Ciguatera

Ciguatera is one out of many Marine Seafood Toxins. It is caused by a specific nerve poison termed ciguatoxin. These toxins are made by small dinoflagellates that live within the beds of macro algae usually found on reef habitats. Herbivorous fish that feed on those algae will also ingest the dinoflagellate and store the toxin within their tissues. These toxins get concentrated as larger predatory fish such as red snapper, grouper, jack and barracuda eat the smaller herbivores.

The epidemiology of the disease usually consists of case reports of acute illness due to the ingestion of seafood. Typical symptoms include a range of distressing and often debilitating gastrointestinal, neurological - paraesthesia, nervousness, inverse temperature perception, muscle cramps headache and dizziness - and cardiovascular disturbances that may last weeks, months and in some cases even years. No antidote is known to exist and treatment is therefore only for apparent symptoms. In 1990 some countries had recorded a decrease in the ciguatera problem (New Caledonia, Marshall Is.), while other countries had recorded an increase (Kiribati, Tuvalu, French Polynesia). Occurrences of Marine Seafood Toxin diseases have primarily been recorded for island and coastal communities. However, increased seafood consumption by tourists and international exports have extended case reports worldwide.
In the case of ciguatera, at least 50,000 to 500,000 people per year who live in or visit tropical and subtropical areas suffer from ciguatera. Less conservative estimates report more than 1,000,000 cases of ciguatera occuring annually worldwide, especially in areas around Puerto Rico, Hawaii, Australia, Indonesia and Micronesia. However, the total number of people suffering from ciguatera is unknown and under reporting is likely as identification tests for the toxins are rarely available the areas where the disease is most prevalent, and lack of medical treatment is prevalent.
Due to the sharing of fish among family and friends, as well as potentially wide distribution by fish markets and restaurant of large fish, ciguatera often occurs in disease clusters. For example, in 1996 there were a reported 159 outbreaks involving 447 individuals were on Reunion Island (Southwest Indian Ocean).
Ciguatera also has social and economic consequences. In some areas, fish is completely ignored as a food source. In Florida for example, the sale of barracuda (one of the major source of ciguatera poisoning) is banned. In the Virgin Islands, many restaurants sell imported fish rather than locally caught one due to the abundance of ciguatera contamination.
A study of ciguatera poisoning in the South Pacific found that the disease caused depression of both the local and exporting fishing industries and tourism. In addition it had an indirect affect on human health due to the avoidance of fresh fish, an important source of proteins for most island communities. In French Polynesia, both the loss of activity due to illness and the loss of earnings due to banned fish were greater than 1 million US$.

Coral bleaching and anything that increases macro algae growth such as sewage input, land runoff, overfishing of herbivorous fish, has been reported to increase the incident of the disease. In the French territories of the Indian Ocean for example, an increased number of cases were reported following the 1998 bleaching disturbance.