A characteristic of Nematoda is the one-way digestive tract, with a pseudocoelom (body cavity made up of only an ectoderm and endoderm).

The adult worms occupy a membrane-bound portion of columnar epithelium, living as intramulticellular parasites of animals, including humans.

Oral ingestion of cyst- or larvae-contaminated tissue is the usual route of infection, but congenital and mammary transmission can occur in rats.

Two main clades are recognized in the genus: one group (T. britovi, T. murrelli, T. nativa, T. nelsoni, T. spiralis) that encapsulates in host muscle tissue and a second (T. papuae, T. pseudospiralis, T. zimbabwensis) that does not.

The nonencapsulated group infects saurians, crocodilians, and other nonavian archosaurs (T. papuae, T. zimbabwensis) and birds (T. pseudospiralis).

Trichinella species can infect swine, wild omnivores (foxes, wolves, bears, skunk, raccoons, rats, and other small mammals), and humans.

Long-standing meat inspection programs in some European countries have drastically lowered prevalence rates among domestic swine.

Documented sources of human infection have also included game meats, such as wild boar, bear, walrus, fox, and cougar.

The decreased incidence of trichinellosis in the United States has resulted from changes in pork industry management standards and government regulations.

[5] In Finland, meat inspection revealed a small but worrisome number of swine infections in the early 1980s, peaking in 1996.

Knowledge on the epidemiology, host range and transmission of Trichinella species occurring in wildlife in sub-Saharan Africa is limited.