Aedes japonicus (Diptera: Culicidae), or the Asian rock pool mosquito, is an invasive mosquito in Europe and America. It was first detected outside of Asia in 1990 in Oceania. It has since expanded to North America and Europe in 1998 and 2000, respectively. Even though it is classified as a secondary vector of pathogens, it is competent to several arboviruses and filarial worms, and it is contributing to the transmission of La Crosse virus (LACV) and West Nile virus (WNV). In this study, CDC light, BG-sentinel, and gravid traps were used to collect mosquitoes between June and October 2021, in Wooster, Northeastern Ohio, USA. Morphological identification or/and Sanger sequencing were performed to identify the collected mosquitoes. Our results revealed that (adult) Ae. japonicus mosquitoes were the most abundant mosquito species collected with gravid traps in Wooster in 2021, confirming its establishment in Ohio. Molecular analyses of Ae. japonicus showed 100% nucleotide similarity with Ae. japonicus collected in Iowa (USA) and Canada, suggesting multiple introductions. Its presence may increase the risk of future arbovirus outbreaks in Wooster, Ohio. This study stresses the importance of actively monitoring the density and distribution of all members of the Ae. japonicus complex.

Aedes japonicus (Diptera: Culicidae), or the Asian rock pool mosquito, is an invasive mosquito in Europe and America. It was first detected outside of Asia in 1990 in Oceania. It has since expanded to North America and Europe in 1998 and 2000, respectively. International sale of used tires and the ability of the mosquito to tolerate low temperatures and colonize several biotopes have contributed to its expansion. Even though it is classified as a secondary vector of pathogens, it is competent to several arboviruses and filarial worms, and it is contributing to the transmission of La Crosse virus (LACV) and West Nile virus (WNV). In addition, in some areas, Ae. japonicus outcompetes primary vectors of arboviruses such as Culex species, suggesting that an increase in its density and distribution may represent a major threat to public health. In this study, CDC light, BG-sentinel, and gravid traps were used to collect Ae. japonicus between June and October 2021, in Wooster, Northeastern Ohio, USA. We sequenced a region of the COI gene and performed a phylogenetic analysis to confirm the identity of the collected mosquitos. Our results revealed that (adult) Ae. japonicus mosquitoes were the most abundant mosquito species collected with gravid traps in Wooster in 2021, confirming its establishment in Ohio. All morphologically identified Ae. japonicus were molecularly confirmed, with several showing 100% nucleotide similarity with Ae. japonicus collected in Iowa (USA), and Canada. Its presence may increase the risk of future arbovirus outbreaks. This study stresses the importance of actively monitoring the density and distribution of all members of the Ae. japonicus complex.