title: Light and electron-microscopical observations of the early developmental stages of Theileria sergenti in the gut of Haemaphysalis longicornis.
abstract: Morphological characteristics of the early developmental stages of Theileria sergenti in the vector tick were observed by light and electron-microscopies and compared with those of other Theileria species. Just before the repletion of nymphs, various stages of the parasite were observed in gut contents of tick by light microscopy: the spherical intra-erythrocytic stage, the ring-form stage, the spindle-shaped stage and the round-form stage. Electron microscopy revealed that the spherical intra-erythrocytic stages were 1-2 microns in diameter and were marginally located in host erythrocytes. The organisms liberated from host erythrocytes into the tick gut lumen had a large nucleus, an endoplasmic reticulum, electron dense-organelles and a double-walled, mitochondrion-like organelle. In addition ticks had ray-bodies in the gut lumen. These bodies had short protrusions containing 1-3 microtubules and a labyrinthine structure containing highly electron-dense organelles, so they were considered as the developing microgamont of T. sergenti.
authors.affiliation: Department of Veterinary Internal Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kawai
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Kurosawa
authors.forename: M
authors.initials: M
authors.lastname: Sonoda
mesh_terms: D000818:Animals; D004064:Digestive System / Q000469:parasitology; D008854:Microscopy, Electron; D016794:Theileria / Q000166:cytology* / Q000502:physiology* / Q000648:ultrastructure; D013987:Ticks / Q000469:parasitology*