France.
| | - Marie Paul Audrey Mayi
- Vector Borne Diseases Laboratory of the Research Unit of Biology and Applied Ecology (VBID-RUBAE), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon
| | - Nelly Armanda Kala-Chouakeu
- Vector Borne Diseases Laboratory of the Research Unit of Biology and Applied Ecology (VBID-RUBAE), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon.,Organisation de Coordination Pour La Lutte Contre Les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | - Raymond Tabue
- Ministry of Public Health, National Malaria Control Programme, Yaoundé, Cameroon
| | - Parfait Awono-Ambene
- Organisation de Coordination Pour La Lutte Contre Les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | - Dorothy Achu-Fosah
- Ministry of Public Health, National Malaria Control Programme, Yaoundé, Cameroon
| | - Christophe Antonio-Nkondjio
- Organisation de Coordination Pour La Lutte Contre Les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | - Timoléon Tchuinkam
- Vector Borne Diseases Laboratory of the Research Unit of Biology and Applied Ecology (VBID-RUBAE), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon.
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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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