Illustration of the Campylobacter sp. bacteria. Individual bacterium are shown as pink, curved shapes with a thin hair-like flagellum which is used for motility. The natural reservoir of Campylobacter is poultry and there are a number of species of the bacteria which can infect humans and animals. For example, Campylobacter jejuni is one of the major causes of food poisoning (campylobacteriosis) in developed countries.