Campylobacteriosis

Campylobacteriosis refers to infection by the group of bacteria known as Campylobacter. The term comes from the Greek word meaning “curved rod,” which refers to the bacteria's curved shape. The most common disease caused by these organisms is diarrhea, which most often affects children and younger adults. Campylobacter infections account for a substantial percent of foodborne illness encountered each year.

There are over 15 different subtypes, all of which are curved Gram-negative rods. C. jeuni is the subtype that most often causes gastrointestinal disease. However, some species such as C. fetus produce disease outside the intestine, particularly in those with altered immune systems, such as people with AIDS, cancer, or liver disease.

Campylobacter bacteria are often found in the intestine of animals raised for food products and pets. Infected animals often have no symptoms. Chickens are the most common source of human infection.

Many industrialized countries have a high incidence of campylobacteriosis. In the U.S., it is estimated that there are 2 million symptomatic infections per year, representing 1% of the U.S. population per year). Incidence in rural areas higher because of more consumption of raw milk.

Improper or incomplete food preparation is the most common way the disease is spread, with poultry accounting for over half the cases. Untreated water and raw milk are also potential sources.

The incubation period after exposure is from one to 10 days. A day or two of mild fever, muscle aches, malaise, and headache occur before intestinal symptoms begin. Diarrhea with or without blood and severe abdominal cramps are the major intestinal symptoms. The severity of symptoms is variable, ranging from only mild fever to dehydration and rarely death (mainly in the very young or old). The disease usually lasts about one week, but persists longer in about 20% of cases. At least 10% will have a relapse, and some patients will continue to pass the bacteria for several weeks.

Dehydration is the most common complication. Especially in younger or older persons, dehydration should be watched for and treated with either Oral Rehydration Solution or intravenous fluid replacement.

Infection may also involve areas outside the intestine. This is unusual, except for infections with C. fetus. C. fetus infections tend to occur in those who have diseases of decreased immunity such as AIDS or cancer. This subtype is particularly adapted to protect itself from the body's defenses.

Areas outside the intestine that may be involved are:

Campylobacter is only one of many causes of acute diarrhea. Culture (growing the bacteria in the laboratory) of freshly obtained diarrhea fluid is the only way to be certain of the diagnosis.

The first aim of treatment is to maintain a nutritious diet and avoid dehydration. Medications used to treat diarrhea by decreasing intestinal motility, such as Loperamide or Diphenoxylate, are also useful, but should only be used with the advice of a physician. Antibiotics are of value, if started within three days of onset of symptoms. They are indicated for those with severe or persistent symptoms. Erythromycin or one of the fluoroquinolones (such as ciprofloxacin) for five to seven days are the accepted therapies.

The U.S. Centers for Disease Control (CDC) began a national surveillance program in 1982 to investigate how Campylobacter causes disease and how the disease is spread. A more detailed active surveillance sentinel system, FoodNet ( www.cdc.gov/foodnet ), was instituted in five sites in 1996 and later expanded to ten sites. FoodNet monitors the incidence and trends of human Campylobacter infection over time and conducts studies to identify risk factors for infection. The U.S. Department of Agriculture conducts research on how to prevent the infection in chickens. The Food and Drug Administration has produced the Model Food Code for restaurants. Adherence to this Code will decrease the risk of campylobacteriosis.

Most patients with Campylobacter infection rapidly recover without treatment. For certain groups of patients, infection becomes chronic and requires repeated courses of antibiotics.

Good hand washing technique as well as proper preparation and cooking of food is the best way to prevent infection. Also it is important to have a safe drinking water supply free from contamination.

See also Food and Drug Administration ; Foodborne illness ; HIV/AIDS .