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In humans, infection caused by Campylobacter ("campylobacteriosis") usually takes the form of a self-limiting gastroenteritis characterised by diarrhoea, fever and abdominal cramps. As these are all non-specific symptoms, it is difficult to make a diagnosis based solely on the clinical presentation. The incubation period is typically 2 to 5 days but can range from 1 to 10 days, with fever, malaise and myalgia frequently preceding the onset of diarrhoea. Fresh blood, mucus and/or pus may appear in the stools, while vomiting is rare. The diarrhoea usually lasts 2 to 3 days but pain and discomfort may persist for longer and weight loss may appear in more severe forms. Antimicrobial therapy is seldom needed.

Complications of campylobacteriosis are generally rare, and are observed mainly in patients with weakened or severely compromised immune systems. At gastrointestinal level, the infection can cause irritable bowel syndrome, including Crohn’s disease and ulcerative colitis. Campylobacteriosis can also lead to immune disorders, such as Guillain-Barré syndrome (a temporary but severe paralysis that may be total), Miller Fisher syndrome (a rare variant of Guillain-Barré, involving the cranial nerves) and reactive arthritis. In a small number of cases, the bacteria can also spread into the bloodstream (sepsis), causing life threatening conditions requiring prompt and effective antimicrobial treatment, although the number of case fatalities remains very low (0.03%). In this regard, health authorities are closely monitoring the increase in antimicrobial resistant strains.

Campylobacteriosis is one of the four key global causes of diarrhoeal diseases with the highest burden on public health worldwide. Its impact on health and the economy is increasingly recognised ( WHO, 2015 ).

The cost of campylobacteriosis to public health systems and to lost productivity in the EU is estimated by EFSA to be around €2.4 billion a year ( EFSA topics page: Campylobacter ).

In animals, Campylobacter, particularly C. jejuni and C. coli species, which are mainly pathogenic for humans, are frequently occurring. They grow best at body temperature of poultry and birds, and seem to be well adapted to them, but are nevertheless commensal organisms also routinely found in cattle, sheep, pigs, and wild mammals. In pets, Campylobacter rarely cause disease with typical symptoms including diarrhoea, lethargy and fever. However, pets infected with Campylobacter can pose a risk of exposure to their owners.

Other Campylobacter species, seldom pathogenic for humans, have been associated with disease in animals. Among these, C. fetus subsp. venerealis is associated with infertility in cattle and abortion in sheep, goats and cattle. C. fetus subsp. fetus are linked to septic abortion and mastitis, in sheep, goats, and cattle.

Campylobacter are often found in warm-blooded animals, considered as natural reservoirs, in which they rarely cause clinical symptoms. The bacterium can be isolated from the faeces of healthy livestock (poultry, cattle, pigs, sheep), wild animals (especially birds) and pets (cats and dogs). Moreover, although this is a fragile microorganism, it is widely present in the environment.

• Poultry and birds, in particular, are believed to be natural amplifying hosts of Campylobacter because of their higher metabolic temperature (42°C), facilitating bacterial growth. This is particularly true in the poultry production system, where high density flocks and - sometimes - suboptimal control strategies can lead to the bacteria spreading rapidly through the entire flock.
• Cattle and sheep can also be colonised, mostly by C. jejuni and C. coli, constituting a significant source of human campylobacteriosis.
• Pigs mainly harbour C. coli.
• Pets and wild birds are known to commonly carry Campylobacter in their digestive tracts.

As a consequence of the colonisation of livestock animals, Campylobacter spp. can also be found in meat and meat products, raw milk and occasionally dairy products. Meat and meat products may be contaminated during the slaughtering process especially when hygiene conditions are poor. On the slaughterline, the Campylobacter present in the intestinal content of the slaughtered animals can be readily transferred onto the surface of the carcases. Unpasteurised cow’s milk and dairy products are also common vehicles of campylobacteriosis due to contamination of the milk with bovine faeces or direct contamination caused by bovine mastitis. More rarely, the bacteria can contaminate fruit and vegetables by the use of natural fertilisers or by droppings, predominantly from birds.

Water is also a relevant vehicle for Campylobacter infection, when contamination by faeces from wild and domestic animals, e.g. in:

• Surface waters
• Agricultural sewage effluents
• Wastewater
• Occasionally, drinking water (usually when cracks occur in the underground pipes, allowing organic matter to enter)

Molluscs raised in contaminated water can also be a source of Campylobacter infection.

Humans can be infected by Campylobacter through various routes:

Foodborne transmission route

The foodborne transmission route is the main source of human infections.

• Eating contaminated raw or undercooked meat, particularly from poultry
• Drinking contaminated unpasteurised raw milk and fresh dairy products
• Eating ready-to-eat (RTE) food products, including those of non-animal origin (vegetables and fruits), contaminated during production by natural fertilisers, by animal droppings, or by contact with contaminated raw meat during preparation and handling in the kitchen

The incomplete cooking of meat is an important risk factor for campylobacteriosis, together with poor or unhygienic handling of food in the kitchen, for example, using the same cutlery for raw meat and RTE foods (bread, salads, other fresh vegetables, etc.).

Travelling either abroad or inland may also be a risk factor, since it might increase the risk of exposure to unsafe food and water.

Environmental transmission route

• Drinking water contaminated by animal faeces

Swimming in untreated freshwater (lakes, rivers, creeks, etc.) potentially contaminated with the faeces of infected animals may pose a risk of Campylobacter infection.

Direct contact with infected animals

• Direct or indirect contact with infected livestock and pets (e.g. dogs and cats)

Campylobacter live in the intestinal tract of infected animals. Therefore, any behaviour that may lead to the ingestion of animal faeces poses a significant risk. This infection route can be more frequently observed in children or in specific occupations, such as in slaughterhouse workers, for example.

Human to human transmission

Direct contact in poor hygiene conditions with an ill person may pose a risk of transmission.

Animals can become infected by contact with:

• Contaminated water
• Faeces from infected animals
• Infected insects
• Infected animals
• Infected owners of animals
• Contaminated equipment

• Campylobacteriosis was the most commonly reported foodborne gastrointestinal infection in humans in the European Union.
• In 2023, there were 148,181 confirmed cases of human campylobacteriosis, corresponding to a European Union notification rate of 45.7 cases per 100,000 population. This was an increase of 4.3% compared with the notification rate in 2022 (43.8 per 100,000 population).
• The overall trend for Campylobacter human infections did not show a statistically significant increase or decrease over the 2019–2023 period.
• Twenty-four Member States and the United Kingdom (Northern Ireland) reported data for 2023 in the context of the Campylobacter process hygiene criterion, set out in  Commission Regulation (EC) No 2073/2005 . Fifteen Member States reported 6686 test results from official controls, with 16.0% Campylobacter-positive samples exceeding the limit of 1000 CFU/g. Twenty Member States and the United Kingdom (Northern Ireland) reported 61,591 test results from the monitoring of food business operators, with 15.8% Campylobacter-positive samples exceeding the limit of 1000 CFU/g. Eleven Member States reported results from both samplers, showing that the number of samples exceeding the limit was significantly higher in official samples (16.6%) than in own-checks (9.0%).
• In 2023, 0.13% of 3070 ‘ready-to-eat’ food sampling units reported by 11 Member States were positive for Campylobacter, with positive samples originating from oysters (N=3) and unspecified ready-to-eat foods (N=1). Of 8588 ‘non-ready-to-eat’ sampling units reported by 15 Member States, 14.2% were positive, with the highest level of contamination (15.5%) found in ‘meat and meat products’. Campylobacter was isolated from all fresh meat categories, with meat from broilers and turkeys showing the highest percentages of contamination, 21.6% and 19.4%, respectively.
• Data on Campylobacter spp. in different animal categories were reported by 16 Member States and the United Kingdom (Northern Ireland) and three non-Member States in 2023. The majority of units tested in the European Union were from broilers (N=6627), cats and dogs (N=6301), and cattle (bovine animals) (N=5939), with positive rates of 4.6%, 1.4% and 6.8%, respectively. Fewer samples were tested for pigs (N=2055) and small ruminants (N=2935), but higher proportions of positives were observed, at 72.3% and 7.2%, respectively.  

 For more information on Campylobacter reported in humans, animals and food in the EU and other reporting countries in 2023 and in previous years, refer to the  2023 EU One Health Zoonoses Report , to the online  dashboard on Campylobacter , and to the online  dashboard on foodborne outbreaks  published by EFSA.  

The prevention of campylobacteriosis relies on a comprehensive "from farm to fork" approach.

The first step is to establish efficient control measures and intervention strategies at the farms, especially for poultry, in order to eliminate or reduce the presence of Campylobacter in animals. Preventing the colonisation of animals at the primary production stage is crucial. Several approaches have been proposed for enforcing stronger on-farm  biosecurity  measures:

• Using specific indoor footwear and clothing.
• Providing dedicated changing facilities for the farm workers.
• Controlling flies on farms.
• Slaughtering at younger ages (broilers at 35 days).
• Discontinuing the practice of flock thinning, which means rearing the birds to the maximum permitted stock density before removing a proportion of the number.
• Implementing continuous biosecurity training for farm managers and farm workers.

Proper food preparation processes must be followed at the manufacturing level:

• Implementig good hygiene practices for meat production.
• Following good hygiene practices for food preparation.
• Applying good manufacturing practices for meat and meat products.
• Implementing continuous food safety training for food business operators.
• Ensuring compliance with the  process hygiene criteria (PHC)  implemented by food business operators ( Regulation (EC) No. 2073/2005 ).

• Implementing proper food handling processes.
• Offering continuous biosecurity training for food business operators.
• Ensuring strict personal hygiene to prevent contacts between food and infected food handlers.
• Maintaining the cold chain constantly during the handling, transport and storage of food items.

The proper handling of food during preparation and cooking is fundamental for preventing infections, since the high level of contamination of certain food (poultry meat) could cause cross-contamination in the kitchen. For this reason, it is necessary to:

• Avoiding the practice of washing raw meat, since it leads to contamination of the kitchen surfaces, utensils and other food products.
• Avoiding the use private water wells for drinking or food preparation, since they pose a significant risk, owing to lack of hygienic barriers or appropriate water treatment.

The “ Five Keys to Safer Food ” were developed by WHO to educate consumers and food handlers on the safe handling of food.

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Surveillance in humans

•  Commission Implementing Decision (EU) 2018/945  provides case definitions for a range of communicable diseases, including campylobacteriosis.
•  Regulation (EU) 2022/2371  establishes rules on relevant cross-border threats to health, including epidemiological surveillance, monitoring, early warning, and response actions.
• ECDC collects, analyses and disseminates data on human cases ( ECDC’s Surveillance Atlas of Infectious Diseases ) in compliance with Regulation (EU) 2022/2371 and uses indicator-based surveillance data to produce its  Annual Epidemiological Reports .

Surveillance in food and feed

• Campylobacter monitoring data on food and animals are collected and reported in compliance with the Zoonoses Directive 2003/99/EC, covering sampling results from both official controls and food business operators (industry sampling,  HACCP  and own-checks). Official controls for Campylobacter on carcases of broilers in poultry slaughterhouses, to verify implementation of the PHC, are based on harmonised sampling and reporting procedures.
•  Regulation (EC) No. 2073/2005  sets a regulatory limit (microbiological process hygiene criterion - PHC) of 1,000 CFU/g of Campylobacter on the neck skins of chilled broiler carcases.
• Compliance with the PHC indicates correct operation of the production process. The purpose of the PHC is to limit the contamination of carcases during the slaughtering process and to take corrective action when the regulatory limit is exceeded.
• Institutional and own-check controls on food are implemented in the event of an outbreak investigation.
• There is no harmonised surveillance in the EU of Campylobacter in feed.

Surveillance in animals

• There is no harmonised surveillance in the EU on Campylobacter in animals.
• Sampling in animals is generally carried out following clinical investigations or as a consequence of the detection of Campylobacter on carcases at the slaughterhouse.

Surveillance of antimicrobial resistance

EU-wide monitoring of antimicrobial resistance in Campylobacter isolates from humans is carried out by the ECDC in accordance with Commission Implementing Decision (EU) 2018/945 and  Decision 1082/2013/EU .

The  antimicrobial resistance  of Campylobacter is monitored by EFSA in broilers, fattening turkeys, bovine animals under one year of age and fattening pigs. Samples of caecal content are normally collected using a randomised sampling scheme in compliance with  Decision (EU) 2020/1729 .

Results from the data collection on antimicrobial resistance in Campylobacter in humans, animals and food are published in the  European Union Summary Report on Antimicrobial Resistance in zoonotic and indicator bacteria from humans, animals and food .

An important component of food safety is safeguarding the health of animals: food safety begins at the farm with the prevention of animal diseases. To protect consumers from this threat, the EU has adopted an integrated approach to food safety from farm to fork, involving all key players: EU Member States, the European Commission, the European Parliament, EFSA, ECDC and the European Union Reference Laboratories.

Data on the occurrence of Campylobacter in animals and food, and in humans are collected by EFSA and ECDC, respectively, and analysed in the annual  EU One Health Zoonoses report  prepared by EFSA and ECDC.

EFSA has a crucial role in:

• Collecting and analysing EU-wide data on the prevalence of Campylobacter in animals and food
• Supplying independent scientific advice and assistance on the food safety aspects relating to Campylobacter through EFSA’s Panel on Biological Hazards
• Supporting European and national risk managers in monitoring and evaluating the prevalence of Campylobacter in animals and foods and suggesting control measures when needed
• Providing risk assessments and recommendations, such as  preparedness and response  in the event of food or feed safety incidents or crisis, in collaboration with the ECDC
• Producing EU-wide baseline survey reports on the prevalence of Campylobacter in food and food-producing animals and on the risk factors contributing to the prevalence of Campylobacter in animal populations

EFSA is assisted by its network on zoonoses monitoring data, a pan-European network of national representatives and international organisations that support EFSA by gathering and sharing information on zoonoses in their respective countries.

The European Union Reference Laboratories (EURLs) 

The European Union Reference Laboratories (EURLs) are appointed by the European Commission and aim to ensure high-quality methods of analysis, as well as uniform testing and diagnosis within the areas of animal health and food microbiology in the EU. EURLs also aim to coordinate the activities of national reference laboratories and provide necessary support to EFSA in monitoring zoonoses (guidance for reporting, advice, etc).

The  EURL for Campylobacter is hosted by the National Veterinary Institute (SVA)  (Sweden).