Aflatoxin is one of the worst, most lethal cancer-causing toxins known to man. It is a mycotoxin, whihc means that it is made by a fungus or a mold. It occurs naturally, produced by certain types of molds (Aspergillus flavus – get it? Aspergillus FLAvus toxin). The mold grows on certain types of grains and if you eat the grain, the toxin is metabolized in the liver and causes severe liver injury with necrosis of the liver, leading to cirrhosis and liver cancer. Not a pleasant way to die. If aflatoxins are contaminating a lot of the grain in Sub-Saharan Africa, there is sure to be famine or if the people get desperate enough to eat the contaminated grain, there will be a humanitarian health crisis as they start to die from liver disease. Big trouble brewing. The microscopic appearance of the mold is pretty beautiful, though.