Hepatitis in vervet monkeys caused by Fusarium moniliforme

The fungus Fusarium moniliforme Sheldon is a common contaminant of maize (Zea mays L.) intended for human and animal consumption throughout the world. Culture material of F. moniliforme MRC 826, isolated from home-grown maize in an area in Transkei, southern Africa, with a high rate of human oesophageal cancer, was highly toxic to vervet monkeys (Cercopithecus pygerythrus). Ten monkeys were fed a standard primate diet which contained various amounts of culture material for 180 days. Two control monkeys received the standard diet without culture material. Pathological changes observed in liver biopsies taken by laparotomy were characterized by focal disturbance of the trabecular structure, degeneration and necrosis of hepatocytes, mononuclear infiltration, and in severe cases by cirrhosis. Biochemical changes, particularly increases in liver enzyme activities in serum, paralleled the liver damage seen by light microscopy. The acute, subacute and chronic toxic hepatitis induced in various degrees in all the monkeys fed fungal culture material showed close similarity with human viral hepatitis. The lesions also have some similarities to those induced in primates by aflatoxin, but differ in several respects. Ultrastructural nuclear and nucleolar changes caused by F. moniliforme, i.e. marginal clumping of chromatin and large nucleoli with segregation of fibrillar and granular components, suggested some similarity with the changes reported to be caused by aflatoxin and some other hepatocarcinogens. A long-term feeding experiment in vervet monkeys with F. moniliforme MRC 826 and attempts to isolate and chemically characterise the hepatotoxic metabolite(s) produced by this fungus are being continued.