Marine bacteria, including vibrio and shewanella species related to cholera, are increasingly prevalent at Danish bathing beaches, posing a potential health risk, especially to individuals with weakened immune systems or open wounds. The Statens Serum Institut (SSI) advises caution due to the bacteria’s ability to cause infections.

Higher water temperatures during increasingly warm summers are contributing to the proliferation of these bacteria along the Danish coasts. Epidemiologist Steen Ethelberg from SSI notes an anticipated rise in infections due to longer periods of warm bathing water.

Research conducted during the hot summer of 2018 revealed approximately 300 registered cases of infection with vibrio and shewanella. The risk of infection is highest on the inner coasts of Denmark, particularly in the Baltic Sea area, where the bacteria thrive in warm, slightly salty water. These bacteria, sometimes referred to as marine cholera, are less likely to be found in freshwater lakes or the North Sea.

While acknowledging the increased presence of marine bacteria, health officials emphasize that healthy individuals generally do not need to avoid swimming at the beach. The primary concern lies with vulnerable populations.