Vaccines to curb ciguatera

Without an effective treatment, IPNA researchers are looking for a method to mitigate the effect of this food poisoning on patients suffering from it.

As a result of climate change, the rise in temperature of traditionally cool waters around the Canary Islands is causing algae and other small marine organisms accustomed to warmer waters to settle around the islands. But these new species have not come on their own to find a place to live in our limited stretch of the Atlantic Ocean. Many of them have brought with them a toxin then also consumed by local fish, which causes a serious illness in the population: ciguatera. There is no effective treatment for the infection, so a group of researchers at the Institute of Natural Products and Agrobiology (IPNA-CSIC) are working on a vaccine that will allow those affected to overcome it without facing its worst consequences. 
Ciguatera is a type of food poisoning that causes a wide range of symptoms. Consumption of fish containing ciguatoxin causes nausea, vomiting, diarrhoea and even a sensation of temperature sensation reversal. The latter is the most characteristic symptom of the poisoning. However, ciguatera poisoning has gone largely unnoticed by health systems in Western countries. The main reason for this under-diagnosis lies in our lack of knowledge of the pathology, since ciguatera is a poisoning endemic to tropical countries in the Caribbean, Indian and Pacific oceans, regions with warmer waters.
The toxin is very elusive and difficult to detect. Ciguatoxin is not only able to withstand high temperatures and polar cold, it is also odourless and tasteless, so it has the right characteristics to survive cooking and freezing and, equally, to pass undetected to the senses of smell and taste of the person consuming it.
The impact caused by ciguatera in the Canary Islands has been such that nowadays the regional government health council has been forced to establish an ‘Epidemiological Surveillance System for Ciguatera Poisoning’, to collect data on cases that reach our health system. Since 2008, there have been 19 outbreaks and 115 cases of ciguatera in the population of the islands. The toxin tends to accumulate in larger and heavier fish, so the Canary Islands Government has limited the weight of fish to be caught to less than 10 kg. All from tropical or warm waters, more than 400 species of fish are known to transmit ciguatera, including grouper (mero), island grouper (abade), snapper, barracuda, horse mackerel, moray eel, and amberjack.
A vaccine would undoubtedly turn the current epidemiological situation in the islands around. "The idea of developing a vaccine to prevent and mitigate the effects of ciguatera would be a great scientific advance from a health point of view," says Juan I. Padrón, the current director of the IPNA. With the help of the Cabildo of Tenerife, his team has made good progress in the forthcoming development of an effective vaccine. "We have managed to obtain the first molecule," says Padrón, who assures that from now on it will be possible to "study its behaviour and efficacy as a vaccine".
The chemical compound designed must finally have the capacity to generate antibodies and block the action of ciguatoxin. Therefore, "it is not just any vaccine", as the researcher points out. This vaccine would be used as treatment, rather than prevention. In other words, it would be aimed at people who have been poisoned by ciguatoxin and show symptoms of ciguatera.

Vacunas para poner freno a la ciguatera