Electron microscopic observations on the normal development of Trichinella spiralis from muscle larvae to adult worms in BALB/c mice with emphasis on the body wall, genital organs and gastrointestinal organs.

Ultrastructural changes during the development of Trichinella spiralis from muscle larvae to adult worms are described with emphasis on the body wall, genital organs and gastrointestinal organs. The cuticle of the body wall and hindgut underwent the first molting at 14 h post-infection (PI). The esophagus cuticle never molted. The hypodermal gland was formed in the lateral cords by 30 h PI. The genital primordium developed to either male or female genitals, accomplishing their sexual maturity and fertilization by 3 days PI. Glycogen disappeared during the development.