What is ciguatera, a new food poisoning that has already arrived in the Canary Islands
The climate crisis and mobility are expanding a disease caused by a microalga that we can contract by consuming some fish
Puerto de la Cruz (Tenerife)There was great anticipation to know what the scientist Ana Gago-Martínez, professor at the University of Vigo, researcher in Analytical and Food Chemistry, and director of the EU reference laboratory for marine biotoxins, would explain. This is because the increase in cases of ciguatera poisoning, contracted by ingesting certain fish, has warranted a significant effort from administrations and the scientific community to manage a potential health problem that, until a few years ago, was not an issue in Europe. In her presentation at the Encuentro de los Mares congress in Tenerife, Gago-Martínez asked for the public to be informed, but without causing alarm. We will try to summarize the key points of a potential risk, to comply with the scientist's request.
¿What is ciguatera
Ciguatera is an food poisoning caused by natural toxins from the marine environment, ciguatoxins. These are generated by a type of microalgae (gambierdiscus and fukuyoa), which enter the food chain. These microalgae are eaten by an herbivorous fish, then a carnivorous one eats the herbivorous one and then, this larger fish is caught, and that is how it reaches human consumption. These microalgae are not native to our coasts, but rather to the Caribbean and the Pacific. But for some years now, it has begun to appear on European coasts such as Madeira and the Canary Islands. The reasons are the climate crisis, changes in ecosystems, and the mobility of tourists and the fishing industry. Knowing which strain has arrived has been key to understanding the extent of the disease, as the Pacific one is more serious than the Caribbean one.
When it appeared
Regarding poisonings of this profile, they appear from The Odyssey by Homer to the chronicles of Alexander the Great, who forbade his soldiers to consume certain fish. The term ciguatera is from the naturalist Antonio Parra. He coined it in 1787 in Cuba, referring to the consumption of cigua, a marine snail. It was the Japanese Takeshi Yasumoto who in 1977 managed to identify what caused it. Later, in 1989, another Japanese, Michio Murata, discovered its chemical structure and named it Cambierdiscus toxicus. This toxin is not killed by cold (freezing the fish) or heat (cooking it).
In the State, the alarm sounded for the first time in 2004, when a family of five caught a círvia in the Canary Islands. All of them contracted the disease. This case could be scientifically proven because remains of the consumed fish were preserved. Although at that time there was no technology to guarantee the presence of ciguatera 100%, Gago-Martínez was able to send samples abroad where they confirmed the positive result and it was established that the outbreak was the Caribbean one, the least aggressive. Even Yasumoto himself highlighted its low toxicological load. It was the first reported case on the islands, but since then there have been several outbreaks with a total of 212 people who have contracted the disease. It is estimated that worldwide, between 10,000 and 50,000 cases occur each year, despite significant underdiagnosis. And more so, because as it has been expanding in recent years, it reaches new areas where health services do not identify it.
Fish susceptible to being contaminated by ciguateragambierdiscus, in the Mediterranean, no contaminated fish has ever been found. However, vigilance is required with imported fish and with fishing that does not undergo any health control, such as recreational fishing. Fish sold in fish markets are safe. But it must be borne in mind that they have been identified in imported contaminated fish from India. Furthermore, there is a very ambiguous European legislation that will need to be addressed.
Fish susceptible to ciguatera poisoning
These are the specimens that must be analyzed before being put on sale: the Círvia (seriola spp) from 10 kilos, the bluefish or grouper (epinephelus marginatus) from 8 kilos, the bluefish (pomatomus saltatrix) from 2 kilos, the pink grouper or bluefish (mycteroperca fusca) from 7 kilos, and the kingfish (acanthocybium solandri) from 35 kilos. “These chemical structures are very complex, and being able to detect and quantify them is important because toxicology depends on how much there is”, explains Gago-Martínez. The method applied is high-resolution mass spectrometry (HRMS).
What symptoms does ciguatera produce
When the disease is contracted, the symptomatology is as follows: gastroenteritis (nausea, vomiting, and diarrhea), tingling, thermal inversion (fever), and weakness. And although less frequent, cardiovascular problems. The treatment is the same as one might have with the flu or intestinal flu. In the event that there is suspected possibility of having contracted it, the remains of the fish that could be contaminated must be kept so that it can be analyzed.