Impact of temperature on the transmission of West Nile virus by Culex mosquitoes

Principal Investigator: William Reisen

This research tests the overarching hypothesis that temperature determines the duration of the extrinsic incubation period (EIP) and therefore the rate of West Nile virus (WNV) amplification during late winter and spring. This study expands upon the current degree-day temperature model by examining the effect of cycling temperatures and more recent WNV strains. The research will address the following objectives: 1) compare the duration of EIP for specific strains of WNV (NY99, WN02, and Kern200-11) at two constant temperatures, 2) if viral isolates differ, estimate duration of EIP at 5 constant temperatures for the Kern2000-11 isolate to revise the EIP model, 3) determine if EIP estimates differ based on constant versus daily cycling temperatures of the California spring. The results will be crucial for creating accurate temperature-related risk estimates in WNV response plans. In addition, the results could yield understanding of how WNV could be transmitted during late winter and spring when average temperatures remain below the previously estimated replication threshold.