Anaplasmosis is an infectious, non-contagious disease caused by the rickettsial pathogen Anaplasma marginale. The organism is globally distributed and infects erythrocytes, resulting in anemia, jaundice, fever, abortions and death. Once infected, animals remain carriers for life. In developing countries anaplasmosis is of great economic losses as it is highly endemic. The present study was designed to determine the prevalence of A. marginale in blood samples of buffaloes since they are important reservoir hosts for A. marginale and can serve as a source of infection for tick. A total of 150 buffalo blood samples was randomly collected from four governorates and was analyzed using PCR assay based on msp1α. Anaplasma marginale DNA was detected in 69.3% (104/150) of the sampled buffaloes, and 86.6% (130/150) of collected
ticks. As anaplasmal infection is endemic in Egypt, it was recommended screening herds to detect A. marginale even when the signs and symptoms of infection were not visible.