Campylobacter is a bacterium. It is found in the intestines of many types of animals. Campylobacter is the most common bacterial cause of diarrhoeal illness. Campylobacteriosis has been found to be more common during the summer months. It also appears to be more common in males than females. It also causes bloody diarrhea and reactive arthritis. It is usually found after eating poultry. Campylobactor jejuni was also thought to be associated with peptic ulcer syndrome.