“This is a phenomenon that could worsen in the coming weeks”, warns ANSES

The National Food Safety Agency (Anses) has warned of the proliferation on the Basque coast of toxic microalgae, called Ostreopsis. “This is a phenomenon that could worsen in the coming weeks” with the persistence of high heat, warns Tuesday June 20 on franceinfo Carole Catastini, coordinator of the Ostreopsis expertise at ANSES. This toxic algae can “lead to coughing” And “breathing difficulties” that resemble flu-like symptoms. They appear “rapidly within 2 to 6 hours after exposure, but also disappears within 24 to 48 hours”she said.

franceinfo: Are the high temperatures the cause of this proliferation?
Carol Catastini: The high spring temperatures are one of the reasons that could explain its proliferation. It is known that Ostreopsis microalgae blooms can grow quite quickly depending on the heat. This is a phenomenon that could worsen in the coming weeks.

When did these algae first appear?
These microalgae develop preferentially at the bottom of the water, either on rocks or on macroalgae. They are rather brown and then they will peel off these rocks. They can be found on the surface in the form of small brown aggregates that float on the surface. They appeared about twenty years ago on the Mediterranean coasts. They are well known all around the Mediterranean and therefore they are already followed.

What are the first symptoms that may appear?
The only distinctive sign of this micro-algae is the sensation of a metallic taste in the mouth, without necessarily having ingested water. This is a sign that may show that the blooms are close to you. Afterwards, it is the appearance of the various symptoms a few hours after being in contact with water, having practiced a nautical activity.

“The main route of exposure is aerosol inhalation when you are on the beach or when you walk along the seafront. It can lead to coughing, flu-like symptoms, sneezing, difficulty breathing. “

Carole Catastini, coordinator of the Ostreopsis expertise at ANSES

on franceinfo

Then, the second route of exposure is when you swim or when you practice a water activity and you are in direct contact with water. Finally, it is the ingestion of seafood, whether shellfish or fish that have been caught or taken from an area where there is this micro-algae. These are symptoms that appear quickly within 2 to 6 hours after exposure, but also disappear within 24 to 48 hours. These are generally mild symptoms.