Campylobacter jejuni / coli

Campylobacter is a genus of Gram-negative, curved or spiral-shaped rod-shaped bacteria found worldwide. To date, more than 30 species have been described, with Campylobacter jejuni and Campylobacter coli responsible for the vast majority of infections in humans. Campylobacter species are among the most significant bacterial causes of gastroenteritis and diarrhoeal diseases worldwide and represent a considerable burden on public health in both industrialised and developing countries [1, 2].

According to the World Health Organisation (WHO), Campylobacter is one of the four most common causes of diarrhoeal diseases worldwide and is considered the most common bacterial cause of gastroenteritis in humans. In Europe, campylobacteriosis is consistently among the most frequently reported foodborne illnesses. According to estimates by the European Food Safety Authority (EFSA), more than 246,000 confirmed cases are recorded annually within the European Union. However, the actual number of infections is likely to be significantly higher due to under-diagnosis and under-reporting [2, 3].

Symptoms

The incubation period for campylobacteriosis is usually two to five days; however, symptoms may appear as early as one day or as late as ten days after exposure. The illness often begins with non-specific symptoms such as fever, headache, a general feeling of being unwell, and muscle e and joint pain. As the illness progresses, gastrointestinal symptoms typically develop as the bacteria colonise the intestinal mucosa and cause inflammation [2, 4].

The most common clinical symptoms include diarrhoea, abdominal cramps, abdominal pain, fever, nausea and, occasionally, vomiting. Diarrhoea can range from mild and watery to severe and bloody. Many patients suffer from severe, cramp-like abdominal pain, which can mimic the clinical presentation of acute appendicitis. In uncomplicated cases, symptoms usually last for three to seven days and subside without specific treatment. However, severe cases may require hospital admission, particularly in older people, immunocompromised individuals and young children [5, 2, 6].

Although most patients make a full recovery, complications may occasionally arise. These include bacteraemia, hepatitis, pancreatitis and severe systemic infections in particularly vulnerable individuals. Clinically significant post-infectious complications include, amongst others, reactive arthritis and Guillain–Barré syndrome, a rare neurological disorder that can cause temporary paralysis. Furthermore, some affected individuals may continue to experience symptoms consistent with post-infectious irritable bowel syndrome [2, 5].

Infected individuals remain infectious for as long as the pathogen is being excreted in the stools. Bacterial shedding typically persists for around two to four weeks after the onset of symptoms, but this may vary from person to person [6].

Routes of transmission

Campylobacter bacteria are zoonotic pathogens and occur naturally in the gastrointestinal tract of numerous animals, including poultry, cattle, pigs, domestic animals and wild birds. Poultry represents the most important reservoir for human infections, as the animals often carry the bacteria asymptomatically [3, 1].

Human infection occurs predominantly through the oral ingestion of contaminated food or contaminated water. Worldwide, the consumption of undercooked poultry meat is regarded as the most significant risk factor. Other significant sources of infection include raw or unpasteurised milk, contaminated drinking water, and food that has been contaminated due to poor kitchen hygiene or cross-contamination during food preparation. Since even a small number of bacteria can be sufficient to cause illness, minor contamination can lead to infection [4, 6, 2].

Less commonly, transmission occurs through direct contact with infected animals or their excreta. Although human-to-human transmission is possible, it is relatively rare compared to foodborne infections. In households, childcare centres and healthcare settings, consistent hand hygiene therefore remains an important measure for reducing the risk of transmission [6, 4].

Distribution

Campylobacter infections occur worldwide and are among the most common bacterial gastrointestinal infections in humans. In Germany and many other European countries, the incidence rises particularly during the warmer months of the year, with seasonal peaks typically observed in summer. Children under the age of five and young adults are among the population groups most frequently affected [1, 6].

Campylobacteriosis poses a significant public health challenge in Europe. According to the EFSA, it is the most frequently reported foodborne illness within the European Union. The disease incurs substantial costs due to medical treatment, lost productivity and food safety measures. Poultry and poultry products continue to be identified as the main sources of infection and are responsible for a significant proportion of cases [3, 5].

The widespread presence of Campylobacter in animal reservoirs makes it difficult to completely eliminate the pathogen. Prevention measures therefore focus on reducing contamination throughout the entire food production chain, improving hygiene standards in the food sector, and promoting safe food handling practices amongst the general public [3, 2].

Measures to prevent infection

The prevention of campylobacteriosis is based primarily on consistent food hygiene and safe food preparation. Poultry meat and other foods of animal origin should be cooked thoroughly before consumption. Raw foods should be stored separately from ready-to-eat products to avoid cross-contamination. Kitchen utensils, chopping boards and work surfaces should be thoroughly cleaned after coming into contact with raw poultry. The consumption of raw milk and untreated water should be avoided [2, 6, 4].

Good hand hygiene is another important preventive measure, particularly after handling raw meat, after using the toilet, after changing nappies and after contact with animals. People working in food preparation, in childcare centres or in healthcare settings should take particular care to observe hygiene measures, as there is an increased risk of transmission to vulnerable groups in these settings [6, 4].

Currently, there is no widely available human vaccine against Campylobacter. Control measures therefore focus on interventions along the food production chain, surveillance programmes, consumer education and compliance with hygiene standards in healthcare settings and food-processing establishments [3, 2].

Disinfectants with proven bactericidal efficacy should be used for hand and surface disinfection. Appropriate hygiene and disinfection measures help to reduce environmental contamination and curb the spread of the pathogen [1, 6].

Sources

1. Robert Koch Institute (RKI). RKI Guide to Campylobacter Enteritis. Updated 2019.
   https://www.rki.de/DE/Aktuelles/Publikationen/RKI-Ratgeber/Ratgeber/Ratgeber_Campylobacter.html (accessed on 09/07/2026)
2. World Health Organisation (WHO). Campylobacter – Fact Sheet. Updated 2020.
   https://www.who.int/news-room/fact-sheets/detail/campylobacter (accessed on 9 July 2026)
3. European Food Safety Authority (EFSA). Campylobacter. Updated 2026.
   https://www.efsa.europa.eu/en/topics/topic/campylobacter (accessed on 9 July 2026)
4. Centres for Disease Control and Prevention (CDC). About Campylobacter Infection. Updated 2024.
   https://www.cdc.gov/campylobacter/about/index.html (accessed 9 July 2026)
5. European Centre for Disease Prevention and Control (ECDC). Campylobacteriosis.
   https://www.ecdc.europa.eu/en/campylobacteriosis (accessed on 9 July 2026)
6. Federal Centre for Health Education (BZgA). Infektionsschutz.de – Campylobacter.
   https://www.infektionsschutz.de/ps/infektionen/erregersteckbriefe/campylobacter/ (accessed on 9 July 2026)