Expanding knowledge of mosquito (Diptera: Culicidae) and California serogroup viruses distributions in the North American Arctic.

Climate change is reshaping Arctic ecosystems, heightening the risk of vector-borne diseases caused by pathogens such as California serogroup (CSG) viruses, including Jamestown Canyon virus (JCV) and Snowshoe Hare virus (SSHV). Despite their emerging public health threat, data on Arctic mosquito populations and CSG virus prevalence remain limited. To address this gap, we conducted a 3-yr mosquito surveillance program at 8 sites across northern Canada and the United States, engaging local community members in mosquito collection through a standardized protocol using a butterfly net. From 4,038 sampled mosquitoes, we identified 18 species-17 of which were from the genus Aedes Meigen, 1818. We also reported new distribution records for Aedes euedes Howard, Dyar, & Knab, 1913, Aedes implicatus Vockeroth, 1954, and Aedes spencerii (Theobald, 1901). JCV was detected in 10 mosquito species across 7 sites, while SSHV was detected in just one species at a single site. Notably, JCV was found in Ae. euedes, Aedes impiger (Walker, 1948), and Aedes pionips Dyar, 1919 for the first time in North America. JCV was detected in Cambridge Bay, Nunavut, where only 3 Arctic mosquito species were present, none of which are recognized as potential JCV vectors. This finding raises the possibility of undocumented vector species or a previously unrecognized transmission role for Arctic mosquitoes. The broad distribution of JCV across species and locations suggests widespread enzootic transmission, underscoring the need to reassess the potential of Arctic mosquitoes as disease vectors in a rapidly changing climate.