Evaluation of resistance against deltamethrin in Aedes mosquitoes from Lahore, Pakistan

In the current study, resistance status of Aedes aegypti was evaluated against pyrethroid insecticide. The resistance in field collected population against Deltamethrin 2.5% EC was compared with susceptible (laboratory reared) population. Field population was collected from two localities of Lahore i.e. Government College University and Government Islamia College for Women Cooper Road, Lahore during JulySeptember, 2010. CDC Bottle Bioassays were carried out on adult female mosquitoes (susceptible) in order to determine the diagnostic dose. A range of concentrations (10, 5, 2.5 and 1.25 μg/ml) of deltamethrin was used for 60 minutes exposure. Diagnostic dose 1.25 ug/ml was found in post 30 minutes exposure. The same concentration caused 100% mortality of field collected populations from GCU and Govt. Islamia College for Women in 30 and 40 minutes exposure respectively. Resistance level was expressed as resistance ratio (RR) of lethal time for 50% death determined in field collected and susceptible strain. Results of bioassays indicated that Ae. aegypti field collected population from Government Islamia College for Women Cooper Road, Lahore was resistant to Deltamethrin at RRLT50 =1.3 and RRLT95=1.37 as compared to laboratory reared susceptible population. However, field population of Ae. aegypti from Government College University, Lahore was found susceptible at RRLT50=1.03 and RRLT95=1.0.