Campylobacter are gram-negative, non-spore-forming, spirally curved bacteria. They grow under microaerobic conditions (increased CO2 demand as well as O2 sensitivity) and react sensitive to acidic and basic pH-values. Campylobacter can be reliably killed by pasteurisation. The most common species are C. jejuni, which causes about 90% of disease cases in humans (campylobacteriosis), and C. coli.
Occurrence
Campylobacter infections are widespread worldwide and occur more frequently during the warm season. Besides salmonella, they are the most important pathogens of bacterial intestinal diseases in humans. In Austria, campylobacteriosis continues to rank first among the reported food-borne bacterial infectious diseases in 2019.
Reservoir
Poultry, pigs, cattle, pets such as dogs and cats, and birds can be carriers of Campylobacter. The bacteria are possible intestinal inhabitants of these animals, which often carry Campylobacter asymptomatically.
Mode of transmission
Human campylobacteriosis is mainly considered to be a food-borne infection. The main sources of infection are insufficiently heated poultry meat, unheated food contaminated with bacteria (e.g. after using the same cutting board without thorough cleaning after cutting the poultry) and raw milk. Strict hygiene measures in food preparation should be implemented to avoid cross-contamination between raw meat and other food. Direct transmission from person to person (faecal-oral) is rare.
Incubation period
Usually 2 to 5 days, depending on the bacteria count absorbed. Already about 500 bacteria are sufficient to cause the disease in humans; more than 10,000 colony-forming units (CFU) can be found on one gram of poultry skin.
Symptoms
High fever, watery to bloody diarrhoea, abdominal pain, headaches and tiredness for one to seven days are symptoms of an infection with Campylobacter. Campylobacteriosis can also lead to autoimmune diseases, which do not appear until several weeks after the acute symptoms have subsided. Late effects such as irritable bowel syndrome, reactive arthritis (including Reiter's disease (inflammation of the joints), urethritis (inflammation of the urethra) and conjunctivitis (inflammation of the conjunctiva)) and Guillain-Barré syndrome, which causes paralysis of the peripheral nerves, can occur.
Treatment
Usually, the disease is self-limiting. The therapy includes regulating the water and electrolyte balance. Infants as well as patients who develop high fever or are immunocompromised can be additionally treated with antibiotics.