Ovine anaplasmosis is a tick-borne rickettsial disease, widespread in tropical and subtropical areas. In the
present study, a PCR-RFLP method based on major surface protein 4 (MSP4) gene, was utilized for the
detection of Anaplasma infection in 119 sheep blood samples collected from different parts of Ahvaz in the
southwest of Iran. PCR identified Anaplasma infections in 87.4% (104/119) of the samples in contrast to the
routine blood smear examination, which revealed inclusion bodies in only 33.6% (40/119) of samples. RFLP
assessment revealed that all PCR positive samples were A. ovis, while for the first time in Iran, a mixed
infection with A. marginale was seen in 50% (52/104) of Anaplasma infected samples. These results suggest
higher sensitivity of PCR method over the conventional microscopic technique for diagnosis of
anaplasmosis, particularly in carrier animals. It also revealed that ovine anaplasmosis caused by A. ovis and
A. marginale is present and highly prevalent in Ahvaz and appears to be the first report from this region.
