What is Neurotoxic Shellfish Poisoning?

Shellfish poisoning refers to food poisoning caused by the consumption of certain toxin-containing shellfish. Common shellfish that cause poisoning are: mussels, clams, snails, oysters, scallops and so on. Shellfish contain different types of toxins, which are paralytic, diarrhea (liver poisoning), and clam poisoning. The symptoms of poisoning are paralyzed. The toxicity of shellfish is related to algae in seawater. Shellfish eat toxic algae, and the toxic substances contained in shellfish enter the shellfish, which can cause poisoning after eating. ^[1]

Shellfish poisoning

Shellfish poisoning refers to food poisoning caused by the consumption of certain toxin-containing shellfish. Common shellfish that cause poisoning are: mussels, clams, snails, oysters, scallops and so on. Shellfish contain different types of toxins, which are paralytic, diarrhea (liver poisoning), and clam poisoning. The symptoms of poisoning are paralyzed. The toxicity of shellfish is related to algae in seawater. Shellfish eat toxic algae, and the toxic substances contained in shellfish enter the shellfish, which can cause poisoning after eating. ^[1]

Shellfish poisoning

shellfish poisoning

Edible toxin

The marine molluscs that cause poisoning are Japanese snails and snails of the snail family, mud snails of the snail family, mussels of the mussel family, mussels of the family mussel, California mussels, long oysters of the oyster family, and clams of the family Curcumidae .

In certain sea areas in some countries and regions, the edible shellfish can be suddenly poisoned, which can cause poisoning after consumption. The cause of edible shellfish poisoning is currently recognized by the biological chain exogenous theory. That is, the shellfish poisoning is related to "red tide". "Red tide" is the discolored erythema that appears in the sea water, accompanied by the death of marine animals. It is the formation of a large number of single-celled microalgae in the seawater. Shellfish feed on toxic algae, which is not poisonous by itself, but has the ability to accumulate and accumulate algae toxins. People can cause food poisoning after eating. The poisonous parts of poisonous shellfish are mainly liver and pancreas.

Poisonous shellfish contains the following toxic ingredients:

1. Saxitoxin and its derivatives: This group of toxins includes 19 species of saxitoxin (STX) and its derivatives neo saxtoxin (neo STX), keliotoxin (GTX) and the like. This group of toxins is stable in high temperature and acidic environment, and unstable in alkaline environment. It cannot be destroyed by ordinary cooking methods. This group of toxins is paralytic shellfish toxin. STX is easily soluble in water and heat resistant. There is no change in toxicity after heating to 80 ° C for 1 hour; the toxicity is only reduced by half after heating to 100 ° C for 30 minutes; stable to acids; unstable to alkalis; easily absorbed by the gastrointestinal tract. STX is a non-protein compound, and the mouse LD50 is 10 mg / kg (ip). The shellfish causing poisoning have been reported in China, such as snails, snails and litchis.

2. Daejeon Soft Spongic Acid and its derivatized products Daejeon Soft Spongic Acid and its more than 10 kinds of derivatized compounds-phycotoxin (Dipteratoxin, DTX-n), scallop toxin (Clam toxin, PTX), etc., are diarrheal Shellfish toxin. This group of toxins is fat-soluble, insoluble in water, stable to heat, and cannot be destroyed by ordinary cooking and heating methods. The shellfish that cause poisoning are limited to bivalves, especially scallops and purple mussels, followed by motley clams, clams, black clams and mussels. The toxic site is the midgut glands.

3. Chondroitic alginic acid and its isomers Chondroitic alginic acid (DA) and its isomers are memory-loss (forgetting) shellfish toxins. DA is an amino acid. The poisonous shellfish is purple mussel. The content of DA detected in poisoned mussels was 0.3-0.9 mg / g.

4. Naked dinoflagellate (BTX) is divided into three toxins A, B, and C, and the chemical structures of BTX-B and BTX-C are determined. BTX is a neurotoxin shellfish toxin. BTX is fat soluble and contains no nitrogen. Poisonous shellfish include giant oysters and curtain clams.

5. Venerupin is a light yellow powder, which is heat-resistant at a pH of 3 to 8, and it is completely toxic when heated to 100 ° C for 1 hour. Venerupin is a liver-damaging shellfish toxin. Shellfish that cause poisoning include clams and oysters. The poisonous part is the liver.

In addition, some shellfish may contain photoallergenic substances, and the shellfish that cause poisoning are mud snails (commonly known as soil paste, yellow mud snail, wheat snail, plum snail, etc.).

Paralytic shellfish poisoning is caused by saxitoxin and its derivatives. The shortest incubation period is 5 minutes, usually 0.5 to 3 hours, and up to 4 hours. Early numbness of lips, tongue, and fingers. Paralysis of the extremities and the neck further; paralysis of the movement, staggering gait, accompanied by dysphonia, salivation, headache, thirst, nausea, vomiting, etc., severe cases died of respiratory muscle paralysis. Death usually occurs within 2 to 12 hours after illness. Before death, the consciousness is clear. If the patient is still alive after 24 hours, the prognosis is generally good.

1. The patient has a history of eating shellfish, and has basically the same clinical manifestations corresponding to the above types.

2. When possible, take suspected poisoned foods to test for toxic ingredients in shellfish. Detection of STX, GTX, OA, DTX-n, DA by high performance liquid chromatography (HPLC) has been reported. The United States and Canada stipulate that the limit of STX in refrigerated fresh shellfish meat is 80ug / 100g. There are no regulations in our country.

The specific diagnosis is based on the national standard GB14938-94 "General Standards for Diagnosis and Technical Treatment of Food Poisoning".

There is no antidote for poisoning shellfish poisoning, and only detoxification measures, symptomatic treatment and supportive therapy are taken.

1. To prevent poisoning by shellfish poisoning, conduct extensive publicity in shellfish-producing areas, so that the masses can understand the relevant knowledge of poisoning shellfish poisoning.

2. Remove the internal organs when eating shellfish.