Be careful if you go swimming on the Basque coast. According to Surfrider Foundation, which has been monitoring the proliferation of microalgae for several years
Ostreopsis47 people reported symptoms of poisoning between July 11 and 14, from Saint-Jean-de-Luz to Biarritz. Information relayed by The Republic of the Pyrenees.
A new wave of poisonings reported on Basque beaches
Sabine Allou, environmental project manager at Surfrider, announces an underestimated figure.
“We have observed a new peak in reports, similar to that recorded at the end of June. The actual number of people who have presented symptoms is certainly higher”she emphasizes.
The association reminds that only people who have taken the time to make a report are counted. The number of people poisoned would probably be much higher.
Another difficulty: proliferation episodes are often very brief. Official water quality tests take about 24 hours, a time frame that can allow the microalgae to disappear before it is even detected.
Result: certain proliferations go under the radar, despite numerous testimonies from swimmers.
A tropical microalgae favored by warming waters
Ostreopsis is a tropical microalgae now established on the Basque coast. It proliferates mainly in summer when the water temperature exceeds 20°C.
Its danger does not come from the algae itself, but from palytoxin, a particularly irritating toxin that it produces. This can be carried in sea spray and inhaled, even without entering water.
In other words, it is not necessary to swim to be exposed: staying a few meters from the shore may be sufficient when the concentration is high.
In certain cases, the microalgae forms “water blooms” on the surface of the water, brownish patches visible on the surface of the sea. Their presence constitutes an important warning signal. Another indicator sometimes reported is the appearance of a metallic taste in the mouth.
What are the symptoms of poisoning?
Symptoms usually appear within a few hours of exposure, sometimes up to six hours later.
They can combine:
- A cough or throat irritation;
- Breathing difficulty;
- Skin or eye irritations;
- Headaches;
- Fever;
- Muscle pain;
- Digestive problems (nausea, diarrhea, abdominal pain).
In the majority of people, these symptoms disappear spontaneously within 24 to 48 hours, or even within a few days.
On the other hand, people who already suffer from asthma, allergies, respiratory or cardiovascular diseases may present more marked symptoms. Professionals exposed to sea spray on a daily basis, such as lifeguards, restaurateurs or beach staff, are also at greater risk.
How to react if you have symptoms?
Health authorities first recommend leaving the seaside as soon as symptoms appear.
After swimming, it is advisable to:
- Take a complete shower, body and hair;
- Avoid remaining exposed to sea spray if symptoms appear;
- Monitor their progress.
If difficulty breathing becomes significant, if muscle pain or tremors persist, or if symptoms last more than three days, seek medical attention promptly and contact a poison control center, specifying possible exposure to Ostreopsis.
During periods of proliferation, vulnerable people (asthmatics, allergies, suffering from respiratory or cardiovascular diseases) are invited to avoid beaches and their surroundings, even without swimming.
Advice to take seriously: with the warming of coastal waters, specialists fear that these episodes will become more frequent in the summers to come.