Campylobacteria - A Major Cause of Food Poisoning

The commonest cause of food poisoning in the US, responsible for 2.1 to 2.4 million episodes of poisoning every year, is a rod-shaped Gram negative bacterium called Campylobacter jejuni. Although most episodes of Campylobacteria food poisoning are relatively mild, resolving within a week or two, the infection occasionally triggers an autoimmune response that can lead to serious, even life-threatening complications. A related concern about this organism is that an increasing number of Campylobacteria infections show resistance to the usual antibiotic therapies. Young children, the very old, people with chronic illnesses, and those with compromised immune systems from HIV or other causes are at particular risk.

In medical care, lost work hours, and pain and suffering, Campylobacteria infections cost the US economy $18.8 billion every year.

The commonest sources of Campylobacteria infection are uncooked poultry, especially skin and giblets, raw (unpasteurized) milk, and untreated water. Some studies have identified campylobacter contamination in hamburger and in veal.

After contaminated food is consumed, the Campylobacteria begin to multiply in the intestine. Within two to five days the colony grows large enough that its toxins begin to disturb the body, with symptoms of diarrhea, often bloody, and muscle pain, nausea and abdominal cramping, headache and fever. Symptoms persist for a week to two weeks, gradually abating as the body expels the bacteria and their toxins. In most cases, as long as the patient is reasonably healthy, antibiotics aren't used, because the illness is self limiting. In about 25% of cases, the patient will relapse some weeks or months later.

For one victim in a thousand, the episode doesn't end there. Campylobacteria infections have the potential to trigger intense responses from the victim's own immune system. These take the form of reactive arthritis, sometimes called Reiter's syndrome, or Guillain-Barre Syndrome, a rare progressive paralysis. Reactive arthritis is a painful inflammation of the joints which can persist for up to six months, with unpredictable recurrences. Other symptoms can include painful urination and irritation of tissues in the eye, with burning, tearing and light sensitivity.

Guillain-Barre Syndrome, also triggered by Campylobacteria infections, is an autoimmune disorder in which the immune system attacks the myelin sheathing that surrounds nerve fibers. Onset is hours to days or weeks after the original infection. Early symptoms are subtle, a tingling or pins-and-needles sensation in the toes and fingers, and for some people, in the facial muscles. The victim experiences muscle weakness that progresses from the feet and lower legs up through the rest of the body. Weakness increases, gait and balance are affected, and muscles become paralyzed, sometimes within a matter of days. Diagnosis and prompt treatment are essential to prevent the victim from suffocating if muscles involved with breathing are affected. If you or a loved one experiences these symptoms, you should seek medical treatment immediately.

There is no known cure. Supportive treatment, including placing the patient on a respirator and heart monitor, aims at assisting with body processes. Plasmapheresis, exchanging the patient's plasma, which contains the antibodies, and high-dose immunoglobulin therapy are used to shorten the episode and mitigate its effects. For most people the paralysis recedes within a few weeks or months, but recovery is not always complete; some degree of muscle weakness may persist.

Campylobacteria are abundant in soil and in untreated stream and pond water. They are routinely found in the intestinal tracts of chickens and turkeys, cows, and other animals raised for human consumption. They are too widespread to eradicate. The key to protecting humans from this dangerous infection is to practice thorough hygiene at every step in the food processing and food handling process.