Birds, both wild and domestic, are the main reservoirs of C. jejuni and C. coli. However, other primary reservoirs have been described: cattle, pigs (mainly C. coli) and small ruminants, but also pets (cats and dogs).
Even if certain species of Campylobacter are pathogenic for animals, and implicated in problems of infertility or abortions, C. jejuni and C. coli are considered to have little or no pathogenicity for animals.
The main route of transmission of Campylobacter to humans is through food, via contaminated products, including drinking water whose treatment is faulty. Direct transmission, by another individual, an infected animal (particularly a pet) or a contaminated carcass, would occur more frequently for certain exposed populations (farmers, veterinarians, slaughterhouse workers, sewer workers, etc.).
Disease
The most frequently observed human disease is acute enteritis (symptoms: diarrhea in 85% of cases, abdominal pain: 79%, bloody stools: 15%, fever: 50%, headache: 41%, vomiting: 15%) caused by an intestinal infection.
The infection can be complicated (in less than one case out of 100) by bacteraemia, secondary localizations and a post-infectious syndrome (less than one case out of 1000). However, the infected individual remains contagious for an average of 38 days (maximum 70 days).
Exceptionally, C. jejuni can cause a post-infectious arthritis-like syndrome, hepatic or renal inflammation, and especially Guillain-Barré syndrome, which is manifested by temporary paralysis of the peripheral nervous system. This syndrome is reputed to be very severe, with mortality that can reach 2 to 3% of cases, and major neurological sequelae for 15 to 22% of cases.
Anyone is susceptible to developing campylobacteriosis. However, the propensity to develop the most severe forms is increased in people:
- elderly;
- alcoholics;
- having a history of digestive surgery;
- on peritoneal dialysis (kidney failure);
- whose immune system is weakened (under immunosuppressants, or suffering from an autoimmune pathology such as HIV infection).
Infection status and frequently contaminated foods
Since the beginning of the 2000s, the annual count (incidence) of cases of human campylobacteriosis has regularly exceeded 40 cases recorded per 100,000 inhabitants (mainly in summer) in the European Union. In France, the National Reference Center (CNR) reported 6.2 cases recorded per 100,000 inhabitants in 2009, due to significant under-reporting.
Most of the cases described are isolated from each other (sporadic).
Collective foodborne illnesses (TIAC) linked to Campylobacter are often correlated with the consumption of contaminated water, raw milk or poultry meat.
The transfer of contamination by the cutting board or the knives used to handle raw poultry, the consumption of undercooked meat (poultry, beef, pork), appear to be the main risk factors.
Due to both the existence of animal reservoirs and the numerous possibilities of contamination transfer, many categories of food (including water) can be contaminated, even if meat and meat products are to be considered. first.
Contamination control methods
In general, freezing stops the growth of these bacteria and probably destroys a small part of the bacterial population, especially in a liquid medium. On the other hand, these bacteria survive well at refrigeration temperatures (0 to 10°C).
Bacteria are also very sensitive to heat: it can be considered that heat treatments above 65°C allow their destruction regardless of the support (liquid or solid).
Note, finally, that these bacteria do not show any particular resistance to salt or acids.
The risks of campylobacteriosis can be greatly reduced by adopting good hygiene practices at home. It is therefore essential to:
- wash hands after handling raw meat;
- use a cutting board (wooden or plastic) for raw meat and fish, and another for other foods;
- rigorously clean the board, the dish and the utensils used for seasoning and preparing the raw meat before reuse;
- ensure sufficient cooking (> 65°C at the core) of poultry and butchery meats, in particular cooking on the barbecue: the thigh/thigh joint of the chicken must not be pink or show traces of blood ;
- handle this meat in good hygienic conditions during the preparation and consumption of this type of food;
- do not consume raw poultry meat (such as “carpaccio”).
Role of ANSES
The Ploufragan-Plouzané health safety laboratory (ANSES) is recognized as the National Reference Laboratory, or NRL, for Campylobacter.
The European Union Reference Laboratory (LR-UE) for Campylobacter (a network composed of, among others, the European NRLs) is hosted by the National Veterinary Institute, SVA, in Uppsala (Sweden).
Until now, the search for Campylobacter in finished food products has not been the subject of specific regulations, including in recent Community texts.
The NRL has also published opinions and reports concerning the risks of animal campylobacteriosis (in ruminants and poultry).