The eggs deposited in feces develop in soil during several weeks to infective stage. When swallowed the larvae penetrate the intestinal wall and a similar cycle as known as Ancylostomideans. If a considerable number of larvae are ingested at one time high fever and pneumonitis are caused. The female migrate through the anus and deposit thousands of ova on the skin of the perianal region. When these eggs are ingested they develop into larvae and adult worms in the intestine.
Laboratory diagnosis is done by microscopic examination of anal swabs.
Trichinella spiralis Is a common parasite of flesh eating animals. It causes thichinosis. Adult trichina worms are just barely visible to the naked eye. They live in the duodenum. The female worm penetrates the intestinal wall and deposits its larvae in the mucosa.