Danish beaches are experiencing a rise in marine bacteria, specifically vibrio and shewanella, prompting caution from health officials. These bacteria, related to cholera, can cause infections, particularly in individuals with weakened immune systems or open wounds.

The Statens Serum Institut (SSI) advises increased awareness due to the bacteria’s proliferation in warmer waters. Higher summer temperatures contribute to their increased presence along Danish coastlines. An epidemiologist at SSI anticipates a continued rise in infections due to increasingly warm summers and extended periods of warm bathing water.

A study of the 2018 summer, which recorded around 300 cases of vibrio and shewanella infections, indicated the greatest risk on Denmark’s inner coasts, notably the Baltic Sea area. The risk is higher towards the end of the summer, as seawater temperatures increase in July and August.

These bacteria flourish in warm, slightly salty water. The risk of infection is minimal in freshwater lakes and very low in the North Sea. However, health officials emphasize that healthy individuals generally do not need to avoid swimming at the beach.