Trichinosis

22.3 Trichinosis Trichinosis is caused by a small worm called Trichinella. Trichinosis is a disease of wild animals and livestock (particularly pigs) and may also infect people. Infection occurs by eating under-cooked meat (or garbage) that contains the trichinella cysts. Once eaten, the cysts shed their outer coating and develop into adults which produce eggs. The eggs hatch to larvae which enter the blood stream and form cysts in muscles and organs. The cysts appear as small (up to 1mm long), white, lemon-shaped capsules.

Symptoms  While in the intestine, the larvae may cause vomiting, pain and diarrhea. (Symptoms appear approximately 4 days after eating infected meat.)

 While entering the muscles and tissues (7 to 10 days after eating infected meat), the larvae may cause muscle pain, headaches, chills, fever, and swollen eyelids. More rarely, there can be a rash, as well as respiratory and neurological signs.

 Symptoms usually last about 10 days, but sometimes muscle pain can persist for months.

Diagnosis  Based on the history of eating raw or improperly cooked meat.

 Special laboratory tests are available to diagnose trichinosis.

Treatment  There is no good treatment except symptomatic treatment (e.g. pain control).

Prevention/Control  This disease has been effectively controlled in some countries by cooking garbage before it is fed to pigs, and by not allowing pigs to run loose (to eat raw garbage).

 Meat inspection also helps to reduce the problem. Some countries examine meat under a special microscope to check for trichinella infection.

 To prevent the disease in people, all meat should be cooked at a temperature of at least 70 C. Freezing meat also kills the trichinella worm.