trichinosis.

Trichinella spiralis is a nematode parasite, occurring in rodents, pigs, horse, bears and humans, and is responsible for the disease trichinosis. It is sometimes referred to as the "pork worm" due to it being found commonly in undercooked pork products.
Description
Trichinella species are the smallest nematode parasite of humans, have an unusual life cycle and are one of the most widespread and clinically important parasites in the world. The small adult worms mature in the intestines of a definitive host such as a pig. Each adult female produces batches of live larvae, which bore through the intestinal wall, enter the blood (to feed on it) and lymphatic system, and are carried to striated muscle. Once in the muscle, they encyst, or become enclosed in a capsule. Humans can be infected by eating infected pork or horse or wild carnivores such as fox, cat or bear.

Morphology
Males of T. spiralis measure between 1.4 mm and 1.6 mm long and are more flat anteriorly than posteriorly. The anus can be found in the terminal (side) and they have a large copulatory pseudobursa on each side. The females of T. spiralis are about twice the size of the males and have an anus found terminally. The vulva is located near the esophagus. The single uterus of the female is filled with developing eggs in the posterior portion, while the anterior portion contained the fully developed juveniles.
Life cycle
Trichinella spiralis is a parasitic nematode that has a direct life cycle, meaning it completes all stages of development in one host. The larval forms are encapsulated as a small cystic structure within the infected host. Humans typically become infected when they eat improperly cooked Trichinella infected pork or other meat. When a human eats the infected meat, the larvae are released from the nurse cell (due to stomach pH) and migrate to the intestine, where they burrow into the intestinal mucosa, mature, and reproduce.[2] Juveniles within nurse cells have an anaerobic or facultative anaerobic metabolism, but when they become activated, they adopt an aerobic metabolism characteristics of the adult.