Live Healthy and Strong

Trichinosis

A food-borne disease caused by the microscopic intestinal roundworm Trichinella spiralis. Any child who eats undercooked meat of infected animals can develop trichinosis; pork products are most often responsible, although cases have appeared after eating infected bear and walrus.

The parasite may be found in a wide variety of animals, including pigs, dogs, cats, rats, and many wild animals (such as fox, wolf, and polar bear). The disease is found only among those who eat pork, primarily in North America and Europe. Up to 5 percent of Americans have had an infestation, usually without symptoms. It is almost never a problem in countries such as France, where pigs eat root vegetables, not garbage.

Cause
Worm larvae exist as cysts in the muscles of infested animals. Within four to six weeks after a child eats undercooked or raw meat of an infested animal, the larvae are released from the cysts and develop into adults in the child’s intestines. The adult worms produce fresh larvae, which travel in the blood to tissues and organs including the heart, tongue, eye, and brain, and to the muscles, where they form cysts. The disease does not spread by person to person contact, but infected animals are infectious for months and the meat from these infected animals remains infectious unless properly cooked.

Symptoms
The incubation period varies depending on the number of parasites in the meat and how much was eaten. Infestation with only a few worms causes no symptoms, whereas a heavy infestation may cause diarrhea and vomiting, PNEUMONIA, heart failure, or respiratory failure. Usually within 10 to 14 days after infection, symptoms of fever, muscle aches, pain, and swelling around the eyes will begin. Thirst, profuse sweating, chills, weakness, and tiredness may develop. If the parasite becomes imbedded in the diaphragm (thin muscle separating lungs from abdominal organs), chest pain may result.

When the larvae attach to the lining of the intestines, the intestines become inflamed, causing abdominal pain, diarrhea, and weakness. As the larvae begin to increase in length and form cysts in the muscles, muscle soreness and pain in muscle fibers will begin. Very rarely, a child becomes seriously ill and dies. Those who survive severe infection maintain a partial immunity.

Diagnosis
A physician may suspect trichinosis from the symptoms; it is confirmed by blood tests which detect antibodies to the larvae, or by a muscle biopsy which reveals the larvae themselves.

Complications
Warning signs include breathing problems, swelling, or shortness of breath. Heart failure may be fatal either in the first two weeks after infection, or between the fourth and eighth week.

Treatment
Painkillers and thiabendazole and corticosteroids may relieve symptoms. Bed rest is recommended to prevent relapse and possible death. After two or three months, the organisms cause no more symptoms. Once the larvae migrate to muscle, mebendazole is the treatment of choice.

Prevention
The best way to prevent the disease is to ensure pork products or wild game are properly cooked to at least 150°F for 35 minutes per pound. Freezing infected meat no higher than –13°F for 10 days will destroy the parasite. Pork or pork products should never be eaten raw, and even smoked or salted meat may still harbor organisms. Pork should not be ground in the same grinder as other meats; the grinder should then be cleaned well after grinding pork. Routine inspection of carcasses for trichinella organisms is not performed in the United States because the disease is on the decline. Irradiation of pork carcasses can also eradicate the larvae.