What is Campylobacter? High and low values | Lab results explained

What is Campylobacter infection?

Campylobacter infection, or campylobacteriosis, is an infectious disease caused by Campylobacterbacteria. It is one of the most common causes of diarrheal illness in the United States. The Foodborne Diseases Active Surveillance Network (FoodNet) indicates that about 14 cases are diagnosed each year for every 100,000 people. Many more cases go undiagnosed or unreported. CDC estimates Campylobacter infection affects more than 1.3 million people every year. Most cases are not part of recognized outbreaks, and more cases occur in summer than in winter.

What are the symptoms of Campylobacter infection?

People with Campylobacter infection usually have diarrhea (often bloody), fever, and abdominal cramps. The diarrhea may be accompanied by nausea and vomiting. These symptoms usually start within two to five days after exposure and last about a week. Some infected people do not have any symptoms. In people with weakened immune systems, such as people with the blood disorders thalassemia and hypogammaglobulinemia, AIDS, or people receiving some kinds of chemotherapy, Campylobacteroccasionally spreads to the bloodstream and causes a life-threatening infection.

What kind of germ is Campylobacter?

Campylobacter are bacteria that can make people and animals sick. Most human illness is caused by one species, called Campylobacter jejuni, but other species also can cause human illness.

How does food and water get contaminated with Campylobacter?

Many chickens, cows, and other birds and animals that show no signs of illness carry Campylobacter. Campylobacter can be carried in the intestines, liver, and giblets of animals and can be transferred to other edible parts of an animal when it’s slaughtered. In 2014, National Antimicrobial Resistance Monitoring System (NARMS) testing found Campylobacter on 33% of raw chicken bought from retailers.

Milk can become contaminated when a cow has a Campylobacter infection in her udder or when milk is contaminated with manure. Other foods, such as fruits and vegetables, can be can become contaminated through contact with soil containing feces from cows, birds, or other animals. Animal feces can also contaminate lakes and streams. Pasteurization of milk, washing or scrubbing of fruits and vegetables, and disinfection of drinking water helps prevent illness.

How do people get infected with Campylobacter bacteria?

It takes very few Campylobacter germs (fewer than 500) to make someone sick. That means a single drop of juice from raw chicken can have enough Campylobacter in it to infect someone.

Most Campylobacter infections are associated with eating raw or undercooked poultry or from contamination of other foods by these items. People can get infected when a cutting board that has been used to cut and prepare raw chicken isn’t washed before it is used to prepare foods that are served raw or lightly cooked, such as salad or fruit. People also can get infected through contact with the feces of a dog or cat. Campylobacter does not usually spread from one person to another.

Outbreaks of Campylobacter infections have been associated most often with poultry, raw (unpasteurized) dairy products, untreated water, and produce.

Campylobacter infection is common in the developing world, and people who travel abroad have a greater chance of becoming infected. About 1 in 5 Campylobacter infections reported to the Foodborne Diseases Active Surveillance Network (FoodNet) are associated with international travel.

Even more rarely, people may become infected through contaminated blood during a transfusion.

How is Campylobacter infection diagnosed and treated?

Campylobacter infection is diagnosed when a laboratory test detects Campylobacter bacteria in stool, body tissue, or fluids. The test could be a culture that isolates the bacteria or a rapid diagnostic test that detects genetic material of the bacteria.

Most people with Campylobacter infection recover without specific treatment. Patients should drink extra fluids as long as the diarrhea lasts. Antibiotics are needed only for patients who are very ill or at high risk for severe disease, such as people with severely weakened immune systems, such as people with the blood disorders thalassemia and hypogammaglobulinemia, AIDS, or people receiving chemotherapy.

Is Campylobacter infection serious?

Most people with a Campylobacter infection recover completely within a week, although they may shed (get rid of) Campylobacter bacteria in their stool for several weeks after recovery, which might result in person-to-person transmission. Campylobacter infection rarely results in long-term consequences. Some studies have estimated that 5–20% of people with Campylobacter infection develop irritable bowel syndrome for a limited time and 1–5% develop arthritis.

About 1 in every 1,000 reported Campylobacter illnesses leads to Guillain-Barré syndrome (GBS). GBS happens when a person’s immune system is triggered by an earlier infection, such as Campylobacter infection. GBS can lead to muscle weakness and sometimes paralysis that can last for a few weeks to several years, and often requires intensive medical care. Most people recover fully, but some have permanent nerve damage, and some have died of GBS. As many as 40% of GBS cases in the United States may be triggered by Campylobacter infection.


Enteric illness is one of the most common diseases throughout the world. Clinical and epidemiological studies have identified Campylobacter jejuni as the most frequent cause of bacterial-induced diarrhea. The isolation rate exceeds that of both Salmonella and Shigella combined. In the U.S., the infection rate has been reported as high as 1,000 per 100,000 population. The prevalence is even greater in developing countries.

Ingestion of 100-1000 organisms is all that is required for the host to become infected.

Possible sources of infection include:

– Fecal-oral transmission
– Ingestion of contaminated animal-based foods (e.g., poultry, red meat, milk)
– Consumption of untreated surface water

Epidemiological studies reveal a marked increase in the incidence of infection over the summer months and into the early fall.

Campylobacter jejuni affects the host by infiltrating and ultimately damaging the intestinal mucosa. From there it may spread to underlying tissue, causing inflammation and ulceration extending along the jejunum, ileum, and colon. While several toxins have been identified, their exact role in the pathogenesis of infection has not been clearly elucidated.

Patients may be asymptomatic to severely ill. Overt symptoms may include fever, abdominal cramping, and diarrhea (with or without the presence of blood or fecal leukocytes). Muscular pain, headaches, or nausea may also be present.

The highest incidence of Campylobacter jejuni infection occurs in infants and young children under age 5. 

Day care centers frequently harbor the organism. Adults aged 20-40 are the next most commonly affected segment of the population.

Symptoms can occur anywhere between 1-5 days after exposure and generally last 7-10 days in duration.

Although uncommon, infection has been known to occur concurrently with the following conditions:

– Reactive arthritis
– Hemolytic uremic syndrome
– Recurrent colitis
– Acute cholecystitis
– Meningitis
– Guillain-Barre syndrome
– Invasion and bacteremia (especially in neonates, debilitated adults, and persons with HIV)
– Spontaneous abortion, stillbirth, prematurity, and neonatal sepsis

Campylobacter jejuni is generally a self-limiting infection with symptoms seldom lasting beyond 7 to 10 days. However, it is estimated that 5% -10% of those infected may develop persistent diarrhea, and in these cases antibiotic therapy is warranted.


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Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you. 

The information on is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.

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