Rhipicephalus bursa is a common tick parasite of small-to-medium size ungulates, principally in warm, temperate, and subtropical areas. Although common in livestock and showing a wide geographic distribution, its epidemiological role in tick-borne bacterial disease is barely known. This study addressed the knowledge gap and aimed to screen for the presence of Anaplasmataceae and spotted fever group (SFG) Rickettsia species in R. bursa ticks collected from domestic animals in Romania, Eastern Europe. A total of 64 pools of R. bursa ticks collected from small ungulates were tested by PCR for Anaplasmataceae DNA presence using group-specific primers. Specific testing was performed for Anaplasma marginale/A. centrale/A. ovis, A. platys, A. phagocytophilum, Ehrlichia canis, and SFG Rickettsia. The positive samples were purified and sequenced, and sequences analysis was used to identify the species and to confirm the PCR results. The only pathogen identified in this study was E. canis. The obtained sequences confirmed the PCR results. The presence of E. canis in R. bursa in Romania and in ticks from sheep was shown for the first time in this study. Based on these findings, it may be presumed that the E. canis DNA originated from ticks; however, the vectorial role of R. bursa (and other arthropod species) in the transmission of E. canis should be proved experimentally.

Transstadial and transovarial transmission of Anaplasma marginale by Dermacentor variabilis were attempted with ticks exposed to the organism once by feeding as larvae or nymphs, and twice by feeding as larvae and nymphs. Typical colonies of A marginale were in gut tissues of adults that were infected as larvae, larvae and nymphs, and as nymphs; repeated exposure of ticks did not appear to result in an increase in the number of colonies in the gut of subsequently molted adults nor did it affect severity of the clinical disease that developed in cattle they fed on. In contrast, colonies of A marginale were not found in the midgut epithelium of unfed nymphs exposed as larvae, even though companion nymphs transmitted the parasite, causing severe clinical anaplasmosis in susceptible calves. The organism was not transmitted transovarially by F1 larvae or nymphs from the groups exposed as parent larvae, nymphs, larvae and nymphs, and as adults. Some of the calves fed on by F1 progeny had a few erythrocytic marginale bodies that looked suspiciously like A marginale, as well as postchallenge exposure prepatent periods that were longer than other calves in the transovarial transmission study. Sera from these calves were tested for antibody to A marginale, using a highly sensitive immunoblot technique. Antibodies were not detected in any of the sera.

We evaluated the efficacy of buparvaquone in eliminating Babesia equi of European origin in carrier horses and in experimentally infected splenectomized ponies. When administered at the rate of 2.5 mg/kg of body weight, IM, 4 times at 96-hour intervals, buparvaquone was effective in eliminating B equi carrier infection in 1 horse. Such results could not be repeated at the same dosage or at 3.5 or 5 mg/kg, IM. Buparvaquone given at the rate of 4 to 6 mg/kg IV and/or IM was therapeutically effective in 4 of 5 acute B equi infections in splenectomized ponies. The treated ponies became carriers.

Eleven adult goats and 32 adult outbred mice were inoculated IV with Cowdria ruminantium-infected blood (Kwanyanga isolate), monitored clinically, then serially euthanatized. Predominant clinical signs of disease in goats were depression, head tremors, seizures, and dyspnea. In mice, dyspnea and depression were the only clinical signs of disease noticed. Tissues were examined histologically and immunohistochemically for C ruminantium colonies or antigen. In goats, C ruminantium was detected only in endothelial cells of the brain, even though gross and microscopic lesions were confined to the thorax. In mice, C ruminantium was detected only in endothelial cells of the heart and lungs.