Trichinosis: what are its symptoms, causes and treatment

Trichinosis, also known as trichinellosis, is a type of roundworm infection. These parasitic nematodes (trichinellae) live and reproduce in a host body. These parasites infect animals such as bears, cougars, walruses, foxes, wild boars and domestic pigs. The infection is acquired by eating the immature forms (larvae) of the nematodes present in raw or undercooked meat.

When humans eat raw or undercooked meat containing trichinella larvae, they develop into adult worms in the small intestine. It takes several weeks. The adult worms produce larvae which travel through the bloodstream to different parts of the body. They are then deposited in the muscle tissue. Trichinosis is widely prevalent in rural areas around the world.

It can be treated with medication, although this is not always necessary. Moreover, it is very easy to prevent.

Signs and symptoms of trichinosis infection and severity can vary. It depends on the number of larvae consumed in the infected meat.

Mild cases of trichinosis (those in which there are a small number of parasites in the body) may not cause any signs or symptoms. Symptoms can manifest as a moderate or heavy infestation, that is, when there are a large number of parasites in the body. These symptoms often worsen when the roundworm larvae circulate through the crow.

You have to swallow roundworm larvae (Trichinella) in small sacs (cysts) that contain the parasite. The digestive juices dissolve the cysts and the larva is released into the body. The larvae then pass through the wall of the small intestine, where they develop into adult worms and mate. Digestive symptoms may begin 1-2 days after infection. At this stage, you may have:

Diarrhea Abdominal (abdominal) pain Severe weakness and fatigue Nausea and vomiting

About a week after infection, adult female parasites produce larvae. The larvae pass through the walls of the intestine and enter the bloodstream. They travel throughout the body and enter muscle tissue. Here, each larva coils up and forms a cyst around itself. The larvae can live inside muscle tissue for months or even years.

Symptoms resulting from muscle tissue invasion usually begin 2-8 weeks after infection and include:

High fever and chills Muscle pain and tenderness Joint pain Swelling of the eyelids or face Weakness Headache Sensitivity to light Conjunctivitis Itchy and irritated skin

If there are a lot of parasites, the pain and muscle weakness can be severe. This can limit movement, breathing, and speech.

Symptoms last for several months. However, they usually disappear when the larvae form the cysts. Even after the infection is gone, fatigue, mild pain, weakness, and diarrhea can last for months or years.

If you have a mild case of trichinosis without symptoms, you may not need medical attention. If you have digestive problems or muscle aches and swelling within a week of eating pork or wild meat, talk to your health care provider.

Risk factors for trichinosis include the following:

Improper food preparation.

Trichinosis infects humans when they eat infected raw or undercooked pork or wild animal meat. It can also be other meats that have been contaminated by grinders or other equipment.

Rural areas.

Trichinosis is more prevalent in rural areas around the world. The infection rate is higher in areas where pigs are raised.

Consumption of meat from wild or non-commercial animals.

Public health measures have significantly reduced the number of trichinosis infections in commercial meats. However, non-commercial farm animals, especially those with access to wild animal carcasses, have higher infection rates. Wild animals are still common sources of infection.

The healthcare provider can diagnose trichinosis by analyzing symptoms and performing a physical exam. It may also ask you if you ate raw or undercooked meat.

To diagnose the infection, the healthcare provider may perform the following tests:

Blood test.

Your healthcare provider may take a blood sample and test it for signs of trichinosis. These signs include an increase in the number of a type of white blood cell (eosinophils) or the formation of antibodies against the parasite after several weeks.

Muscle biopsy.

A blood test is usually enough to make a diagnosis. However, the healthcare provider may also recommend a muscle biopsy. A small piece of muscle is removed and examined under a microscope for nematode larvae (trichinella).

Trichinella larvae travel from the small intestine through the bloodstream to burrow into muscle tissue. For this reason, stool sample testing usually does not provide evidence that the parasite is present.

Trichinosis usually heals on its own. In cases where the number of larvae is light or moderate, most signs and symptoms usually disappear within a few months. However, fatigue, mild pain, weakness, and diarrhea may persist for several months or years. Infection with a large number of larvae can cause more serious symptoms requiring immediate treatment.

Your health care provider may prescribe medications based on your symptoms and the severity of the infection.

Antiparasitic drugs. Antiparasitic drugs are part of the initial treatment for trichinosis. If your healthcare provider finds out early that you have parasitic roundworms (trichinella), albendazole (Albenza) or mebendazole (Emverm) can kill the worms and larvae in your small intestine. The drugs can cause nausea, vomiting, diarrhea, and stomach pain during treatment.

If the health care provider discovers the infection after the larvae have burrowed into muscle tissue, deworming medications may not kill all the parasites. However, they may prescribe one if you have problems with your brain, heart, or lungs, as the larvae cause pain and swelling (inflammation) in these organs.

Analgesics.

Once the larvae have entered the muscles, your healthcare provider may prescribe pain medication to help relieve muscle pain and swelling (inflammation). Over time, larval cysts in the muscles tend to harden into calcium (calcify). As a result, the larvae die, and muscle pain and weakness usually disappear.

Steroid drugs.

In some cases, trichinosis can cause an allergic reaction. This happens when the parasite enters muscle tissue or when dead or dying larvae release chemicals into muscle tissue. Your health care provider may prescribe steroids to control pain and swelling.