SUMMARY:We surveyed Rickettsiales bacteria, including Rickettsia, Ehrlichia, Anaplasma, and Neoehrlichia, in wild sika deer (Cervus nippon nippon) from Shizuoka prefecture, Japan. In spleen samples from 187 deer, Anaplasma phagocytophilum (deer type), A. bovis, and A. centrale were successfully detected by PCR assay targeting to 16S rDNA or p44/msp2, and their positive rates were 96.3z (180/187), 53.5z (100/187), and 78.1z (146/187), respectively. Additionally, 2 or 3 Anaplasma species could be detected from a single deer in 165 spleen samples (88.2z), indicating dual or triple infection. In contrast, A. phagocytophilum (human type) 16S rDNA, Rickettsia gltA, Ehrlichia p28/omp-1, and Neoehrlichia 16S rDNA could not be amplified. The serological test of 105 deer serum samples by immunofluorescence assay showed that the detection of antibodies against antigens of A. phagocytophilum HZ (US-human isolate) and Rickettsia japonica YH were 29.5z (31/105) and 75.2z (79/105), respectively. These findings suggest that A. phagocytophilum (deer type), A. centrale, and A. bovis are highly dominant and prevalent in wild sika deer from Shizuoka, a central region of Japan, and that the antibodies against some Rickettsiales bacteria have also been retained in deer blood.