Trichinellosis

Overview

Trichinosis, also called trichinellosis, or trichiniasis, is a parasitic disease caused by eating raw or undercooked pork and wild game infected with the larvae of a species of roundworm Trichinella spiralis, commonly called the trichina worm. The few cases in the United States are mostly the result of eating undercooked game, bear meat, or home reared pigs. It is most common in the developing world and where pigs are commonly fed raw garbage

Symptoms

The great majority of trichinosis infections have either minor or no symptoms and no complications. Trichinosis initially involves the intestines. Within 1-2 days of contagion, symptoms such as nausea, heartburn, dyspepsia, and diarrhea may appear; the severity of these symptoms depends on the extent of the infection. Later on, as the worms encyst in different parts of the human body, other manifestations of the disease may appear, such as headache, fever, chills, cough, eye swelling, joint pain and muscle pain, petechiae, and itching.

Causes

Trichinellosis is acquired by eating raw or undercooked meat that contains Trichinella larvae. After being released by the digestive process in the stomach, larvae mature in the small intestine within a few days and reproduce. The adult female worms survive and shed larvae for about 2-3 weeks. The newborn larvae enter the circulatory system and invade skeletal muscle where they typically form cysts and can survive for years until consumed by a new host. Different host species have specific muscle sites (predilection sites) which contain more larvae than other muscles. The tongue, masseter, and diaphragm muscle are the most common of these sites. All mammals are susceptible to infection, but the number of larvae required for infection varies according to the genotype of the parasite and the host species.

Diagnosis

A blood test or muscle biopsy can identify trichinosis. Stool studies can identify adult worms, with females being about 3 mm long and males about half that size

Treatment

Symptoms can be treated with aspirin and corticosteroids. Thiabendazole can kill adult worms in the intestine; however, there is no treatment that kills the larvae