Campylobacter

What is campylobacteriosis?
Campylobacteriosis is the commonest form of bacterial gastroenteritis (bowel infection) in Ireland (see HPSC's Annual Reports on Campylobacter). It is caused by a bacterium (bug) known as Campylobacter. To cause illness, the bug must be swallowed (generally via contamination of food or water). Most human illness (>90%) is caused by one type of Campylobacter, called Campylobacter jejuni. Campylobacter jejuni grows best at the body temperature of birds, particularly poultry, and seems to be well adapted to birds, which carry it without becoming ill. Campylobacter bugs are delicate; they cannot stand drying and can be killed by oxygen. Freezing reduces the number of Campylobacter present on raw meat and unlike bugs such as Salmonella, Campylobacter does not multiply in food. 

What are the symptoms of infection?
Most people who become ill develop diarrhoea, abdominal pain and fever within 2-5 days after swallowing the bug. The diarrhoea may be bloody and there may be a little nausea but vomiting is uncommon. The illness typically lasts 1 week. Some people who become infected may not have any symptoms. In people with weak immune systems, Campylobacter occasionally spreads to the bloodstream and causes a serious life-threatening infection. Campylobacteriosis is a notifiable disease in Ireland.

How is it treated?
People who get sick with campylobacteriosis almost always get better without any need for specific medical treatment. While the diarrhoea lasts, patients should drink plenty of fluids. If the illness is very severe, antibiotics can be used to treat the infection. Your doctor will make the decision about whether antibiotics are necessary.

Are there any complications?
Most people who get campylobacteriosis recover completely within 2-5 days, although sometimes recovery can take up to 10 days. Occasionally, arthritis may develop following infection and in very rare instances, a neurological condition known as Guillain-Barré Syndrome may develop. This develops when a person's immune system damages its own nerves (outside of the brain and spinal cord) following infection, leading to muscle weakness and sometimes paralysis. It can last weeks or months and most people make a full recovery. Some do go on to develop more chronic weakness and it can, occasionally, lead to death. It is estimated that approximately one in every 1000 reported campylobacteriosis cases leads to Guillain-Barré Syndrome. 

How do you become infected?
Most cases of infection come about as a result of handling raw poultry or eating raw or undercooked poultry meat. It doesn't take many bacteria to cause illness (fewer than 500 is enough) and this can mean that even one drop of juice from raw chicken can make a person ill. 

It is extremely important to prevent cross-contamination in the kitchen by not sharing the same chopping board or knives and other utensils for meat/poultry with any other foods. Wash all chopping boards, work surfaces and utensils with soap and hot water after preparing raw poultry and meat. 

Drinking contaminated untreated water or unpasteurised milk may also spread campylobacteriosis. Person to person spread is unusual but has been reported. Infection may occasionally be spread from an infected dog or cat.

Outbreaks of campylobacteriosis are rare and when they do occur they tend to be small family outbreaks associated with contaminated food.

How does food or water get contaminated with Campylobacter?
Poultry is very commonly infected with Campylobacter but birds rarely show signs of illness. Infection spreads within flocks through infected drinking water or infected bird droppings. When an infected bird is slaughtered, Campylobacter in the bird's intestines can contaminate the meat.

Unpasteurised milk can become contaminated through contact with an infected cow's udder or contact with manure. Surface water and mountain streams can become contaminated from infected faeces from cows or wild birds. 

Tips for preventing campylobacteriosis  

• Cook all poultry products thoroughly. All meat and poultry should have reached a temperature of 75°C or above at their thickest part during cooking.  The meat will be cooked properly when it is no longer pink and the juices from deep inside the meat run clear.
• Do not eat poultry that is only partially cooked.
• Wash hands with soap before and after preparing or handling raw poultry and meat and before touching anything else.
• Prevent cross-contamination in the kitchen by never using the same chopping board for meat/poultry and other foods. Wash all chopping boards, work surfaces and utensils with soap and hot water after preparing raw poultry and meat.
• The Food Safety Authority of Ireland (FSAI) does not recommend washing poultry in running water before preparation.  This can spray contaminated juices.  The FSAI provides advice on preparing and cooking poultry here.
• Avoid drinking unpasteurised milk and untreated surface water.
• Make sure that people with diarrhoea (especially children) wash their hands carefully and frequently with soap to reduce the risk of spreading infection.
• Wash hands with soap after having contact with pets and their droppings.

Updated: 24 November 2022