POISONING BY THE RED-ALGA-OGONORI (GRACILARIA-VERRUCOSA) ON THE NOJIMA COAST, YOKOHAMA, KANAGAWA PREFECTURE, JAPAN

A food poisoning case due to the ingestion of 'ogonori', an edible red alga, occurred at Yokohama, Kanagawa Prefecture, Japan, in late Octob er 1993, resulting in two victims, including one death (female). No ca usative agent present in the ogonori was found from a routine bioassay for marine toxins. From the production of increased amounts of prosta glandins (PGs), mainly PGE(2), by the alga on stimulation by cutting o r soaking in fresh water, and further increase of PGE(2) by addition o f arachidonic acid, it appeared that an enzyme, probably fatty acid cy clooxygenase, in the ogonori and the body of the victim, was acting on the highly unsaturated fatty acids in the oil of the ingested seafood and in the blood hemorrhaged from the stomach of the victim. This res ulted in the production of over 30 mg of PGE(2) and small amounts of o ther PGs in a comparatively short time, With this dosage the victim su ffered from nausea, vomiting, and hypotension, and died of hypotensive shock. PGE(2) seems to work more selectively on females. This type of poisoning is very unusual, and differs from the more familiar forms o f poisoning occurring after ingestion of marine organisms.