Aflatoxicosis

Aflatoxicosis is a fungal toxicosis that may affect all species of animals. The fungus grows on carbohydrate-rich feeds such as peanuts, cottonseed, corn, sorghum and cereal grains when they are stored in hot conditions without adequate drying and aeration. Peanuts and corn can be contaminated before harvest, when drought leads to premature drying of the developing seeds.

Cause

Aflatoxins are produced mainly by 2 fungi, Aspergillus flavus and A. parasiticus.

Distribution

Aflatoxins can occur anywhere.

Hosts

Carbohydrate-rich feeds such as peanuts, cottonseed, corn, sorghum and cereal grains

Life cycle

Grows on carbohydrate-rich feeds when stored in hot conditions without adequate drying and aeration. Peanuts and corn can be contaminated before harvest, when drought leads to premature drying of the developing seeds.

Affected animals

  • cattle
  • pigs
  • ducklings
  • turkeys
  • horses

Symptoms

In cattle

  • Blindness
  • Walking in circles
  • Ear twitching
  • Teeth grinding
  • Frothing at the mouth
  • Diarrhoea
  • Straining
  • Abortion
  • Anal prolapse

Terminally affected animals usually die within 48 hours after lying down which is followed by convulsions.

Lower levels of the toxin in the feed may cause loss of appetite, resulting in a reduction in weight gain or milk production.

In pigs

Young pigs are at greater risk than adults and a variety of clinical signs are seen. Depression, jaundice, lethargy and death occur in acute cases. Uneven growth across a litter is common in more chronic cases.

In birds

Ducklings and turkey poults are sensitive to aflatoxin. Reduced growth rates are the most common sign, but increased mortality and disease can occur due to immunosuppression (weakened immune system). Chickens show similar signs, but are more resistant than ducks and turkeys. Laying hens are even more resistant, but immunosuppression is possible.

In horses

Horses can show signs from sudden death to more chronic signs such as lack of appetite and energy, weight loss, anaemia and jaundice.

Impacts

Aflatoxins produced by the fungus mainly cause damage to the liver.

How it is spread

Mouldy bread has been known to cause poisoning in dogs.

Risk period

When adequate drying and aeration are not available or during drought.

Monitoring and action

Submit samples of suspect feed material and the stomach contents of affected animals for aflatoxin testing. Submit liver samples for histological examination.

Control

Do not feed noticeably contaminated feed to animals. Correct harvesting, handling, drying and storage of grains and seeds are the main means of control.

There is no effective treatment. Mildly affected animals will recover.

Further information