Molecular detection and identification of Anaplasma species in sheep from Ahvaz, Iran

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.