In vitro cultivation of Cowdria ruminantium

Cowdria ruminantium was cultivated in a calf endothelial cell line after the cells had been irradiated at 45 & 90 GY. Another experiment in which the inoculum and non-irradiated cells were centrifuged together also yielded positive results. In some irradiated cultures, colonies of organisms could be demonstrated microscopically up to 70 days after the cultures had been inoculated with infected tick stabilate. The infectivity of cultures, even after 4 passages and 88 days post-inoculation, was demonstrated by their intravenous injection in sheep.