Blue algae warnings issued for German lakes and the Danube
Health authorities in several German regions have issued warnings about blue‑green algae (cyanobacteria) in local waters. In the Kleiner See side arm of the Bodensee near Lindau, officials confirmed the presence of Oscillatoriales cyanobacteria and advised the public not to swim and to keep dogs away, while official bathing sites on the Bavarian shoreline remain safe.
The Weißenburg‑Gunzenhausen health office warned against swimming at all beaches of the Altmühlsee due to a strong blue‑algae bloom, though a separated bathing area at Schlungenhof has been cleared for use. Other nearby lakes are still open.
On the Danube between Vohburg and Kelheim, two people suffered nausea, vomiting and diarrhea after extended contact with the water; a dog died after bathing in the river. Authorities suspect a cyanobacterial bloom and continue to advise against all river bathing.
A broader report noted similar bans and alerts in Niedersachsen, Bremen and Bayern, including a bathing prohibition at Blender See (Verden) and warnings at several lakes in Lower Saxony and Bremen. Officials stress that cyanotoxins can cause skin and eye irritation, gastrointestinal illness in humans and can be lethal for dogs, and they urge avoidance of affected waters and continued monitoring.