Survey finds ticks in Graubünden as high as 2,300 metres

Ticks have been found at elevations of up to about 2,300 metres in the Swiss canton of Graubünden, according to preliminary results from a survey by the Institute for Snow and Avalanche Research in Davos, reported by SRF.

More than 900 people responded over the summer, reporting where they had seen ticks or been bitten. The institute’s biologist Anne Kempel said the responses were spread across the canton and its elevation ranges, allowing researchers to draw conclusions about tick distribution in the mountains.

Initial analysis suggests ticks are found across almost all areas up to about 1,400 metres. Above 1,500 metres, people report seeing them much less often, but they have not disappeared: some respondents found ticks above 2,000 metres, with a few reports from around 2,300 metres.

Researchers plan to examine more closely where ticks occur and how their range has changed in recent years. From 2027, they intend to collect and analyse ticks at different elevations, including to determine whether those found higher up carry the same disease-causing pathogens as ticks in valley areas. The findings from the survey are also expected to inform a scientific publication.

Reports from livestock owners point to ticks on animals at every second or third alpine pasture above 2,000 metres, Kempel said. The reports do not show a widespread pattern, but suggest ticks occur at higher elevations than was long assumed. Researchers consider climate warming a likely explanation, as rising temperatures may improve conditions for ticks at higher elevations. Whether their spread increases the risk of Lyme disease or tick-borne encephalitis remains to be established.

After a tick bite, the institute advises removing the tick as soon as possible with tweezers or a tick-removal tool, pulling it straight out close to the skin without squeezing it. The bite should then be disinfected. People should note the date and location of the bite and monitor the skin for two to three weeks. A spreading red mark or flu-like symptoms, including fever, headaches or muscle and joint pain, are reasons to seek medical advice.