Pyrethroid and Carbamate Resistance in Giles along Lake Kariba in Southern Zambia.

Whereas data on insecticide resistance and its underlying mechanisms exist for parts of Zambia, data remain limited in the southern part of the country. This study investigated the status of insecticide resistance, metabolic mechanisms, and parasite infection in along Lake Kariba in southern Zambia. Indoor-resting mosquitoes were collected from 20 randomly selected houses within clusters where a mass drug administration trial was conducted and raised to F1 progeny. Non-blood-fed 2- to 5-day-old female were exposed to WHO insecticide-impregnated papers with 0.05% deltamethrin, 0.1% bendiocarb, 0.25% pirimiphos-methyl, or 4% dichloro-diphenyl-trichloroethane (DDT). In separate assays, were pre-exposed to piperonyl butoxide (PBO) to determine the presence of monooxygenases. Wild-caught that had laid eggs for susceptibility assays were screened for circumsporozoite protein of by ELISA, and sibling species were identified by polymerase chain reaction. showed resistance to deltamethrin and bendiocarb but remained susceptible to pirimiphos-methyl and DDT. The pre-exposure of to PBO restored full susceptibility to deltamethrin but not to bendiocarb. The overall sporozoite infection rate in populations was 5.8%. Detection of pyrethroid and carbamate resistance in calls for increased insecticide resistance monitoring to guide planning and selection of effective insecticide resistance management strategies. To prevent the development of resistance and reduce the underlying vectorial capacity of mosquitoes in areas targeted for malaria elimination, an effective integrated vector management strategy is needed.