Jellyfish accidents happen for a long time in South Brazil, but not at the current levels

According to the jellyfish accident expert, Dr. Vidal Haddad, these poisonings, that sporadically happen, have occurred in a greater scale in the past five years on the coast of Paraná and Santa Catarina


In the upper left: Chrysaora lactea, the jellyfish linked to the mass accidents in the South region. In the upper right, Olindias sambaquiensis, another jellyfish involved in mass accidents, however, in lower scale. In the bottom left, Lychnorrhiza lucerna, common in the area, but not involved in the accidents. In the bottom right: typical accident by Chrysaora or Olindias, with irregular and non-linear marks

The serial accidents caused by jellyfish in South Brazil are not news. These poisonings, that always occurred sporadically, have happened more frequently in the past 5 years in the Paraná and Santa Catarina coasts, with a gradual increase in the number of patients, until reaching the impressive 12 thousand patients in Paraná and 6 thousand in Santa Catarina, since mid-December until early February. However, assistant Professor at the Dermatology Department at Botucatu Medical School and Sao Paulo State University, Dr. Vidal Haddad, member of the Brazilian Society of Tropical Medicine (BSTM), field expert, says the statistics about the cases from the past 5 years have not always been adequate. Last year we had a similar increase in accidents, but the reports were not very precise, he adds. Another problem is the growing number of tourists every year, which adds to a not yet explained increase in the population of two jellyfish species in the region (Chrysaora lactea – mainly – and Olindias sambaquiensis). To the physician, the outbreaks in the South region are not caused by a single determinant and can be credited to all these factors.

This years summer accidents begun at the same period of the last episodes, possibly with an increase in the jellyfish populations (reproduction season, increase of water temperature and other factors being assessed, but there is not a final cause). However, the water temperature increase took place in all Brazilian coastline and there were no outbreaks. Maybe the geographical conditions at the sites summed to the water temperature increase and the reproductive season (another crowd on the beaches) creating multiple accidents. Dr. Haddad takes the opportunity to clarify the term jellyfish burn is not ideal, since it is a poisoning caused by toxins from venom-producing cells. The pain is similar to a burn, but the term should be avoided.

How can swimmers avoid these accidents

Disclosing correct information should help. For this, we are developing a report along with firefighters, physicians and zoologists. Regarding biological control, zoologists at São Paulo University (USP) are studying the problem, but the issue is multifactorial and will not be easily controlled. To the expert, prevention is possible by blocking the beaches where the accidents are more frequent. Another practice was the development of a blue flag, already being used in Santa Catarina, to alert swimmers of the problem.

Dr. Haddad clarifies that the accidents in South Brazil are not severe. The pain is intense, but short. Pain treatment includes cold-water wads and vinegar baths. The low temperature is anesthetic and the vinegar stops the active venom cells to increase the poisoning. Both work and are excellent for mild poisonings (over 90% of the observed cases). These measures do not prevent severe cases, since they do not have any effect over the venom. There are severe accidents by venom and some can strike potentially fatal allergic reactions. These severe accidents are caused by Portuguese Man o war and a class of jellyfish known as Box jellyfish, but are sparse in the region, being more common in Brazils North and Northeast.

Standardizing treatment and knowledge about the animals are fundamental to control the outbreaks and calming the population. We still do not know if the increase of the Cnidarian populations is reversible, but the explosive combination of these animals in the water and the immense human population during the summer is the cause of these outbreaks and we must prepare for seasons with increased numbers of accidents, since they probably are the most common animal poisonings in Brazil, he ends.…