Pyrethroids and DDT tolerance of Anopheles gambiae s.l. from Sengerema District, an area of intensive pesticide usage in north‐western Tanzania

Abstract

Abstractobjective To assess the susceptibility status of malaria vectors to pyrethroids and dichlorodiphenyltrichloroethane (DDT), characterise the mechanisms underlying resistance and evaluate the role of agro-chemical use in resistance selection among malaria vectors in Sengerema agro-ecosystem zone, Tanzania.methods Mosquito larvae were collected from farms and reared to obtain adults. The susceptibility status of An. gambiae s.l. was assessed using WHO bioassay tests to permethrin, deltamethrin, lambdacyhalothrin, etofenprox, cyfluthrin and DDT. Resistant specimens were screened for knockdown resistance gene (kdr), followed by sequencing both Western and Eastern African variants. A gas chromatography-mass spectrophotometer (GC-MS) was used to determine pesticide residues in soil and sediments from mosquitoes' breeding habitats.results Anopheles gambiae s.l. was resistant to all the insecticides tested. The population of Anopheles gambiae s.l was composed of Anopheles arabiensis by 91%. The East African kdr (L1014S) allele was found in 13 of 305 specimens that survived insecticide exposure, with an allele frequency from 0.9% to 50%. DDTs residues were found in soils at a concentration up to 9.90 ng/g (dry weight).conclusion The observed high resistance levels of An. gambiae s.l., the detection of kdr mutations and pesticide residues in mosquito breeding habitats demonstrate vector resistance mediated by pesticide usage. An integrated intervention through collaboration of agricultural, livestock and vector control units is vital.

Bio-efficacy of DuraNet® long-lasting insecticidal nets against wild populations of Anopheles arabiensis in experimental huts

“…The wide coverage of LLINs is thought to have contributed to the development of insecticide resistance in the local malaria vectors population due to the insecticide selection pressure encountered by vectors [ 9 , 17 ]. Many vector species have developed resistance to one or more classes of insecticides commonly used in Tanzania [ 18 – 20 ]. Development of vector resistance may be caused by many factors including overuse of insecticides by ITNs, IRS, and household pest control or by agricultural pesticides use [ 19 , 21 – 24 ].…”

Metabolomics‐on‐a‐chip approach to study hepatotoxicity of DDT, permethrin and their mixtures

“…The majority of these studies have demonstrated the toxicological effects of these compounds in animals and humans (Singh, ; Turusov et al, ; Wang et al, ). Although simultaneous exposure to DDT and PMT was demonstrated (Bouwman & Kylin, ; Gunier et al, ; Philbert et al, ; ul Hassan et al, ; Xu et al, ), the toxic effects caused by the DDT + PMT interaction remain unknown and are rarely studied. In this study, we have used metabolomics‐on‐a‐chip approach to investigate the effect of DDT, PMT and DDT + PMT mixture on liver cells.…”

“…Although DDT has been prohibited in most countries since 1970, it remains widespread in the environment at high concentrations because of its high resistance to degradation (Hurd‐Brown et al, ; Shi et al, ). Moreover, DDT is still used in countries in which malaria is a public health problem (Chaumeau et al, ; Philbert, Lyantagaye, Pradel, Ngwa, & Nkwengulila, ).…”

“…DDT and PMT are among the most widespread pesticides in the environment. In the last years, a number of studies have shown that residues of DDT and PMT coexist in soil, water, residential environment and food (Bouwman & Kylin, ; Gunier et al, ; Philbert et al, ; ul Hassan, Tabinda, Abbas, & Khan, ; Xu, Bui, Lamerdin, & Schlenk, ). DDT and PMT have been widely studied and their toxicities demonstrated.…”

Magnetic solid‐phase extraction of pyrethroid pesticides in environmental water samples with CoFe2O4‐embedded porous graphitic carbon nanocomposites

“…Many modern analytical methods for pyrethroids detection have been reported, such as GC with electron capture detection and GC–MS . However, the concentrations of analytes are very low and the sensitivity of direct detection is often inadequate in complex matrix.…”