Electron microscopic observations of the stichosome during the normal development of Trichinella spiralis from muscle larvae to adult worms in BALB/c mice.

The exocrine granules of the stichosome of Trichinella spiralis contain excretory and secretory (ES) products that may alter host cell physiology in such a way that T.spiralis can establish parasitism in the host [1,2]. The stichosome is the most intriguing but still mysterious exocrine organ. This paper describes ultrastructural changes of the stichosome during the normal development from muscle larvae to adult worms. Stichocyte granules of the muscle larva stage were excreted by 14 h post-infection (PI). Then the stichosome synthesized a new type of granules, which disappeared from the stichosome by 30 h PI. These transient granules were morphologically different from granules of muscle larva and adult stages.