Campylobacter species are motile, curved, microaerophilic, gram-negative bacilli that normally inhabit the gastrointestinal tract of many domestic animals and fowl. Several species of campylobacter can infect humans, with most infections coming from contaminated food and water. The two main versions of campylobacter are C. jejuni and C. fetus.
C. jejuni affects both healthy and immunocompromised people, causing diarrhea. It accounts for more cases of diarrhea than both Salmonella and Shigella combined. It also causes meningitis in infants. Though C. fetus can infect healthy people, it is more likely to affect people with underlying conditions and pregnant women.
C. fetus frequently causes bacteremia, the presence of bacteria in the bloodstream, and systemic infections. The nerve disorder Guillain-Barré syndrome develops in about 1 in 2,000 cases of Campylobacter colitis because the infection-fighting antibodies sometimes attack nerves. Guillain-Barré syndrome causes weakness or paralysis. While most people recover, extreme muscle weakness may persist. With muscle weakness comes difficulty breathing, and some people need a ventilator to breathe. Some people who develop Guillain-Barré syndrome do not have the weakness resolve. Another long-lasting side effect of Campylobacter infections is reactive arthritis. This can take days to weeks to develop, and usually affects the knees, hips, and Achilles tendon. This condition causes pain and inflammation in the affected joints.