Carriers of diseases Tiger mosquitoes appear in Zurich - city warns population

This August, eggs and tiger mosquitoes were also found outside the long-distance bus station for the first time since 2019. The public is asked to report sightings immediately.

Tiger mosquito eggs were first found at the long-distance bus station behind the main train station in the fall of 2016. Since then, the City of Zurich has been monitoring the area with traps and combating the mosquito larvae in the surrounding dunes with a biological agent if tiger mosquitoes or their eggs are found. Thanks to consistent monitoring and the help of the population, it has so far been possible to prevent the tiger mosquito from settling and spreading.

Tiger mosquitoes are particularly troublesome. Unlike native mosquito species, they also bite during the day. Their bites are painful and they can transmit various diseases. The risk of contracting a disease from a tiger mosquito bite in Switzerland is currently classified as low.

First findings in the neighborhoods

In August 2024, tiger mosquito eggs were found for the first time in a trap on Hafnerstrasse, and tiger mosquitoes were reported in the Industrie and Wipkingen districts. The tiger mosquito arrives in new areas on coaches, cars or trucks. It bites during the journey, sucks blood and leaves the vehicle on arrival to lay its eggs. Small containers or drinks cans with accumulated rainwater are sufficient for this. The Pest Prevention Unit is currently investigating the reports and setting up egg-laying traps. The manholes and drains around the sites are being treated with a biological larvicide against the larvae of the tiger mosquito.

The help of the public is important

The public can play a key role in combating tiger mosquitoes: "It is important that residents eliminate potential breeding sites and catch, photograph and immediately report black-and-white striped mosquitoes. In this way, the occurrence can be detected early and the colonization and spread can be contained," says Gabi Müller, Head of Pest Prevention at the City of Zurich. Ideal breeding grounds for tiger mosquitoes are small pools of standing water, such as on tarpaulins, in saucers and watering cans. Regularly emptying or renewing the water prevents the reproduction of tiger mosquitoes, as they need about a week to develop from an egg into an adult mosquito. Invasive mosquitoes cannot breed in ponds, flowing waters or chlorinated pools.

Report findings

Sightings in the urban area can be reported via zueriwieneu.ch or with the "Züri wie neu" app, while reports from the rest of the canton can be submitted to the Swiss Mosquito Network at muecken-schweiz.ch. The Pest Prevention Unit of the City of Zurich's Environmental and Health Protection Department is one of the four official reporting offices for invasive mosquitoes in Switzerland. In this function, it accepts reports of mosquitoes from the entire canton of Zurich as well as the cantons of Appenzell Ausserrhoden, Appenzell Innerrhoden, St. Gallen, Schaffhausen, Thurgau and Zug.