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Longo-Pendy NM, Sevidzem SL, Makanga BK, Ndotit-Manguiengha S, Boussougou-Sambe ST, Obame Ondo Kutomy P, Obame-Nkoghe J, Nkoghe-Nkoghe LC, Ngossanga B, Mvoubou FK, Koumba CRZ, Adegnika AA, Razack AS, Mavoungou JF, Mintsa-Nguema R. Assessment of environmental and spatial factors influencing the establishment of Anopheles gambiae larval habitats in the malaria endemic province of Woleu-Ntem, northern Gabon. Malar J 2024; 23:158. [PMID: 38773512 PMCID: PMC11106858 DOI: 10.1186/s12936-024-04980-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 05/10/2024] [Indexed: 05/23/2024] Open
Abstract
BACKGROUND This study aimed to assess the spatial distribution of Anopheles mosquito larval habitats and the environmental factors associated with them, as a prerequisite for the implementation of larviciding. METHODS The study was conducted in December 2021, during the transition period between the end of the short rainy season (September-November) and the short dry season (December-February). Physical, biological, and land cover data were integrated with entomological observations to collect Anopheles larvae in three major towns: Mitzic, Oyem, and Bitam, using the "dipping" method during the transition from rainy to dry season. The collected larvae were then reared in a field laboratory established for the study period. After the Anopheles mosquitoes had emerged, their species were identified using appropriate morphological taxonomic keys. To determine the influence of environmental factors on the breeding of Anopheles mosquitoes, multiple-factor analysis (MFA) and a binomial generalized linear model were used. RESULTS According to the study, only 33.1% out of the 284 larval habitats examined were found to be positive for Anopheles larvae, which were primarily identified as belonging to the Anopheles gambiae complex. The findings of the research suggested that the presence of An. gambiae complex larvae in larval habitats was associated with various significant factors such as higher urbanization, the size and type of the larval habitats (pools and puddles), co-occurrence with Culex and Aedes larvae, hot spots in ambient temperature, moderate rainfall, and land use patterns. CONCLUSIONS The results of this research mark the initiation of a focused vector control plan that aims to eradicate or lessen the larval habitats of An. gambiae mosquitoes in Gabon's Woleu Ntem province. This approach deals with the root causes of malaria transmission through larvae and is consistent with the World Health Organization's (WHO) worldwide objective to decrease malaria prevalence in regions where it is endemic.
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Affiliation(s)
- Neil-Michel Longo-Pendy
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon.
| | - Silas Lendzele Sevidzem
- Laboratoire d'Ecologie des Maladies Transmissibles (LEMAT), Université Libreville Nord (ULN), Libreville, Gabon
| | | | - Saturnin Ndotit-Manguiengha
- Institut de Recherche en Écologie Tropicale (IRET), Libreville, Gabon
- Agence Gabonaise d'Etudes et d'Observations Spatiales (AGEOS), Libreville, Gabon
| | | | - Piazzy Obame Ondo Kutomy
- Programme National de Lutte Contre Le Paludisme (PNLP), Libreville, Gabon
- Universite Cheikh Anta Diop de Dakar (UCAD), Dakar, Sénégal
| | - Judicaël Obame-Nkoghe
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon
- Université des Sciences et Techniques de Masuku (USTM), Franceville, Gabon
- Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of the Free State, Phuthaditjhaba, Republic of South Africa
| | - Lynda-Chancelya Nkoghe-Nkoghe
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon
| | | | | | | | - Ayôla Akim Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institut Für Tropenmedizin, Eberhard Karls Universität, Tübingen, Germany
- Fondation Pour la Recherche Scientifique (FORS), P.O. Box 88, Cotonou, Benin
- German Center for Infection Research (DZIF), Partner site Tübingen, Tübingen, Germany
| | | | | | - Rodrigue Mintsa-Nguema
- Laboratoire d'Ecologie des Maladies Transmissibles (LEMAT), Université Libreville Nord (ULN), Libreville, Gabon
- Institut de Recherche en Écologie Tropicale (IRET), Libreville, Gabon
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Fouet C, Ashu FA, Ambadiang MM, Tchapga W, Wondji CS, Kamdem C. Clothianidin-resistant Anopheles gambiae adult mosquitoes from Yaoundé, Cameroon, display reduced susceptibility to SumiShield® 50WG, a neonicotinoid formulation for indoor residual spraying. BMC Infect Dis 2024; 24:133. [PMID: 38273227 PMCID: PMC10811947 DOI: 10.1186/s12879-024-09030-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND Chronic exposure of mosquito larvae to pesticide residues and cross-resistance mechanisms are major drivers of tolerance to insecticides used for vector control. This presents a concern for the efficacy of clothianidin, an agricultural neonicotinoid prequalified for Indoor Residual Spraying (IRS). METHODS Using standard bioassays, we tested if reduced susceptibility to clothianidin can affect the efficacy of SumiShield® 50WG, one of four new IRS formulations containing clothianidin. We simultaneously monitored susceptibility to clothianidin and to SumiShield 50WG, testing adults of Anopheles gambiae, An. coluzzii and Culex sp sampled from urban, suburban and agricultural areas of Yaoundé, Cameroon. RESULTS We found that in this geographic area, the level of susceptibility to the active ingredient predicted the efficacy of SumiShield 50WG. This formulation was very potent against populations that reached 100% mortality within 72 h of exposure to a discriminating concentration of clothianidin. By contrast, mortality leveled off at 75.4 ± 3.5% within 7 days of exposure to SumiShield 50WG in An. gambiae adults collected from a farm where the spraying of the two neonicotinoids acetamiprid and imidacloprid for crop protection is likely driving resistance to clothianidin. CONCLUSIONS Despite the relatively small geographic extend of the study, the findings suggest that cross-resistance may impact the efficacy of some new IRS formulations and that alternative compounds could be prioritized in areas where neonicotinoid resistance is emerging.
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Affiliation(s)
- Caroline Fouet
- Department of Biological Sciences, The University of Texas at El Paso, 500 W. University Ave, El Paso, TX, 79968, USA
| | - Fred A Ashu
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Marilene M Ambadiang
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Williams Tchapga
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, L3 5QA, UK
| | - Colince Kamdem
- Department of Biological Sciences, The University of Texas at El Paso, 500 W. University Ave, El Paso, TX, 79968, USA.
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Akirso A, Tamiru G, Eligo N, Lindtjørn B, Massebo F. High human blood meal index of mosquitoes in Arba Minch town, southwest Ethiopia: an implication for urban mosquito-borne disease transmission. Parasitol Res 2024; 123:102. [PMID: 38233721 PMCID: PMC10794327 DOI: 10.1007/s00436-024-08121-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 01/03/2024] [Indexed: 01/19/2024]
Abstract
Unplanned human population shifts in urban areas are expected to increase the prevalence of vector-borne diseases. This study aimed to investigate mosquito species composition, blood meal sources, and malaria vectors in an urban area. Indoor-resting adult mosquitoes were collected using Prokopack and host-seeking mosquitoes using Centers for Disease Control and Prevention light traps in Arba Minch town. Larval collection from artificial containers was done in those houses selected for adult mosquito collection. Anopheles adults collected and emerged from larvae were identified morphologically using a taxonomic key. ELISA was used to identify blood meal sources in freshly fed Anopheles and Culex mosquitoes, and CSP of Anopheles mosquitoes. A total of 16,756 female mosquitoes were collected. Of these, 93% (15,571) were Culex, 6% (1016) were Anopheles, and 1% (169) were Aedes mosquitoes. Out of the 130 adult mosquitoes that were raised from larvae collected from the containers, 20% were An. rhodesiensis, while the remaining 80% were Aedes mosquitoes. Out of 823 mosquitoes tested for blood meal origins, 86.3% (710/823) tested positive for human blood, 2.2% (18/823) tested positive for bovine blood, and 11.5% (95/823) were negative for human and bovine antibodies. Anopheles gambiae complex had a human blood meal index (HBI) of 50% (90/180; CI 42.3-57.5%) and a bovine blood meal index (BBI) of only 0.5% (95% CI 0.01-3.1%). Culex HBI was 96.7% (620/641), and its BBI index was 2.4% (15/641). While it was low (0.8%) in Culex, the proportion of An. gambiae complex with unidentified blood meal sources was 49.5% (95 CI% 41.9-56.9%). Among the 1016 Anopheles mosquitoes tested, a single An. gambiae complex (0.1%; 1/1016) was positive for P. vivax CSP. The high HBI indicates frequent contact between humans and vectors. To reduce human exposure, personal protection tools should be implemented.
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Affiliation(s)
- Adisu Akirso
- Department of Biology, Arba Minch University, Arba Minch, Ethiopia
| | - Girum Tamiru
- Department of Biology, Arba Minch University, Arba Minch, Ethiopia
| | - Nigatu Eligo
- Department of Biology, Arba Minch University, Arba Minch, Ethiopia
| | - Bernt Lindtjørn
- Department of Biology, Arba Minch University, Arba Minch, Ethiopia
- Centre for International Health, University of Bergen, Bergen, Norway
| | - Fekadu Massebo
- Department of Biology, Arba Minch University, Arba Minch, Ethiopia.
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Lau CL, Mills DJ, Mayfield H, Gyawali N, Johnson BJ, Lu H, Allel K, Britton PN, Ling W, Moghaddam T, Furuya-Kanamori L. A decision support tool for risk-benefit analysis of Japanese encephalitis vaccine in travellers. J Travel Med 2023; 30:taad113. [PMID: 37602668 DOI: 10.1093/jtm/taad113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/22/2023]
Abstract
BACKGROUND During pre-travel consultations, clinicians and travellers face the challenge of weighing the risks verus benefits of Japanese encephalitis (JE) vaccination due to the high cost of the vaccine, low incidence in travellers (~1 in 1 million), but potentially severe consequences (~30% case-fatality rate). Personalised JE risk assessment based on the travellers' demographics and travel itinerary is challenging using standard risk matrices. We developed an interactive digital tool to estimate risks of JE infection and severe health outcomes under different scenarios to facilitate shared decision-making between clinicians and travellers. METHODS A Bayesian network (conditional probability) model risk-benefit analysis of JE vaccine in travellers was developed. The model considers travellers' characteristics (age, sex, co-morbidities), itinerary (destination, departure date, duration, setting of planned activities) and vaccination status to estimate the risks of JE infection, the development of symptomatic disease (meningitis, encephalitis), clinical outcomes (hospital admission, chronic neurological complications, death) and adverse events following immunization. RESULTS In low-risk travellers (e.g. to urban areas for <1 month), the risk of developing JE and dying is low (<1 per million) irrespective of the destination; thus, the potential impact of JE vaccination in reducing the risk of clinical outcomes is limited. In high-risk travellers (e.g. to rural areas in high JE incidence destinations for >2 months), the risk of developing symptomatic disease and mortality is estimated at 9.5 and 1.4 per million, respectively. JE vaccination in this group would significantly reduce the risk of symptomatic disease and mortality (by ~80%) to 1.9 and 0.3 per million, respectively. CONCLUSION The JE tool may assist decision-making by travellers and clinicians and could increase JE vaccine uptake. The tool will be updated as additional evidence becomes available. Future work needs to evaluate the usability of the tool. The interactive, scenario-based, personalised JE vaccine risk-benefit tool is freely available on www.VaxiCal.com.
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Affiliation(s)
- Colleen L Lau
- School of Public Health, Faculty of Medicine, The University of Queensland, Herston, QLD, Australia
- Dr Deb The Travel Doctor, Travel Medicine Alliance, Brisbane, QLD, Australia
| | - Deborah J Mills
- Dr Deb The Travel Doctor, Travel Medicine Alliance, Brisbane, QLD, Australia
| | - Helen Mayfield
- School of Public Health, Faculty of Medicine, The University of Queensland, Herston, QLD, Australia
| | - Narayan Gyawali
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Brian J Johnson
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Hongen Lu
- School of Public Health, Faculty of Medicine, The University of Queensland, Herston, QLD, Australia
| | - Kasim Allel
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Philip N Britton
- Department of Infectious Diseases and Microbiology, Children's Hospital Westmead, Westmead, NSW, Australia
- Child and Adolescent Health and Sydney ID, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Weiping Ling
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, QLD, Australia
| | - Tina Moghaddam
- School of Information Technology and Electrical Engineering, Faculty of Science, The University of Queensland, St Lucia, QLD, Australia
| | - Luis Furuya-Kanamori
- School of Public Health, Faculty of Medicine, The University of Queensland, Herston, QLD, Australia
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Silva ALD, Azevedo LS, Gonçalves TPR, Coimbra MC, Siqueira EPD, Alves SN, Lima LARDS. Larvicidal activity of hexane extract, fatty acids, and methyl esters from Tecoma stans pericarps against Culex quinquefasciatus. Nat Prod Res 2023; 37:4227-4231. [PMID: 36735355 DOI: 10.1080/14786419.2023.2172725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 01/15/2023] [Indexed: 02/04/2023]
Abstract
Culex quinquefasciatus (Diptera: Culicidae) is responsible for the transmission of lymphatic filariasis. The search for natural sources of new insecticides to control mosquitoes has intensified in recent years. Tecoma stans is an exotic species in Brazil, known as 'ipê de jardim'. T. stans pericarps were extracted with hexane in Soxhlet apparatus, and fatty acids (FA) and methyl esters (FAME) were obtained by transesterification reaction of hexane extract (HE). HE, FA, and FAME were evaluated against 3rd. and 4th. instar larvae of Culex quinquefasciatus. Analysis by gas chromatography-mass spectrometry (GC/MS) identified the hydrocarbon nonacosane (81.69%) as the major compound in HE, and linolenic (16.89%), linoleic (16.83%), and palmitic acids (21.00%) were predominant in FA. FA and HE, at a concentration of 250 µg/mL, promoted mortality of 81.67% and 68.66% of larvae, respectively. HE and FA obtained from T. stans pericarps have larvicidal potential for the control of C. quinquefasciatus.
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Affiliation(s)
| | | | | | | | - Ezequias Pessoa de Siqueira
- Centro de Pesquisa René Rachou - Fiocruz/MG, Laboratório de Química de Produtos Naturais, Belo Horizonte, Minas Gerais, Brazil
| | - Stênio Nunes Alves
- Universidade Federal de São João Del-Rei, Divinópolis, Minas Gerais, Brazil
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Okafor MA, Ekpo ND, Opara KN, Udoidung NI, Ataya FS, Yaro CA, Batiha GES, Alexiou A, Papadakis M. Pyrethroid insecticides susceptibility profiles and evaluation of L1014F kdr mutant alleles in Culex quinquefasciatus from lymphatic filariasis endemic communities. Sci Rep 2023; 13:18716. [PMID: 37907533 PMCID: PMC10618241 DOI: 10.1038/s41598-023-44962-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 10/13/2023] [Indexed: 11/02/2023] Open
Abstract
This study investigated the dynamics in pyrethriod resistance and the presence/frequencies of L1014F knockdown resistance mutant allelles in Culex quinquefasciatus vector populations from Uruan Local Government Area of AkwaIbom State, Southern Nigeria between the months of March and November, 2021. Uruan LGA is among the endemic LGAs for lymphatic filariasis in AkwaIbomState. Female Anopheles mosquitoes from Eman Uruan, Ituk Mbang and Idu Uruan were exposed to permethrin, deltamethrin and alphacypermethrin in CDC insecticide coated bottles for susceptibility bioassay following standard protocols. The mosquitoes were obtained as aquatic forms from the study sites and reared under laboratory conditions to adults. The adult mosquitoes were used for this study. All the mosquitoes used for the insecticide susceptibility bioassay were morphologically identified. Standard Polymerase chain reaction (PCR) was used for authenticating the Culex quinquefasciatus species. A portion of the vgsc (917 bp) gene spanning the entire intron and the exon containing the L1014F mutation associated with knockdown resistance (kdr) in the vectorswere amplified using Allele-SPECIFIC POLYMERASE CHAIN REACTION (AS-PCR) in order to detect target site insensitivity in the vectors from the study sites. Results obtained revealed that vectors from all the study sites were resistant to permethrin insecticide (mortality rate: 18-23%). Suspected resistance (mortality rate: 90-93%) to deltamethrin and low resistance (mortality rate: 82-85%) to alphacypermethrin insecticides were detected. knockdown was more rapid with deltamethrin and alphacypermethrin than with permethrin across the study sites considering their KDT50 and KDT95. The frequency of the resistant phenotypes ranged from 35.14 to 55.3% across the study sites with a net of 45.1% resistant phenotype recorded in this study. The 1014F allelic frequency calculated from Hardy-Weinberg principle for vector populations across the study sites ranged from 0.500 (50.00%) to 0.7763 (77.63%). All populations witnessed significant (p < 0.05) deviations from Hardy-Weinberg equilibrium in the distribution of these alleles. The findings of this study show that there is a tendency to record an entire population of resistant vectors in this study area over time due to natural selection. The public health implication of these findings is that the use of pyrethroid based aerosols, coils, sprays, LLITNs and others for the purpose of controlling vectors of lymphatic filariasis and other diseases may be effort in futility.
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Affiliation(s)
- Martina Anurika Okafor
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Ndifreke Daniel Ekpo
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria.
| | - Kenneth Nnamdi Opara
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Nsima Ibanga Udoidung
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Farid S Ataya
- Department of Biochemistry, College of Science, King Saud University, PO Box 2455, 11451, Riyadh, Saudi Arabia.
| | - Clement Ameh Yaro
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria.
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, AlBeheira, 22511, Egypt
| | - Athanasios Alexiou
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham, NSW, 2770, Australia
- AFNP Med, 1030, Wien, Austria
| | - Marios Papadakis
- Department of Surgery II, University Hospital Witten-Herdecke, University of Witten-Herdecke, Heusnerstrasse 40, 42283, Wuppertal, Germany.
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Tia IZ, Barreaux AMG, Oumbouke WA, Koffi AA, Ahoua Alou LP, Camara S, Wolie RZ, Sternberg ED, Dahounto A, Yapi GY, Thomas MB, N'Guessan R. Efficacy of a 'lethal house lure' against Culex quinquefasciatus from Bouaké city, Côte d'Ivoire. Parasit Vectors 2023; 16:300. [PMID: 37641104 PMCID: PMC10463874 DOI: 10.1186/s13071-023-05883-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 07/14/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND Eave tube technology is a novel method of insecticide application that uses an electrostatic coating system to boost insecticide efficacy against resistant mosquitoes. A series of previous experiments showed encouraging insecticidal effects against malaria vectors. This study was undertaken to assess the effects of the eave tube approach on other Culicidae, in particular Culex quinquefasciatus, under laboratory and semi-field conditions. METHODS Larvae of Cx. quinquefasciatus from Bouaké were collected and reared to adult stage, and World Health Organization (WHO) cylinder tests were performed to determine their resistance status. WHO standard 3-min cone bioassays were conducted using PermaNet 2.0 netting versus eave tube-treated inserts. To assess the transient exposure effect on Cx. quinquefasciatus, eave tube assay utilizing smelly socks as attractant was performed with exposure time of 30 s, 1 min, and 2 min on 10% beta-cyfluthrin-treated inserts. Residual activity of these treated inserts was then monitored over 9 months. Field tests involving release-recapture of Cx. quinquefasciatus within enclosures around experimental huts fitted with windows and untreated or insecticide-treated eave tubes were conducted to determine house entry preference and the impact of tubes on the survival of this species. RESULTS Bouaké Cx. quinquefasciatus displayed high resistance to three out of four classes of insecticides currently used in public health. After 3 min of exposure in cone tests, 10% beta-cyfluthrin-treated inserts induced 100% mortality in Cx. quinquefasciatus, whereas the long-lasting insecticidal net (LLIN) only killed 4.5%. With reduced exposure time on the eave tube insert, mortality was still 100% after 2 min, 88% after 1 min, and 44% after 30 s. Mortality following 1 h exposure on 10% beta-cyfluthrin-treated insert was > 80% continuously up to 7 months post-treatment. Data suggest that Cx. quinquefasciatus have a stronger preference for entering a house through the eaves than through windows. Beta-cyfluthrin-treated inserts were able to kill 51% of resistant Cx. quinquefasciatus released within the enclosure. CONCLUSIONS Eave tubes are a novel method for delivery of insecticide to the house. They attract nuisance host-seeking Cx. quinquefasciatus mosquitoes and are as effective in controlling them as they are against pyrethroid-resistant Anopheles gambiae, despite the high level of resistance Cx. quinquefasciatus have developed.
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Affiliation(s)
- Innocent Z Tia
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire.
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire.
- Université Alassane Ouattara, Bouaké, Côte d'Ivoire.
- Centre d'Entomologie Médical et Vétérinaire (CEMV), Bouaké, Côte d'Ivoire.
| | - Antoine M G Barreaux
- Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), 34398, Montpellier, France
| | - Welbeck A Oumbouke
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L35 QA, UK
| | - Alphonsine A Koffi
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Ludovic P Ahoua Alou
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Soromane Camara
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Rosine Z Wolie
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
- Unité de Recherche et de Pédagogie de Génétique, UFR Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Eleanore D Sternberg
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L35 QA, UK
| | - Amal Dahounto
- Laboratoire de Bio-Mathématique et d'Estimation Forestière, Université d'Abomey Calavi, Cotonou, Bénin
| | - Gregoire Y Yapi
- Université Alassane Ouattara, Bouaké, Côte d'Ivoire
- Centre d'Entomologie Médical et Vétérinaire (CEMV), Bouaké, Côte d'Ivoire
| | | | - Raphael N'Guessan
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire. raphael.n'
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire. raphael.n'
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK. raphael.n'
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8
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Talipouo A, Doumbe-Belisse P, Ngadjeu CS, Djamouko-Djonkam L, Nchoutpouen E, Bamou R, Sonhafouo-Chiana N, Mayi APM, Dadji Foko GA, Awono-Ambene P, Kekeunou S, Wondji CS, Antonio-Nkondjio C. Larviciding intervention targeting malaria vectors also affects Culex mosquito distribution in the city of Yaoundé, Cameroon. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2023; 4:100136. [PMID: 37693015 PMCID: PMC10491826 DOI: 10.1016/j.crpvbd.2023.100136] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 07/20/2023] [Accepted: 07/21/2023] [Indexed: 09/12/2023]
Abstract
Although Culex species are considered to be equally affected by control measures targeting malaria vectors, there is still not enough evidence of the impact of interventions such as larviciding on the distribution of these mosquito species. The present study assessed the impact of a larviciding trial targeting malaria vectors on Culex mosquito species in the city of Yaoundé, Cameroon. A cluster randomized trial comparing 13 treated clusters and 13 untreated clusters was implemented. Data were collected at baseline and during the larviciding intervention, from March 2017 to November 2020. The microbial larvicide VectoMax G was applied once every 2 weeks in the intervention areas. Adult mosquitoes were collected using CDC light traps in both intervention and non-intervention areas and compared between arms. Globally, larviciding intervention was associated with 69% reduction in aquatic habitats with Culex larvae and 36.65% reduction of adult Culex densities in houses. Adult Culex densities were reduced both indoors (35.26%) and outdoors (42.37%). No change in the composition of Culex species was recorded. The study suggests a high impact of larviciding on Culex mosquito species distribution. The impact of the intervention can be improved if typical Culex breeding habitats including pit latrines are targeted.
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Affiliation(s)
- Abdou 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, Cameroon
- Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Patricia 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, Cameroon
- Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Carmène 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, Cameroon
- Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, 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
- Faculty of Sciences, University of Dschang, Box 337, Dschang, Cameroon
| | - Elysée Nchoutpouen
- Centre for Research in Infectious Disease (CRID), Yaoundé, P.O. Box 13591, Cameroon
| | - 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
- Faculty of Sciences, University of Dschang, Box 337, Dschang, Cameroon
| | - Nadège 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 Health Sciences, University of Buea, Buea, Cameroon
| | - Audrey Paul Marie Mayi
- 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 Sciences, University of Dschang, Box 337, Dschang, Cameroon
| | - Gisèle Aurélie Dadji Foko
- Laboratory of Zoology, Higher Teacher Training College, University of Yaoundé I, P.O. Box 47, 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
| | - Sévilor Kekeunou
- Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Charles S. Wondji
- Centre for Research in Infectious Disease (CRID), Yaoundé, P.O. Box 13591, 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
- Vector Biology Liverpool School of Tropical Medicine Pembroke Place, Liverpool, L3 5QA, UK
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9
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Fillinger U, Denz A, Njoroge MM, Tambwe MM, Takken W, van Loon JJA, Moore SJ, Saddler A, Chitnis N, Hiscox A. A randomized, double-blind placebo-control study assessing the protective efficacy of an odour-based 'push-pull' malaria vector control strategy in reducing human-vector contact. Sci Rep 2023; 13:11197. [PMID: 37433881 DOI: 10.1038/s41598-023-38463-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 07/08/2023] [Indexed: 07/13/2023] Open
Abstract
Novel malaria vector control strategies targeting the odour-orientation of mosquitoes during host-seeking, such as 'attract-and-kill' or 'push-and-pull', have been suggested as complementary tools to indoor residual spraying and long-lasting insecticidal nets. These would be particularly beneficial if they can target vectors in the peri-domestic space where people are unprotected by traditional interventions. A randomized double-blind placebo-control study was implemented in western Kenya to evaluate: a 'push' intervention (spatial repellent) using transfluthrin-treated fabric strips positioned at open eave gaps of houses; a 'pull' intervention placing an odour-baited mosquito trap at a 5 m distance from a house; the combined 'push-pull' package; and the control where houses contained all elements but without active ingredients. Treatments were rotated through 12 houses in a randomized-block design. Outdoor biting was estimated using human landing catches, and indoor mosquito densities using light-traps. None of the interventions provided any protection from outdoor biting malaria vectors. The 'push' reduced indoor vector densities dominated by Anopheles funestus by around two thirds. The 'pull' device did not add any benefit. In the light of the high Anopheles arabiensis biting densities outdoors in the study location, the search for efficient outdoor protection and effective pull components needs to continue.
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Affiliation(s)
- Ulrike Fillinger
- International Centre of Insect Physiology and Ecology (Icipe), Human Health Theme, Nairobi, 00100, Kenya.
| | - Adrian Denz
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwil, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
| | - Margaret M Njoroge
- International Centre of Insect Physiology and Ecology (Icipe), Human Health Theme, Nairobi, 00100, Kenya
- Laboratory of Entomology, Wageningen University & Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
| | - Mohamed M Tambwe
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwil, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
- Vector Control Product Testing Unit (VCPTU), Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Willem Takken
- Laboratory of Entomology, Wageningen University & Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
| | - Joop J A van Loon
- Laboratory of Entomology, Wageningen University & Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
| | - Sarah J Moore
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwil, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
- Vector Control Product Testing Unit (VCPTU), Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
- The Nelson Mandela African Institution of Science and Technology (NM-AIST), Tengeru, P.O. Box 447, Arusha, Tanzania
| | - Adam Saddler
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwil, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
- Vector Control Product Testing Unit (VCPTU), Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
- Telethon Kids Institute, Perth, Australia
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwil, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
| | - Alexandra Hiscox
- Laboratory of Entomology, Wageningen University & Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
- Arctech Innovation Ltd., The Cube, Londoneast-Uk Business and Technical Park, Yew Tree Avenue, Dagenham, RM10 7FN, UK
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10
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Koh C, Frangeul L, Blanc H, Ngoagouni C, Boyer S, Dussart P, Grau N, Girod R, Duchemin JB, Saleh MC. Ribosomal RNA (rRNA) sequences from 33 globally distributed mosquito species for improved metagenomics and species identification. eLife 2023; 12:82762. [PMID: 36688360 PMCID: PMC10014081 DOI: 10.7554/elife.82762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 01/19/2023] [Indexed: 01/24/2023] Open
Abstract
Total RNA sequencing (RNA-seq) is an important tool in the study of mosquitoes and the RNA viruses they vector as it allows assessment of both host and viral RNA in specimens. However, there are two main constraints. First, as with many other species, abundant mosquito ribosomal RNA (rRNA) serves as the predominant template from which sequences are generated, meaning that the desired host and viral templates are sequenced far less. Second, mosquito specimens captured in the field must be correctly identified, in some cases to the sub-species level. Here, we generate mosquito rRNA datasets which will substantially mitigate both of these problems. We describe a strategy to assemble novel rRNA sequences from mosquito specimens and produce an unprecedented dataset of 234 full-length 28S and 18S rRNA sequences of 33 medically important species from countries with known histories of mosquito-borne virus circulation (Cambodia, the Central African Republic, Madagascar, and French Guiana). These sequences will allow both physical and computational removal of rRNA from specimens during RNA-seq protocols. We also assess the utility of rRNA sequences for molecular taxonomy and compare phylogenies constructed using rRNA sequences versus those created using the gold standard for molecular species identification of specimens-the mitochondrial cytochrome c oxidase I (COI) gene. We find that rRNA- and COI-derived phylogenetic trees are incongruent and that 28S and concatenated 28S+18S rRNA phylogenies reflect evolutionary relationships that are more aligned with contemporary mosquito systematics. This significant expansion to the current rRNA reference library for mosquitoes will improve mosquito RNA-seq metagenomics by permitting the optimization of species-specific rRNA depletion protocols for a broader range of species and streamlining species identification by rRNA sequence and phylogenetics.
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Affiliation(s)
- Cassandra Koh
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, F-75015ParisFrance
| | - Lionel Frangeul
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, F-75015ParisFrance
| | - Hervé Blanc
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, F-75015ParisFrance
| | - Carine Ngoagouni
- Institut Pasteur de Bangui, Medical Entomology LaboratoryBanguiCentral African Republic
| | - Sébastien Boyer
- Institut Pasteur du Cambodge, Medical and Veterinary Entomology UnitPhnom PenhCambodia
| | | | - Nina Grau
- Institut Pasteur de Madagascar, Medical Entomology UnitAntananarivoMadagascar
| | - Romain Girod
- Institut Pasteur de Madagascar, Medical Entomology UnitAntananarivoMadagascar
| | - Jean-Bernard Duchemin
- Institut Pasteur de la Guyane, Vectopôle Amazonien Emile AbonnencCayenneFrench Guiana
| | - Maria-Carla Saleh
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, F-75015ParisFrance
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11
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Hadidy DE, El Sayed AM, Tantawy ME, Alfy TE, Farag SM, Haleem DRA. Larvicidal and repellent potential of Ageratum houstonianum against Culex pipiens. Sci Rep 2022; 12:21410. [PMID: 36496475 PMCID: PMC9741651 DOI: 10.1038/s41598-022-25939-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
Mosquitoes are unquestionably the most medic arthropod vectors of disease. Culex pipiens, usually defined as a common house mosquito, is a well-known carrier of several virus diseases. Crude ethanol extracts of different organs of Agratum houstonianum are tested with Culex pipiens Linnaeus (Diptera: Culicidae) to determine their larvicidal, antifeedant, and repellency effects. Alongside biochemical analysis, the activity of the AChE, ATPase, CarE, and CYP-450 is detected in the total hemolymph of the C. pipiens larvae to examine the enzymatic action on the way to explain their neurotoxic effect and mode of action. Through HPLC and GC-MS analysis of the phytochemical profile of A. houstonianum aerial parts is identified. The larvicidal activity of aerial parts; flower (AF), leaf (AL), and stem (AS) of A. houstonianum extracts are evaluated against the 3rd instar larvae of C. pipiens at 24-, 48- and 72-post-treatment. A. houstonianium AF, AL, and AS extracts influenced the mortality of larvae with LC50 values 259.79, 266.85, and 306.86 ppm, respectively after 24 h of application. The potency of AF and AL extracts was 1.69- and 1.25-folds than that of AS extract, respectively. A high repellency percentage was obtained by AF extract 89.10% at a dose of 3.60 mg/cm2. A. houstonianium AF prevailed inhibition on acetylcholinesterase and decrease in carboxylesterase activity. Moreover, a significant increase in the ATPase levels and a decrease in cytochrome P-450 monooxegenase activity (- 36.60%) are detected. HPLC analysis prevailed chlorogenic and rosmarinic acid as the major phenolic acids in AL and AF, respectively. GC-MS analysis of A. houstonianum results in the identification of phytol as the major makeup. Precocene I and II were detected in AF. Linoleic, linolenic, and oleic acid were detected in comparable amounts in the studied organs. Overall, results suggest that the A. houstonianum flower extract (AF) exhibits significant repellent, antifeedant, and larvicidal activities.
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Affiliation(s)
- Doaa El Hadidy
- grid.419698.bDepartment of Medicinal Plants and Natural Products, National Organization for Drug Control and Research (NODCAR), 51-Wezaret El-Zeraa St, Giza, 12611 Egypt
| | - Abeer M. El Sayed
- grid.7776.10000 0004 0639 9286Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, Kasr El Aini, 11562 Egypt
| | - Mona El Tantawy
- grid.419698.bDepartment of Medicinal Plants and Natural Products, National Organization for Drug Control and Research (NODCAR), 51-Wezaret El-Zeraa St, Giza, 12611 Egypt
| | - Taha El Alfy
- grid.7776.10000 0004 0639 9286Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, Kasr El Aini, 11562 Egypt
| | - Shaimaa M. Farag
- grid.7269.a0000 0004 0621 1570Department of Entomology, Faculty of Science, Ain Shams University, Cairo, 11566 Egypt
| | - Doaa R. Abdel Haleem
- grid.7269.a0000 0004 0621 1570Department of Entomology, Faculty of Science, Ain Shams University, Cairo, 11566 Egypt
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12
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Chamnanya S, Yanola J, Nachaiwieng W, Lumjuan N, Walton C, Somboon P. Novel real-time PCR assay detects widespread distribution of knock down resistance (kdr) mutations associated with pyrethroid resistance in the mosquito, Culex quinquefasciatus, in Thailand. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 186:105172. [PMID: 35973764 DOI: 10.1016/j.pestbp.2022.105172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/30/2022] [Accepted: 07/05/2022] [Indexed: 06/15/2023]
Abstract
Susceptibility to pyrethroids in the mosquito Culex quinquefasciatus, the major vector of lymphatic filariasis, is being seriously threatened worldwide. Knockdown resistance (kdr), caused by mutations in the voltage gated sodium channel (VGSC) gene, particularly the L1014F mutation, is an important resistance mechanism. Our aim was to develop a real-time PCR with melt curve analysis to evaluate the distribution of the L1014F mutation in Cx. quinquefasciatus throughout Thailand and to determine the polymorphism pattern of a VGSC gene fragment spanning the L1014F mutation. A total of 3760 females from 18 localities across five regions of Thailand were bio-assayed by exposure to 0.05% deltamethrin WHO papers, showing mortality rates ranging from 2.4% to 83.0%. Genotyping of 753 dead and surviving mosquitoes using our novel real-time PCR assay with melt curve analysis and tetra-primer allele-specific PCR revealed the mutant F1014 allele is closely associated with the deltamethrin resistance phenotype. The L1014F mutation was found at high frequency throughout Thailand, particularly in the North. However, some survivors were homozygous for wild type L1014 allele, which were further sequenced for the IIP-IIS6 region of VGSC gene. The haplotype network of phenotypically characterized individuals indicated the presence of other possible kdr alleles/resistance mechanisms at play including two novel mutations, V978E and D992E. The finding of new putative kdr alleles and widespread distribution of the F1014 allele emphasizes the significant role of kdr mutations in pyrethroid resistance in Thai Cx. quinquefasciatus populations. Monitoring kdr variations and phenotypic resistance is critical for managing resistance in Cx. quinquefasciatus.
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Affiliation(s)
- Saowanee Chamnanya
- Department of Parasitology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Jintana Yanola
- Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand.
| | | | - Nongkran Lumjuan
- Research Institute for Health Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Catherine Walton
- Department of Earth and Environmental Sciences, School of Natural Sciences, Faculty of Science and Engineering, University of Manchester, Manchester M13 9PT, United Kingdom.
| | - Pradya Somboon
- Department of Parasitology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
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David Forfuet F, Mayi MPA, Fru-Cho J, Kowo C, Nota Anong D, Esack Fonda A, Djomo C, Tchuinkam T, Brisco KK, Sehgal R, John Cornel A. Efficacy of Trapping Methods in the Collection of Eretmapodites (Diptera: Culicidae) Mosquitoes in an Afrotropical Rainforest Region, South western Cameroon. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1394-1403. [PMID: 35640028 DOI: 10.1093/jme/tjac060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Indexed: 06/15/2023]
Abstract
Very little data exist on the biology of an afrotropical rainforest mosquito Eretmapodites (Er.) in a world undergoing dramatic changes due to deforestation. The aim was to assess the efficacy of different trapping methods in the collection of Er. mosquito in forested area. This was a longitudinal study involving collection of mosquitoes for over two years. Multiple collection methods (grouped into two categories), were used; i) net baited and un-baited traps to collect adults, ii) techniques that target immature stages subsequently reared to adults. All males were identified by genitalia dissection. Five thousand seven hundred and four mosquitoes representing 11 genera among which 2,334 Er. were identified. Mosquito abundance was highest in the net traps (n = 1276 (56.4%)) and sweep nets (n = 393(17.4%)) respectively. The abundance was highest in green colored net traps (435(34.09%)) with significant value of χ2= 40.000, P < 0.001 and in pigeons baited traps (473 (37.06%)) with significant value of χ2= 42.000, P = 0.003. The diversity ranges from H' = 2.65; DS = 0.84; SR = 24; ACE = 24.77 in sweep net to H' = 0; DS = 0; SR = 1; ACE = 1 in rock pool among males mosquitoes. While for females, H = 1.14; DS = 0.71; SR = 5; ACE = 5.16, in sweep net to H = 0; DS = 0; SR = 1; ACE = 1 in rock pool, tarpaulin, resting cage. Net traps, bamboo pot, and sweep netting are efficient in collecting high abundance of forest mosquitoes in the Talanagaye rainforest.
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Affiliation(s)
| | - Marie Paul Audrey Mayi
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Sciences of the University of Dschang, Cameroon
| | - Jerome Fru-Cho
- Department of Microbiology and Parasitology, University of Buea, Cameroon
| | - Cyril Kowo
- Department of Microbiology and Parasitology, University of Buea, Cameroon
| | - Damian Nota Anong
- Department of Microbiology and Parasitology, University of Buea, Cameroon
| | | | - Charlene Djomo
- Higher Institute of Environmental Science, Department of Environmental Health, PO Box 35460, Yaounde, Cameroon
| | - Timoleon Tchuinkam
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Sciences of the University of Dschang, Dschang, Cameroon
| | - Katherine K Brisco
- Mosquito Control Research Laboratory, Department of Entomology and Nematology and Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology, University of California at Davis, Parlier, CA, USA
| | - Ravinder Sehgal
- Department of Biology, San Francisco State University, San Francisco, CA, USA
| | - Anthony John Cornel
- Mosquito Control Research Laboratory, Department of Entomology and Nematology and Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology, University of California at Davis, Parlier, CA, USA
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14
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Omotayo AI, Dogara MM, Sufi D, Shuaibu T, Balogun J, Dawaki S, Muktar B, Adeniyi K, Garba N, Namadi I, Adam HA, Adamu S, Abdullahi H, Sulaiman A, Oduola AO. High pyrethroid-resistance intensity in Culex quinquefasciatus (Say) (Diptera: Culicidae) populations from Jigawa, North-West, Nigeria. PLoS Negl Trop Dis 2022; 16:e0010525. [PMID: 35727843 PMCID: PMC9249174 DOI: 10.1371/journal.pntd.0010525] [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: 02/01/2022] [Revised: 07/01/2022] [Accepted: 05/20/2022] [Indexed: 11/26/2022] Open
Abstract
This study examined pyrethroid resistance intensity and mechanisms in Culex quinquefasciatus (Say) (Diptera: Culicidae) populations from Jigawa, North-West Nigeria. Resistance statuses to permethrin, lambda-cyhalothrin and alphacypermethrin were determined with both WHO and CDC resistance bioassays. Synergist assay was conducted by pre-exposing the populations to Piperonyl butoxide (PBO) using the WHO method. Resistance intensities to 2x, 5x and 10x of diagnostic concentrations were determined with the CDC bottle method. Species analysis and presence of knockdown mutation (Leu-Phe) were done using Polymerase Chain Reaction (PCR). Results showed that Cx. quinquefasciatus was the only Culex spp. present and “Kdr-west” mutation was not detected in all analyzed samples. Using WHO method, Cx. quinquefasciatus resistance to permethrin was detected in Dutse (12.2%) and Kafin-Hausa (77.78%). Lambda-cyhalothrin resistance was recorded only in Kafin-Hausa (83.95%) with resistance suspected in Ringim (90%). Resistance to alphacypermethrin was recorded in all locations. Pre-exposure to PBO led to 100% mortality to alphacypermethrin and lambda-cyhalothrin in Ringim while mortality to permethrin and alphacypermethrin in Dutse increased from 12.2% to 97.5% and 64.37% to 79.52% respectively. Using CDC bottle bioassay, resistance was also recorded in all populations and the result shows a significant positive correlation (R2 = 0.728, p = 0.026) with the result from the WHO bioassay. Results of resistance intensity revealed a very high level of resistance in Kafin-Hausa with susceptibility to lambda-cyhalothrin and alphacypermethrin not achieved at 10x of diagnostic doses. Resistance intensity was also high in Dutse with susceptibility to all insecticides not achieved at 5x of diagnostic doses. Widespread and high intensity of resistance in Cx. quinquefasciatus from North-West Nigeria is a major threat to the control of diseases transmitted by Culex and other mosquito species. It is a challenge that needs to be adequately addressed so as to prevent the failure of pyrethroid-based vector control tools. Development of resistance to insecticide by mosquitoes has been identified to be a major challenge in the prevention and control of diseases transmitted by mosquitoes. This informs this study that investigated the level of resistance of Culex mosquitoes from Jigawa, North-West Nigeria to Pyrethroids. The main type of Culex mosquitoes found in the sampled area was Cx. quinquefasciatus. The Cx. quinquefasciatus populations were found to be resistant to permethrin, lambda-cyhalothrin and alphacypermethrin. Resistance in Cx. quinquefasciatus from the three LGAs is more pronounced to alphacypermethrin. The methods employed by the mosquitoes in developing resistance involve detoxification of the insecticides by metabolic enzymes. Cx. quinquefasciatus from the three LGAs were observed to be highly resistant and can withstand multiple of the recommended doses. This development whereby Cx. quinquefasciatus populations were highly resistant to these recommended insecticides is of serious concern as it can lead to failure of all efforts geared towards prevention and control of diseases transmitted by Culex mosquitoes in North-West Nigeria.
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Affiliation(s)
- Ahmed Idowu Omotayo
- Molecular Entomology and Vector Control Research Laboratory, Department of Public Health and Epidemiology, Nigeria Institute of Medical Research, Yaba, Lagos, Nigeria
- Department of Zoology, Faculty of Life Sciences, University of Ilorin, Ilorin, Kwara State, Nigeria
- * E-mail:
| | - Musa Mustapha Dogara
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Danjuma Sufi
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Tasiu Shuaibu
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Joshua Balogun
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Salwa Dawaki
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Bature Muktar
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Kamoru Adeniyi
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Nura Garba
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Isah Namadi
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Hafiz Abdullahi Adam
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Shuaibu Adamu
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Hamza Abdullahi
- Department of Biological Sciences, Federal University Kashere, Gombe State, Nigeria
| | - Abubakar Sulaiman
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
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15
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Sonhafouo-Chiana N, Nkahe LD, Kopya E, Awono-Ambene PH, Wanji S, Wondji CS, Antonio-Nkondjio C. Rapid evolution of insecticide resistance and patterns of pesticides usage in agriculture in the city of Yaoundé, Cameroon. Parasit Vectors 2022; 15:186. [PMID: 35655243 PMCID: PMC9164381 DOI: 10.1186/s13071-022-05321-8] [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: 01/03/2022] [Accepted: 05/11/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The practice of agriculture in urban settings contributes to the rapid expansion of insecticide resistance in malaria vectors. However, there is still not enough information on pesticide usage in most urban settings. The present study aims to assess the evolution of Anopheles gambiae (s.l.) population susceptibility to insecticides and patterns of pesticide usage in agriculture in the city of Yaoundé, Cameroon. METHODS WHO susceptibility tests and synergist PBO bioassays were conducted on adult An. gambiae (s.l.) mosquitoes aged 3 to 5 days emerging from larvae collected from the field. Seven insecticides (deltamethrin, permethrin, DDT, bendiocarb, propoxur, fenitrothion and malathion) were evaluated. The presence of target site mutation conferring knockdown (kdr) resistance was investigated using TaqMan assay, and mosquito species were identified using SINE-PCR. Surveys on 81 retailers and 232 farmers were conducted to assess general knowledge and practices regarding agricultural pesticide usage. RESULTS High resistance intensity to pyrethroids was observed with a high frequency of the kdr allele 1014F and low frequency of the kdr 1014S allele. The level of susceptibility of An. gambiae (s.l.) to pyrethroids and carbamates was found to decrease with time (from > 34% in 2017 to < 23% in 2019 for deltamethrin and permethrin and from 97% in 2017 to < 86% in 2019 for bendiocarb). Both An. gambiae (s.s.) and An. coluzzii were recorded. Over 150 pesticides and fertilizers were sold by retailers for agricultural purposes in the city of Yaoundé. Most farmers do not respect safety practices. Poor practices including extensive and inappropriate application of pesticides as well as poor management of perished pesticides and empty pesticide containers were also documented. CONCLUSIONS The study indicated rapid evolution of insecticide resistance and uncontrolled usage of pesticides by farmers in agriculture. There is an urgent need to address these gaps to improve the management of insecticide resistance.
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Affiliation(s)
- Nadège Sonhafouo-Chiana
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Leslie Diane Nkahe
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Edmond Kopya
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Parfait Herman Awono-Ambene
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon
| | - Samuel Wanji
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), P.O. Box 474, Buea, 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
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon
- Vector Biology, Liverpool School of Tropical medicine, Pembroke Place, Liverpool, L3 5QA UK
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16
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Identification and virtual based screening of the bioinsecticidal potential of Metarhizium anisopliae destruxins as inhibitors of Culex quinquefasciatus chitinase activity. Biologia (Bratisl) 2022. [DOI: 10.1007/s11756-022-01103-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Zamble BZH, Yao SS, Adja AM, Bakli M, Zoh DD, Mathieu-Daudé F, Assi SB, Remoue F, Almeras L, Poinsignon A. First evaluation of antibody responses to Culex quinquefasciatus salivary antigens as a serological biomarker of human exposure to Culex bites: A pilot study in Côte d'Ivoire. PLoS Negl Trop Dis 2021; 15:e0010004. [PMID: 34898609 PMCID: PMC8699949 DOI: 10.1371/journal.pntd.0010004] [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: 07/23/2021] [Revised: 12/23/2021] [Accepted: 11/17/2021] [Indexed: 12/03/2022] Open
Abstract
Background Culex mosquitoes are vectors for a variety of pathogens of public health concern. New indicators of exposure to Culex bites are needed to evaluate the risk of transmission of associated pathogens and to assess the efficacy of vector control strategies. An alternative to entomological indices is the serological measure of antibodies specific to mosquito salivary antigens. This study investigated whether the human IgG response to both the salivary gland extract and the 30 kDa salivary protein of Culex quinquefasciatus may represent a proxy of human exposure to Culex bites. Methodology/Principal findings A multidisciplinary survey was conducted with children aged 1 to 14 years living in neighborhoods with varying exposure to Culex quinquefasciatus in the city of Bouaké, Côte d’Ivoire. Children living in sites with high exposure to Cx quinquefasciatus had a significantly higher IgG response to both salivary antigens compared with children living in the control site where only very few Culex were recorded. Moreover, children from any Culex-high exposed sites had significantly higher IgG responses only to the salivary gland extract compared with children from the control village, whereas no difference was noted in the anti-30 kDa IgG response. No significant differences were noted in the specific IgG responses between age and gender. Sites and the use of a bed net were associated with the level of IgG response to the salivary gland extract and to the 30 kDa antigen, respectively. Conclusions/Significance These findings suggest that the IgG response to Culex salivary gland extracts is suitable as proxy of exposure; however, the specificity to the Culex genus needs further investigation. The lower antigenicity of the 30 kDa recombinant protein represents a limitation to its use. The high specificity of this protein to the Culex genus makes it an attractive candidate and other specific antibody responses might be more relevant as a biomarker of exposure. These epidemiological observations may form a starting point for additional work on developing serological biomarkers of Culex exposure. The evaluation of exposure to mosquitoes is a key parameter in assessing the risk of transmission of associated pathogens, including zoonoses. Entomological methods represent the gold standard but have several limitations, and efforts are being made to develop new indicators to accurately assess human–Culex contact. This study showed the IgG response to Culex quinquefasciatus salivary gland extract is suitable proxy of exposure to Culex bites. The lower antigenicity of the 30 kDa recombinant protein represents a limitation to its use. The high specificity of this protein to the Culex genus makes it an attractive candidate and other isotypic antibody responses specific to this salivary antigen might be more relevant as a biomarker of exposure.
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Affiliation(s)
- Bi Zamble H. Zamble
- Institut Pierre Richet / Institut National de Santé Publique, Bouaké, Côte d’Ivoire
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
- * E-mail:
| | - Serge S. Yao
- Institut Pasteur de Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Akré M. Adja
- Institut Pierre Richet / Institut National de Santé Publique, Bouaké, Côte d’Ivoire
- UFR Biosciences, University Felix Houphouët Boigny, Abidjan, Côte d’Ivoire
| | | | - Dounin D. Zoh
- Institut Pierre Richet / Institut National de Santé Publique, Bouaké, Côte d’Ivoire
- UFR Biosciences, University Felix Houphouët Boigny, Abidjan, Côte d’Ivoire
| | | | - Serge B. Assi
- Institut Pierre Richet / Institut National de Santé Publique, Bouaké, Côte d’Ivoire
- Programme National de Lutte contre le Paludisme, Abidjan, Côte d’Ivoire
| | - Franck Remoue
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
| | - Lionel Almeras
- IHU Méditerranée Infection, Marseille, France
- Unité Parasitologie et Entomologie, Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France
- Aix Marseille Univ, IRD, SSA, AP-HM, VITROME, Marseille, France
| | - Anne Poinsignon
- Institut Pierre Richet / Institut National de Santé Publique, Bouaké, Côte d’Ivoire
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
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18
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Bamou R, Mayi MPA, Djiappi-Tchamen B, Nana-Ndjangwo SM, Nchoutpouen E, Cornel AJ, Awono-Ambene P, Parola P, Tchuinkam T, Antonio-Nkondjio C. An update on the mosquito fauna and mosquito-borne diseases distribution in Cameroon. Parasit Vectors 2021; 14:527. [PMID: 34635176 PMCID: PMC8507310 DOI: 10.1186/s13071-021-04950-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 08/12/2021] [Indexed: 11/10/2022] Open
Abstract
The expansion of mosquito-borne diseases such as dengue, yellow fever, and chikungunya in the past 15 years has ignited the need for active surveillance of common and neglected mosquito-borne infectious diseases. The surveillance should be designed to detect diseases and to provide relevant field-based data for developing and implementing effective control measures to prevent outbreaks before significant public health consequences can occur. Mosquitoes are important vectors of human and animal pathogens, and knowledge on their biodiversity and distribution in the Afrotropical region is needed for the development of evidence-based vector control strategies. Following a comprehensive literature search, an inventory of the diversity and distribution of mosquitoes as well as the different mosquito-borne diseases found in Cameroon was made. A total of 290 publications/reports and the mosquito catalogue website were consulted for the review. To date, about 307 species, four subspecies and one putative new species of Culicidae, comprising 60 species and one putative new species of Anopheles, 67 species and two subspecies of Culex, 77 species and one subspecies of Aedes, 31 species and one subspecies of Eretmapodites, two Mansonia, eight Coquillettidia, and 62 species with unknown medical and veterinary importance (Toxorhynchites, Uranotaenia, Mimomyia, Malaya, Hodgesia, Ficalbia, Orthopodomyia, Aedeomyia, and Culiseta and Lutzia) have been collected in Cameroon. Multiple mosquito species implicated in the transmission of pathogens within Anopheles, Culex, Aedes, Eretmapodites, Mansonia, and Coquillettidia have been reported in Cameroon. Furthermore, the presence of 26 human and zoonotic arboviral diseases, one helminthic disease, and two protozoal diseases has been reported. Information on the bionomics, taxonomy, and distribution of mosquito species will be useful for the development of integrated vector management programmes for the surveillance and elimination of mosquito-borne diseases in Cameroon. ![]()
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Affiliation(s)
- Roland Bamou
- 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. .,Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon. .,Aix Marseille Univ, IRD, SSA, AP-HM, UMR Vecteurs-Infections Tropicales et Méditerranéennes (VITROME), Marseille, France. .,IHU Méditerranée Infection, Marseille, France.
| | - Marie Paul Audrey Mayi
- 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
| | - Borel Djiappi-Tchamen
- 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.,Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | - Stella Mariette Nana-Ndjangwo
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon.,Laboratoire de Parasitologie et d'écologie, Université de Yaoundé 1, Yaoundé, Cameroun
| | - Elysée Nchoutpouen
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | - Antony John Cornel
- Department of Entomology and Nematology, Mosquito Control Research Laboratory, University of California, Davis, California, USA
| | - Parfait Awono-Ambene
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | - Phillipe Parola
- Aix Marseille Univ, IRD, SSA, AP-HM, UMR Vecteurs-Infections Tropicales et Méditerranéennes (VITROME), Marseille, France.,IHU Méditerranée Infection, Marseille, France
| | - Timoléon Tchuinkam
- 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
| | - Christophe Antonio-Nkondjio
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon.,Vector Biology Liverpool School of Tropical Medicine, Liverpool, UK
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19
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Badejo O, Skaldina O, Peräniemi S, Carrasco-Navarro V, Sorvari J. Phenotypic Plasticity of Common Wasps in an Industrially Polluted Environment in Southwestern Finland. INSECTS 2021; 12:insects12100888. [PMID: 34680656 PMCID: PMC8540993 DOI: 10.3390/insects12100888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/18/2021] [Accepted: 09/27/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Social insects are ecologically and economically important as ecosystem engineers, agricultural pest predators, pollinators, and seed dispersers. Many of the vespid wasps are social insects. Our study species, Common wasp Vespula vulgaris, is native to Finland and classified as invasive in some other parts of the world. The Common wasp have conspicuous yellow and black pigmentation. Their functions and activities in the environment expose the species to environmental pollutants and this study assessed the effect of heavy-metals on common wasps collected from the vicinity of a metal smelter in southwestern Finland. The samples collected were analyzed using various methods such as color morph categorization, electron microscopy, metal analysis, and energy dispersive X-ray analysis (EDX). The methods were used to understand the effects of metal pollution on the species and the adaptive response. Our results indicated phenotypic variation between common wasp samples across the pollution gradient and an adaptive melanin encapsulation process. Abstract Insects vary in the degree of their adaptability to environmental contamination. Determining the responses with phenotypic plasticity in ecologically important species in polluted environments will ease further conservation and control actions. Here, we investigated morphological characteristics such as body size, body mass, and color of the common wasp Vespula vulgaris in an industrially polluted environment, considering different levels of metal pollution, and we studied the localization of contaminants in the guts of wasps. We revealed some differences in morphological characteristics and melanization of wasps collected in habitats with high, moderate, and low levels of pollution. The results indicated that V. vulgaris from highly polluted environments had reduced melanin pigmentation on the face but increased melanin pigmentation on the 2nd tergite of the abdomen. In addition, with transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX), we found metal particles from the midgut of wasps originating from the polluted environment. Most of the particles were encapsulated with melanin pigment. This finding confirmed that in wasps, ingested metal particles are accumulated in guts and covered by melanin layers. Our data suggest that wasps can tolerate metal contamination but respond phenotypically with modification of their size, coloration, and probably with the directions of the melanin investments (immunity or coloration). Thus, in industrially polluted areas, wasps might probably survive by engaging phenotypic plasticity with no significant or visible impact on the population.
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Affiliation(s)
- Oluwatobi Badejo
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; (O.S.); (V.C.-N.)
- Correspondence: (O.B.); (J.S.); Tel.: +358-41-3150497 (J.S.)
| | - Oksana Skaldina
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; (O.S.); (V.C.-N.)
| | - Sirpa Peräniemi
- School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland;
| | - Victor Carrasco-Navarro
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; (O.S.); (V.C.-N.)
| | - Jouni Sorvari
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; (O.S.); (V.C.-N.)
- Department of Biology, University of Turku, FI-20014 Turku, Finland
- Correspondence: (O.B.); (J.S.); Tel.: +358-41-3150497 (J.S.)
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20
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Antonio-Nkondjio C, Doumbe-Belisse P, Djamouko-Djonkam L, Ngadjeu CS, Talipouo A, Kopya E, Bamou R, Mayi MPA, Sonhafouo-Chiana N, Nkahe DL, Tabue R, Fosah DA, Bigoga JD, Awono-Ambene P, Wondji CS. High efficacy of microbial larvicides for malaria vectors control in the city of Yaounde Cameroon following a cluster randomized trial. Sci Rep 2021; 11:17101. [PMID: 34429446 PMCID: PMC8385066 DOI: 10.1038/s41598-021-96362-z] [Citation(s) in RCA: 3] [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: 04/27/2021] [Accepted: 08/03/2021] [Indexed: 11/12/2022] Open
Abstract
The rapid expansion of insecticide resistance and outdoor malaria transmission are affecting the efficacy of current malaria control measures. In urban settings, where malaria transmission is focal and breeding habitats are few, fixed and findable, the addition of anti-larval control measures could be efficient for malaria vector control. But field evidences for this approach remains scarce. Here we provide findings of a randomized-control larviciding trial conducted in the city of Yaoundé that support the efficacy of this approach. A two arms random control trial design including 26 clusters of 2 to 4 km2 each (13 clusters in the intervention area and 13 in the non-intervention area) was used to assess larviciding efficacy. The microbial larvicide VectoMax combining Bacillus thuringiensis var israelensis (Bti) and Bacillus sphaericus in a single granule was applied every 2 weeks in all standing water collection points. The anopheline density collected using CDC light traps was used as the primary outcome, secondary outcomes included the entomological inoculation rate, breeding habitats with anopheline larvae, and larval density. Baseline entomological data collection was conducted for 17 months from March 2017 to July 2018 and the intervention lasted 26 months from September 2018 to November 2020. The intervention was associated with a reduction of 68% of adult anopheline biting density and of 79% of the entomological inoculation rate (OR 0.21; 95% CI 0.14-0.30, P < 0.0001). A reduction of 68.27% was recorded for indoor biting anophelines and 57.74% for outdoor biting anophelines. No impact on the composition of anopheline species was recorded. A reduction of over 35% of adult Culex biting densities was recorded. The study indicated high efficacy of larviciding for reducing malaria transmission intensity in the city of Yaoundé. Larviciding could be part of an integrated control approach for controlling malaria vectors and other mosquito species in the urban environment.
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Affiliation(s)
- Christophe Antonio-Nkondjio
- Laboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour La Lutte Contre Les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun.
- Department of Vector Biology, Liverpool School of Tropical Medicine Pembroke Place, Liverpool, L3 5QA, UK.
| | - P Doumbe-Belisse
- Laboratoire de Recherche Sur Le Paludisme, 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
- Laboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour La Lutte Contre Les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun
- 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
| | - C S Ngadjeu
- Laboratoire de Recherche Sur Le Paludisme, 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
| | - A Talipouo
- Laboratoire de Recherche Sur Le Paludisme, 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
- Laboratoire de Recherche Sur Le Paludisme, 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
| | - R Bamou
- Laboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour La Lutte Contre Les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun
- 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
| | - M P Audrey Mayi
- 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
| | - N Sonhafouo-Chiana
- Laboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour La Lutte Contre Les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun
- Faculty of Sciences, University of Buea, P.O. Box 63, Buea, Cameroon
| | - D L Nkahe
- Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - R Tabue
- Ministry of Public Health, National Malaria Control Programme, Yaoundé, Cameroon
| | - D Achu Fosah
- Ministry of Public Health, National Malaria Control Programme, Yaoundé, Cameroon
| | - Jude D Bigoga
- Laboratory for Vector Biology and Control, National Reference Unit for Vector Control, The Biotechnology Center, Nkolbisson-University of Yaounde I, P.O. Box 3851, Messa, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaounde I, Yaoundé, Cameroon
| | - P Awono-Ambene
- Laboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour La Lutte Contre Les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroun
| | - Charles S Wondji
- Department of Vector Biology, Liverpool School of Tropical Medicine Pembroke Place, Liverpool, L3 5QA, UK
- Centre for Research in Infectious Diseases, Yaoundé, Cameroon
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21
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Longo-Pendy NM, Tene-Fossog B, Tawedi RE, Akone-Ella O, Toty C, Rahola N, Braun JJ, Berthet N, Kengne P, Costantini C, Ayala D. Ecological plasticity to ions concentration determines genetic response and dominance of Anopheles coluzzii larvae in urban coastal habitats of Central Africa. Sci Rep 2021; 11:15781. [PMID: 34349141 PMCID: PMC8338965 DOI: 10.1038/s41598-021-94258-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 06/29/2021] [Indexed: 02/07/2023] Open
Abstract
In Central Africa, the malaria vector Anopheles coluzzii is predominant in urban and coastal habitats. However, little is known about the environmental factors that may be involved in this process. Here, we performed an analysis of 28 physicochemical characteristics of 59 breeding sites across 5 urban and rural sites in coastal areas of Central Africa. We then modelled the relative frequency of An. coluzzii larvae to these physicochemical parameters in order to investigate environmental patterns. Then, we assessed the expression variation of 10 candidate genes in An. coluzzii, previously incriminated with insecticide resistance and osmoregulation in urban settings. Our results confirmed the ecological plasticity of An. coluzzii larvae to breed in a large range of aquatic conditions and its predominance in breeding sites rich in ions. Gene expression patterns were comparable between urban and rural habitats, suggesting a broad response to ions concentrations of whatever origin. Altogether, An. coluzzii exhibits a plastic response to occupy both coastal and urban habitats. This entails important consequences for malaria control in the context of the rapid urban expansion in Africa in the coming years.
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Affiliation(s)
| | | | - Robert E. Tawedi
- grid.473396.cInstitut de Recherches Géologiques Et Minières / Centre de Recherches Hydrologiques, Yaoundé, Cameroon
| | | | - Celine Toty
- grid.462603.50000 0004 0382 3424MIVEGEC, Univ Montpellier, CNRS, IRD, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France
| | - Nil Rahola
- grid.462603.50000 0004 0382 3424MIVEGEC, Univ Montpellier, CNRS, IRD, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France
| | - Jean-Jacques Braun
- grid.473396.cInstitut de Recherches Géologiques Et Minières / Centre de Recherches Hydrologiques, Yaoundé, Cameroon ,grid.462928.30000 0000 9033 1612Géosciences Environnement Toulouse, Université de Toulouse, CNRS, IRD, Toulouse, France ,International Joint Laboratory DYCOFAC, IRGM-UY1-IRD, BP 1857, Yaoundé, Cameroon
| | - Nicolas Berthet
- grid.418115.80000 0004 1808 058XCIRMF, Franceville, Gabon ,grid.428999.70000 0001 2353 6535Institut Pasteur, Unité Environnement Et Risque Infectieux, Cellule D’Intervention Biologique D’Urgence, Paris, France
| | - Pierre Kengne
- grid.418115.80000 0004 1808 058XCIRMF, Franceville, Gabon ,grid.462603.50000 0004 0382 3424MIVEGEC, Univ Montpellier, CNRS, IRD, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France
| | - Carlo Costantini
- grid.462603.50000 0004 0382 3424MIVEGEC, Univ Montpellier, CNRS, IRD, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France
| | - Diego Ayala
- grid.418115.80000 0004 1808 058XCIRMF, Franceville, Gabon ,grid.462603.50000 0004 0382 3424MIVEGEC, Univ Montpellier, CNRS, IRD, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France
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Azlan A, Halim MA, Mohamad F, Azzam G. Identification and characterization of long noncoding RNAs and their association with acquisition of blood meal in Culex quinquefasciatus. INSECT SCIENCE 2021; 28:917-928. [PMID: 32621332 DOI: 10.1111/1744-7917.12847] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/20/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
The Southern house mosquito, Culex quinquefasciatus (Cx. quinquefasciatus) is an important vector that transmit multiple diseases including West Nile encephalitis, Japanese encephalitis, St. Louis encephalitis and lymphatic filariasis. Long noncoding RNAs (lncRNAs) involve in many biological processes such as development, infection, and virus-host interaction. However, there is no systematic identification and characterization of lncRNAs in Cx. quinquefasciatus. Here, we report the first lncRNA identification in Cx. quinquefasciatus. By using 31 public RNA-seq datasets, a total of 4763 novel lncRNA transcripts were identified, of which 3591, 569, and 603 were intergenic, intronic, and antisense respectively. Examination of genomic features revealed that Cx. quinquefasciatus shared similar characteristics with other species such as short in length, low GC content, low sequence conservation, and low coding potential. Furthermore, compared to protein-coding genes, Cx. quinquefasciatus lncRNAs had lower expression values, and tended to be expressed in temporally specific fashion. In addition, weighted correlation network and functional annotation analyses showed that lncRNAs may have roles in blood meal acquisition of adult female Cx. quinquefasciatus mosquitoes. This study presents the first systematic identification and analysis of Cx. quinquefasciatus lncRNAs and their association with blood feeding. Results generated from this study will facilitate future investigation on the function of Cx. quinquefasciatus lncRNAs.
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Affiliation(s)
- Azali Azlan
- School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia
| | | | - Faisal Mohamad
- School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia
| | - Ghows Azzam
- School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia
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Mohammed B, Yayo A, Ajanusi O, Lawal I. Relative abundance and molecular identification of Culex pipiens complex (Diptera: Culicidae), in Kura Local Government Area, North-western Nigeria. Parasite Epidemiol Control 2021; 14:e00213. [PMID: 34027142 PMCID: PMC8131315 DOI: 10.1016/j.parepi.2021.e00213] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/07/2021] [Accepted: 04/28/2021] [Indexed: 11/20/2022] Open
Abstract
Culex species are the most widespread mosquito species across the world and are known to be highly opportunistic, feeding on humans and livestock. They are known to acquire the potential to transmit zoonotic diseases, including Rift Valley Fever (RVF). However, despite their public health significance, they remain understudied in North-western Nigeria, compared to Anophelines. This study was therefore aimed at determining the relative abundance and Multiplex polymerase chain reaction (Multiplex PCR) identification of members of the Culex pipiens complex, in Kura Local Government Area (LGA), North-western, Nigeria. Adult mosquitoes were collected using Center for Disease Control (CDC) miniature light traps from August to October 2019. Mosquitoes were identified using morphological identification keys. Members of the Culex pipiens complex were further identified using Multiplex PCR to assess the presence of sibling species. A total of 413 mosquitoes, belonging to 3 genera, Culex, Anopheles and Aedes were collected. Of this figure, 120 Culex spp. females were collected. Homes with livestock had the highest occurrence of mosquitoes, 123 (61.19%) compared to those without livestock, 78 (38.81%). There was no statistical difference among the two (2) categories of homes (P ≥ 0.005). Culicoides spp. were the most common with 130 collected (65.38%). Again, homes with livestock had the highest occurrence, 85 whilst homes without livestock had 45 of the other flies caught. Multiplex- PCR revealed no expected bands for Cx. quinquefasciatus and Cx. pipiens from the DNA obtained from field collected mosquitoes as confirmed by using genomic DNA of an insectary Culex quinquefasciatus as control. Cx. spp. is presently regarded as a biting nuisance having no significant epidemiological importance. Efforts at its control should be intensified before it is too late. This study provides useful information on the occurrence and multiplex PCR of Culex spp in Kura Local Government Area, North-western Nigeria. These results have implications for the control of Culex spp. mosquito populations and the spread of human, livestock and avian diseases.
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Affiliation(s)
- B.R. Mohammed
- Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Abuja, P.M.B. 117, Abuja, Nigeria (Formerly of Abertay University, DD1 1HG, Dundee, UK)
- College of Veterinary Surgeons of Nigeria (CVSN), (Zaria Study Center), Ahmadu Bello University, Zaria, Nigeria
| | - A.M. Yayo
- Centre for Infectious Diseases Research, Bayero University, Kano, Nigeria
- Department of Medical Microbiology/Parasitology, Faculty of Medicine, Bayero University, Kano State, Nigeria
| | - O.J. Ajanusi
- College of Veterinary Surgeons of Nigeria (CVSN), (Zaria Study Center), Ahmadu Bello University, Zaria, Nigeria
| | - I.A. Lawal
- College of Veterinary Surgeons of Nigeria (CVSN), (Zaria Study Center), Ahmadu Bello University, Zaria, Nigeria
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Djiappi-Tchamen B, Nana-Ndjangwo MS, Mavridis K, Talipouo A, Nchoutpouen E, Makoudjou I, Bamou R, Mayi AMP, Awono-Ambene P, Tchuinkam T, Vontas J, Antonio-Nkondjio C. Analyses of Insecticide Resistance Genes in Aedes aegypti and Aedes albopictus Mosquito Populations from Cameroon. Genes (Basel) 2021; 12:genes12060828. [PMID: 34071214 PMCID: PMC8229692 DOI: 10.3390/genes12060828] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/03/2021] [Accepted: 05/05/2021] [Indexed: 01/13/2023] Open
Abstract
The emergence of insecticide resistance in Aedes mosquitoes could pose major challenges for arboviral-borne disease control. In this paper, insecticide susceptibility level and resistance mechanisms were assessed in Aedes aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1894) from urban settings of Cameroon. The F1 progeny of Aedes aegypti and Aedes albopictus collected in Douala, Yaoundé and Dschang from August to December 2020 was tested using WHO tube assays with four insecticides: deltamethrin 0.05%, permethrin 0.75%, DDT 4% and bendiocarb 0.1%. TaqMan, qPCR and RT-qPCR assays were used to detect kdr mutations and the expression profiles of eight detoxification genes. Aedes aegypti mosquitoes from Douala were found to be resistant to DDT, permethrin and deltamethrin. Three kdr mutations, F1534C, V1016G and V1016I were detected in Aedes aegypti populations from Douala and Dschang. The kdr allele F1534C was predominant (90%) in Aedes aegypti and was detected for the first time in Aedes albopictus (2.08%). P450s genes, Cyp9J28 (2.23-7.03 folds), Cyp9M6 (1.49-2.59 folds), Cyp9J32 (1.29-3.75 folds) and GSTD4 (1.34-55.3 folds) were found overexpressed in the Douala and Yaoundé Aedes aegypti populations. The emergence of insecticide resistance in Aedes aegypti and Aedes albopictus calls for alternative strategies towards the control and prevention of arboviral vector-borne diseases in Cameroon.
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Affiliation(s)
- Borel Djiappi-Tchamen
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science, University of Dschang, P.O. Box 067 Dschang, Cameroon; (R.B.); (A.M.P.M.); (T.T.)
- 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; (M.S.N.-N.); (A.T.); (E.N.); (I.M.); (P.A.-A.)
- Correspondence: (B.D.-T.); (C.A.-N.)
| | - Mariette Stella Nana-Ndjangwo
- 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; (M.S.N.-N.); (A.T.); (E.N.); (I.M.); (P.A.-A.)
- Department of Animal Physiology and Biology, Faculty of Science, University of Yaoundé I, P.O. Box 337 Yaoundé, Cameroon
| | - Konstantinos Mavridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Greece; (K.M.); (J.V.)
| | - Abdou 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, Cameroon; (M.S.N.-N.); (A.T.); (E.N.); (I.M.); (P.A.-A.)
- Department of Animal Physiology and Biology, Faculty of Science, University of Yaoundé I, P.O. Box 337 Yaoundé, Cameroon
| | - Elysée Nchoutpouen
- 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; (M.S.N.-N.); (A.T.); (E.N.); (I.M.); (P.A.-A.)
| | - Idene Makoudjou
- 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; (M.S.N.-N.); (A.T.); (E.N.); (I.M.); (P.A.-A.)
- Department of Animal Physiology and Biology, Faculty of Science, University of Yaoundé I, P.O. Box 337 Yaoundé, Cameroon
| | - Roland Bamou
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science, University of Dschang, P.O. Box 067 Dschang, Cameroon; (R.B.); (A.M.P.M.); (T.T.)
- 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; (M.S.N.-N.); (A.T.); (E.N.); (I.M.); (P.A.-A.)
| | - Audrey Marie Paul Mayi
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science, University of Dschang, P.O. Box 067 Dschang, Cameroon; (R.B.); (A.M.P.M.); (T.T.)
| | - 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; (M.S.N.-N.); (A.T.); (E.N.); (I.M.); (P.A.-A.)
| | - Timoléon Tchuinkam
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science, University of Dschang, P.O. Box 067 Dschang, Cameroon; (R.B.); (A.M.P.M.); (T.T.)
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Greece; (K.M.); (J.V.)
- Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, 11855 Athens, Greece
| | - 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; (M.S.N.-N.); (A.T.); (E.N.); (I.M.); (P.A.-A.)
- Department of Vector Biology, Liverpool School of Tropical medicine, Pembroke Place, Liverpool L3 5QA, UK
- Correspondence: (B.D.-T.); (C.A.-N.)
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Talipouo A, Mavridis K, Nchoutpouen E, Djiappi-Tchamen B, Fotakis EA, Kopya E, Bamou R, Kekeunou S, Awono-Ambene P, Balabanidou V, Balaska S, Wondji CS, Vontas J, Antonio-Nkondjio C. High insecticide resistance mediated by different mechanisms in Culex quinquefasciatus populations from the city of Yaoundé, Cameroon. Sci Rep 2021; 11:7322. [PMID: 33795804 PMCID: PMC8017000 DOI: 10.1038/s41598-021-86850-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/22/2021] [Indexed: 02/01/2023] Open
Abstract
Culex mosquitoes particularly Culex quinquefasciatus are important arboviral and filariasis vectors, however despite this important epidemiological role, there is still a paucity of data on their bionomics. The present study was undertaken to assess the insecticide resistance status of Cx. quinquefasciatus populations from four districts of Yaoundé (Cameroon). All Culex quinquefasciatus populations except one displayed high resistance to bendiocarb and malathion with mortalities ranging from 0 to 89% while high resistance intensity against both permethrin and deltamethrin was recorded. Molecular analyses revealed high frequencies of the ACE-1 G119S mutation (ranging from 0 to 33%) and kdr L1014F allele (ranging from 55 to 74%) in all Cx. quinquefasciatus populations. Significant overexpression was detected for cytochrome P450s genes CYP6AA7 and CYP6Z10, as well as for Esterase A and Esterase B genes. The total cuticular hydrocarbon content, a proxy of cuticular resistance, was significantly increased (compared to the S-lab strain) in one population. The study confirms strong insecticide resistance mediated by different mechanisms in Cx. quinquefasciatus populations from the city of Yaoundé. The expansion of insecticide resistance in Culex populations could affect the effectiveness of current vector control measures and stress the need for the implementation of integrated vector control strategies in urban settings.
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Affiliation(s)
- Abdou Talipouo
- Laboratoire de Recherche Sur Le PaludismeLaboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), B. P. 288, Yaoundé, Cameroun.
- Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé 1, P.O. Box 337, Yaoundé, Cameroon.
| | - Konstantinos Mavridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - Elysée Nchoutpouen
- Laboratoire de Recherche Sur Le PaludismeLaboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), B. P. 288, Yaoundé, Cameroun
| | - Borel Djiappi-Tchamen
- Laboratoire de Recherche Sur Le PaludismeLaboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), B. P. 288, Yaoundé, Cameroun
- Vector Borne Diseases Laboratory of the Research Unit Biology and Applied Ecology (VBID-RUBAE), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon
| | - Emmanouil Alexandros Fotakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - Edmond Kopya
- Laboratoire de Recherche Sur Le PaludismeLaboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), B. P. 288, Yaoundé, Cameroun
- Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé 1, P.O. Box 337, Yaoundé, Cameroon
| | - Roland Bamou
- Laboratoire de Recherche Sur Le PaludismeLaboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), B. P. 288, Yaoundé, Cameroun
- Vector Borne Diseases Laboratory of the Research Unit Biology and Applied Ecology (VBID-RUBAE), Department of Animal Biology, Faculty of Science of the University of Dschang, Dschang, Cameroon
| | - Sévilor Kekeunou
- Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé 1, P.O. Box 337, Yaoundé, Cameroon
| | - Parfait Awono-Ambene
- Laboratoire de Recherche Sur Le PaludismeLaboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), B. P. 288, Yaoundé, Cameroun
| | - Vasileia Balabanidou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - Sofia Balaska
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - Charles Sinclair Wondji
- Department of Vector Biology Liverpool School of Tropical Medicine Pembroke Place, Liverpool, L3 5QA, UK
- Centre for Research in Infectious Disease (CRID), P.O. Box 13591, Yaoundé, Cameroun
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
- Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, 11855, Athens, Greece
| | - Christophe Antonio-Nkondjio
- Laboratoire de Recherche Sur Le PaludismeLaboratoire de Recherche Sur Le Paludisme, Organisation de Coordination Pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), B. P. 288, Yaoundé, Cameroun.
- Department of Vector Biology Liverpool School of Tropical Medicine Pembroke Place, Liverpool, L3 5QA, UK.
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Soh S, Aik J. The abundance of Culex mosquito vectors for West Nile Virus and other flaviviruses: A time-series analysis of rainfall and temperature dependence in Singapore. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:142420. [PMID: 33254953 DOI: 10.1016/j.scitotenv.2020.142420] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/27/2020] [Accepted: 09/14/2020] [Indexed: 06/12/2023]
Abstract
Culex mosquitoes are important vectors of West Nile Virus (WNV), St. Louis Encephalitis Virus (SLEV) and Japanese Encephalitis Virus (JEV). Climate change is expected to alter their ability to spread diseases in human populations. Studies examining the influence of climate variability on Culex mosquitoes in South East Asia are scarce. We examined the influence of climate variability on reported Culex mosquito larval habitats from 2009 to 2018 in Singapore. We analysed the non-linear immediate and lagged weather dependence of Culex habitats over 5 weeks in negative binomial regression models using nationally representative data. We adjusted for the effects of long-term trend, seasonality, public holidays and autocorrelation. There were 41,170 reported Culex larval habitats over the study period. Non-residential premises were associated with more reports of habitats compared to residential premises [Rate Ratio (RR): 113.9, 95% CI: 110.9, 116.9]. Larvae in more than 90% of these habitats were entomologically identified as Culex quinquefasciatus. In residences, every 10 mm increase in rainfall above a 90 mm threshold was associated with a 10.1% [Incidence Rate Ratio (IRR): 0.899, 95% CI: 0.836, 0.968] cumulative decline in larval habitats. Public holidays were not significantly included in the model analysing larval habitats in residences. In non-residences, a 1 °C increase in the ambient air temperature with respect to the mean was associated with a 36.0% (IRR: 1.360, 95% CI: 1.057, 1.749) cumulative increase in Culex larval habitats. Public holidays were associated with a decline in Culex larval habitats in the same week. Our study provides evidence of how ambient air temperature and rainfall variability influences the abundance of Culex mosquito larval habitats. Our findings support the utility of using weather data in predictive models to inform the timing of vector control measures aimed at reducing the risk of WNV and other Culex-borne flavivirus transmission in urban areas.
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Affiliation(s)
- Stacy Soh
- Environmental Health Institute, National Environment Agency, 40 Scotts Road, Environment Building, #13-00, 228231, Singapore.
| | - Joel Aik
- Environmental Health Institute, National Environment Agency, 40 Scotts Road, Environment Building, #13-00, 228231, Singapore.
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Murindahabi MM, Takken W, Misago X, Niyituma E, Umupfasoni J, Hakizimana E, van Vliet AJH, Poortvliet PM, Mutesa L, Murindahabi NK, Koenraadt CJM. Monitoring mosquito nuisance for the development of a citizen science approach for malaria vector surveillance in Rwanda. Malar J 2021; 20:36. [PMID: 33423679 PMCID: PMC7798336 DOI: 10.1186/s12936-020-03579-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 12/31/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Many countries, including Rwanda, have mosquito monitoring programmes in place to support decision making in the fight against malaria. However, these programmes can be costly, and require technical (entomological) expertise. Involving citizens in data collection can greatly support such activities, but this has not yet been thoroughly investigated in a rural African context. METHODS Prior to the implementation of such a citizen-science approach, a household entomological survey was conducted in October-November 2017 and repeated one year later in Busoro and Ruhuha sectors, in southern and eastern province of Rwanda, respectively. The goal was to evaluate the perception of mosquito nuisance reported by citizens as a potential indicator for malaria vector hotspots. Firstly, mosquito abundance and species composition were determined using Centers for Disease Control and Prevention (CDC) light traps inside the houses. Secondly, household members were interviewed about malaria risk factors and their perceived level of mosquito nuisance. RESULTS Tiled roofs, walls made of mud and wood, as well as the number of occupants in the house were predictors for the number of mosquitoes (Culicidae) in the houses, while the presence of eaves plus walls made of mud and wood were predictors for malaria vector abundance. Perception of mosquito nuisance reported indoors tended to be significantly correlated with the number of Anopheles gambiae sensu lato (s.l.) and Culicidae collected indoors, but this varied across years and sectors. At the village level, nuisance also significantly correlated with An. gambiae s.l. and total mosquito density, but only in 2018 while not in 2017. CONCLUSIONS Perception of mosquito nuisance denoted in a questionnaire survey could be used as a global indicator of malaria vector hotspots. Hence, involving citizens in such activities can complement malaria vector surveillance and control.
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Affiliation(s)
- Marilyn Milumbu Murindahabi
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands.,College of Sciences and Technology, University of Rwanda, Kigali, Rwanda
| | - Willem Takken
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
| | - Xavier Misago
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Kigali, Rwanda
| | - Elias Niyituma
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Kigali, Rwanda
| | - Jackie Umupfasoni
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Kigali, Rwanda
| | - Emmanuel Hakizimana
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Kigali, Rwanda
| | - Arnold J H van Vliet
- Environmental Systems Analysis Group, Wageningen University & Research, Wageningen, The Netherlands
| | - P Marijn Poortvliet
- Strategic Communication Group, Wageningen University & Research, Wageningen, the Netherlands
| | - Leon Mutesa
- College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
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Amini M, Hanafi-Bojd AA, Aghapour AA, Chavshin AR. Larval habitats and species diversity of mosquitoes (Diptera: Culicidae) in West Azerbaijan Province, Northwestern Iran. BMC Ecol 2020; 20:60. [PMID: 33213441 PMCID: PMC7677836 DOI: 10.1186/s12898-020-00328-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 11/10/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The characteristics of a larval habitat is an important factor which affects the breeding pattern and population growth of mosquitoes Information about the larval habitat characteristics and pupal productivity can be utilized for the surveillance of the level of population growth, species diversity, and preferred breeding sites of mosquitoes, which are important aspects of integrated vector control. In the present study, mosquito larvae were collected from 22 natural habitats in five counties of the West Azerbaijan Province in the Northwest of Iran during May-November 2018. Physicochemical characteristics of the habitats were investigated. These included alkalinity, chloride (Cl) content, water temperature (°C), turbidity (NTU), Total Dissolved Solids (TDS) (ppm), Electrical Conductivity (EC) (μS/cm), and acidity (pH). The index of affinity between the collected species was calculated using Fager & McGowan test. RESULTS A total of 2715 specimens were collected and identified. Seven different species belonging to four genera were identified in our study sites. The species included, Culex pipiens Linnaeus 1758, Culex theileri Theobald 1903, Culex mimeticus Noé 1899, Culex modestus Ficalbi 1947, Culiseta longiareolata Macquart 1838, Anopheles maculipennis Meigen 1818complex, and Aedes caspius Pallas 1771. There was a significant difference in chloride content and water temperature preferences among the different species (P < 0.05). Also, there was no significant difference in pH, Alkalinity, Turbidity, TDS, and EC preferences among the different species (P > 0.05). The affinity between the pair of species Cx. mimeticus/Cs. longiareolata was 0.526. There was no affinity between other pairs of species or the affinity was very weak. CONCLUSIONS The physicochemical and biological characteristics of mosquito larval habitats play an important role in zoning of areas suitable for breeding and distribution. Surveillance of these characteristics can provide valuable information for entomological monitoring of mosquito vectors and for designing targeted control programs. Also, further studies should be undertaken in a wider geographical area, taking into account the complex characteristics of the physicochemical and ecological factors of the study area and their interaction with various mosquito species.
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Affiliation(s)
- Mojtaba Amini
- Department of Medical Entomology and Vector Control, School of Public Health and Social Determinants of Health Research Center, Urmia University of Medical Sciences, Urmia, Iran.,Student Research Committee, Urmia University of Medical Sciences, Urmia, Iran
| | - Ahmad Ali Hanafi-Bojd
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Ahmad Aghapour
- Department of Environmental Health Engineering, School of Public Health, Urmia University of Medical Sciences, Urmia, Iran
| | - Ali Reza Chavshin
- Department of Medical Entomology and Vector Control, School of Public Health and Social Determinants of Health Research Center, Urmia University of Medical Sciences, Urmia, Iran. .,Social Determinants of Health Research Center, Urmia University of Medical Sciences, Urmia, Iran.
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Yokoly FN, Zahouli JBZ, Méite A, Opoku M, Kouassi BL, de Souza DK, Bockarie M, Koudou BG. Low transmission of Wuchereria bancrofti in cross-border districts of Côte d'Ivoire: A great step towards lymphatic filariasis elimination in West Africa. PLoS One 2020; 15:e0231541. [PMID: 32282840 PMCID: PMC7153895 DOI: 10.1371/journal.pone.0231541] [Citation(s) in RCA: 5] [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: 10/24/2019] [Accepted: 03/25/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) is widely endemic in Côte d'Ivoire, and elimination as public health problem (EPHP) is based on annual mass drug administration (MDA) using ivermectin and albendazole. To guide EPHP efforts, we evaluated Wuchereria bancrofti infection indices among humans, and mosquito vectors after four rounds of MDA in four cross-border health districts of Côte d'Ivoire. METHODOLOGY We monitored people and mosquitoes for W. bancrofti infections in the cross-border health districts of Aboisso, Bloléquin, Odienné and Ouangolodougou, Côte d'Ivoire. W. bancrofti circulating filarial antigen (CFA) was identified using filariasis test strips, and antigen-positive individuals were screened for microfilaremia. Moreover, filarial mosquito vectors were sampled using window exit traps and pyrethrum sprays, and identified morphologically at species level. Anopheles gambiae s.l. and Culex quinquefasciatus females were analyzed for W. bancrofti infection using polymerase chain reaction (PCR) technique. PRINCIPAL FINDINGS Overall, we found a substantial decline in W. bancrofti infection indices after four rounds of MDA compared to pre-MDA baseline data. CFA prevalence fell from 3.38-5.50% during pre-MDA to 0.00-1.53% after MDA interventions. No subjects had detectable levels of CFA in Ouangolodougou. Moreover, post-MDA CFA prevalence was very low, and below the 1% elimination threshold in Aboisso (0.19%) and Odienné (0.49%). Conversely, CFA prevalence remained above 1% in Bloléquin (1.53%). W. bancrofti microfilariae (Mf) were not found in Aboisso, Bloléquin, and Ouangolodougou, except for Odienné with low prevalence (0.16%; n = 613) and microfilaremia of 32.0 Mf/mL. No An. gambiae s.l. and Cx. quinquefasciatus pools were infected with W. bancrofti in Bloléquin and Ouangolodougou, while they exhibited low infection rates in Aboisso (1% and 0.07%), and Odienné (0.08% and 0.08%), respectively. CONCLUSIONS In cross-border areas of Côte d'Ivoire, LF infection indices in humans and mosquito vectors substantially declined after four rounds of MDA. CFA prevalence fell under the World Health Organization (WHO)-established threshold (1%) in Aboisso, Ouangolodougou and Odienné. Moreover, W. bancrofti prevalence in mosquitoes was lower than WHO-established threshold (2%) in all areas. This might suggest the interruption of W. bancrofti transmission, and possible MDA cessation. However, a formal transmission assessment survey (TAS) and molecular xenomonitoring in mosquito vectors should be implemented before eventual MDA cessation. However, MDA should pursue in Bloléquin where W. bancrofti infection prevalence remained above 1%. Our results provided important ramifications for LF control efforts towards EPHP in Côte d'Ivoire.
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Affiliation(s)
- Firmain N. Yokoly
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Julien B. Z. Zahouli
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Centre d’Entomologie Médicale et Vétérinaire, Université Alassane Ouattara, Bouaké, Côte d’Ivoire
| | - Aboulaye Méite
- Programme National de Lutte contre les Maladies Tropicales Négligées à Chimiothérapie Préventive, Ministère de la Santé, Abidjan, Côte d’Ivoire
| | - Millicent Opoku
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
- European & Developing Countries Clinical Trials Partnership, Cape Town, South Africa
| | - Bernard L. Kouassi
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Dziedzom K. de Souza
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Moses Bockarie
- European & Developing Countries Clinical Trials Partnership, Cape Town, South Africa
- Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Benjamin G. Koudou
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
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Ngadjeu CS, Doumbe-Belisse P, Talipouo A, Djamouko-Djonkam L, Awono-Ambene P, Kekeunou S, Toussile W, Wondji CS, Antonio-Nkondjio C. Influence of house characteristics on mosquito distribution and malaria transmission in the city of Yaoundé, Cameroon. Malar J 2020; 19:53. [PMID: 32000786 PMCID: PMC6993434 DOI: 10.1186/s12936-020-3133-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/22/2020] [Indexed: 12/31/2022] Open
Abstract
Background Improving house structure is known to limit contact between humans and mosquitoes and reduce malaria transmission risk. In the present study, the influence of house characteristics on mosquito distribution and malaria transmission risk was assessed in the city of Yaoundé. Methods The study was conducted from March 2017 to June 2018 in 32 districts of the city of Yaoundé. Mosquito collections were performed indoor in 10 to 15 houses per district using CDC light traps. A total of 467 houses, selected randomly were used. A pretested questionnaire was submitted to participants of the study to collect information on the household: the number of people per house, education level, type of walls, presence of ceilings and eaves, number of windows, usage of long-lasting insecticidal nets (LLINs), number of bedroom and number of window. Mosquitoes collected were identified morphologically. Anophelines were tested by ELISA to detect infection by Plasmodium parasites. General Estimating Equations adjusting for repeated measures in the same house fitting negative binomial analysis were used to assess the influence of house characteristics on mosquito distribution. Results A total of 168,039 mosquitoes were collected; Culex spp emerged as the predominant species (96.48%), followed by Anopheles gambiae sensu lato (s.l.) (2.49%). Out of the 1033 An. gambiae s.l. identified by PCR, 90.03% were Anopheles coluzzii and the remaining were An. gambiae sensu stricto (s.s.) (9.97%). The high number of people per household, the presence of screens on window and the possession of LLINs were all associated with fewer mosquitoes collected indoors, whilst opened eaves, the high number of windows, the presence of holes in walls and living close to breeding sites were associated with high densities of mosquitoes indoor. Out of 3557 Anophelines tested using ELISA CSP, 80 were found infected by Plasmodium falciparum parasites. The proportion of mosquitoes infected did not vary significantly according to house characteristics. Conclusion The study indicated that several house characteristics such as, the presence of holes on walls, opened eaves, unscreened window and living close to breeding sites, favored mosquito presence in houses. Promoting frequent use of LLINs and house improvement measures, such as the use of screen on windows, closing eaves, cleaning the nearby environment, should be integrated in strategies to improve malaria control in the city of Yaoundé.
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Affiliation(s)
- Carmene 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, Cameroon.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Patricia 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, Cameroon.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Abdou 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, Cameroon.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, 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.,Faculty of Sciences, University of Dschang, P.O. Box 337, Dschang, 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
| | - Sevilor Kekeunou
- Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Wilson Toussile
- Ecole Nationale Supérieure Polytechnique University of Yaoundé I, P.O. Box 8390, Yaounde, Cameroon.,Faculty of Medicine Paris-Sud, 63 rue Gabriel Peri, 94276, Le Kremlin-Bicêtre, Paris, France
| | - Charles S Wondji
- 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. .,Vector Biology Liverpool School of Tropical Medicine Pembroke Place, Liverpool, L3 5QA, UK.
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Nditanchou R, Dixon R, Pam D, Isiyaku S, Nwosu C, Sanda S, Schmidt E, Koudou B, Molyneux D. Testing a method of sampling for entomological determination of transmission of Wuchereria bancrofti to inform lymphatic filariasis treatment strategy in urban settings. Parasit Vectors 2020; 13:37. [PMID: 31973747 PMCID: PMC6979341 DOI: 10.1186/s13071-020-3905-x] [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: 06/03/2019] [Accepted: 01/11/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There is on-going debate about scale-up of lymphatic filariasis treatment to include urban areas. Determining Wuchereria bancrofti transmission is more complex in these settings and entomological methodologies suggested as a solution as yet have no clear guidance. METHODS The study was conducted in six communities in Minna and Kaduna cities in Nigeria selected based on pre-disposing risk factors for mosquitoes and Transmission Assessment Survey (TAS) results in 2016 indicating need for treatment (> 1% prevalence). In each community, 4 gravid traps (GT), 15 exit traps (ET) and 21 pyrethrum spray catches (PSC) were used for 5 months targeting a sample size of 10,000 mosquitoes inclusive of at least 1500 Anopheles. Community researchers were selected and trained to facilitate community acceptability and carry out collection. We have evaluated the mosquito sampling and trapping methodology in terms of success at reaching targeted sample size, cost effectiveness, and applicability. RESULTS Community researchers were influential in enabling high acceptability of the methods of collection and were able to conduct collections independently. Overall, 12.1% of trapping events (one trapping event corresponds to one visit to one trap to collect mosquitoes) were affected by householder actions, weather conditions or trap malfunction leading to lower than optimal catches. Exit traps were the most cost-effective way to catch Anopheles (6.4 USD per trapping event and 12.8 USD per Anopheles caught). Sample size of 10,000 mosquitoes overall in each city was met though Anopheles catch was insufficient in one city. However, sample size was met only in one implementation unit out of the four. CONCLUSIONS Methods need adapting to maximise Anopheles catch: we propose planning 250 gravid trap and 3724 exit trap trapping events in similar settings in West African urban areas where Culex is dominant, not using pyrethrum spray catches, and weighting trapping events later in the rainy season. Planning should increase involvement of community researchers, incorporate null catches and participants' actions to predict catches. Importantly, evaluation units should be analogous with implementation units, the units at which treatment decisions will be made in the urban context.
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Affiliation(s)
- Rogers Nditanchou
- Policy & Programme Strategy, Sightsavers, Cameroon Country Office, BP 4484, Bastos, Yaoundé, Cameroon.
| | - Ruth Dixon
- Policy & Programme Strategy, Sightsavers, 35 Perrymount Road, Haywards Heath, West Sussex, RH16 3BW, UK
| | - Dung Pam
- Department of Zoology, University of Jos, Bauchi Road, 2084, Jos, Plateau State, Nigeria
| | - Sunday Isiyaku
- Sightsavers, Nigeria Country Office, 1 Golf Course Road, Kaduna, Kaduna State, Nigeria
| | - Christian Nwosu
- Sightsavers, Nigeria Country Office, 1 Golf Course Road, Kaduna, Kaduna State, Nigeria
| | - Safiya Sanda
- Sightsavers, Nigeria Country Office, 1 Golf Course Road, Kaduna, Kaduna State, Nigeria
| | - Elena Schmidt
- Policy & Programme Strategy, Sightsavers, 35 Perrymount Road, Haywards Heath, West Sussex, RH16 3BW, UK
| | - Benjamin Koudou
- Liverpool School of Tropical Medicine, Pembroke Pl, Liverpool, L3 5QA, UK
| | - David Molyneux
- Liverpool School of Tropical Medicine, Pembroke Pl, Liverpool, L3 5QA, UK
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Madewell ZJ, Sosa S, Brouwer KC, Juárez JG, Romero C, Lenhart A, Cordón-Rosales C. Associations between household environmental factors and immature mosquito abundance in Quetzaltenango, Guatemala. BMC Public Health 2019; 19:1729. [PMID: 31870343 PMCID: PMC6929347 DOI: 10.1186/s12889-019-8102-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/17/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Aedes aegypti-borne diseases are becoming major public health problems in tropical and sub-tropical regions. While socioeconomic status has been associated with larval mosquito abundance, the drivers or possible factors mediating this association, such as environmental factors, are yet to be identified. We examined possible associations between proximity to houses and roads and immature mosquito abundance, and assessed whether these factors and mosquito prevention measures mediated any association between household environmental factors and immature mosquito abundance. METHODS We conducted two cross-sectional household container surveys in February-March and November-December, 2017, in urban and rural areas of Quetzaltenango, Guatemala. We used principal components analysis to identify factors from 12 variables to represent the household environment. One factor which included number of rooms in house, electricity, running water, garbage service, cable, television, telephone, latrine, well, and sewer system, was termed "environmental capital." Environmental capital scores ranged from 0 to 5.5. Risk factors analyzed included environmental capital, and distance from nearest house/structure, paved road, and highway. We used Poisson regression to determine associations between distance to nearest house/structure, roads, and highways, and measures of immature mosquito abundance (total larvae, total pupae, and positive containers). Using cubic spline generalized additive models, we assessed non-linear associations between environmental capital and immature mosquito abundance. We then examined whether fumigation, cleaning containers, and distance from the nearest house, road, and highway mediated the relationship between environmental capital and larvae and pupae abundance. RESULTS We completed 508 household surveys in February-March, and we revisited 469 households in November-December. Proximity to paved roads and other houses/structures was positively associated with larvae and pupae abundance and mediated the associations between environmental capital and total numbers of larvae/pupae (p ≤ 0.01). Distance to highways was not associated with larval/pupal abundance (p ≥ 0.48). Households with the lowest and highest environmental capital had fewer larvae/pupae than households in the middle range (p < 0.01). CONCLUSIONS We found evidence that proximity to other houses and paved roads was associated with greater abundance of larvae and pupae. Understanding risk factors such as these can allow for improved targeting of surveillance and vector control measures in areas considered at higher risk for arbovirus transmission.
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Affiliation(s)
- Zachary J Madewell
- Centro de Estudios en Salud, Universidad del Valle de Guatemala, Guatemala City, Guatemala. .,Program in Public Health (Epidemiology), University of California, San Diego/San Diego State University, San Diego, CA, USA.
| | - Silvia Sosa
- Centro de Estudios en Salud, Universidad del Valle de Guatemala, Guatemala City, Guatemala
| | - Kimberly C Brouwer
- Department of Family Medicine & Public Health, Division of Global Health, University of California, San Diego, CA, USA
| | - José Guillermo Juárez
- Centro de Estudios en Salud, Universidad del Valle de Guatemala, Guatemala City, Guatemala.,Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Carolina Romero
- Centro de Estudios en Salud, Universidad del Valle de Guatemala, Guatemala City, Guatemala
| | - Audrey Lenhart
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Celia Cordón-Rosales
- Centro de Estudios en Salud, Universidad del Valle de Guatemala, Guatemala City, Guatemala
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Lopes RP, Lima JBP, Martins AJ. Insecticide resistance in Culex quinquefasciatus Say, 1823 in Brazil: a review. Parasit Vectors 2019; 12:591. [PMID: 31852489 PMCID: PMC6921570 DOI: 10.1186/s13071-019-3850-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/10/2019] [Indexed: 11/10/2022] Open
Abstract
Culex quinquefasciatus is a successful invasive species broadly distributed in subtropical regions, including Brazil. It is an extremely annoying mosquito due to its nocturnal biting behavior, in high-density populations and it is a potential bridge between sylvatic arbovirus from birds to man in urban territories. Herein, we present a review concerning the methods of chemical control employed against Cx. quinquefasciatus in Brazil since the 1950’s and insecticide resistance data registered in the literature. As there is no specific national programme for Cx. quinquefasciatus control in Brazil, the selection of insecticide resistance is likely due in part to the well-designed chemical campaigns against Aedes aegypti and the elevated employment of insecticides by households and private companies. There are very few publications about insecticide resistance in Cx. quinquefasciatus from Brazil when compared to Ae. aegypti. Nevertheless, resistance to organophosphates, carbamate, DDT, pyrethroids and biolarvicides has been registered in Cx. quinquefasciatus populations from distinct localities of the country. Concerning physiological mechanisms selected for resistance, distinct patterns of esterases, as well as mutations in the acetylcholinesterase (ace-1) and voltage-gated sodium channel (NaV) genes, have been identified in natural populations. Given environmental changes and socioeconomical issues in the cities, in recent years we have been experiencing an increase in the number of disease cases caused by arboviruses, which may involve Cx. quinquefasciatus participation as a key vector. It is urgent to better understand the efficiency and susceptibility status to insecticides, as well as the genetic background of known resistant mechanisms already present in Cx. quinquefasciatus populations for an effective and rapid chemical control when eventually required.
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Affiliation(s)
- Ramon Pereira Lopes
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - José Bento Pereira Lima
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Ademir Jesus Martins
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil. .,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
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Mayi MPA, Foncha DF, Kowo C, Tchuinkam T, Brisco K, Anong DN, Ravinder S, Cornel AJ. Impact of deforestation on the abundance, diversity, and richness of Culex mosquitoes in a southwest Cameroon tropical rainforest. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2019; 44:271-281. [PMID: 31729796 DOI: 10.1111/jvec.12359] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/01/2019] [Indexed: 06/10/2023]
Abstract
Deforestation is a major threat to biodiversity but little data exist on how deforestation in real-time affects the overall mosquito species community despite its known role in the transmission of diseases. We compared the abundance and diversity of Culex mosquitoes before and after deforestation along a gradient of three different anthropogenic disturbance levels in a tropical rainforest in southwestern Cameroon. The collections were conducted in unlogged forest (January, 2016), selectively logged forest (January, 2017), and within a young palm plantation (October, 2017) using net traps, sweep nets, resting traps, and dipping for immature stages in water bodies. Mosquitoes were morphologically identified to subspecies, groups, and species. A total of 2,556 mosquitoes was collected of which 1,663 (65.06%) belong to the genus Culex, (n=427 (25.68%) in the unlogged forest; n=900 (54.12%) in the selectively logged forest; and n=336 (20.2%) in the young palm plantation) with a significant difference among the habitats. Diversity and richness of mosquitoes varied significantly among habitats with the highest values found in the selectively logged forest (H=2.4; DS=0.87; S=33) and the lowest value in the unlogged forest (H=1.37; DS=0.68; S=13). The results of this study showed that deforestation affects the abundance and diversity of Culex mosquitoes and favors the invasion of anthropophilic mosquitoes. Higher mosquito abundance and diversity in the selectively logged forest than in the pristine forest is notable and some explanations for these differences are discussed.
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Affiliation(s)
- Marie Paul Audrey Mayi
- Department of Animal Biology, Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), University of Dschang, Dschang, Cameroon
| | | | - Cyril Kowo
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Timoleon Tchuinkam
- Department of Animal Biology, Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), University of Dschang, Dschang, Cameroon
| | - Katherine Brisco
- Department of Entomology and Nematology, Mosquito Control Research Laboratory, University of California, Parlier, CA 93648, U.S.A
| | - Damian Nota Anong
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Sehgal Ravinder
- Department of Biology, San Francisco State University, San Francisco, CA 94132, U.S.A
| | - Anthony John Cornel
- Department of Entomology and Nematology, Mosquito Control Research Laboratory, University of California, Parlier, CA 93648, U.S.A
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Tan K, Faierstein GB, Xu P, Barbosa RMR, Buss GK, Leal WS. A popular Indian clove-based mosquito repellent is less effective against Culex quinquefasciatus and Aedes aegypti than DEET. PLoS One 2019; 14:e0224810. [PMID: 31689339 PMCID: PMC6830767 DOI: 10.1371/journal.pone.0224810] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 10/22/2019] [Indexed: 11/19/2022] Open
Abstract
Insect repellents are widely used as the first line of defense against mosquito bites and transmission of disease-causing agents. However, the cost of daily applications of even the most affordable and the gold standard of insect repellents, DEET, is still high for low-income populations where repellents are needed the most. An Indian clove-based homemade recipe has been presented as a panacea. We analyzed this homemade repellent and confirmed by behavioral measurements and odorant receptor responses that eugenol is the active ingredient in this formulation. Prepared as advertised, this homemade repellent is ineffective, whereas 5x more concentrated extracts from the brand most enriched in eugenol showed moderate repellency activity against Culex quinquefasciatus and Aedes aegypti. DEET showed higher performance when compared to the 5x concentrated formulation and is available in the same market at a lower price than the cost of the ingredients to prepare the homemade formulation.
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Affiliation(s)
- Kaiming Tan
- Department of Molecular and Cellular Biology, University of California-Davis, Davis, CA, United States of America
| | - Gabriel B. Faierstein
- Department of Entomology, Instituto Aggeu Magalhaes, Fundação Oswaldo Cruz (FIOCRUZ-PE), Recife-PE, Brazil
| | - Pingxi Xu
- Department of Molecular and Cellular Biology, University of California-Davis, Davis, CA, United States of America
| | - Rosângela M. R. Barbosa
- Department of Entomology, Instituto Aggeu Magalhaes, Fundação Oswaldo Cruz (FIOCRUZ-PE), Recife-PE, Brazil
| | - Garrison K. Buss
- Department of Entomology, Instituto Aggeu Magalhaes, Fundação Oswaldo Cruz (FIOCRUZ-PE), Recife-PE, Brazil
| | - Walter S. Leal
- Department of Molecular and Cellular Biology, University of California-Davis, Davis, CA, United States of America
- * E-mail:
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Cadmium tolerance pathway in Anopheles gambiae senso stricto. Acta Trop 2019; 198:105033. [PMID: 31121147 DOI: 10.1016/j.actatropica.2019.05.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 05/16/2019] [Accepted: 05/18/2019] [Indexed: 02/05/2023]
Abstract
Cadmium is one of the widely used heavy metals (HM) in commercial and industrial products and contributes to environmental contamination in an urban setting. In our previous studies, we established that An. gambiae sensu stricto, a vector of malaria, had adapted to HM pollutants in nature despite their proclivity for unpolluted aquatic habitats. We further demonstrated that heavy metal tolerance adaptation process impacts a biological cost to the fitness of the mosquito and potentially involves the induction of specific HM-responsive transcripts and proteins. Here we interrogated differential proteomic profiles of the cadmium tolerant vs. naïve strains of An. gambiae to shed light on proteomic processes that underpinned biological cost to fitness. We identified a total of 1067 larval proteins and observed significant down-regulation of proteins involved in larval immune responses, energy metabolism, antioxidant enzymes, protein synthesis, and proton transport. Our results suggest that mosquitoes can adjust their biological program through proteome changes to counter HM pollution. Since our study was done in controlled laboratory settings, we acknowledge this may not wholly represent the conditions HM polluted environments. Nevertheless, mosquitoes deploying this strategy have the potential of creating an urban enclave for breeding and thrive and become agents of sporadic malaria epidemics.
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