After spreading to several cantons since 2003, the tiger mosquito appeared on Valais territory for the first time in 2019. It is particularly undesirable because, unlike native species, it is active during the day. In addition to the discomfort caused by its bites, this species of mosquito can also transmit exotic diseases such as dengue fever, Zika and chikungunya. Although the likelihood of an encounter between the tiger mosquito and an infected person returning from a trip is very low, there is a risk of transmission and a local epidemic that can be contained by reducing the spread of the mosquito. In order to control the spread of the invasive mosquito, the canton of Valais has been implementing a surveillance and control program in collaboration with the municipalities and the Swiss Mosquito Network since 2019.

The tiger mosquito uses road transport to move around. It is currently only found in Valais to a limited extent, but could potentially occur throughout the canton. They only settle in low-lying urban areas. It is important to note that it does not develop in natural waters and garden ponds, as its larvae are preyed upon by other aquatic organisms.

In Valais, it is found throughout the valley of the town of Monthey. A first occurrence was observed in 2022 in the neighboring municipality of Collombey-Muraz. It has also been observed sporadically in the Brig-Glis customs zone and in Fully since 2023. So far, however, it has not settled there permanently.

The role of the public in combating the tiger mosquito is crucial, as80% of itsegg-laying sites are small pools of water in gardens in residential areas.

The public is invited to participate in the control as follows:

• Removing all containers where water can collect, such as watering cans, flower pot saucers (or fill them with sand), buckets, tires, gutters, rainwater collection containers, etc.
• Report any suspicious presence on the website www.muecken-schweiz.ch

If these simple measures are followed, the possibility of the tiger mosquito becoming established in Valais will be greatly reduced and its spread delayed as much as possible. Disturbances and health risks caused by this invasive species will also be reduced to a minimum.

Further information can be found at the following link: https: //www.vs.ch//web/sfnp/moustique-tigre