|Nassarius pappilosus snails (Photo: Zing News)|
Recently, Dr. Dao Viet Ha, Director of the Institute of Oceanography, Vietnam Academy of Science and Technology, said that the agency has identified the names and toxins of snails that poisoned 3 fishermen in Khanh Hoa, among which, one person died.
Dr. Ha said that the Laboratory of Food Safety and Environment, Institute of Oceanography in Nha Trang, Khanh Hoa has analyzed the chemical composition of 30 sea snail samples, 29 of which were identified as the serrated snail species Nassarius papillosus. The other one belongs to the Bong Nassarius glans mud snail. In particular, this agency determined a large amount of tetrodotoxin present in all specimens of the two snail species mentioned above.
Tetrodotoxin is a neurotoxin. They affect the central nervous system of humans and higher animals. It is estimated that 5-10 individuals containing this toxin can kill the average person within 30 minutes to a few hours after eating. Tetrodotoxin does not decompose at high temperatures. As a result, they can exist in processed foods, even frozen and canned products.
After eating poisonous sea snails about 30 minutes, the victim will develop symptoms of tongue numbness, lip numbness, dizziness, headache, abdominal cramps, nausea, vomiting, difficulty speaking, difficulty swallowing, imbalance (walking staggered).
In severe cases, the victim seizures, foam in the mouth, loses consciousness and possibly dies from paralysis of the respiratory muscles. Currently, cases of tetrodotoxin poisoning in general and poisonous sea snails in particular do not have a specific antidote. Therefore, when poisoned, the victim should be taken to the nearest medical facility.
|Nassarius glans snails (Photo: Zing News)|
According to Dr. Ha, in fact, a number of similar poisoning cases from eating sea snails have been recorded in the Pacific region. Species such as the ốc Mặt trăng (Turban), ốc Đụn (The top of shells), ốc Tù (Trumpet shells), ốc Hương Nhật Bản (Ivory snails), and ốc Trám (Oliva)… are at risk of causing extreme toxic.
Depending on the species of snail, the poison can be saxitoxin (microalgal toxin accumulating in bivalve animals, some species of crabs…) or tetrodotoxin (toxin in pufferfish, squid or horseshoe crab). The origin of toxins in sea snails is quite complex because not all individuals in the same species contain toxins. Toxicity in each individual also depends on geographic region and seasonal conditions. Dr. Ha recommends that people not eat snails that have a history of poisoning or have no proven origin.
Previously, the Department of Food Safety and Hygiene, Khanh Hoa Department of Health, said that at 9 am on September 11, 3 fishermen caught some snails in the waters of Van Ninh district, Khanh Hoa. After that, they stopped at Khai Luong island, Van Thanh commune to give the family of acquaintances half of the snails caught. The remaining snails were steamed and eaten by 3 mentioned fishermen at 4:00 p.m. on the same day.
30 minutes eating those snails, all 3 people showed symptoms of numbness of lips, hands, and legs, dizziness, nausea, headache. By 7 pm, one in the 3 had severe symptoms and died outside the hospital.
At around 1 am on September 12, the remaining two victims got emergency treatment at the Medical Center of Van Ninh district, then transferred to Khanh Hoa Provincial General Hospital and were fortunate to pass the danger. The family in Khai Luong island doubted the strange snails so only 2 of them ate a few. They showed no signs of poisoning.