Aflatoxicosis is a fungal toxicosis caused by eating feed contaminated with aflatoxins. Aflatoxins are a specific type of mycotoxin that are produced by two types of fungi, Aspergillus flavus and A. parasitus. There are over 20 types of aflatoxins, although the four major types are designated as B1, B2, G1 and G2. Aflatoxin B1 is the most dangerous. Aflatoxins mainly cause damage to the horse's liver. Clinical signs that may or may not develop prior to death, are related to liver failure resulting from damage caused by aflatoxins.

Clinical signs of Aflatoxicosis

Horses may develop acute or chronic aflatoxicosis, depending on the amount of the toxin they've eaten. Horses that develop acute aflatoxicosis usually won't show any clinical signs other than sudden death. In chronic cases, which are the most common, clinical signs include loss of appetite, weakness, depression, anemia, jaundice (yellowing of mucous membranes), weight loss, and eventually death from liver failure.

Risk of Feed Contamination

The fungi which produce the toxins grow on carbohydrate rich feeds such as peanuts, cottonseed, corn, sorghum and cereal grains when they are stored in warm (78-90°F (25.5-32°C)), humid (relative humidity of 97-99%) conditions. Peanuts and corn can be contaminated before harvest, when drought leads to premature drying of the developing seeds.