Inhalation of sea spray containing brevetoxins can cause poisoning

Brevetoxins produced by microalgae were first detected in France in 2018. Inhalation of contaminated sea spray during swimming or water sports can cause poisoning. Professionals working in contaminated areas are the most exposed, with pregnant women and people with asthma being the most vulnerable. Although no cases have been reported to date in France, further knowledge is needed.

Complementing its first opinion issued in 2021 on the ingestion of mussels contaminated by brevetoxins (BTX) in Corsica, the Agency has reviewed other routes of exposure to these marine toxins.

Inhalation of contaminated sea spray during microalgae blooms is the main exposure route reported in other parts of the world, such as Florida. This can occur during swimming or professional or leisure activities on the beach or near the coast. Inhalation can cause sneezing, a runny nose and a sore throat. BTX-contaminated sea spray coming into contact with the face or skin can also cause skin rashes and sore eyes. Professionals working in contaminated areas, including lifeguards, scientists and people collecting shellfish, are the most exposed, with pregnant women and people with asthma and other chronic respiratory problems being the most vulnerable.

Although skin rashes have been observed following direct contact with contaminated water, no study has yet confirmed this route of exposure.

While BTX have been monitored in shellfish since January 2018, they are not currently monitored in seawater. As BTX are emerging toxins, new knowledge is needed, in particular through the environmental monitoring of swimming sites located near REPHY monitoring sites where potential BTX-producing species have been detected in the past. This knowledge will be useful to predict the occurrence of “red tides” on the French coast – a sign of the presence of abundant BTX-producing microalgae – and to identify the most appropriate management measures.

Did you know?

No human deaths from poisoning by these toxins have been reported so far in the world. However, their toxicity for marine fauna is known and can lead to massive mortality of fish, seabirds, turtles and marine mammals, mainly in the Gulf of Mexico.