2023-07-07 08:03:17
Since 2021, microscopic algae of the genus Ostreopsis appeared on the Basque coast. These algae can represent a health risk for swimmers as well as for people who frequent the seafront. They are subject to enhanced monitoring by the Regional Health Agency (ARS) of New Aquitaine. Explanations.
The tropical microalgae Ostreopsis present on the French coasts
In the summer of 2021, the first blooms of this microscopic algaeor microalgueof the kind Ostreopsis, have been reported on the Basque coast. Microscopic and therefore invisible to the naked eye, this algae can, by proliferating, give metallic salt water taste and form gelatinous brown films on rocks and large algae (macroalgae). Beyond its appearance, it is above all the toxins it releases that are problematic. These toxins disperse with the winds and currents, not only in the water, but also in the air.
The toxins produced by Ostreopsis can thus affect swimmers, people on the sand or rocks, but also walkers by the sea. Of tropical origin, microalgae Ostreopsis arrived in the Mediterranean regarding twenty years ago with the rise in temperatures and more recently on the Basque coast. As they proliferate, these microalgae produce significant amounts of toxins, which can cause multiple symptoms in exposed people:
An irritating cough; A runny nose; A sore throat; Skin irritation; Eye burns or irritation; Nosebleeds; Breathing difficulty; A fever ; Tremors; Muscle pain; Headaches ; Nausea. Read also – A marine toxin responsible for poisoning following inhaling sea spray
A microalgae under close surveillance on the Basque coast
The first signs appear during the first six hours following exposure to toxins fromOstreopsis and usually disappear within a few days, without complications. But such symptoms are enough to spoil the trip to the seaside. Since the first reports in 2021, a specific monitoring plan has been set up to identify microalgae and inform the population. This plan is coordinated among others by the ARS of New Aquitaine, IFREMER, the poison control centers, the Urban Community of the Basque Country and Rivage Pro Tech.
Microalgae are sought in samples of seawater and macroalgae, the microalgae developing on the surface of the macroalgae. When a start of proliferation is detected (when the temperature of the sea water exceeds 20°C), the samples are intensified to better monitor the level of toxins. To inform the population, a poster has been designed and is displayed in 4 languages (French, Basque, English, Spanish). A mobile application, Kalilo, has also been developed for the general public. Nowadays, nearly 900 poisonings with toxins fromOstreopsis have been recorded on the Basque coast. No cases have yet been detected for the 2023 season.
Read also – Jellyfish, sea urchins, live fish: the dangers of the beach!
4 essential tips to protect yourself fromOstreopsis
What precautions should be taken to prevent poisoning in the event of a proliferation? ANSES recently issued several recommendations for protect yourself from toxinsOstreopsis in case of proliferation of microalgae :
Systematically take a shower when returning from the beach or the seaside (being a few meters from the beach can be enough to be intoxicated), and washing your body and hair; Eviscerate all fish caught, even the smallest (toxins accumulate in the digestive system) before eating them; Do not consume other seafood during this period (molluscs, crustaceans); Do not go to the beach for fragile people (children and infants, the elderly, people with chronic pathologies, etc.) and consult a doctor in the event of the appearance of unusual symptoms.
The symptoms disappear by themselves in a few days, but a doctor should be consulted if the signs of intoxication persist for more than 3 to 4 days or if they worsen, in particular, in the event of significant difficulty breathing, persistent muscle pain, prolonged shaking or a generalized rash. Suspicion of poisoning can be reported to the poison control center which will indicate the action to be taken. The emergency services should only be contacted in an emergency.
Read also – Datura, a risk of poisoning even in vegetable gardens!
Estelle B., Doctor of Pharmacy
Sources
– Prevent Ostreopsis poisoning on the Basque coast. www.anses.fr. Accessed June 26, 2023.
– Ostreopsis microalgae – Risks, recommendations and reporting. www.nouvelle-aquitaine.ars.sante.fr. Accessed June 26, 2023.
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#Poisoning #Ostreopsis #microalgae
