A NUMBER of lakes running alongside the Loire in the Rhône Alpes have been closed to the public after more than 200 birds were found dead in the water.
Fishing and watersports have been banned in the gravel-pit lakes around the town of Roanne, between Lyon and Clermont-Ferrand, "as a precautionary measure".
The local préfecture said tests were being carried out on the dead swans, herons, ducks and moorhens to find out what happened.
The results will take a week, but early analysis has ruled out the H5N1 strain of bird flu, which can be passed on to humans.
Roanne sous-préfet Joël Mathurin said the most likely explanation was a toxin – harmless to human beings – produced by the bacteria in stagnant water during hot weather.
The toxin attacks a bird's nervous system and paralyses them. They then die from asphyxiation or drowning.