Current status of in vitro cultivation of Cowdria ruminantium

Heartwater caused by Cowdria ruminantium infection is the most important tick-borne disease of ruminants in southern Africa. The in vitro culture system for this rickettsia, developed less than a decade ago, is responsible for the great majority of research accomplishments currently being reported in the areas of epidemiology, diagnosis and control of heartwater. Despite this progress, cultivation of C. ruminantium remains more of an art than a science, inasmuch as significant discrepancies exist, both among and within laboratories, in the ability to successfully and repeatedly produce cultured organisms. The current status of the in vitro system and its contributions are reviewed, and ongoing research in these areas by the Onderstepoort Veterinary Laboratory and collaborating institutions is discussed.