Ciguatera fish poisoning is caused by a toxin that can be found in some large saltwater fish, including barracuda, grouper and amberjack. Previous research has suggested that 10,000 to 50,000 people are sickened by ciguatera poisoning each year worldwide. However, a new study has revealed that ciguatera fish poisoning may be more common than previously thought. But, the reasons behind the under-reporting of ciguatera poisoning still remain unclear.
Unlike other kinds of food poisoning which may occur due to raw or undercooked meats, there is no way to tell while eating a fish if it is tainted by ciguatoxins, which are found in algae that grow in coral reefs. Nor is there any laboratory test to confirm a diagnosis in people, though the fish themselves can be tested.
The researcher team found that in Florida, cases of ciguatera are under-reported to public health authorities. Until now, the Florida state Department of Health estimated 0.2 cases per 100,000 people. But, Beth Radke, a researcher at the Emerging Pathogens Institute at the University of Florida, said, "It may actually be closer to 5.6 cases per 100,000 people statewide."
Radke analyzed 291 ciguatera reports from 2000 to 2011 and also conducted a survey of 5,352 recreational fishermen to see if they had ever experienced any symptoms of ciguatera from eating fish that they had caught in saltwater. The study found that areas around Miami and the Florida Keys were particularly affected by ciguatera, with rates ranging from 28 to 84 per 100,000 people.
Radke said, "Hispanics are at higher risk and we believe that may be because of different certain cultural preferences for eating high-risk foods like barracuda. They are a fish we really recommend not eating at all. The reasons behind the under-reporting of ciguatera are unclear. it may be that people are not accurately diagnosed, or that doctors do not report the illness to health authorities as they should."
Previous research has shown the risk is highest in the Caribbean Sea and the Pacific and Indian Oceans, where as many as 3% of travelers are sickened by ciguatera. People who come down with the illness may experience a range of unusual symptoms, including tingling extremities, pain, hot-cold reversal and a feeling of heaviness or paralysis, as well as anxiety. While Radke's study did not show that ciguatera poisonings are on the rise, the study findings do provide a baseline rate of infection that scientists can use in the future, as they study the impact of warming waters and climate change on the spread of ciguatera.
The study is published in the American Journal of Tropical Medicine and Hygiene.