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Insecticide susceptibility status in two medically important mosquito vectors , Anopheles gambiae, and Culex quinquefasciatus to three insecticides commonly used in Niger State, Nigeria. Saudi J Biol Sci 2023; 30:103524. [PMID: 36660609 PMCID: PMC9843493 DOI: 10.1016/j.sjbs.2022.103524] [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: 10/29/2021] [Revised: 11/05/2022] [Accepted: 12/01/2022] [Indexed: 12/28/2022] Open
Abstract
High resistance ability on insecticides among major mosquito vectors of diseases in Nigeria is of growing concern for severe control strategies. The objective of this study was to assess the susceptibility status of females Anopheles gambiae and Culex quinquefasciatus complexes mosquitoes to permethrin (21.5 μg/bottle-pyrethroids), propoxur(12.5 μg/bottle-carbamate) and malathion (50 μg/bottle organophosphate), in Niger State, North-Central, Nigeria. Anopheline and Culecine larvae were collected from the larval habitats of the studied sites (Bosso, Katcha, Lapai, and Shiroro) larvae and pupae were identified guided by standard keys and reared to adults in troughs. Insecticide susceptibility bioassays were performed according to the CDC bottle bioassay standard operating procedures on 3 days old, sugar-fed female Anopheles and Culex mosquitoes. Post-exposure mortality after 24hr and knockdown values for KDT50 were calculated. Knock-down at 1-hour insecticide exposure ranged (84-96 %) permethrin, (94-100 %) propoxur and (100 %) malathion for An. gambiae and (86-97 %) permethrin, (92-100 %) propoxur and (96-100 %) malathion for Cx. quinquefasciatus. Mortality, after 24hr post-exposure was 100 % in malathion, indicating the high effect of the insecticide. Tested samples were found potentially resistant to permethrin recorded against mosquitoes collected from all study sites, in two locations of the study sites to propoxur and one location site to malathion. All the tested mosquitoes were found to be potentially resistant to permethrin, however, mosquitoes tested in Katcha and Shiroro resist potentially to propoxur. Except, Culex quinqufasciatus from Lapai that partially resist malathion, all the tested mosquitoes were found to be susceptible to malathion, across the study sites.
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Oliver SV, Lyons CL, Brooke BD. The effect of blood feeding on insecticide resistance intensity and adult longevity in the major malaria vector Anopheles funestus (Diptera: Culicidae). Sci Rep 2022; 12:3877. [PMID: 35264696 PMCID: PMC8907345 DOI: 10.1038/s41598-022-07798-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 02/18/2022] [Indexed: 11/09/2022] Open
Abstract
Insecticide-based vector control is key to the reduction and elimination of malaria. Although insecticide resistance is common in malaria vector populations, the operational implications are often unclear. High intensity pyrethroid resistance in the major malaria vector Anopheles funestus has been linked to control failure in Southern Africa. The aim of this study was to assess linkages between mosquito age, blood feeding and the intensity of pyrethroid resistance in two An. funestus laboratory strains that originate from southern Mozambique, namely the moderately pyrethroid resistant FUMOZ and the highly resistant FUMOZ-R. Resistance tended to decline with age. This effect was significantly mitigated by blood feeding and was most apparent in cohorts that received multiple blood meals. In the absence of insecticide exposure, blood feeding tended to increase longevity of An. funestus females and, following insecticide exposure, enhanced their levels of deltamethrin resistance, even in older age groups. These effects were more marked in FUMOZ-R compared to FUMOZ. In terms of programmatic decision-making, these data suggest that it would be useful to assess the level and intensity of resistance in older female cohorts wherever possible, notwithstanding the standard protocols for resistance testing using age-standardised samples.
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Affiliation(s)
- Shüné V Oliver
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, 1 Modderfontein Road, Sandringham, Johannesburg, 2192, South Africa. .,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2193, South Africa.
| | - Candice L Lyons
- Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa
| | - Basil D Brooke
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, 1 Modderfontein Road, Sandringham, Johannesburg, 2192, South Africa.,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2193, South Africa
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N'Do S, Bandibabone JB, Soma DD, Musaka BZ, Prudhomme J, Habamungu CC, Namountougou M, Sangaré I, Kientega M, Kaboré DAP, Bayili K, Yerbanga RS, Diabate A, Dabire RK, Ouedraogo JB, Belem AMG, Boëte C, Guardiola-Claramonte M, Chimanuka B. Insecticide resistance profiles in malaria vector populations from Sud-Kivu in the Democratic Republic of the Congo. Trans R Soc Trop Med Hyg 2021; 115:1339-1344. [PMID: 34324683 DOI: 10.1093/trstmh/trab116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/02/2021] [Accepted: 07/14/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Insecticide resistance has become a widespread problem causing a decline in the effectiveness of vector control tools in sub-Saharan Africa. In this situation, ongoing monitoring of vector susceptibility to insecticides is encouraged by the WHO to guide national malaria control programmes. Our study was conducted from April to November 2018 in Tchonka (Sud-Kivu, Democratic Republic of the Congo) and reported primary data on the resistance status of Anopheles funestus and Anopheles gambiae. METHODS Insecticide susceptibility bioassays were performed on wild populations of A. funestus and A. gambiae using WHO insecticide-impregnated papers at discriminating concentration. In addition, PCR was performed to identify mosquito species and to detect kdr and ace-1R mutations involved in insecticide resistance. RESULTS Bioassay results show resistance to all tested insecticides except pirimiphos-methyl, propoxur, fenitrothion and malathion with a mortality rate ranging from 95.48 to 99.86%. The addition of piperonyl butoxide (PBO) increased the susceptibility of vectors to deltamethrin and alpha-cypermethrin by exhibiting a mortality ranging from 91.50 to 95.86%. The kdr mutation was detected at high frequencies (approximately 0.98) within A. gambiae while ace-1R was not detected. CONCLUSIONS This study provides useful data on the insecticide resistance profiles of malaria vector populations to better manage vector control. Our results highlight that, despite the high level of resistance, organophosphorus compounds and pyrethroids + PBO remain effective against the vectors.
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Affiliation(s)
- Sévérin N'Do
- Médecins Sans Frontières (MSF) OCBA, Barcelona, Spain.,Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso.,Université Nazi Boni (UNB), Bobo-Dioulasso, Burkina Faso
| | - Janvier B Bandibabone
- Centre de Recherche en Sciences Naturelles de Lwiro (CRSN/Lwiro), Bukavu, Sud-Kivu, DRC
| | - Dieudonné D Soma
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso.,Université Nazi Boni (UNB), Bobo-Dioulasso, Burkina Faso
| | - Bertin Z Musaka
- Centre de Recherche en Sciences Naturelles de Lwiro (CRSN/Lwiro), Bukavu, Sud-Kivu, DRC
| | - Jorian Prudhomme
- Médecins Sans Frontières (MSF) OCBA, Barcelona, Spain.,Institut de Recherche pour le Développement (IRD), Marseille, France
| | - Claude C Habamungu
- Centre de Recherche en Sciences Naturelles de Lwiro (CRSN/Lwiro), Bukavu, Sud-Kivu, DRC
| | - Moussa Namountougou
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso.,Université Nazi Boni (UNB), Bobo-Dioulasso, Burkina Faso
| | - Ibrahim Sangaré
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso.,Université Nazi Boni (UNB), Bobo-Dioulasso, Burkina Faso
| | - Mahamadi Kientega
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso.,Université Nazi Boni (UNB), Bobo-Dioulasso, Burkina Faso
| | - Didier A P Kaboré
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso.,Université Nazi Boni (UNB), Bobo-Dioulasso, Burkina Faso
| | - Koama Bayili
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - R Serge Yerbanga
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - Roch K Dabire
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - Jean-Bosco Ouedraogo
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | | | - Christophe Boëte
- Médecins Sans Frontières (MSF) OCBA, Barcelona, Spain.,ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | | | - Bantuzeko Chimanuka
- Centre de Recherche en Sciences Naturelles de Lwiro (CRSN/Lwiro), Bukavu, Sud-Kivu, DRC.,Université Officielle de Bukavu (UOB), Bukavu, Sud-Kivu, DRC
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Species Composition, Phenotypic and Genotypic Resistance Levels in Major Malaria Vectors in Teso North and Teso South Subcounties in Busia County, Western Kenya. J Parasitol Res 2020; 2020:3560310. [PMID: 32411419 PMCID: PMC7204121 DOI: 10.1155/2020/3560310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/12/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022] Open
Abstract
Introduction Knockdown resistance (kdr) is strongly linked to pyrethroid insecticide resistance in Anopheles gambiae in Africa, which may have vital significance to the current increased use of pyrethroid-treated bed net programmes. The study is aimed at determining species composition, levels of insecticide resistance, and knockdown patterns in Anopheles gambiae sensu lato in areas with and areas without insecticide resistance in Teso North and Teso South subcounties, Western Kenya. Materials and Methods For WHO vulnerability tests, mosquito larvae were sampled using a dipper, reared into 3-5-day-old female mosquitoes (4944 at 100 mosquitoes per insecticide) which were exposed to 0.75% permethrin, 0.05% deltamethrin, and 0.1% bendiocarb using the WHO tube assay method. Species identification and kdr East gene PCRs were also performed on randomly selected mosquitoes from the collections; including adult mosquitoes (3448) sampled using standard collection methods. Results Anopheles gambiae sensu stricto were the majority in terms of species composition at 78.9%. Bendiocarb caused 100% mortality while deltamethrin had higher insecticidal effects (77%) on female mosquitoes than permethrin (71%). Susceptible Kengatunyi cluster had higher proportion of An. arabiensis (20.9%) than resistant Rwatama (10.7%). Kengatunyi mosquitoes exposed to deltamethrin had the highest KDT50 R of 8.2. Both Anopheles gambiae sensu stricto and Anopheles arabiensis had equal S allelic frequency of 0.84. Indoor resting mosquitoes had 100% mortality rate after 24 h since exposure. Overall SS genotypic frequency in Teso North and Teso South subcounties was 79.4% against 13.7% homozygous LL genotype and 6.9% heterozygous LS genotype. There was a significant difference (ρ < 0.05) in S allele frequencies between Kengatunyi (0.61) and Rwatama (0.95). Mosquito samples collected in 2013 had the highest S allelic frequency of 0.87. Discussion. Most likely, the higher the selection pressure exerted indoors by insecticidal nets, the higher were the resistance alleles. Use of pyrethroid impregnated nets and agrochemicals may have caused female mosquitoes to select for pyrethroid resistance. Different modes of action and chemical properties in different types of pyrethroids aggravated by a variety of edaphic and climatic factors may have caused different levels of susceptibility in both indoor and outdoor vectors to pyrethroids and carbamate. Species composition and populations in each collection method may have been influenced by insecticide resistance capacity in different species. Conclusions and Recommendations. Both phenotypic and genotypic insecticide resistance levels have been confirmed in Teso North and Teso South subcounties in Western Kenya. Insecticide resistance management practices in Kenya should be fast tracked and harmonized with agricultural sector agrochemical-based activities and legislation, and possibly switch to carbamate use in order to ease selection pressure on pyrethroids which are useable in insecticidal nets and indoor residual spray due to their low human toxicity. The implication of such high resistance levels in mosquitoes collected in Teso subcounties is that resistance is likely to persist and or even increase if monomolecules of permethrin and deltamethrin or both continue to be used in all net- and nonnet-based mosquito control purposes. Usage of mutually reinforcing piperonyl butoxide (PBO) that prohibits particular enzymes vital in metabolic activities inside mosquito systems and has been integrated into pyrethroid-LLINs to create pyrethroid-PBO nets is an extremely viable option.
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Lien NTK, Ngoc NTH, Lan NN, Hien NT, Tung NV, Ngan NTT, Hoang NH, Binh NTH. Transcriptome Sequencing and Analysis of Changes Associated with Insecticide Resistance in the Dengue Mosquito ( Aedes aegypti) in Vietnam. Am J Trop Med Hyg 2020; 100:1240-1248. [PMID: 30834881 DOI: 10.4269/ajtmh.18-0607] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The mosquito Aedes aegypti is a transmission vector for dangerous epidemic diseases in humans. Insecticides have been used as the most general vector control method in the world. However, Ae. aegypti have developed many resistant mechanisms such as reduced neuronal sensitivity to insecticides (target-site resistance), enhanced insecticide metabolism (metabolic resistance), altered transport, sequestration, and other mechanisms. It has become a major problem for vector control programs. Transcriptome sequencing and bioinformatic analysis were used to compare transcription levels between a susceptible strain (Bora7) and a resistant strain (KhanhHoa7) collected from the field. A total of 161 million Illumina reads, including 66,076,678 reads from the Bora7 strain and 69,606,654 reads from the KhanhHoa7 strain, were generated and assembled into 11,174 genes. A comparison of the KhanhHoa7 transcriptome to that of Bora7 showed 672 upregulated genes and 488 downregulated genes. We identified the highly upregulated genes: cytochrome P450 4C1, 4C3, 4C21, 4D1, 4D1 isoform X2, 4D2, 4D2 isoform X2, 4G15, 6A2, 6A8, 6D3, and 9E2; Glutathione S transferase (GST1), UGT1-3, 1-7, 2B15, and 2B37; binding cassette transporter (ABC) transporter F family member 4 and ABC transporter G family member 20. Interestingly, there was a significant increase in the expression of the genes such as CYP9E2 (8.3-fold), CYP6A8 (5.9-fold), CYP6D3 (5.4-fold), CYP4C21 (5.4-fold), CYP4G15 (5.2-fold), GST1 (3.5-fold), and ABC transporter 4 (2.1-fold). Our results suggested a potential relationship between the expression of the genes in metabolic processes and insecticide resistance in the studied strain. These results may contribute to the understanding of the mechanisms of insecticide resistance in Ae. aegypti.
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Affiliation(s)
- Nguyen Thi Kim Lien
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | | | - Nguyen Ngoc Lan
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Nguyen Thu Hien
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam.,Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Nguyen Van Tung
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam.,Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Nguyen Thi Thanh Ngan
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Nguyen Huy Hoang
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam.,Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
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Liu H, Xie L, Cheng P, Xu J, Huang X, Wang H, Song X, Liu L, Wang H, Kou J, Yan G, Chen XG, Gong M. Trends in insecticide resistance in Culex pipiens pallens over 20 years in Shandong, China. Parasit Vectors 2019; 12:167. [PMID: 30975185 PMCID: PMC6460514 DOI: 10.1186/s13071-019-3416-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 03/27/2019] [Indexed: 11/15/2022] Open
Abstract
Background Culex pipiens pallens is the most abundant Culex mosquito species in northern China and is an important vector of bancroftian filariasis and, potentially, West Nile virus. Insecticides, particularly pyrethroids, are widely used for adult mosquito control. Insecticide resistance has become common in several mosquito species, and vector control is the main method currently available to prevent disease transmission. The voltage-gated sodium channel (Vgsc) gene is the target site of pyrethroids, and mutations in this gene cause knockdown resistance (kdr). Methods Culex pipiens pallens larvae were collected from May to November over two decades, from 1992 to 2018, in four cities in Shandong Province, China. The World Health Organization (WHO) standard resistance bioassay was applied to test the resistance levels of Cx. p. pallens larvae to five different insecticides and to test deltamethrin resistance in adults, using the F1 generation. Mutations at Vgsc codon 1014 were also screened in 471 adult samples collected in 2014 to determine the association between kdr mutations and phenotypic resistance. Results Larval resistance against deltamethrin showed an increasing trend from the 1990s until 2018, which was statistically significant in all populations; resistance to cypermethrin increased significantly in mosquitoes from the Zaozhuang population. However, larval resistance to other insecticides remained relatively stable. Larval resistance against deltamethrin was consistent with adult bioassays in 2014, in which all tested populations were highly resistant, with mortality rates ranging from 39.4 to 55.23%. The L1014S and L1014F mutations were both observed in five Cx. p. pallens populations, with L1014F significantly associated with deltamethrin resistance. Conclusions The long-term dataset from Shandong demonstrates major increases in pyrethroid resistance over a 20-year period. The L1014F kdr mutation may be considered a viable molecular marker for monitoring pyrethroid resistance in Cx. p. pallens. Electronic supplementary material The online version of this article (10.1186/s13071-019-3416-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hongmei Liu
- Department of Medical Entomology, Shandong Academy of Medical Sciences, Shandong Institute of Parasitic Diseases, Jining, 272033, Shandong, People's Republic of China.
| | - Lihua Xie
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, People's Republic of China
| | - Peng Cheng
- Department of Medical Entomology, Shandong Academy of Medical Sciences, Shandong Institute of Parasitic Diseases, Jining, 272033, Shandong, People's Republic of China
| | - Jiabao Xu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, People's Republic of China
| | - Xiaodan Huang
- Department of Medical Entomology, Shandong Academy of Medical Sciences, Shandong Institute of Parasitic Diseases, Jining, 272033, Shandong, People's Republic of China
| | - Haifang Wang
- Department of Medical Entomology, Shandong Academy of Medical Sciences, Shandong Institute of Parasitic Diseases, Jining, 272033, Shandong, People's Republic of China
| | - Xiao Song
- Department of Medical Entomology, Shandong Academy of Medical Sciences, Shandong Institute of Parasitic Diseases, Jining, 272033, Shandong, People's Republic of China
| | - Lijuan Liu
- Department of Medical Entomology, Shandong Academy of Medical Sciences, Shandong Institute of Parasitic Diseases, Jining, 272033, Shandong, People's Republic of China
| | - Huaiwei Wang
- Department of Medical Entomology, Shandong Academy of Medical Sciences, Shandong Institute of Parasitic Diseases, Jining, 272033, Shandong, People's Republic of China
| | - Jingxuan Kou
- Department of Medical Entomology, Shandong Academy of Medical Sciences, Shandong Institute of Parasitic Diseases, Jining, 272033, Shandong, People's Republic of China
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, USA
| | - Xiao-Guang Chen
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, People's Republic of China.
| | - Maoqing Gong
- Department of Medical Entomology, Shandong Academy of Medical Sciences, Shandong Institute of Parasitic Diseases, Jining, 272033, Shandong, People's Republic of China.
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Ismail BA, Kafy HT, Sulieman JE, Subramaniam K, Thomas B, Mnzava A, Abu Kassim NF, Ahmad AH, Knox TB, Kleinschmidt I, Donnelly MJ. Temporal and spatial trends in insecticide resistance in Anopheles arabiensis in Sudan: outcomes from an evaluation of implications of insecticide resistance for malaria vector control. Parasit Vectors 2018; 11:122. [PMID: 29499751 PMCID: PMC5834846 DOI: 10.1186/s13071-018-2732-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Accepted: 02/20/2018] [Indexed: 11/10/2022] Open
Abstract
Background Long-lasting insecticidal nets (LLINs) (with pyrethroids) and indoor residual spraying (IRS) are the cornerstones of the Sudanese malaria control program. Insecticide resistance to the principal insecticides in LLINs and IRS is a major concern. This study was designed to monitor insecticide resistance in Anopheles arabiensis from 140 clusters in four malaria-endemic areas of Sudan from 2011 to 2014. All clusters received LLINs, while half (n = 70), distributed across the four regions, had additional IRS campaigns. Methods Anopheles gambiae (s.l.) mosquitoes were identified to species level using PCR techniques. Standard WHO insecticide susceptibility bioassays were carried out to detect resistance to deltamethrin (0.05%), DDT (4%) and bendiocarb (0.1%). TaqMan assays were performed on random samples of deltamethrin-resistant phenotyped and pyrethrum spray collected individuals to determine Vgsc-1014 knockdown resistance mutations. Results Anopheles arabiensis accounted for 99.9% of any anopheline species collected across all sites. Bioassay screening indicated that mosquitoes remained susceptible to bendiocarb but were resistance to deltamethrin and DDT in all areas. There were significant increases in deltamethrin resistance over the four years, with overall mean percent mortality to deltamethrin declining from 81.0% (95% CI: 77.6–84.3%) in 2011 to 47.7% (95% CI: 43.5–51.8%) in 2014. The rate of increase in phenotypic deltamethrin-resistance was significantly slower in the LLIN + IRS arm than in the LLIN-only arm (Odds ratio 1.34; 95% CI: 1.02–1.77). The frequency of Vgsc-1014F mutation varied spatiotemporally with highest frequencies in Galabat (range 0.375–0.616) and New Halfa (range 0.241–0.447). Deltamethrin phenotypic-resistance correlated with Vgsc-1014F frequency. Conclusion Combining LLIN and IRS, with different classes of insecticide, may delay pyrethroid resistance development, but the speed at which resistance develops may be area-specific. Continued monitoring is vital to ensure optimal management and control. Electronic supplementary material The online version of this article (10.1186/s13071-018-2732-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bashir Adam Ismail
- Khartoum Malaria Free Initiative, PO Box 1517, Khartoum, Khartoum State, Sudan. .,School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Pulau Penang, Malaysia.
| | - Hmooda Toto Kafy
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Pulau Penang, Malaysia.,Integrated Vector Management Unit, Federal Ministry of Health, PO Box 303, Khartoum, Sudan
| | - Jihad Eltaher Sulieman
- Sennar Malaria Research and Training Centre, Federal Ministry of Health, PO Box 303, Sennar, Sudan
| | - Krishanthi Subramaniam
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Brent Thomas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Abraham Mnzava
- African Leaders Malaria Alliance (ALMA), 14 Kanisa Road, Corridor Area, P.O. Box 1973, Arusha, Tanzania
| | - Nur Faeza Abu Kassim
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Pulau Penang, Malaysia
| | - Abu Hassan Ahmad
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Pulau Penang, Malaysia
| | - Tessa B Knox
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Immo Kleinschmidt
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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Viana-Medeiros PF, Bellinato DF, Martins AJ, Valle D. Insecticide resistance, associated mechanisms and fitness aspects in two Brazilian Stegomyia aegypti (= Aedes aegypti) populations. MEDICAL AND VETERINARY ENTOMOLOGY 2017; 31:340-350. [PMID: 28752548 DOI: 10.1111/mve.12241] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 03/13/2017] [Accepted: 03/24/2017] [Indexed: 06/07/2023]
Abstract
In Brazil, insecticide resistance in Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) populations to pyrethroids and to the organophosphate (OP) temephos is disseminated. Currently, insect growth regulators (IGRs) and the OP malathion are employed against larvae and adults, respectively. Bioassays with mosquitoes from two northeast municipalities, Crato and Aracaju, revealed, in both populations, susceptibility to IGRs and malathion (RR95 ≤ 2.0), confirming the effectiveness of these compounds. By contrast, temephos and deltamethrin (pyrethroid) resistance levels were high (RR95 > 10), which is consistent with the use of intense chemical control. In Crato, RR95 values were > 50 for both compounds. Knock-down-resistant (kdr) mutants in the voltage-gated sodium channel, the pyrethroid target site, were found in 43 and 32%, respectively, of Aracaju and Crato mosquitoes. Biochemical assays revealed higher metabolic resistance activity (esterases, mixed function oxidases and glutathione-S-transferases) at Aracaju. With respect to fitness aspects, mating effectiveness was equivalently impaired in both populations, but Aracaju mosquitoes showed more damaging effects in terms of longer larval development, decreased bloodmeal acceptance, reduced engorgement and lower numbers of eggs laid per female. Compared with mosquitoes in Crato, Aracaju mosquitoes exhibited lower OP and pyrethroid RR95 , increased activity of detoxifying enzymes and greater effect on fitness. The potential relationship between insecticide resistance mechanisms and mosquito viability is discussed.
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Affiliation(s)
- P F Viana-Medeiros
- Laboratório de Biologia Molecular de Flavivírus, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
| | - D F Bellinato
- Laboratório de Biologia Molecular de Flavivírus, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
| | - A J 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 (INCT-EM), Rio de Janeiro, Brazil
| | - D Valle
- Laboratório de Biologia Molecular de Flavivírus, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM), Rio de Janeiro, Brazil
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Wei X, Yan G, Zhou G, Zhong D, Fang Q, Yang X, Hu D, Chang X. A neural network prediction of environmental determinants of Anopheles sinensis knockdown resistance mutation to pyrethroids in China. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2016; 41:295-302. [PMID: 27860007 DOI: 10.1111/jvec.12226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 09/20/2016] [Indexed: 06/06/2023]
Abstract
Selection pressure caused by long-term intensive use of insecticides is the key driving force in resistance development. Additional parameters such as environmental conditions may affect both the mosquito response to insecticides and the selection of resistance mechanisms. In this context, we analyzed the environmental determinants of kdr prevalence in Anopheles sinensis across China. We collected kdr frequency from 48 sites across central and southern China, together with key environmental factors including long-term climatic data, topographic features, main crops, and land cover types. Trend surface analysis found that the distribution of kdr frequency can be partitioned into three regions, namely central China (kdr frequency >80%), western China (kdr frequency varies from 0% to 60%), and southern China (kdr frequency <10%). Seven predictor variables were selected based on a radial basis function neural network model. A multilayer perceptron (MLP) network model revealed that the number of crops in a year was the most important predictor for the kdr mutation rate. Topography, long-term mean climate and land cover all contributed to the kdr mutation rate. The observed mean kdr frequency was 53.0% and the MLP network model-predicted mean was 52.6%, a 0.1% relative error. Predicted kdr frequencies closely matched the observed values. The model explained 92% of the total variance in kdr frequency. The results indicated that kdr was associated with the intensity of pesticide usage. Crop cultivation information, together with environmental factors, may well predict the spatial heterogeneity of kdr mutations in An. sinensis in China.
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Affiliation(s)
- Xing Wei
- Institute of Information Security and Big Data, Central South University, Changsha 410083, Hunan, China
- Department of Microbiology and Parasitology, Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, Bengbu 233000, Anhui, China
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California 92697, U.S.A
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California 92697, U.S.A
| | - Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California 92697, U.S.A
| | - Qiang Fang
- Department of Microbiology and Parasitology, Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, Bengbu 233000, Anhui, China
| | - Xiaodi Yang
- Department of Microbiology and Parasitology, Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, Bengbu 233000, Anhui, China
| | - Dehua Hu
- Institute of Information Security and Big Data, Central South University, Changsha 410083, Hunan, China
| | - Xuelian Chang
- Department of Microbiology and Parasitology, Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, Bengbu 233000, Anhui, China
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Ketseoglou I, Bouwer G. The persistence and ecological impacts of a cyanobacterium genetically engineered to express mosquitocidal Bacillus thuringiensis toxins. Parasit Vectors 2016; 9:273. [PMID: 27165108 PMCID: PMC4863325 DOI: 10.1186/s13071-016-1544-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/27/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The cyanobacterium Anabaena PCC 7120#11 has been genetically engineered to act as a delivery vehicle for Bacillus thuringiensis subspecies israelensis mosquitocidal toxins. To address ecological concerns about releasing this genetically engineered microorganism into the environment for mosquito larva control, the persistence and ecological impacts of PCC 7120#11 was evaluated using multi-species, standardized aquatic microcosms. METHODS The microcosms were set up as described in ASTM E1366-02 (Standard Practice for Standardized Aquatic Microcosms: Fresh Water), with a few modifications. The treatment group microcosms were inoculated with PCC 7120#11 and key water quality parameters and non-target effects were compared between the treatment and control groups over a period of 35 days. RESULTS PCC 7120#11 decreased from a concentration of 4.50 × 10(6) cells/ml (at inoculation) to 1.32 × 10(3) cells/ml after 4 weeks and larvicidal activity against third instar larvae of Anopheles arabiensis was only evident for two weeks after treatment. Both treatment and the interaction of treatment and time had a significant effect on nitrate, phosphate and photosynthetic microorganism concentrations. Treatment with PCC 7120#11 caused a temporary spike in ammonia in the microcosms a week after treatment, but the concentrations were well below acute and chronic criteria values for ammonia in freshwater ecosystems. Cyprinotus vidua concentrations were not significantly different between PCC 7120#11 and control microcosms. In PCC 7120#11 microcosms, Daphnia pulex concentrations were significantly lower than control concentrations between days 18 and 25. By the end of the experiment, none of the measured variables were significantly different between the treatment groups. CONCLUSIONS The standard aquatic microcosm experiments provided more data on the ecological impacts of PCC 7120#11 than single-organism assessments would have. On the basis of the relatively minor, short-term effects that PCC 7120#11 had on water quality parameters and non-target invertebrates, further evaluation of PCC 7120#11 for use in integrated vector management is warranted.
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Affiliation(s)
- Irene Ketseoglou
- School of Molecular and Cell Biology, University of the Witwatersrand, , Private Bag 3, Wits, 2050, Johannesburg, South Africa
| | - Gustav Bouwer
- School of Molecular and Cell Biology, University of the Witwatersrand, , Private Bag 3, Wits, 2050, Johannesburg, South Africa.
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Oliver SV, Brooke BD. The effect of multiple blood-feeding on the longevity and insecticide resistant phenotype in the major malaria vector Anopheles arabiensis (Diptera: Culicidae). Parasit Vectors 2014; 7:390. [PMID: 25150975 PMCID: PMC4161849 DOI: 10.1186/1756-3305-7-390] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/13/2014] [Indexed: 11/10/2022] Open
Abstract
Background Anopheles arabiensis is a major malaria vector in Africa. Adult females are likely to imbibe multiple blood meals during their lifetime. This results in regular exposure to potential toxins and blood-meal induced oxidative stress. Defence responses to these stressors may affect other factors of epidemiological significance, such as insecticide resistance and longevity. The aims of this study were to examine the effect of multiple blood-feeding on insecticide tolerance/resistance with increasing age, to assess the underlying biochemical mechanisms for the responses recorded, and to assess the effect of multiple blood-feeding on the life histories of adult females drawn from insecticide resistant and susceptible laboratory reared An. arabiensis. Methods Laboratory reared An. arabiensis females from an insecticide resistant and an insecticide susceptible colony were offered either a single blood meal or multiple blood meals at 3-day intervals. Their tolerance or resistance to insecticide was then monitored by WHO bioassay four hours post blood-feeding. The biochemical basis of the phenotypic response was assessed by examining the effect of blood on detoxification enzyme activity and the effect of blood-meals on detoxification enzyme activity in ageing mosquitoes. Results Control cohorts that were not offered any blood meals showed steadily decreasing levels of insecticide tolerance/resistance with age, whereas a single blood meal significantly increased tolerance/resistance primarily at the age of three days. The expression of resistance/tolerance in those cohorts fed multiple blood meals generally showed the least variation with age. These results were consistent following exposure to DDT and pyrethroids but not to malathion. Multiple blood-meals also maintained the DDT and permethrin resistant phenotype, even after treatment females had stopped taking blood-meals. Biochemical analysis suggests that this phenotypic effect in resistant females may be mediated by the maintenance of increased glutathione s-transferase activity as a consequence of multiple blood-feeding. Multiple blood-feeding increased the longevity of insecticide resistant females regardless of their mating status, but only increased the longevity of unmated susceptible females. Conclusion These data suggest that multiple blood-feeding confers a competitive advantage to insecticide resistant females by increased longevity and maintenance of the expression of resistance with age.
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Affiliation(s)
- Shüné V Oliver
- Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases/NHLS, Sandringham, Johannesburg, South Africa.
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Otali D, Novak RJ, Wan W, Bu S, Moellering DR, De Luca M. Increased production of mitochondrial reactive oxygen species and reduced adult life span in an insecticide-resistant strain of Anopheles gambiae. BULLETIN OF ENTOMOLOGICAL RESEARCH 2014; 104:323-33. [PMID: 24555527 PMCID: PMC4008687 DOI: 10.1017/s0007485314000091] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Control of the malaria vector An. gambiae is still largely obtained through chemical intervention using pyrethroids, such as permethrin. However, strains of An. gambiae that are resistant to the toxic effects of pyrethroids have become widespread in several endemic areas over the last decade. The objective of this study was to assess differences in five life-history traits (larval developmental time and the body weight, fecundity, hatch rate, and longevity of adult females) and energy metabolism between a strain of An. gambiae that is resistant to permethrin (RSP), due to knockdown resistance and enhanced metabolic detoxification, and a permethrin susceptible strain reared under laboratory conditions. We also quantified the expression levels of five antioxidant enzyme genes: GSTe3, CAT, GPXH1, SOD1, and SOD2. We found that the RSP strain had a longer developmental time than the susceptible strain. Additionally, RSP adult females had higher wet body weight and increased water and glycogen levels. Compared to permethrin susceptible females, RSP females displayed reduced metabolic rate and mitochondrial coupling efficiency and higher mitochondrial ROS production. Furthermore, despite higher levels of GSTe3 and CAT transcripts, RSP females had a shorter adult life span than susceptible females. Collectively, these results suggest that permethrin resistance alleles might affect energy metabolism, oxidative stress, and adult survival of An. gambiae. However, because the strains used in this study differ in their genetic backgrounds, the results need to be interpreted with caution and replicated in other strains to have significant implications for malaria transmission and vector control.
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Affiliation(s)
- Dennis Otali
- Department of Biology, University of Alabama at Birmingham, 1720 2 Ave. South, Birmingham, AL 35294-1170, USA
- Corresponding Author: Dennis Otali, Department of Biology, University of Alabama at Birmingham, Campbell Hall 464, 1720 2 Ave S, Birmingham AL 35294-1170, Phone: (+1) 205-975-6205, Fax: (+1) 205-975-7128,
| | - Robert J. Novak
- William C Gorgas Center for Geographic Medicine, Division of Infectious Diseases, Department of Medicine, University of Alabama at Birmingham, 845 19th St. South, Birmingham, AL 35294-2170, USA
- Department of Global Health, University of South Florida, 13201 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Wen Wan
- Department of Biostatistics, Virginia Commonwealth University Medical Center, P.O. Box 980032, Richmond, VA 23298-0032, USA
| | - Su Bu
- Department of Nutrition Sciences, University of Alabama at Birmingham, 1720 2 Ave. South, Birmingham, AL 35294-3360, USA
| | - Douglas R. Moellering
- Department of Nutrition Sciences, University of Alabama at Birmingham, 1720 2 Ave. South, Birmingham, AL 35294-3360, USA
| | - Maria De Luca
- Department of Nutrition Sciences, University of Alabama at Birmingham, 1720 2 Ave. South, Birmingham, AL 35294-3360, USA
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Abdalla H, Wilding CS, Nardini L, Pignatelli P, Koekemoer LL, Ranson H, Coetzee M. Insecticide resistance in Anopheles arabiensis in Sudan: temporal trends and underlying mechanisms. Parasit Vectors 2014; 7:213. [PMID: 24886129 PMCID: PMC4026821 DOI: 10.1186/1756-3305-7-213] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 04/08/2014] [Indexed: 12/03/2022] Open
Abstract
Background Malaria vector control in Sudan relies mainly on indoor residual spraying (IRS) and the use of long lasting insecticide treated bed nets (LLINs). Monitoring insecticide resistance in the main Sudanese malaria vector, Anopheles arabiensis, is essential for planning and implementing an effective vector control program in this country. Methods WHO susceptibility tests were used to monitor resistance to insecticides from all four WHO-approved classes of insecticide at four sentinel sites in Gezira state over a three year period. Insecticide resistance mechanisms were studied using PCR and microarray analyses. Results WHO susceptibility tests showed that Anopheles arabiensis from all sites were fully susceptible to bendiocarb and fenitrothion for the duration of the study (2008–2011). However, resistance to DDT and pyrethroids was detected at three sites, with strong seasonal variations evident at all sites. The 1014 F kdr allele was significantly associated with resistance to pyrethroids and DDT (P < 0.001) with extremely high effects sizes (OR > 7 in allelic tests). The 1014S allele was not detected in any of the populations tested. Microarray analysis of the permethrin-resistant population of An. arabiensis from Wad Medani identified a number of metabolic genes that were significantly over-transcribed in the field-collected resistant samples when compared to the susceptible Sudanese An. arabiensis Dongola strain. These included CYP6M2 and CYP6P3, two genes previously implicated in pyrethroid resistance in Anopheles gambiae s.s, and the epsilon-class glutathione-S-transferase, GSTe4. Conclusions These data suggest that both target-site mechanisms and metabolic mechanisms play an important role in conferring pyrethroid resistance in An. arabiensis from Sudan. Identification in An. arabiensis of candidate loci that have been implicated in the resistance phenotype in An. gambiae requires further investigation to confirm the role of these genes.
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Affiliation(s)
| | | | | | | | | | | | - Maureen Coetzee
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
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Nardini L, Christian RN, Coetzer N, Koekemoer LL. DDT and pyrethroid resistance in Anopheles arabiensis from South Africa. Parasit Vectors 2013; 6:229. [PMID: 23924547 PMCID: PMC3751093 DOI: 10.1186/1756-3305-6-229] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/02/2013] [Indexed: 11/11/2022] Open
Abstract
Background Pyrethroid resistance has been well documented in Anopheles arabiensis, one of the major African malaria vectors, and the predominant malaria vector in South Africa. Methods In this study, the genetic basis of pyrethroid resistance in a selected laboratory strain of An. arabiensis from South Africa was investigated using a custom-made microarray, known as the An. gambiae detoxification chip. Results A large number of P450 genes were over-transcribed, as well as a suite of redox genes and glutathione S-transferases. The five genes that showed the highest level of gene transcription when compared with an insecticide susceptible strain were: CYP6AG2, CYPZ1, TPX2, CYPZ2 and CYP6P1. Conclusions Permethrin resistance in South African An. arabiensis is associated with increased transcription of multiple genes, and a large proportion of these genes were also previously recorded as over-transcribed in another An. arabiensis strain selected for resistance to DDT with cross-resistance to deltamethrin. The deltamethrin resistance developed de novo in the DDT-selected strain and is most likely due to increased transcription of those genes associated with DDT resistance. However, of particular interest was the fact that the strain selected for resistance to pyrethroids did not develop de novo resistance to DDT. These differences are compared and discussed.
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Affiliation(s)
- Luisa Nardini
- Division of the National Health Laboratory Services, Vector Control Reference Laboratory, Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Johannesburg , Sandringham, South Africa.
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Nkya TE, Akhouayri I, Kisinza W, David JP. Impact of environment on mosquito response to pyrethroid insecticides: facts, evidences and prospects. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:407-16. [PMID: 23123179 DOI: 10.1016/j.ibmb.2012.10.006] [Citation(s) in RCA: 196] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/18/2012] [Accepted: 10/18/2012] [Indexed: 05/23/2023]
Abstract
By transmitting major human diseases such as malaria, dengue fever and filariasis, mosquito species represent a serious threat worldwide in terms of public health, and pose a significant economic burden for the African continent and developing tropical regions. Most vector control programmes aiming at controlling life-threatening mosquitoes rely on the use of chemical insecticides, mainly belonging to the pyrethroid class. However, resistance of mosquito populations to pyrethroids is increasing at a dramatic rate, threatening the efficacy of control programmes throughout insecticide-treated areas, where mosquito-borne diseases are still prevalent. In the absence of new insecticides and efficient alternative vector control methods, resistance management strategies are therefore critical, but these require a deep understanding of adaptive mechanisms underlying resistance. Although insecticide resistance mechanisms are intensively studied in mosquitoes, such adaptation is often considered as the unique result of the selection pressure caused by insecticides used for vector control. Indeed, additional environmental parameters, such as insecticides/pesticides usage in agriculture, the presence of anthropogenic or natural xenobiotics, and biotic interactions between vectors and other organisms, may affect both the overall mosquito responses to pyrethroids and the selection of resistance mechanisms. In this context, the present work aims at updating current knowledge on pyrethroid resistance mechanisms in mosquitoes and compiling available data, often from different research fields, on the impact of the environment on mosquito response to pyrethroids. Key environmental factors, such as the presence of urban or agricultural pollutants and biotic interactions between mosquitoes and their microbiome are discussed, and research perspectives to fill in knowledge gaps are suggested.
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Affiliation(s)
- Theresia Estomih Nkya
- National Institute of Medical Research of Tanzania, Amani Medical Research Centre, Muheza, Tanga, Tanzania
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Sun Y, Zou P, Yu XY, Chen C, Yu J, Shi LN, Hong SC, Zhou D, Chang XL, Wang WJ, Shen B, Zhang DH, Ma L, Zhu CL. Functional characterization of an arrestin gene on insecticide resistance of Culex pipiens pallens. Parasit Vectors 2012; 5:134. [PMID: 22768923 PMCID: PMC3425237 DOI: 10.1186/1756-3305-5-134] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 06/29/2012] [Indexed: 11/12/2022] Open
Abstract
Background Continuous and excessive application of insecticides has resulted in the rapid development of insecticide resistance in several mosquito species, including Culex pipiens pallens. Previous studies in our laboratory found that arrestin gene expression was higher in the deltamethrin-resistant (DR) strain than in the deltamethrin-susceptible (DS) strain of Cx. pipiens pallens. Similarly, other studies reported that arrestin was highly expressed in permethrin-resistant Cx. quinquefasciatus and in dichlorodiphenyltrichloroethane (DDT)-resistant Drosophila melanogaster. Methods Full-length cDNAs of an arrestin gene were cloned from Cx. pipiens pallens via polymerase chain reaction (PCR) and rapid amplification of cDNA end (RACE). The mRNA levels of the arrestin gene in the whole life cycle of DR and DS strains of Cx. pipiens pallens were investigated via quantitative real-time PCR. In addition, the relationship between arrestin and deltamethrin (DM) resistance were identified using genetic overexpression strategies and arrestin RNAi in mosquito cells. Cell viability was analyzed with cholecystokinin octapeptide after DM treatment. Moreover, the mRNA levels of cytochrome P450 6A1 (CYP6A1) and opsin in the transfected cells and controls were analyzed. Results Complete arrestin gene sequence was cloned and expressed throughout the life cycle of Cx. pipiens pallens. Moreover, arrestin was significantly upregulated in the DR strain, compared with that in the DS strain at the egg, pupae, and adult stages. Arrestin overexpression comparably increased the mosquito cell viability, whereas arrestin knockdown by siRNA decreased mosquito cell viability with deltamethrin (DM) treatment. Meanwhile, the mRNA levels of CYP6A1 and opsin were upregulated in mosquito cells transfected with arrestin and downregulated in mosquito cells with arrestin knockdown. Conclusion This study presented the first evidence that arrestin might be associated with insecticide resistance in Cx. pipiens pallens.
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Affiliation(s)
- Yan Sun
- Department of Pathogen Biology, Nanjing Medical University, 140 Hanzhong Road., Nanjing 210029, Jiang Su Province, People's Republic of China
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Nardini L, Christian RN, Coetzer N, Ranson H, Coetzee M, Koekemoer LL. Detoxification enzymes associated with insecticide resistance in laboratory strains of Anopheles arabiensis of different geographic origin. Parasit Vectors 2012; 5:113. [PMID: 22676389 PMCID: PMC3430573 DOI: 10.1186/1756-3305-5-113] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 06/03/2012] [Indexed: 11/28/2022] Open
Abstract
Background The use of insecticides to control malaria vectors is essential to reduce the prevalence of malaria and as a result, the development of insecticide resistance in vector populations is of major concern. Anopheles arabiensis is one of the main African malaria vectors and insecticide resistance in this species has been reported in a number of countries. The aim of this study was to investigate the detoxification enzymes that are involved in An. arabiensis resistance to DDT and pyrethroids. Methods The detoxification enzyme profiles were compared between two DDT selected, insecticide resistant strains of An. arabiensis, one from South Africa and one from Sudan, using the An. gambiae detoxification chip, a boutique microarray based on the major classes of enzymes associated with metabolism and detoxification of insecticides. Synergist assays were performed in order to clarify the roles of over-transcribed detoxification genes in the observed resistance phenotypes. In addition, the presence of kdr mutations in the colonies under investigation was determined. Results The microarray data identifies several genes over-transcribed in the insecticide selected South African strain, while in the Sudanese population, only one gene, CYP9L1, was found to be over-transcribed. The outcome of the synergist experiments indicate that the over-transcription of detoxification enzymes is linked to deltamethrin resistance, while DDT and permethrin resistance are mainly associated with the presence of the L1014F kdr mutation. Conclusions These data emphasise the complexity associated with resistance phenotypes and suggest that specific insecticide resistance mechanisms cannot be extrapolated to different vector populations of the same species.
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Affiliation(s)
- Luisa Nardini
- Vector Control Reference Unit, Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa.
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Nwane P, Etang J, Chouaїbou M, Toto JC, Mimpfoundi R, Simard F. Kdr-based insecticide resistance in Anopheles gambiae s.s populations in. BMC Res Notes 2011; 4:463. [PMID: 22035176 PMCID: PMC3221647 DOI: 10.1186/1756-0500-4-463] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 10/28/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The spread of insecticide resistance in the malaria mosquito, Anopheles gambiae is a serious threat for current vector control strategies which rely on the use of insecticides. Two mutations at position 1014 of the S6 transmembrane segment of domain II in the voltage gated sodium channel, known as kdr (knockdown resistance) mutations leading to a change of a Leucine to a Phenylalanine (L1014F) or to a Serine (L1014S) confer resistance to DDT and pyrethroid insecticides in the insect. This paper presents the current distribution of the kdr alleles in wild Anopheles gambiae populations in Cameroon. RESULTS A total of 1,405 anopheline mosquitoes were collected from 21 localities throughout Cameroon and identified as An. gambiae (N = 1,248; 88.8%), An. arabiensis (N = 120; 8.5%) and An. melas (N = 37; 2.6%). Both kdr alleles 1014F and 1014S were identified in the M and S molecular forms of An. gambiae s.s. The frequency of the 1014F allele ranged from 1.7 to 18% in the M-form, and from 2 to 90% in the S-form. The 1014S allele ranged from 3-15% in the S-form and in the M-form its value was below 3%. Some specimens were found to carry both resistant kdr alleles. CONCLUSION This study provides an updated distribution map of the kdr alleles in wild An. gambiae populations in Cameroon. The co-occurrence of both alleles in malaria mosquito vectors in diverse ecological zones of the country may be critical for the planning and implementation of malaria vector control interventions based on IRS and ITNs, as currently ongoing in Cameroon.
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Affiliation(s)
- Philippe Nwane
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroun.
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19
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Himeidan YE, Muzamil HMA, Jones CM, Ranson H. Extensive permethrin and DDT resistance in Anopheles arabiensis from eastern and central Sudan. Parasit Vectors 2011; 4:154. [PMID: 21812972 PMCID: PMC3170279 DOI: 10.1186/1756-3305-4-154] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 08/03/2011] [Indexed: 11/10/2022] Open
Abstract
Background The distribution of insecticide treated nets (ITN) has been dramatically scaled up in eastern and central Sudan. Resistance to insecticides has already been reported in this region and there is an urgent need to develop appropriate resistance management strategies, which requires detailed information on the extent and causes of resistance. This study assessed resistance to permethrin and DDT in seven populations of Anopheles arabiensis from Sudan. Results Three out of the seven populations were defined as resistant to permethrin and five of six populations resistant to DDT according to WHO criteria. The 1014F kdr allele was present in all six populations tested and the presence of this allele was significantly correlated with resistance to permethrin (P = 0.0460). While homozygous 1014F individuals were statistically not more likely to survive (53.7%) permethrin than to be killed (38.6%) by the diagnostic dose, there was no difference in the likelihood of permethrin survival in heterozygotes (P = 0.7973). The susceptible genotypes were more likely to be killed by permethrin exposure than to survive (P = 0.0460). The 1014F allele failed to confer a survival advantage to the WHO diagnostic dose of DDT in either the homozygous or heterozygous state. The 1014S allele was not detected in any of the populations tested. Conclusion The kdr allele is certainly contributing to the extensive resistance to permethrin and DDT in Sudan but the high number of DDT (43%) and permethrin (16.7%) survivors that did not contain either kdr alleles suggests that other resistance mechanisms are also present in these populations. The high frequency of permethrin resistance throughout central and eastern Sudan is a cause of great concern for malaria control activities.
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Affiliation(s)
- Yousif E Himeidan
- Entomology Unit, Faculty of Agriculture and Natural Resources, University of Kassala, New Halfa, Sudan.
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Min-Oo G, Gros P. Genetic analysis in mice identifies cysteamine as a novel partner for artemisinin in the treatment of malaria. Mamm Genome 2011; 22:486-94. [DOI: 10.1007/s00335-011-9316-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 01/21/2011] [Indexed: 11/29/2022]
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Sinka ME, Bangs MJ, Manguin S, Coetzee M, Mbogo CM, Hemingway J, Patil AP, Temperley WH, Gething PW, Kabaria CW, Okara RM, Van Boeckel T, Godfray HCJ, Harbach RE, Hay SI. The dominant Anopheles vectors of human malaria in Africa, Europe and the Middle East: occurrence data, distribution maps and bionomic précis. Parasit Vectors 2010; 3:117. [PMID: 21129198 PMCID: PMC3016360 DOI: 10.1186/1756-3305-3-117] [Citation(s) in RCA: 406] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 12/03/2010] [Indexed: 11/10/2022] Open
Abstract
Background This is the second in a series of three articles documenting the geographical distribution of 41 dominant vector species (DVS) of human malaria. The first paper addressed the DVS of the Americas and the third will consider those of the Asian Pacific Region. Here, the DVS of Africa, Europe and the Middle East are discussed. The continent of Africa experiences the bulk of the global malaria burden due in part to the presence of the An. gambiae complex. Anopheles gambiae is one of four DVS within the An. gambiae complex, the others being An. arabiensis and the coastal An. merus and An. melas. There are a further three, highly anthropophilic DVS in Africa, An. funestus, An. moucheti and An. nili. Conversely, across Europe and the Middle East, malaria transmission is low and frequently absent, despite the presence of six DVS. To help control malaria in Africa and the Middle East, or to identify the risk of its re-emergence in Europe, the contemporary distribution and bionomics of the relevant DVS are needed. Results A contemporary database of occurrence data, compiled from the formal literature and other relevant resources, resulted in the collation of information for seven DVS from 44 countries in Africa containing 4234 geo-referenced, independent sites. In Europe and the Middle East, six DVS were identified from 2784 geo-referenced sites across 49 countries. These occurrence data were combined with expert opinion ranges and a suite of environmental and climatic variables of relevance to anopheline ecology to produce predictive distribution maps using the Boosted Regression Tree (BRT) method. Conclusions The predicted geographic extent for the following DVS (or species/suspected species complex*) is provided for Africa: Anopheles (Cellia) arabiensis, An. (Cel.) funestus*, An. (Cel.) gambiae, An. (Cel.) melas, An. (Cel.) merus, An. (Cel.) moucheti and An. (Cel.) nili*, and in the European and Middle Eastern Region: An. (Anopheles) atroparvus, An. (Ano.) labranchiae, An. (Ano.) messeae, An. (Ano.) sacharovi, An. (Cel.) sergentii and An. (Cel.) superpictus*. These maps are presented alongside a bionomics summary for each species relevant to its control.
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Affiliation(s)
- Marianne E Sinka
- Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
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