Evaluation of Yellow Fever Virus Infection in Aedes aegypti Mosquitoes from Pakistan with Distinct Knockdown Resistance Genotypes

Abstract

Background: Yellow fever (YF) is a serious disease found in Africa and Latin America that is potentially transmitted by Aedes aegypti in urban regions. Surprisingly, YF did not occur in Asia, despite the presence of these mosquitoes. This may be related to environmental factors, genetic aspects of the virus strains and mosquito populations. Moreover, as insecticide resistance mutations, such as kdr, influence mosquito physiology, such mutations might affect its infectivity by the yellow fever virus (YFV). Therefore, we examined whether mosquitoes from Pakistan with distinct kdr genotypes could be infected and replicate the YF virus. Methods: Female Aedes aegypti from Pakistan were exposed to two YFV strains in the laboratory. A laboratory mosquito strain was used for comparison. After two weeks, the mosquitoes were tested to determine if the virus had spread through their bodies. Genetic analysis was performed to identify kdr mutations related to insecticide resistance. Results: Pakistani mosquitoes were susceptible to YFV, with infection rates similar to those of laboratory strains. Two kdr mutations were detected; however, these mutations did not affect the ability of mosquitoes to become infected with YFV. Conclusions: Ae. aegypti mosquitoes from Pakistan can become infected with YFV even if they possess mutations associated with insecticide resistance.