Eating tropical coral reef fish, such as tiger grouper, east star grouper, west star grouper, cypress grouper, humphead wrasse and other groupers, as well as sea bass, can easily increase the risk of ciguatera poisoning. Scientists point out that ciguatera poisoning incidents have gradually increased in recent years, the reason being the great damage to coral reefs caused by marine pollution and global warming, and coral reefs are the habitat for most tropical deep-sea fish.
Regarding ciguatera, Chinese people should not be unfamiliar. In 2006 alone, the number of people with ciguatera poisoning in Guangdong Province exceeded several hundred. Large-scale ciguatera poisoning incidents have occurred in places like Shantou, Zhongshan, and Shenzhen. The main culprit is mostly the deep-sea tropical fish favored by people along the coast of Guangdong—groupers.
Transmitted to the human body through the food chain
Ciguatera is a neurotoxin, colorless and odorless, fat-soluble, insoluble in water, heat-resistant, and not easily destroyed by stomach acid. It is mainly found in the viscera and muscles of tropical coral reef fish, with the highest concentration in the viscera. Ciguatera mainly affects the human gastrointestinal and nervous systems. The symptoms of ciguatera poisoning are somewhat similar to organophosphate poisoning. Some victims initially feel a tingling in the lips, tongue, and throat, followed by numbness in these areas. In other cases, the first symptoms are nausea and vomiting, followed by symptoms such as dry mouth, intestinal cramps, diarrhea, headache, collapse, chills, fever, and muscle pain. Contact with cold water feels like an electric shock. The poisoning continues to worsen until the patient cannot walk. Poisoning symptoms can last for several hours to several weeks, or even months. In severe cases, it can lead to death.According to marine biology experts, more than 50,000 people worldwide suffer from ciguatera poisoning each year, but only 10% of these incidents are known to the public through news reports. Scientists point out that ciguatera poisoning incidents have gradually increased in recent years, the reason being the great damage to coral reefs caused by marine pollution and global warming, and coral reefs are the habitat for most tropical deep-sea fish.
Scientists say that the greenhouse effect is continuously raising the temperature of the ocean, and at the same time, more and more toxic waste is being discharged into the ocean by humans. These two factors have damaged coral reefs, and algae containing ciguatera have grown and flourished. Originally, small fish living near coral reefs survive by eating algae, and the groupers, mullets and other fish that humans eat long-term feed on these small fish. In this way, the toxin is transmitted to the human body through the food chain.
Rapid spread in the last 10 years
Although people have paid more attention to ciguatera only in recent years, humans actually knew about it long ago. Ben Kaneyi, a professor at the University of Hawaii, introduced that in Homer's epic "The Odyssey," there is a description of fish poisoning; and Alexander the Great once ordered his troops not to eat fish to prevent poisoning.
In the last 10 years, ciguatera from tropical regions has rapidly spread to many places in Asia, Europe, and the United States, mainly because many high-end restaurants have started to offer expensive coral reef fish. In the United States, more than 250 people get ciguatera poisoning each year now, five times more than in the 1970s. The places with the most ciguatera poisoning incidents are Florida, Texas, and Hawaii.
Difficult to identify and treat
Although scientists already know that the reason for the rampant ciguatera is global warming and increasing pollution, public health officials still face huge challenges because there is currently no reliable method to test for ciguatera, and it is difficult for people to tell which fish has it. At the same time, scientists have not found an effective way to treat ciguatera poisoning. In addition, doctors also lack effective equipment to diagnose ciguatera poisoning, so in many areas, ciguatera poisoning is often misdiagnosed as other diseases.
Dr. Edgar Portigo of Iloilo General Hospital in the Philippines is facing this problem: the Roja family was sent to this hospital after eating poisoned fish. The emergency room was full of vomiting and groaning patients. "Normally, only one or two people come to the emergency room, but that day, more than 30 patients came at once," said Dr. Portigo.
At first, Dr. Portigo thought these people had heavy metal poisoning, but all the patients mentioned mullet. He immediately sent a sample of the fish to the capital, Manila, for testing. The results showed that the fish meat contained a large amount of ciguatera. After treatment by Dr. Portigo, all thirty-plus patients eventually recovered.
Most patients with ciguatera poisoning will recover quickly, but some will be left with permanent sequelae.
Professor Richard Lewis of the University of Queensland, Australia, is a long-term expert on ciguatera. He believes, "Ciguatera is very difficult to deal with. Unless you don't eat fish at all, you cannot eliminate the danger of ciguatera."
Expert opinions
Don't eat fish viscera
This is a comprehensive report. Tropical coral reef fish containing ciguatera are widely found around coral reefs and near coasts in tropical and subtropical seas such as the Pacific and Indian Oceans. There are about 400 species worldwide. China has more than 30 species, mainly distributed in Guangdong and the South China Sea Islands, including common seafood market and table dishes such as tiger grouper, east star grouper, west star grouper, cypress grouper, humphead wrasse and other groupers, as well as sea bass. Ciguatera is a neurotoxin, colorless and odorless, fat-soluble, insoluble in water, heat-resistant, and not easily destroyed by stomach acid. It is mainly found in the viscera and muscles of coral reef fish, with the highest concentration in the viscera.Experts say that ciguatera is not innate to fish; it is an acquired toxin. Algae containing ciguatera adhere to the surface of coral. Small fish eat the toxic algae, and then big fish eat the small fish, and the toxin accumulates in the big fish's body. In this way, the toxin is concentrated and concentrated through the food chain. Therefore, although coral reef fish become more valuable as they get bigger, their toxicity also becomes greater, and the risk of eating them is higher.
There are at least 4 known types of ciguatera, and their molecular structures and chemical properties are different. The toxicity of ciguatera is 20 times stronger than that of tetrodotoxin. Ciguatera poisoning is very harmful to the human body. In mild cases, there will be gastrointestinal symptoms. In severe cases, there will be neurological and cardiovascular symptoms, shock, and even respiratory paralysis leading to death.
Experts remind that for safety's sake, do not eat fish viscera. Ciguatera mostly accumulates in the liver, gallbladder, eggs and other internal organs of fish. Removing the internal organs is a good way to avoid poisoning. In addition, methods such as heating, refrigeration, and sun-drying cannot remove the toxin. It should be reminded that when eating, avoid drinking alcohol and eating peanuts or beans at the same time to avoid aggravating the degree of poisoning.