FATAL MASS POISONING IN MADAGASCAR FOLLOWING INGESTION OF A SHARK (CARCHARHINUS-LEUCAS) - CLINICAL AND EPIDEMIOLOGIC ASPECTS AND ISOLATION OF TOXINS

In November 1993, 188 people were admitted to hospital after eating th e meat from a single shark (Carcharhinus leucas) in Manakara, a medium -sized town on the south-east coast of Madagascar. This shark and its meat had no unusual characteristics. The attack rate was about 100%. T he first clinical signs appeared within 5-10 hr after ingestion. The p atients presented with neurological symptoms almost exclusively, the m ost prominent being a constant, severe ataxia. Gastrointestinal troubl es, like diarrhoea and vomiting, were rare. The overall case mortality ratio was close to 30% among the 200 poisoned inhabitants. There were no reports of previous similar poisonings in this area, and fishermen in Manakara usually eat this kind of shark without problems. Bacterio logical and chemical causes were eliminated. Two liposoluble toxins we re isolated from the liver and tentatively named carchatoxin-A and -B, respectively. They were distinct from ciguatoxin in their chromatogra phic properties.