They cause anemia due to blood loss. The human roundworm is common where human feces is used as plant fertilizer. People ingest eggs when they eat plant material. The immature stages travel through the human body in blood vessels. Mature human roundworms live in the intestine where they produced eggs that are released with feces.
People can become accidentally infected with the trichina worm by eating undercooked port.
The muscle of pork may contain immature stages of trichina worm. When people ingest the larval stage, it matures in the intestine where the adult worms reproduced. Immature stages migrate from the intestine to muscle tissue. There the larva forms a cyst. Since humans aren t generally eaten, the cysts become coated with calcium carbonate.