Molecular detection of Anaplasma phagocytophilum in carrier cattle of Iran - first documented report

Anaplasma phagocytophilum is a zoonotic, tick borne rickettsial pathogen. A. phagocytophilum has been detected in North America, Europe, Africa and Asia by molecular methods. In Iran we have little information about the distribution of this agent in human and animals. From March 2007 to July 2007, one hundred and fifty blood samples and corresponding blood smears of cattle without any signs of disease were prepared from a region in Isfahan, Iran with previous history of tick borne disease outbreak.The blood smears were first stained with Giemsa and analyzed for the presence of A. phagocytophilum in the neutrophils. The extracted DNA from blood cells were analyzed by A. phagocytophilum specific nested PCR using primers derived from the 16S rRNA gene. All blood smears were negative for A. phagocytophilum like structures by Giemsa staining, but 2 out of 150 blood samples (1.33%) were positive for A. phagocytophilum specific nested PCR using specific primers derived from 16S rRNA gene. This study is the first detection of A. phagocytophilum in carrier cattle in Iran. The present study showed that A. Phagocytophilum is detectable in cattle without any sign of infection but maintained a persistant sub-clinical state in the cattle reservoir, which can be inferred as possible risk for management of public health.