Detection of exposure to aflatoxin in an African population.

Urinary excretion of 8,9-dihydro-8-(7'-guanyl)-9-hydroxyaflatoxin (AFB-Gua) was studied in areas of different liver cancer incidence in Kenya. Of 983 urine samples analysed for AFB-Gua by high-performance liquid chromatography, 12.6% gave positive results. The chemical identity of AFB-Gua was verified by synchronous scanning fluorescence spectrophotometry. A moderate degree of correlation between prevalence of exposure to aflatoxin B1 and liver cancer incidence could be established in Bantu. People living in areas with high exposure to aflatoxin B, form antibodies that recognize an aflatoxin B1 epitope.