Trichinosis (trik-ih-NO-sis), sometimes called trichinellosis, is a type of roundworm infection. Roundworms are parasites that use a host body to stay alive and reproduce. Trichinosis occurs primarily among meat-eating animals (carnivores), especially bears, foxes and walruses. Trichinosis infection is acquired by eating larvae in meat.
When humans eat undercooked meat containing trichinella larvae, the larvae mature into adult worms in the intestine over several weeks. The adults then produce larvae that migrate through various tissues, including muscle. Trichinosis is most widespread in rural areas throughout the world.
Trichinosis can be treated with medication, though it's not always necessary. It's also easy to prevent.
Abdominal symptoms can occur within two to seven days of infection. Other symptoms usually start one to eight weeks later. Severity of symptoms usually depends on the number of larvae consumed in the infected meat.
Possibly no signs or symptoms
Initial signs and symptoms
Later signs and symptoms
When to see a doctor
There is no effective treatment to eliminate trichinella once larvae invade tissue. At that point, treatment is for symptoms only until the parasites die on their own.
After you eat trichinella larvae, they mature into adult worms in your intestine. The adults then produce larvae that migrate through various tissues, including muscle tissue, shown here....
People get trichinosis when they eat undercooked meat — such as pork, bear, walrus or horse — that is infected with the immature form (larvae) of the trichinella roundworm. In nature, animals are infected when they feed on other infected animals. Pigs and horses can become infected with trichinosis when they feed on garbage containing infected meat scraps. Other cases have been linked to eating beef that was mixed with infected pork or ground in a grinder previously used for contaminated pork.
Due to increased regulation of pork feed and products in the United States, pigs have become a less common source of infection. Wild animals, including bear, continue to be sources of infection.
Risk factors for trichinosis include:
Except in severe cases, complications related to trichinosis are rare. In cases of heavy infestation, larvae can migrate to vital organs, causing potentially dangerous complications, including:
Preparing for your appointment
You're likely to start by seeing your family doctor or a general practitioner. However, in some cases when you call to set up an appointment, you may be referred immediately to an infectious disease specialist.
To get the most from your appointment, it's good to be well prepared. Here's some information to help you.
What you can do
Preparing a list of questions will help you make the most of your time with your doctor. List your questions from most important to least important. For trichinosis, some basic questions to ask your doctor include:
In addition, don't hesitate to ask questions during your appointment any time you don't understand something or need more information.
What to expect from your doctor
Tests and diagnosis
Trichinella larvae bury themselves inside muscle tissue rather than remain in the intestine as in other roundworm infections, so stool sample tests don't often show evidence of the parasite. The initial diagnosis relies on the classic signs and symptoms — swelling around the eyes, muscle inflammation and fever. To confirm the diagnosis, your doctor may use these tests:
Treatments and drugs
Trichinosis usually isn't serious and often gets better on its own, usually within a few months. However, fatigue, mild pain, weakness and diarrhea may linger for months or even years. Symptomatic infections may respond to treatment with medication.
The best defense against trichinosis is proper food preparation. Follow these tips to avoid trichinosis:
Last Updated: 2010-02-20
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