by Lauren Beyenhof

Created on: June 09, 2009

The roundworm Trichinella spiralis is the parasitic culprit behind the infection commonly referred to as Trichinosis. Although outbreaks of Trichinosis are quite rare in the United States, they are not altogether absent. An infection begins when a person eats meat that is contaminated with Trichinella. Trichinella larvae are typically found in the muscle tissue of pigs, wild bears, horses and a large number of carnivores. Eating the raw of undercooked meat of any of these animals is how a Trichinosis infection begins.

An animal infected by Trichinella will have cystspockets of infectionthroughout their muscle tissue. When eaten, the wall of the cyst is broken down by the stomach's acids resulting in the cysts living content of larvae to be released into the body. The larvae then proliferate the intestine where they grow and ultimately multiply their numbers. A mature Trichinella can burrow deep into the walls of the intestine where more cysts of eggs and larvae are deposited. The lifespan of an egg-producing female Trichinella is approximately four to six weeks. From there it only takes one week for an egg to mature to the larvae stage.

Larvae that have been hatched in the muscle of the intestine are carried throughout the body via the bloodstream and the lymphatic system. Within a short period of time, the infection of Trichinosis is experienced as aching, inflamed muscle tissue. The most commonly affected areas of the body are the muscles of the tongue, the eye area and throughout the muscle tissue of the ribcage. It takes about three months before the cysts are viable and detectable in the muscle.

Major symptoms of Trichinosis depend on the number of larvae, which tissue is involved, and the overall medical condition of the host organism. Some people have Trichinosis with no symptoms whatsoever. Others notice a slight fever that starts two weeks after eating the undercooked meat. Most symptoms take anywhere from 1 to 3 weeks to appear. These include:

Muscle weakness

Muscle pain

Swelling of upper eyelids

Non-itchy skin rash

Diarrhea

Difficulty breathing

Difficulty chewing and talking

Left untreated, Trichinosis can run its course on its own. This usually takes about three months from the time the infection begins. Unfortunately, even after the underlying infection has remitted, muscle pain and weakness can linger for awhile longer. A doctor can diagnose Trichinosis by doing a blood test that measures the presence of a particular type of white blood cells call eosinophils. A muscle tissue biopsy is occasionally ordered in addition to the blood test, but is not necessary for diagnosis.

In order to prevent Trichinosis, meat should be thoroughly cooked at a temperature of at least 140 degrees Fahrenheit. This is especially important for pork, which is a common source of the Trichinella parasite. Alternatively, meat can be frozen for three weeks prior to use. This ensures that the larvae are all killed. Medications that are effective in clearing up Trichinosis are mebendazole or albendazole (anti-parasitics) while bed rest and corticosteroids to reduce inflammation are also useful.

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