title: Heartwater: an in vitro study of the ultrastructure of Cowdria ruminatium.
abstract: Notwithstanding morphological differences, the ultrastructure of Cowdria ruminatium cultured in vitro concurred to a large extent with that in previous in vivo studies. Two distinct forms of the organism, elementary and reticulate bodies, and a 3rd group of intermediate organisms were identified. Organisms within a particular vacuole were generally a specific form, but in cells containing many colonies different forms were present in the same colony. Most organisms were enveloped by 2 membranes and a few were surrounded by a 'capsule'. C. ruminantium multiplies mainly by binary fission, but it appears that multiplication can also take place by means of budding. The taxonomy of C. ruminantium is briefly discussed.
mesh_terms: D000818:Animals; D006357:Heartwater Disease / Q000382:microbiology; D008854:Microscopy, Electron; D012287:Rickettsiaceae / Q000145:classification / Q000648:ultrastructure*; D012756:Sheep; D014617:Vacuoles