Abstract: Aedes albopictus and Aedes japonicus are introduced mosquito species that can transmit several North American arboviruses. However, these species contributions to local amplification and transmission cycles are poorly understood. Aedes triseriatus, in contrast, are native and the primary enzootic vector of La Crosse virus (LACV), the leading cause of pediatric arboviral encephalitis in the U.S. To investigate their role in arbovirus transmission, we reserved 2,634 mosquitoes taxonomically identified as Ae. albopictus (92%), Ae. japonicus (3%) and Ae. triseriatus (5%), submitted from 29 Air Force installations (2018 – 2020). Most were captured in 3 states: Virginia (39%), Florida (26%) and North Carolina (6%). We pooled mosquitoes by species (≤10/pool) and tested them with either TaqMan or SYBR green assays for La Crosse, California serogroup (CAL) and Jamestown Canyon (JCV) viruses. Most pools were negative for all viruses tested, but some samples generated low positives for LACV (15), CAL (12) and JCV (2). We expected the CAL assay to confirm LACV and JCV findings but interestingly, results were not confirmed for most of these. Most LACV positives came from Virginia (4) and Florida (4). The Florida findings were unexpected as LACV human cases are rarely reported there. Among CAL positives, 4 came from Virginia: one Ae. triseriatus pool from June 2019 and 3 Ae. albopictus pools from August 2020, all from different locations on the installation. The 2 JCV positives were from Mississippi and Georgia. This appears to be a novel finding; we found no reports of JCV in mosquitoes from these states. Results suggest circulation of bunyavirus variants on several installations. Given that sample sizes per installation were generally small, and 2020 surveillance was reduced due to COVID-19, future targeted sampling at specific installations can validate whether these invasive mosquitoes are infected with any bunyaviruses.
.jpg "Joshua M. Lassen (he/him/his) photo")