Botulism: not an innocent disease

Botulism is a disease that must be reported once identified. It is caused by toxins produced by the Clostridium botulinum bacteria. These are bacteria that can appear anywhere in the environment, especially in the shape of spores that are immune to dehydration and freezing. The bacteria are also present in the gastrointestinal tract of both humans and animals. The bacteria themselves are not harmful, but the toxins or harmful substances that are produced by the bacteria, are. The toxins are divided into 7 types (A to G).

Botulism is caused by the same poison used in a Botox treatment. The poison blocks the signal transfer from nerve to muscle. Too much of the poison will get an animal paralysed and mostly killed.

Poultry, ducks and wild birds

Wild birds mostly get infected by a combination of warm and dry weather and the presence of carcasses and many droppings in pools. In poultry farms the carcasses are the largest cause of infection.

Horse, sheep, goat, bovine animals

Carcasses from (small) animals in the feed are often the cause of infection. The toxins are especially found in the large bales of haylage (1.2 to 1.5 metres in diameter): in those bales there is a larger risk that the pH does not go down enough during the fermentation process to curb any growth of Clostridium botulinum. This way the ideal conditions for the growth of Clostridium botulinum and the production of botulinum toxins are created.

How to prevent infections? eend
  • Pay extra attention to harvesting and ensiling: make sure no carcasses are processed in the roughage.
  • Do not let horses, bovine animals, sheep and goats drink from creeks, but always make sure they have fresh water.


Botulism only occurs rarely in this species.

Dogs and cats

Dogs are little susceptible to botulism. This disease is only reported a few times a year. It is also rare in cats. It is important, though, that dogs and cats are kept away from bird carcasses as much as possible, especially around still water, because aviary botulism frequently occurs in water birds. Also, do not feed any raw meat.


If the disease is already in a too advanced stage, the animals are beyond rescue. That is why animals with botulism always have to be treated as emergency. There are no drug treatments available, only supportive therapy. Birds can be treated with several gastric lavages with activated carbon.



  • FAVV
  • Medisch Centrum voor Dieren – Amsterdam
  • Literature study as a part of a master's thesis by Daphne Van Waes 2015
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