Pyrethroids resistance intensity and resistance mechanisms in Anopheles gambiae from malaria vector surveillance sites in Nigeria.

Autor: Awolola TS; Nigerian Institute of Medical Research, 6 Edmund Crescent, Yaba, Lagos, Nigeria., Adeogun A; Nigerian Institute of Medical Research, 6 Edmund Crescent, Yaba, Lagos, Nigeria., Olakiigbe AK; Nigerian Institute of Medical Research, 6 Edmund Crescent, Yaba, Lagos, Nigeria., Oyeniyi T; Nigerian Institute of Medical Research, 6 Edmund Crescent, Yaba, Lagos, Nigeria., Olukosi YA; Nigerian Institute of Medical Research, 6 Edmund Crescent, Yaba, Lagos, Nigeria., Okoh H; Department of Biological Sciences, Federal University Oye, Oye, Ekiti State, Nigeria., Arowolo T; World Health Organization, Lagos, Nigeria., Akila J; National Malaria Elimination Program, Federal Ministry of Health, Abuja, Nigeria., Oduola A; Department of Zoology, University of Ilorin, Ilorin, Kwara State, Nigeria., Amajoh CN; Community Vision Initiative, Abuja, Nigeria.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2018 Dec 05; Vol. 13 (12), pp. e0205230. Date of Electronic Publication: 2018 Dec 05 (Print Publication: 2018).
DOI: 10.1371/journal.pone.0205230
Abstrakt: Anopheles gambiae, An. coluzzii and An. arabiensis are the three major vectors of malaria in Nigeria. These mosquitoes have developed resistance to different insecticides. Insecticides resistance intensity assay was recently introduced to provide insight into the potential operational significance of insecticide resistance. Here, we present data on pyrethroids resistance intensity and resistance mechanisms from six vector surveillance sites (Lagos, Ogun, Edo, Anambra, Kwara and Niger) in Nigeria. Adult Anopheles reared from larval collections were tested using WHO insecticides susceptibility protocol with 1x concentration of permethrin and deltamethrin followed with intensity assays with 5x and 10x concentrations of both insecticides. Synergistic and biochemical assays were carried out and underlying resistance mechanisms determined following standard protocols. Anopheles gambiae constituted >50% samples tested in five sites. Permethrin and deltamethrin resistance was observed at all the sites. The Kdt50 varied from 15 minutes (CI = 13.6-17.2) in deltamethrin to 42.1 minutes (CI = 39.4-44.1) in permethrin. For both insecticides, Kdt95 was >30 minutes with 25% to 87% post exposure mortality at the different sites. The West Africa knock down resistance (kdr-w) mechanism was found at each site. Resistant An. gambiae from Lagos, Ogun and Niger synergized prior to permethrin or deltamethrin exposure showed significant mortality (89-100%) compared to unsynergized mosquitoes (Lagos, p = 0.031; Ogun, p = 0.025; Niger, p = 0.018). Biochemical analyses revealed significant increased levels of P450 enzymes in resistant Anopheles gambiae from Lagos (p = 0.038); Ogun (p = 0.042) and Niger (p = 0.028) in addition to GST in Lagos (p = 0.028) and Ogun (p = 0.033). Overall, the results revealed high pyrethroid resistance associated with increased activities of metabolic enzymes (P450 + GST) in An. gambiae and An. coluzzii from Lagos and Ogun. The presence of kdr + P450 conferred moderate resistance whereas low resistance was the case where kdr was the sole resistance mechanism. Findings thus suggests that elevated levels of cytochrome P450 enzymes together with GST were responsible for high or severe pyrethroid resistance.
Competing Interests: This research was partly funded by Vestergaard Frandsen (EA) Ltd through research grant No. IRB/11/168. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
Databáze: MEDLINE
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