Listeriosis can affect many animal species as well as humans.
Listeria are relatively small gram-positive rods with a tendency to grow in chains. Within the genus, Listeria monocytogenes has the greatest significance. Listeria ivanovii has low virulence, but is pathogenic to humans and sheep. The pathogen has also been isolated from monkeys suffering from meningitis.
Listeriosis is predominantly a disease in sheep that contract the disease through the ingestion of spoiled silage. Cattle, chickens, pigs, rabbits and goats are much less prone to the disease. Individual cases have been described in horses, dogs and cats.
In more than 80% of the cases of ovine listeriosis, the brain is affected and the characteristic clinical picture of this disease develops – the animals run in circles and show further signs up to recumbency due to a usually unilateral dysfunction of cranial nerves.
Other forms are septic listeriosis of newborn or young animals, organ listeriosis (e.g. mastitis) or gestation listeriosis with abortions.
Listeriosis (L. monocytogenes) is a notifiable disease in Germany.