Isolation and identification of Babesia ovis in Extremadura (Spain).

A morphological and morphometric comparison was made of a Babesia ovis strain isolated in Extremadura (Spain) and a B. ovis strain from Turkey. Strains were morphologically similar, with a clear predominance of single sub-spherical or anaplasmoid forms. The use of an image analyser to measure B. ovis merozoites revealed significant differences in the long axis, short axis and volume between the two strains. Both strains however behaved in a similar manner in the indirect fluorescent antibody (IFA) test, which suggests a high degree of common antigenicity, despite morphometric differences. Conversely, no cross-reaction was observed between these strains of B. ovis and the other antigens used: B. motasi (The Netherlands), B. motasi (Turkey), B. crassa (Iran) and Theileria ovis (Turkey). B. ovis is therefore considered to be the aetiological agent of babesiosis in the area under study.