29.06.2020: Around 50 mosquito species are known in Austria – and new potentially invasive species are being added, as a newly presented study by Vetmeduni Vienna shows. According to this, several mosquito species originally originating in Asia are spreading in Tyrol. This also increases the risk of transmission of dangerous viruses such as dengue, chikungunya and Zika. The researchers therefore recommend monitoring of the mosquito fauna.

The central results of the study are not very encouraging: there are first indications that the Asian tiger mosquito (Aedes albopictus) is establishing, i.e. overwintering in Tyrol and not being introduced every year. The Japanese bush mosquito (Aedes japonicus) is now native to Tyrol, as well as in all other federal states in Austria. In addition, the researchers succeeded in detecting another mosquito species for the first time in Austria: the Korean bush mosquito (Aedes koreicus).

Study author Hans-Peter Führer from the Institute of Parasitology at Vetmeduni Vienna says: "The detection of the Asian tiger mosquito, the Japanese bush mosquito and the Korean bush mosquito is of great importance for the population, for public health and for the relevant stakeholders. Asian tiger mosquitoes in particular can transmit dangerous pathogens such as dengue, chikungunya and Zika. Local mosquitoes are not able to do this. In addition, the new mosquito species have some other unpleasant side effects, as they are very annoying, can occur in large masses and also bite during the day."

Frequent distribution along motorways and for the first time also in cities

The researchers investigated the spread of mosquitoes using so-called ovitraps, a device on which the mosquitoes lay their eggs. As part of the scientific mosquito monitoring program, ovitraps were installed weekly at 67 locations from May to October 2018 – 17 in East Tyrol and 50 in North Tyrol. Sampling was carried out on motorways as well as in urban and rural areas. The prevalence of mosquitoes is already quite high: at 18 out of 67 locations (27%) eggs of alien mosquitoes have been found. Both the Asian tiger mosquito and the Japanese bush mosquito have been documented on highways and in urban areas in East and North Tyrol. The Korean bush mosquito was also detected for the first time in East Tyrol.

Führer explains: "Alien mosquito species are introduced mainly by goods transfer, but they can also simply travel by car. This is why motorways are the most important gateway for invasive mosquito species. The Asian tiger mosquito was found along the Inntal motorway in earlier years. However, repeated evidence is new in the urban area, specifically in Innsbruck, Kufstein and Lienz."

Further monitoring is important for public health

Mosquitoes (Culicidae) – there are around 3,500 species worldwide – are of great importance for human and animal health due to their ability to transmit various pathogens. In Europe, mosquitoes have become very important for public health with the establishment of alien mosquitoes of the genus Aedes in recent years. The tiger mosquito leads to local transmissions of the potentially life-threatening viral diseases dengue and chikungunya, for example in France and Italy. "Based on our findings, there is an urgent need for ongoing monitoring of the new mosquito species," Führer ads.

The article „Monitoring of alien mosquitoes in Western Austria (Tyrol, Austria, 2018)“ by Hans-Peter Führer, Ellen Schöner, Stefanie Weiler, Bita Shahi-Barogh, Carina Zittra and Gernot Walder was published in PLOS Neglected Tropical Diseases.