Transmission of a spotted fever group rickettsia by Amblyomma hebraeum (Acari: Ixodidae).

Amblyomma hebraeum, a cattle tick common in southern Africa, was demonstrated to be capable of maintaining an infection with an unclassified spotted fever group rickettsia both transtadially and transovarially. All feeding stages of the tick transmitted the infection to rabbits. The rickettsia was isolated and found to be serotypically distinct from three strains of Rickettsia conorii by microimmunofluorescence. Rabbit serum titers were found to be higher with indirect fluorescent antibody (IFA) tests using the Amblyomma isolate than with those using a commercially available IFA test for R. conorii.