Conditions which favour the growth of this organism occur in decaying carcasses and other decaying plant and animal matter and also in stagnant pools contaminated by rotting animal or plant material. When material containing the toxin is eaten by birds the characteristic symptoms of intoxication known as botulism will occur if the dose of toxin is high enough. Carrion-eating birds can withstand large doses of the toxin without showing any symptoms. Botulism occurs sporadically in poultry raised under conditions where hygiene is poor and where birds have access to rotting carcasses or other contaminated or decaying material. It also occurs occasionally in wild birds particularly water birds feeding in stagnant water holes.
Botulism is usually more common in the warmer months.
Symptoms First signs are seen 12 to 48 hours after toxin ingestion. Birds appear drowsy and are disinclined to move, their head droops, later they rest it on the ground. Wings and legs may also become paralysed. There may be mucoid saliva from the beak, greenish diarrhoea, loss of appetite, eyelids are closed, and wings trailing. The bird may lapse into a coma then die.