Bayonne (AFP)

A toxic microalgae, which can cause respiratory disorders and flu-like conditions, has appeared in recent days on the French Basque Coast, forcing coastal towns to close their beaches on Sunday and ban swimming, measures however in the process of being lifted on Monday. , we learned from elected officials.

Analyzes by the Regional Health Agency (ARS) made it possible to establish Monday that the algae is ostreopsis siamensis, a cousin species but less toxic than ostreopsis ovata, known for years in the Mediterranean, where it has been in the past at the origin of poisoning and beach closures.

Respiratory problems, itching of the eyes, cough and nausea are among the symptoms experienced in recent days by swimmers, surfers or walkers.

Sunday afternoon, alerted by the lifeguards of the beaches, Biarritz had taken the decision to ban swimming, like the neighboring municipalities of Bidart and Saint-Jean-de-Luz.

"The presence of this algae is a first in Biarritz," the town hall said on Monday.

But cases of similar infections had already been reported in September 2020 on the beaches of Hendaye.

The micro-algae, attached to other algae and riprap, "is released by the swell and is found in the water, sometimes on the surface. The cytotoxin it contains can also be transported by the wind, in the spray. ", explains Marc Valmassoni, in charge of the Water and Health program of the NGO Surfrider Foundation. Global warming is responsible for the proliferation of these algae, which were previously confined to tropical waters ".

Samples taken throughout the Basque Coast, between Anglet and Hendaye, are being analyzed.

But "the reported facts and scientific knowledge at this date seem to allow a reopening, according to the recommendations of the ARS", told the press Emmanuel Alzuri, mayor of Bidart and elected in charge of the coast in the Basque Country agglomeration.

In Biarritz, "all the beaches are reopened but we maintain daily monitoring with ARS and the prefecture and do not rule out closures on a case-by-case basis," the mayor's chief of staff, Nicolas Hénault, told AFP.

Other cities were to reopen their beaches on Tuesday.

A priori the symptoms "are mild and would pass on their own", but they are close to a flu-like state, therefore to Covid-19, and therefore a source of questions.

"Today, people who have these symptoms are asked to go first to be tested for Covid and, if it is negative, to see a doctor," said Mr. Alzuri.

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