Severe hepatotoxicity caused by the tropical cyanobacterium (blue-green alga) Cylindrospermopsis raciborskii (Woloszynska) Seenaya and Subba Raju isolated from a domestic water supply reservoir.

Cylindrospermopsis raciborskii, a tropical blooming species of cyanobacterium (blue-green alga), was isolated from the domestic water supply reservoir on Palm Island, a continental island off the tropical northeast coast of Australia. This species, not previously known to be toxic, was shown to be severely hepatotoxic for mice. The 50% lethal dose at 24 h after injection was found to be 64 +/- 5 mg of freeze-dried culture per kg of mouse. The principal lesion produced was centrilobular to massive hepatocyte necrosis, but various degrees of injury were also seen in the kidneys, adrenal glands, lungs, and intestine. The possible implication of this finding in relation to an incident of hepatoenteritis in humans living on the island is discussed.