Trichinosis Fact Sheet

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Trichinosis Fact Sheet (PDF)

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What is trichinosis?
How do people get trichinosis?
What are the symptoms of trichinosis?
How is trichinosis diagnosed?
What is the treatment for trichinosis?
How can I prevent getting trichinosis?

What is it trichinosis?

Trichinosis is a parasitic disease that develops after ingestion of roundworms of the genus Trichinella. People primarily get this disease from eating undercooked meat from infected animals. This disease is rare in Minnesota and most people are infected from eating wild game.

How do people get trichinosis?

People can get trichinosis from eating raw or undercooked meat that contains the larvae of roundworms of the genus Trichinella. Larvae can be found in the meat of wild and domestic animals such as bears, cougars, wild boars, walruses, and domestic pigs. After the meat with the parasite larvae is eaten, the larvae burrow into the intestines, grow into adult worms, and reproduce to make more larvae. Those larvae enter the bloodstream and migrate to muscles, where they embed. The symptoms of trichinosis can occur during all phases of parasite development.

What are the symptoms of trichinosis?

The signs and symptoms of trichinosis vary, and the severity depends on the number of larvae ingested. In some cases, symptoms are entirely absent; in others, symptoms can last for months. Mild cases can resemble influenza-like illness or other common illnesses. When larvae are in the intestines, symptoms can include abdominal pain, diarrhea, fever, nausea, and vomiting. When larvae enter the bloodstream and embed in muscles, symptoms can include headaches, fever, muscle pain, and weakness, swelling (especially of the face and around the eyes), rash, eye redness, and itchy skin. In severe cases, the brain, heart, or lungs can be affected, and patients can develop symptoms of encephalitis or meningitis (swelling of the brain or its lining), myocarditis (heart muscle inflammation), or pneumonia.

How is trichinosis diagnosed?

Trichinosis may be suspected based on symptoms and a history of eating raw or undercooked wild game meat or pork. The diagnosis can be confirmed through laboratory testing of blood (for antibodies to Trichinella) or muscle biopsy tissue (for Trichinella larvae).

What is the treatment for trichinosis?

Trichinosis can be treated with safe and effective anti-parasitic drugs that are available by prescription. Treatment decisions should be made as early as possible, in consultation with medical experts. Mild cases can resolve on their own, but severe cases can be fatal without treatment. There is no treatment once the larvae are embedded in muscles.

How can I prevent getting trichinosis?

The best way to prevent trichinosis is to cook meat to safe internal temperatures: at least 165ºF for wild game and at least 160ºF for pork. Cooking temperature should be verified with a meat thermometer. Larvae in cuts of pork (from domestic pigs) less than 6 inches thick can be killed by freezing at 5ºF (-15°C) or less for at least 20 days. However, freezing does not reliably kill the all the types of Trichinella typically found in game animals. Curing (salting), drying, smoking, or microwaving are not effective methods for killing the larvae. Additional measures to prevent trichinosis include safe handling of raw meat (i.e., separating raw or undercooked meat and its juices from other foods), thorough cleaning of any equipment used to prepare the meat, and hand washing after handling raw meat, are also recommended.