A statement released Monday 14 August urged people and animals to avoid contact with water where the algae is prominent and to avoid swallowing this water.

Also known as cyanobacteria, the blue algae was particularly prominent in areas where the water was slow-moving.

The bacteria is normally present in the Moselle however, under certain conditions it develops excessively and forms greenish-blue carpets.

Under these conditions, these bacteria can produce toxins that can cause health problems for humans and animals. Depending on the length of exposure and amount of toxins absorbed, symptoms can include skin irritations, headaches, nausea, gastroenteritis, cramps, paralysis, and liver damage.
The bacteria proliferates when high levels of the nutrients on which it feeds are present and the water temperature is high.