Learn about the symptoms, treatment and prevention of this type of roundworm infection.
Trichinosis (trik-ih-NO-sis), sometimes called trichinellosis (trik-ih-nuh-LOW-sis), is a type of roundworm infection. Roundworm parasites use a host body to live and reproduce. These parasites primarily infect meat-eating animals (carnivores) such as bears and foxes, or meat- and plant-eating animals (omnivores) such as domestic pigs and wild boars. The infection is acquired by eating roundworm larvae in raw or undercooked meat.
When humans eat undercooked meat containing trichinella larvae, the larvae mature into adult worms in the small intestine over several weeks. The adult worms then produce larvae that travel 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.
Signs and symptoms of trichinosis infection and their severity vary depending on the number of larvae consumed in the infected meat. Abdominal symptoms can occur one to two days after infection. Other symptoms usually start two to eight weeks after infection.
Mild cases of trichinosis — those with only a small number of parasites in your body — may cause no recognizable signs or symptoms. Symptoms can develop with moderate or heavy infestation, sometimes progressing as the parasite travels through your body.
You swallow trichinella larvae encased in a cyst. Your digestive juices dissolve the cyst, releasing the parasite into your body. The larvae then penetrate the wall of the small intestine, where they mature into adult worms and mate. At this stage, you may experience:
About a week after infection, the adult female worms produce larvae that go through the intestinal wall, enter your bloodstream, and eventually burrow into muscle or other tissue. This tissue invasion can cause:
If you have a mild case of trichinosis with no symptoms, you might not need medical attention. If you experience gastrointestinal problems or muscle pain and swelling about a week after eating pork or wild-animal meat, talk to your doctor.
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. Cattle don't eat meat, but some cases of trichinosis in humans 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, even fatal, complications, including:
The best defense against trichinosis is proper food preparation. Follow these tips to avoid trichinosis:
Avoid undercooked meat. Be sure to thoroughly cook cuts of meat until brown. Cook pork and meat from wild animals to an internal temperature of 160 F (71 C) throughout. For whole cuts and ground varieties of poultry, cook to a temperature of at least 165 F (74 C). Don't cut or eat the meat for at least three minutes after you've removed it from the heat.
Use a meat thermometer to ensure that the meat is thoroughly cooked.
Trichinella larvae travel from the small intestine through the arteries to bury themselves inside muscle tissue, so stool sample tests don't often show evidence of the parasite. Your doctor can diagnose trichinella infection by performing a physical exam and discussing your signs and symptoms such as swelling around the eyes, muscle inflammation and fever.
To confirm the diagnosis, your doctor might use these tests:
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 years. Your doctor may prescribe medications depending on your symptoms and the severity of infection.
Anti-parasitic medication. Anti-parasitic medication is the first line of treatment for trichinosis. If the trichinella parasite is discovered early, albendazole (Albenza) or mebendazole (Emverm) can be effective in eliminating the worms and larvae in the intestine. You may have mild gastrointestinal side effects during the course of treatment.
If the disease is discovered after the larvae bury themselves in muscle tissues, the benefit of anti-parasitic medications is less certain. Your doctor might prescribe one if you have central nervous system, cardiac or respiratory problems as a result of the invasion.
You're likely to start by seeing your family doctor. In some cases, you may be referred to an infectious disease specialist.
Here's some information to help you prepare for your appointment.
Preparing a list of questions will help you make the most of your time with your doctor. For trichinosis, some basic questions to ask your doctor include:
Don't hesitate to ask other questions.
Your doctor is likely to ask you a number of questions, including:
May 29th, 2020