Several Campylobacter species could be detected in mammals, birds and also in humans. Some species are part of the normal gastrointestinal microbiota or their pathogenicity is still unclear.
In cattle, C. fetus subsp. veneralis causes epidemic abortions and fertility disorders (bovine genital campylobacteriosis, also called vibriosis in cattle; in Germany, notifiable upon suspicion). C. jejuni can lead to diarrhoea or mastitis. In sheep, C. fetus subsp. fetus is known as pathogen of the enzootic campylobacter abortion; occasional abortions caused by C. jejuni have also been described. The importance of campylobacter infections in birds lies in the contamination of carcasses and the risk of food poisoning associated with it. Most frequently, birds are infected with C. jejuni. Diarrhoea or hepatitis are rare.
In dogs and cats, C. jejuni can often be isolated from healthy animals, but can cause diarrhoea especially in young animals. This diarrhoea is often self-limiting. Feeding a barf diet presents a risk of infection.
In humans, campylobacter (especially C. jejuni) is one of the most common causes of bacterial diarrhoea and is usually food-associated (particularly insufficiently heated poultry meat, but also unpasteurised milk and raw minced meat). Rare complications which can occur are Guillain-Barré syndrome (polyradiculitis) and reactive arthritis.
Campylobacter of the species C. jejuni, C. coli, C. lani and C. upsalensis are collectively called thermophilic campylobacter. In Germany, campylobacteriosis (thermophilic campylobacter) is notifiable upon diagnosis in dogs, cats, ruminants and poultry.