Trichinellosis is a parasitic disease that can be spread to people. It is caused by a roundworm called Trichinella spiralis. People usually become infected with trichinellosis by eating undercooked infected meat, most commonly pork or bear, although other meat-eating animals can also carry the parasite.
In nature, the parasite circulates among wild meat-eating animals, and most mammals can be infected. Infection begins when an animal eats meat containing Trichinella larvae (the immature stage of the parasite) contained in cysts (protective capsules surrounding the larvae). Once inside the body, the larvae are released in the intestine and then migrate through the bloodstream to different areas of the body. They eventually form cysts in muscles.
Larvae can remain alive inside muscle cysts for years. The parasite continues its life cycle only when infected muscle containing these cysts is eaten by another animal. If larvae pass through the intestine and out into the feces of an animal without developing into mature worms, they can still infect other animals.
To decrease risk, meat should be cooked thoroughly. Pork should reach an internal temperature of at least 145°F (63°C) for roasts and 160°F (71°C) for ground meat.
Freezing pork can also kill the parasite if done correctly:
5°F (−15°C) for 20 days
−9.4°F (−23°C) for 10 days
−22°F (−30°C) for 6 days
However, freezing is not a reliable means of eliminating this parasite in meats other than pork, so proper cooking is the safest method for all meat products.
In most animals, trichinellosis causes no obvious signs. In people, however, heavy infections can cause severe illness and are sometimes fatal. Infections in both wild and domestic animals are often never diagnosed, but infection may be suspected if there is a history of eating rodents, dead wildlife, or raw infected meat.
Treatment is usually not practical in animals. The most effective approach is to prevent animals from ingestingTrichinella larvae in meat.
In North America, pork should always be considered potentially infected unless labeled “ready to eat.”
For More Information
Also see professional content regarding trichinellosis.
