Insecticide resistance and molecular characterization of knockdown resistance (kdr) in Culex quinquefasciatus mosquitoes in Sri Lanka

ABSTRACTResistance to pyrethroids (PY) and organophosphate (OP) insecticides is widespread among populations ofCulex quinquefasciatus, the major vector of lymphatic filariasis (LF). The present study was designed to detect the L1014Fkdr (knockdown resistant) mutation amongCx. quinquefasciatus populations in the filarial belt of Sri Lanka. Mosquitoes were reared from field ‐caught larvae from seven localities where LF is endemic. Susceptibility status ofCx. quinquefasciatus to adulticides, 0.05% deltamethrin, 0.75% permethrin, 5% malathion, and the larvicide temephos was determined using the standard WHO susceptibility tests. A fragment ofvgsc gene was amplified and sequenced to identify the responsiblekdr mutations. The susceptibility test results revealed less than 90% mortalities for 0.05% deltamethrin, and 0.75% permethrin and temephos. For 5% malathion, all study sites except Maharagama revealed greater than 90% mortality. The L1014Fkdr mutation was observed in all studied populations. Although the overall microfilaria rate is less than 1% in the country, there is a high risk of re ‐emergence of LF in Sri Lanka due to abundantCx. quinquefasciatus mosquitoes, increased resistant status to currently used insecticides, imported LF cases, higher rates of microfilaria among neighboring countries, and the advancement of tourism.
Source: Journal of Vector Ecology - Category: Biology Authors: Tags: Original Article Source Type: research