Malaria vectors in the Democratic Republic of the Congo: the mechanisms that confer insecticide resistance in Anopheles gambiae and Anopheles funestus

Malaria Journal

Research

Nanette Christie¹  Riann N. Christian²  Luisa Nardini²  Yael L. Dahan-Moss²  Richard H. Hunt²  Maureen Coetzee²  Lizette L. Koekemoer² 

[1] Department of Genetics, Forestry and Agricultural Biotechnology Institute, University of Pretoria, 0028, Pretoria, South Africa;Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, 2000, Johannesburg, South Africa;Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, 2131, Johannesburg, South Africa;

关键词: Anopheles funestus;    Anopheles gambiae;    Deltamethrin resistance;    kdr;    Metabolic resistance;    P450s;    GST;   

DOI  :  10.1186/s12936-017-2099-y

 received in 2017-07-29, accepted in 2017-10-28,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundThe Democratic Republic of the Congo (DRC) is characterized as a holoendemic malaria area with the main vectors being Anopheles funestus and members of the Anopheles gambiae complex. Due to political instability and socio-economic challenges in the region, knowledge of insecticide resistance status and resistance mechanisms in these vectors is limited. Mosquitoes were collected from a mining site in the north-eastern part of the country and, following identification, were subjected to extensive testing for the target-site and biochemical basis of resistance. Quantitative real-time PCR was used to assess a suite of 10 genes frequently involved in pyrethroid and dichlorodiphenyltrichloroethane (DDT) resistance in An. gambiae females and males. In An. funestus, gene expression microarray analysis was carried out on female mosquitoes.ResultsIn both species, deltamethrin resistance was recorded along with high resistance and suspected resistance to DDT in An. gambiae and An. funestus, respectively. A total of 85% of An. gambiae carried the kdr mutations as either homozygous resistant (RR) (L1014S, L1014F or both) or heterozygous (RS), however only 3% carried the rdl mutant allele (RS) and no ace-1 mutations were recorded. Synergist assays indicated a strong role for P450s in deltamethrin resistance in both species. In An. gambiae, analysis of transcription levels showed that the glutathione-S-transferase, GSTS1-2, produced the highest fold change in expression (7.6-fold in females and 31-fold in males) followed by GSTE2, thioredoxin peroxidase (TPX2), and cytochrome oxidases (CYP6M2 and CYP6P1). All other genes tested produced fold change values below 2. Microarray analysis revealed significant over-transcription of cuticular proteins as well as CYP6M7, CYP6P9a and CYP6P9b in insecticide resistant An. funestus.ConclusionsThese data show that high levels of deltamethrin resistance in the main malaria vector species, conferred by enzymatic detoxification, are present in the DRC.

【 授权许可】

CC BY   
© The Author(s) 2017