Tallink Silja is cancelling several of its departures after legionella bacteria were found on board the ship Silja Serenade.

The bacteria were found in the vessel's water system during a routine check. 

Currently, around 1,000 passengers are on board the vessel. They will be able to travel back to Stockholm, after which the ship will undergo extensive disinfection before it can be put back into service.

Legionella can cause a dry cough, fever, headache, muscle aches and shortness of breath. 

At present, it is not believed that anyone has fallen ill, but travellers are urged to be vigilant for symptoms.

Source: Aftonbladet.se