Published 5.6.2025

Several cases of stomach illness on Karhunkierros hiking trail – bring your own shelter and pay extra attention to hygiene

Several cases of stomach illness have been reported along the Karhunkierros Trail in Oulanka National Park. Between late May and early June, Metsähallitus’ Parks & Wildlife Finland received six reports involving symptoms, affecting at least 11 people. It is always advisable to carry your own shelter when staying overnight in national parks. Proper hand hygiene, boiling and disinfecting drinking water are also important precautions.

A bear-shaped opening has been cut into a metal plate, revealing a river and forest landscape through the hole.
Photo: Minna Koramo.

The first reported case to Metsähallitus involved two hikers who stayed overnight at the Savilampi wilderness hut on 29–30 May. By Thursday morning, a total of six separate reports had been received, with symptoms affecting at least 11 hikers. On Monday, a hiker was evacuated from Ansakämppä hut by the Northern Ostrobothnia Rescue Department due to exhaustion caused by stomach illness. The cause of the outbreak remains unknown.

The reported cases are spread across various points along the 82-kilometre Karhunkierros Trail, with tens of kilometres between locations. As stomach illnes spreads easily, Metsähallitus advises hikers to take special care with hand hygiene and recommends using personal accommodation – such as a tent or hammock – instead of shared huts.

“It’s always wise to bring your own shelter, in case the huts are full or plans change. In unexpected situations like illness, having your own tent or a hammock is particularly sensible,” says Airi Kallunki, Recreation Specialist at Metsähallitus Parks & Wildlife Finland.

Attention should also be paid to water hygiene. Natural water should be boiled for at least five minutes or treated with purification tablets.

Metsähallitus thanks hikers for reporting symptoms

Metsähallitus informed the public about the illness cases on Wednesday via social media and on the Luontoon.fi pages for Karhunkierros and Oulanka National Park, after receiving the first two reports. During the same day, four more cases were reported via the feedback channel.

“Receiving these reports is very important. They help us build a clearer picture and share information across our communication channels. Sincere thanks to everyone who has contacted us,” says Kallunki.

Hikers can report symptoms at luontoon.fi/en/feedback or by calling the Oulanka Visitor Centre on +358 206 396 850.

Luontoon.fi also provides guidance on drinking water hygiene, general hygiene during hiking, and what to do if you fall ill while hiking.

Stomach flus are not uncommon on popular trails and may occur both in winter and summer seasons.

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