How many species of snail poison?

The poisoning incident caused by eating sea snail on April 4 in Phu Yen has caused one death and two people must be emergency. On October 17, a similar poisoning occurred in Quang Ngai, resulting in two of the three victims dying after all three people ate about 500g of grilled snail. How many species of snail poison?

So far, in Vietnam, at least three species of shellfish (conus) have been identified in the form of venom (venom), which is potentially lethal, but by way of injection when we accidentally touch, grasp them. In natural life, shells use toxins as hunting weapons, potentially causing paralysis in very short time.

For poisoning by sea snail through food route like the poisoning mentioned above is the first case recorded in Vietnam. However, similar cases of poisoning have occurred quite commonly in the Pacific region, typically in Japan.

Nassarius papillosus mud crab (Linnaeus, 1758) was identified as the cause of the poisoning on October 17, 2006 in Quang Ngai (Anh: CTV)

Normally, sea snail species are edible, but suddenly become poisonous, we cannot know why they become poisonous. Some snails are unique in a certain part (usually the salivary glands), but there are also snails that are completely poisonous and very dangerous to life if we accidentally eat them.

Most cases of poisoning are caused by improper contact of the person holding them, the wound is usually a deep wound.If mild, like bee or insect sting;From the spot the puncture starts to cause a lot of pain, darkening or signs of ischemia, external appearance of mottling or spotting spots around the bite and numbness.If it gets worse, it can cause paresthesia in the wound area, quickly spread around the mouth, then everywhere.

Clinical symptoms: itching, dysphagia, weakness, loss of speech, reflexes, bifurcation, fainting, lethargy, paralysis of muscles, respiratory collapse, heart failure and death.

THANH HUONG

Recently, many snail species have been recorded as the cause of human poisoning through food routes such as moon snails (turban), the top of shells, prison snails (trumpet shells). ), Japanese snail (ivory snails), snails (oliva) .

In Brunei, five children died after eating snails (also known as olive snails); In Taiwan, 17 victims of poisoning (one death) after eating stir-fries prepared from catut Nassarius castus mud snails and N. conoides cones.

Depending on the species of snail, the toxin nature may be saxitoxin (microalgae toxin accumulated in bivalve organisms, some species of reef crabs .) or tetrodotoxin (pufferfish toxin, blue-spot squid, so .). Toxins in the moon snail, snail and snail have been identified as saxitoxin (a common neurotoxin in some Alexandrium species of microalgae).

Meanwhile, the toxins of the prison snail and Charonia sauliae, Japanese snail Babylonia japonica, the snail and the red mouth of Tutufa lissostoma, mud snail (Niotha, Zeuxis), the jade snail (Natica and Polinices didyma) are tetrodotoxin. Notably, saxitoxin or tetrodotoxin are both of low molecular weight compounds, due to their special chemical structure, they are not decomposed, denatured at high temperatures when processing and therefore they exist in processed, fried or even food products, including frozen or canned products.

The origin of toxins in snail species is currently unknown, as they are quite complex: not all individuals in the same species carry toxins, and toxicity is also very different according to individual. The cause of this complex nature is that the snail toxin is also derived from symbiotic microorganisms (like the puffer toxin case). This problem is now becoming a new challenge for marine toxin researchers, not only in Vietnam but also in Asia and the world.

To avoid damage to human health and life, we need to be very careful first, avoid curiosity to grasp, touch strange snail species, colorful colors . and absolutely not It is advisable to eat prehistoric species suspected of having toxic or unconfirmed food safety.

DAO VIET HA (Nha Trang Oceanographic Institute)