Evidence for the spread of the alien species Aedes koreicus in the Lombardy region, Italy

Background: Aedes koreicus is a mosquito species characterized by marked anthropophilic behavior, and a potential vector of nematodes and viruses. It is native to East Asia, but its presence has recently been reported in many regions of Europe. In Italy, these mosquitoes had been detected in the northeast since 2011 and are now spreading towards the southwest of the country. Methods: In 2020, during a surveillance program for invasive mosquito species in the district of Bergamo (Lombardy Region, Italy), about 6000 mosquito larvae were collected. Emerged adults were assigned to mosquito species according to morphological analyses, followed by amplification and sequencing of genetic markers (COI, ND4, ITS2 and D2). Results: According to the morphological and genetic data, about 50 individuals belonged to the species Ae. koreicus. Conclusion: We report the presence of Ae. koreicus in the district of Bergamo, which confirms the spread of this species in the north of Italy and raises concerns about its possible role as a vector of diseases in the Alpine area.