Ultrastructural study of Trichinella spiralis with emphasis on adult female reproductive organs.

The ultrastructure of the reproductive organs of adult female T. spiralis was described on the basis of extensive observation under an electron microscope. The organisms were recovered from the host intestine 7 days after oral infection. The organs consisted of a single ovary, seminal receptacle, uterus and vagina, confirming the reports described by previous authors at light microscopical level. All the organs were surrounded by a basal lamina and epithelial cells, and were bathed in haemolymph. Ova were formed in a germinal zone on the ovary wall exhibiting a half-moon shape, and spread to other sides of the ovary. Mature ova exhibited a smooth cell surface, cuboidal shape, prominent cytoplasmic polysomes, a clear nucleus and a well-developed nucleolus. Embryos in early stage of development consisted of numerous small cells and were surrounded by a sheath. As they matured they shed the sheath and left a pool of sheaths in the uterus. During oogenesis and embryogenesis of adult worms in normal development, three occurred lipid droplets and the degradation of embryos; reportedly signs of worm damage.