Puffer Japan

Pioneering studies were made to determine the structure of tetrodotoxin 1, one of the most toxic compounds among the low-molecular-weight poisons, found in the ovaries and liver of puffer fish, which is a highly esteemed delicacy in Japan. With a combination of the most versatile instrumental facilities, the complex perhydroquinazoline structure of 1 was established (65T2059) in the early 1960s. 

Many fish species, over 700 species worldwide, are either directly toxic or upon ingestion are poisonous to humans. A classic example is the toxin produced by the puffer fishes (Sphaeroides spp.) called tetrodotoxin (TTX). Tetrodotoxin is concentrated in the gonads, liver, intestine, and skin, and poisonings occurs most frequently in Japan and other Asian countries where the flesh, considered a delicacy, is eaten as fugu. Death occurs within 5 to 30 minutes and the fatality rate is about 60%. TTX is an inhibitor of the voltage-sensitive Na channel (like saxitoxin) it may also be found in some salamanders and may be bacterial in origin. 

The poisonous properties of the puffer fish have been known for centuries, and were described as early as ad 220 in China. A Chinese treatise written in ad 600 by Chaun Yanfang (Studies on the Origin of Diseases) described the liver, ovaries, and roe as the most poisonous. Despite the risks, puffer fish is stiU eaten as a delicacy in Japan, where it is known as fugu. Fish that contain the toxin are also accidentally eaten sometimes. Consequently poisoning cases do occur. Between 1974 and 1983 there were 646 cases and 179 fatalities. It has been estimated that as many as 200 cases a year may occur, with a mortality rate of up to 50 per cent. A trained chef should know which parts of the fish to avoid. 

A puffer fish is regarded as a culinary delicacy in Japan. [Fred Bavendam/ Peter Arnold.]... 

CDC (1996) Tetrodotoxin poisoning associated with eating puffer fish transported from Japan-Cali-fornia. Morbidity and Mortality Weekly Report 45 389-391. 

The puffer fish toxin. Captain Cook severely affected in 1774. The fish is prepared by trained cooks and eaten as fugu in Japan. Also found in ovaries and liver of related fish species and some cephalopods. Non-protein MW 319. Effects numbness and tingling of lips, vomiting, fall in BP, weakness, paralysis, respiratory failure, death. Lethal dose in mice 5 pg/kg among the most potent of toxins. Blocks sodium channels and prevents depolarization. Believed to be produced by bacteria in the fish. Looked at by Japan in WWII as a potential CW agent. 

No reliable incidence data exist for tetrodotoxin poisoning. The most extensive data on tetrodo-toxin poisoning comes from Japan where 6386 cases of puffer fish poisoning were reported during the 78-year-period 1886-1963 (59.4% were fatal) [134, 135]. If the average population during this time is assumed to have been approximately 60,000,000, this implies a minimum incidence of... 

Tsunenari S, Uchknura Y, Kanda M. Puffer poisoning in Japan—a case report. J Forensic Sci 25 240-245, 1980. 

Recently, several poisoning cases due to ingestion of, in addition to those of puffers, big and small gastropods have caused in Japan, Taiwan, and China. Especially small gastropods in China have caused many poisoning for a long time, resulting in many deaths and caused serious problems in public health. 

Recently, 80% of puffer in fish market are cultured and rarely are they toxic. Accordingly, puffer is imaged from toxic to nontoxic. On the contrary, the poisoning events due to ingestion of other marine animals bearing TTX have occurred. The toxicity of puffers is related to their spawning with the highest toxicity levels, especially in the ovary, between March and June in Japan. 

To prevent the gourmets from ingestion, it is the best way to advise them not to take the liver of toxic puffer. Recently, because harvest of wild puffer is decreasing, cultured puffer is flourishingly reared in many districts of Japan, which is supplied to meet up the big demand of consumer. Hopefully, these puffer fish reared in net in Japan are found to be nontoxic. In near future, nontoxic liver of these puffers generally may be served to the gourmets, with safety. 

On the other hand, to ensure the safety of consumers in some other Asian countries where the puffer consumption has been increasing, a comprehensive toxicological study should be carried out to identify the toxic and nontoxic puffer fish. On the basis of the results, consumer awareness should be created through several media in order to reduce the poisoning cases. In Japan, as described before, the death number decreases to less than one order although food poisoning cases occur every year. 

It is well known that puffer generally contains TTX. TTX intoxication in humans most often results from ingestion of the liver of certain toxic species. Takahashi and Inoko (1889a,b) first attempted to study the chemical and physical properties of TTX partially purified from puffer. Later, TTX was successfully purified from the ovaries of puffer Spheroides rubripes. The structure of TTX was, however, approved in 1964 at the Fourth International Symposium on the Chemistry of Natural Products held in Japan, with the molecular formula of CnHnNsOg. Subsequently, the adopted term TTX attracted the attention of toxicologists, chemists, and pharmacologists, particularly for human intoxication. 

Records of puffer poisoning have been described in the ancient literature from various parts of the world, particularly in Japan and China (Halstead, 1965 Kainuma and Baba, 1984). In Japan, the oldest record of puffer poisoning is found in Nara and Heian eras (800 AD). 

The issue how to make wild puffer safe to eat has been carefully elucidated in the section on prevention. Now, harvest of wild puffer in Japan has recently outstandingly decreased on account of their overfishing since 10 years ago. Instead, puffer culture has increased resulting in 80% of total marketed puffer. 

Khora, S.S., Isa, J., and Yasumoto, T. 1991. Toxicity of puffers from Okinawa, Japan. Nippon Suisan GakkaisUSl, 163-167. 

Mahmud, Y., Tanu, M.B., Takatani, T., Asayama, E., Arkawa, O., and Noguchi, T. 2001. Chelodon patoca, a highly toxic marine puffer in Japan. J. Nat. Toxins 10, 69-74. 

---