First Nationwide Monitoring Program for the Detection of Potentially Invasive Mosquito Species in Austria

SIMPLE SUMMARY: In the last years several alien mosquito species have been introduced into Austria. Those species pose a threat, as they—especially the Asian tiger mosquito (Aedes albopictus)—can transmit many pathogens. The aim of this study is a nationwide overview on the situation of alien mosquitoes in Austria. Using traps representing ideal breeding sites for those mosquitoes, we collected, counted and identified the species of the mosquito eggs laid in the traps. The Asian tiger mosquito was found at two sites, once in Tyrol, where this species has been reported before, and for the first time in the province of Lower Austria. The Asian bush mosquito (Aedes japonicus) was widespread and abundant in Austria. Although it was found in all provinces, the Asian bush mosquito was more often found in the South than the North and more eggs were collected in urban/industrial/transport areas than in (mostly) natural areas. Further, more eggs from the Asian bush mosquito were found in samples collected at higher daily mean temperatures, and fewer eggs in samples collected at higher daily maximum wind speeds. The results of this study will help to better understand the risk from alien mosquitoes to human health in Austria and will be useful to show future changes in the distribution of those species. ABSTRACT: In Austria, only fragmented information on the occurrence of alien and potentially invasive mosquito species exists. The aim of this study is a nationwide overview on the situation of those mosquitoes in Austria. Using a nationwide uniform protocol for the first time, mosquito eggs were sampled with ovitraps at 45 locations in Austria at weekly intervals from May to October 2020. The sampled eggs were counted and the species were identified by genetic analysis. The Asian tiger mosquito Aedes albopictus was found at two sites, once in Tyrol, where this species has been reported before, and for the first time in the province of Lower Austria, at a motorway rest stop. The Asian bush mosquito Aedes japonicus was widespread in Austria. It was found in all provinces and was the most abundant species in the ovitraps by far. Aedes japonicus was more abundant in the South than in the North and more eggs were found in habitats with artificial surfaces than in (semi-) natural areas. Further, the number of Ae. japonicus eggs increased with higher ambient temperature and decreased with higher wind speed. The results of this study will contribute to a better estimation of the risk of mosquito-borne disease in Austria and will be a useful baseline for a future documentation of changes in the distribution of those species.