ABORTION IN A HEIFER ASSOCIATED WITH THE INTRAUTERINE TRANSMISSION OFCOWDRIA RUMINANTIUM-LIKE ORGANISMS FOLLOWING HEARTWATER VACCINATION

A Nguni heifer aborted a 6-month-old foetus 35 days after intravenous inoculation with Onderstepoort heartwater vaccine. Histopathological e xamination of the brain revealed numerous suspected Cowdria ruminantiu m organisms in the endothelial cells of the blood vessels. The organis ms were ultrastructurally and immunohistochemically compatible with Co wdria ruminantium, although, owing to autolysis and cross-reactions, t he possibility that they represent another rickettsial or related orga nism could not be completely excluded. As far as we could ascertain th is is the first recorded case of suspected intra-uterine transmission of Cowdria ruminantium in ruminants.