Trichinosis is an infection by the larvae of a roundworm, Trichinella spiralis. This parasite can infect virtually every meat-eating mammal. Unlike the other parasitic roundworm diseases that have been discussed, trichinosis is not an intestinal infection in the usual sense. It is the migration of T. spiralis larvae through the body and their encystment (becoming enclosed in a capsule) in a muscle that creates serious problems. The parasite is especially common in rats and in pigs that feed on uncooked garbage. The disease occurs in humans when they eat undercooked infected pork. It is for that reason that this infection is more common in those who eat pork.

The average case of trichinosis is not severe and produces no noticeable discomfort. It can produce symptoms that are frequently overlooked or ignored - mild abdominal pain and aches in the muscles and joints. Invasion by a large number of parasites, however, produces symptoms that mimic food poisoning followed by severe "muscular rheumatism."

A doctor can prescribe medicines only to relieve symptoms. There is no treatment for the infection. If the doctor diagnoses infection while the patient is still having digestive symptoms, standard antiparasite drugs can be used to dislodge some of the worms. Once encystment of the parasite has begun, treatment will be for the symptoms. In most cases, the chances of recovery are good.

Thiabendazole may help patients with trichinosis if treatment is begun very early, during the incubation state. Corticosteroids can relieve the inflammatory reaction during the larval migration state, and the patient should take them with thiabenazole. Steroids could, however, prolong the intestinal phase of the infection.