Botulism in poultry

Botulism is a disease characterised by paralysis of the neck and limbs of poultry. Usually, a number of birds are affected and they succumb quickly.

All domestic poultry, including fowls, turkeys, water fowl, pheasants, emus and most wild birds are susceptible. Carrion-eating birds can withstand large doses of the toxin without showing any symptoms.

Scientific name

Clostridium botulinum

Cause

Caused by the ingestion of a toxin produced by a bacterium (Clostridium botulinum) that lives on decaying animal and vegetable matter.

Other names

Limberneck

Distribution in Queensland

Botulism occurs sporadically in poultry raised under conditions where hygiene is poor and birds have access to rotting carcasses, or other contaminated or decaying material. It also occurs occasionally in wild birds, particularly if they feed in stagnant water holes.

Hosts

Wild birds are frequently the source of avian influenza (AI) infection in domestic poultry.  Wild birds may contaminate domestic poultry feed or water supplies which, when ingested, may lead to infection or disease. Infected backyard poultry and live bird markets can be a source of AI virus for commercial poultry.

Symptoms

Symptoms first start to appear 12 to 48 hours after the toxin has been ingested. Affected birds will first appear weak, drowsy and reluctant to move. The bird's head will droop, later resting it on the ground, with their eyes closed and wings drooped. They may then lapse into a coma and die. Their neck may be coiled over or lie straight on the ground due to flaccid (relaxed) paralysis. Feathers may be easily plucked.

Impacts

Botulism causing spores can remain dormant in contaminated soil for years and germinate into toxin producing bacteria when a suitable nutrient source and an anaerobic environment are available. The toxin can also be found in maggots and litter beetles that feed on infected carcasses. Botulism is usually more common in the warmer months.

Conditions that favour the growth of this organism are found in decaying carcasses, and other decaying plant and animal matter, and in stagnant pools contaminated by rotting animal or plant material. When birds eat material containing the toxin, and if the toxin's dose is high enough, the characteristic signs of botulism will occur.

Control

Botulism is best prevented by:

  • removing dead birds daily
  • removing the source of the toxin
  • supplying clean feed and water
  • keeping birds away from stagnant or pooled water
  • providing feed in containers and not on the ground.

Sick birds should be isolated and provided with food and water. Supportive therapy with antibiotics and vitamins has been helpful in some cases. Birds that live through 48 hours of illness usually recover.

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