Germany warns of cyanobacteria and harmful bacteria in lakes and coasts

Health authorities in southern Germany have issued a bathing warning for the Kleine See area of Lake Constance near Lindau after detecting toxic benthic cyanobacteria, known as “Krötenhaut”. The bacteria can cause diarrhoea in people and pose a life‑threatening risk to dogs.

In the North Sea, officials alert holiday‑makers to the presence of jellyfish such as compass and yellow‑hair (fire) jellyfish, whose stings can cause skin irritation, and to Vibrio bacteria that multiply when water temperatures exceed 20 °C. Infections can lead to wounds, fever and, in rare cases, sepsis, especially in immunocompromised individuals.

In Mecklenburg‑Vorpommern, several lakes—including the Peenestrom near Usedom and numerous lakes in the Rostock and Mecklenburg‑Seenplatte districts—have shown increased cyanobacterial blooms and a rise in “Zerkarien”, larvae of parasitic worms that can embed in skin and cause itching. Authorities advise avoiding visible blooms, keeping children out of affected shorelines, and promptly drying and changing out of wet swimwear.