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Wondji, Charles 
ORCID: https://orcid.org/0000-0003-0791-3673, De Silva, W. A. P. P., Hemingway, Janet ORCID: https://orcid.org/0000-0002-3200-7173, Ranson, Hilary ORCID: https://orcid.org/0000-0003-2332-8247 and Karunaratne, S. H. P. P.
(2008)
'Characterization of knockdown resistance in DDT- and pyrethroid-resistant Culex quinquefasciatus populations from Sri Lanka'. Tropical Medicine & International Health, Vol 13, Issue 4, pp. 548-555.
Abstract
DDT and pyrethroid resistance in Culex quinquefasciatus have been previously reported in Sri Lanka, but the mechanisms involved have yet to be characterized. We report the presence of two mutant alleles of the sodium channel gene, the target site for both DDT and pyrethroid insecticides. Both mutations resulted in classic knockdown resistance (kdr) L1014F mutation because of either an A-to-T substitution or an A-to-C substitution. We developed two alternative assays to distinguish between the two mutations and used these to screen 214 individuals from nine geographic locations throughout Sri Lanka. Very high levels of kdr mutations were found throughout the country. A predominance of the A-to-C mutation was observed over the A-to-T with an average allele frequency of 50% and 2%, respectively. In addition to these non-synonymous kdr substitutions, we also found an indel (TCACA) in the intron downstream of the kdr mutation. After genotyping this indel in 136 individuals, we found no evident correlation between kdr genotypes and intronic indel. The presence of two alternative kdr mutations has implications for the reliance on single molecular diagnostics for detection of resistance in field populations. Furthermore, the high levels of these kdr mutations in C. quinquefasciatus populations throughout Sri Lanka are of concern for the future of pyrethroid-based control programmes on this island.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | culex quinquefasciatus pyrethroid insecticide resistance sodium channel knockdown resistance sri lanka gated sodium-channel anopheles-gambiae west-africa mechanisms mosquitos gene identification transmission insecticides mutations |
| Subjects: | QX Parasitology > Insects. Other Parasites > QX 530 Culex QX Parasitology > Insects. Other Parasites > QX 600 Insect control. Tick control QX Parasitology > Insects. Other Parasites > QX 510 Mosquitoes QX Parasitology > Insects. Other Parasites > QX 650 Insect vectors |
| Faculty: Department: | Groups (2002 - 2012) > Vector Group |
| Depositing User: | Users 183 not found. |
| Date Deposited: | 05 Jul 2010 09:20 |
| Last Modified: | 13 Sep 2019 15:47 |
| URI: | https://archive.lstmed.ac.uk/id/eprint/661 |
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