Reverse transcription-PCR detection of LaCrosse virus in mosquitoes and comparison with enzyme immunoassay and virus isolation.

A reverse transcription-PCR (RT-PCR) assay was developed and compared with enzyme immunoassay (EIA) and virus isolation for detecting LaCrosse virus (LAC) in mosquito pools. All three techniques were able to detect a single LAC-infected mosquito in a pool of 99 negative mosquitoes. Virus isolation was the most sensitive of the three techniques; it was possible to isolate virus immediately following intrathoracic inoculation of mosquitoes. RT-PCR was second in sensitivity; LAC RNA was detected 1 day postinfection. EIA detected LAC antigen 2 days postinfection. Additionally, RT-PCR and EIA were able to detect LAC RNA and protein, respectively, from mosquito samples which were subjected to seven freeze-thaw cycles, and RT-PCR was able to detect LAC RNA from mosquito samples which remained at room temperature for up to 7 days.