Six of 20 sera from apparently healthy dogs in Mutare, Zimbabwe, contained antibodies which were reactive with Cowdria ruminantium and Ehrlichia canis in indirect fluorescent antibody tests at similar titres. In Western blots these sera recognised the immunodominant antigen bands of the two organisms. Sera with high titres (> 1/80) recognised additional antigen bands of each organism. It was not possible to determine whether these dogs had been exposed to C ruminantium, E canis or other Ehrlichia species. In areas where these organisms coexist serological tests for canine ehrlichiosis should be interpreted with caution.

A resident of Florida returned from a short visit to southern Africa to find a male Amblyomma hebraeum tick attached to the skin behind her knee. Amblyomma hebraeum is a major vector of 2 pathogens that cause important diseases in southern Africa, heartwater of ruminants and African tick-bite fever of humans. The tick was tested by polymerase chain reaction assay for evidence of infection with Cowdria ruminantium and Rickettsia africae (the causative agents of heart-water and African tick-bite fever, respectively) and was found to be negative for both agents. This is the second record of the exotic tick, A. hebraeum, being introduced into the United States on a human host.

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