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The ciguateraItch, also called itch, is the most common type of non-bacterial food poisoning more famous across the world. It occurs as a result of the consumption of marine organisms (fish and invertebrates) contaminated with toxins from microalgae (microalgae) belonging to the genus Gamberdiscus.
Ciguatera and microalgae
These microalgae are dinoflagellates (a group of microalgae) benthicthat need support to develop (rocks, algae, ropes, plastic…).
This is usually a result of environmental disturbances from Coral reefs After they lost their ability to steadfastness (as in cases of bleaching) in which macroscopic cells (macroscopic algae or higher aquatic plants) settle leading to the development of dinoflagellates (living plant-related) such as Gamberdiscus. These dinoflagellates can also reproduce pillars Inert materials of synthetic origin (ropes, immersed plastic).
Previously restricted to the tropics, theDomain From Gamberdiscus It has stretched since the 2000s towards the subtropical and temperate regions. The climate change In general, the lack of ballast water treatment and the degradation of the marine environment are conditions that lie at the root of the health, social, economic and environmental problems associated with ciguatera attacks.
So far, the sex Gamberdiscus Includes 18 types formally described, which owns the morphemes and hereditary distinct, showing different toxicity and toxin profiles.
Currently, the compounds can be identified as sigwat toxins (toxins involved in Syndrome ciguatera) only in the Pacific Ocean, particularly in G. polynesiensis. These toxins become a problem when they are incorporated into the food web. Through the process of biomagnification, the concentration of siguatoxin increases with each nutritional level To reach high concentrations in Predators higher (as in trevallies and barracudas), making it unfit for consumption.
In addition, biotransformation phenomena occur and compounds are modified in marine organisms. This makes studying them particularly complex, because the compounds found in fish can be very different from those produced by dinoflagellates. Being Ciguatoxins thermally stable (does not degrade either during freezing or during cooking), consumption of contaminated fish exposes the population to health risks.
This syndrome It is rarely fatal It will affect at least every year 25,000 people Worldwide, an estimate that would represent only 20% of the actual number of cases, given the variance symptoms (More than 170 have been reported) related to this poisoning.
Ciguatera in the West Indies
The Caribbean Basin is the second most affected area in the world by Ciguatera, after the Pacific Ocean. In the West Indies, it is generally manifested by gastrointestinal symptoms (nausea and vomiting, pain ventral, Diarrhea). may be accompanied or followed by neurological disturbances (eager, eagerburning sensations when touching cold objects, headache, fatigue) which is observed less frequently than other foci of ciguatera. Although the most common cardiovascular symptoms are hypotension and Bradycardiathe percentage of the latter varies from one study to another.
Epidemiological studies have shown that the distribution of ratesEffect of ciguatera is not homogeneous in this region: her Spread Stronger in the northern islands of the West Indies than those in the south, where Martinique is the focal region.
Annual incidence rates between 1996 and 2006 exceeded 15 cases/10,000 population inepicenter (higher diffusion area), which extends from Virgin Islands to Montserratwhile the highest annual rate in the low prevalence area was 0.67 cases/10,000 population between 2012 and 2018 concerned Martinique.
In the French West Indies, cases of ciguatera are reported systematically to the regional health agency.
Recently, the annual incidence of ciguatera in Guadeloupe Sharp increase, reaching 1.43 cases/10,000 population between 2013 and 2016, which is an increase of 5 in 10 years.
This increase may be due to new consumption Ocean Possible vectors of ciguatera (eg, berberine), which are not on the endangered species list.
Prohibited types vary from country and even from region to region.
Thus, since 2002 there has been Governor’s decree in Guadeloupe It regulates the fishing and marketing of certain types of fish. In this decree, 15 species of fish are listed as the most poisonous.
The hunting and sale of certain species is prohibited everywhere and regardless of the weight of the caught specimens, while for others the restrictions are only related to the hunting area or the weight of the individuals caught. Conversely, there are no restrictions in Martinique yet, although the incidence of ciguatera has doubled by 3 in 10 years.
subordinate Gamberdiscus Observed on the coast of this island can partly explain the poisonings that occurred locally, calling into question the local belief regarding the origin of the ciguatoxic fish in Martinique.
Carmina Project for the Caribbean Basin
Ciguatera is closely related to the degradation Ecosystems O sailors, the study of this poisoning must be controlled according to the method one health (“One Health”).
Although ciguatera risks exist in the Caribbean, few recent large-scale studies have jointly focused on studying diversity, Poisoning and features of toxins Gamberdiscus. It is in this context that the Carmina project appeared.
The Carmina Project is a scientific project funded by the French Development Agency, which aims to study the diversity and toxicity of microalgae Responsible for ciguatera in the Caribbean Basin.
In cooperation with laboratories NOAA And thehandlesdifference Ifremer It aims to improve knowledge of the microalgae associated with ciguatera to enable better risk management in this region.
Species targeted in this study are those belonging to the genus Gamberdiscusbut also those of species Fukuiwa And the cola. In fact, some metabolites synthesized Gamberdiscus It is found in some species of genera Fukuiwa And the colasuggesting that they, too, may contribute to ciguatera.
This project, which includes eleven Caribbean countries, began in May 2022 and will promote scientific collaboration on the topic of Ciguatera, which could grow in the coming years. The first results of this study will be presented at the progress meeting to be held in 2023 in Martinique.
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