Characterization of p44/msp2 multigene family of Anaplasma phagocytophilum from two different tick species, Ixodes persulcatus and Ixodes ovatus, in Japan.

Anaplasma phagocytophilum, which belongs to the order Rickettsiales, is an obligate intracellular bacterium and causes an emerging, tickborne, and febrile infectious disease, anaplasmosis, in humans and other mammals. This bacterium expresses a variety of 44-kDa immunodominant proteins encoded by the p44/msp2 multigene family on the surface for the purpose of avoiding the host immune defense due to the antigenic variation. In Japan, little is known about the molecular and biological features of A.