title: Ultrastructural observations on Ehrlichia equi organisms in equine granulocytes.
abstract: The ultrastructure of the etiological agent of equine ehrlichiosis, Ehrlichia equi, was studied in equine peripheral leukocytes. The organisms occurred within membrane-lined cytoplasmic vacuoles of neutrophils and eosinophils. Ovoid, round, and rod-shaped profiles were observed. From 1 to 33 organisms were present in a thin-section profile of a cytoplasmic vacuole. Many cells contained multiple organism-containing vacuoles. The organisms had a cell wall and plasma membrane, and internally they consisted of electron-dense and lucid areas. A great variation in size was observed. The morphological features were most consistent with agents of the genus Ehrlichia.
mesh_terms: D000818:Animals; D004536:Ehrlichia / Q000648:ultrastructure*; D004804:Eosinophils / Q000648:ultrastructure; D006098:Granulocytes / Q000648:ultrastructure*; D006736:Horses; D007962:Leukocytes / Q000648:ultrastructure*; D009504:Neutrophils / Q000648:ultrastructure; D012287:Rickettsiaceae / Q000648:ultrastructure*