What to do in the event of the presence of Ostreopsis microalgae?

It had been the cause of various respiratory and skin symptoms in swimmers and walkers on the Basque coast in August 2021. Although it has not reappeared since, the microalgae Ostreopsis is the subject of particular attention.

The Pyrénées-Atlantiques prefecture is issuing a series of recommendations on Monday, as very high temperatures are expected in the region these days. “Invisible to the naked eye, the presence ofOstreopsis sometimes results in a metallic taste of the water” she indicates, and, “when their concentration is high, these microalgae can appear in the form of gelatinous brown matter on the surface or in deposits on the rocks and on the macroalgae “.

Toxins that can disperse in sea spray

In case of presence ofOstreopsis, exposed persons “may experience flu-like/irritant or skin symptoms which are generally of low severity (cough, sore throat, runny nose and eyes, nosebleeds, difficulty breathing, fever, tremors, muscle aches, headaches , nausea, etc.). These symptoms appear within six hours of exposure and usually disappear within 3 to 4 days without complications. »

Because of the toxins it produces, this microalgae can affect the health of swimmers, but also walkers, or professionals working near beaches. “These toxins can disperse in the spray and affect people (by inhalation), even if they do not bathe” specifies the prefecture.

Monitoring of microalgae set up

In case of high concentration of microalgae, it is recommended to take a shower (hair and body) after swimming. “Fragile people (with an ENT or pulmonary history, allergies, cardiovascular diseases, etc.) should not frequent the beach and its surroundings. » A doctor should be consulted promptly if any unusual symptoms appear, or contact the poison control centre.

Finally, the prefecture recalls that monitoring of this microalgae, which was not known on the Basque coast before the summer of 2021, has been set up with Ifremer.