Detection of spotted fever group Rickettsiae in ticks from Zhejiang Province, China.

Tick species distribution and prevalence of spotted fever group Rickettsiae (SFGR) in ticks were investigated in Zhejiang Province, China in 2010 and 2011. PCR was used to detect SFGR and positive amplicons were sequenced, compared to published sequences and phylogenic analysis was performed using MEGA 4.0. A total of 292 adult ticks of ten species were captured and 7.5 % (22/292) of the ticks were PCR-positive for SFG Rickettsia. The PCR-positive rates were 5.5 % (6/110) for Haemaphysalis longicornis, 3.6 % (1/28) for Amblyomma testudinarium and 16 % (15/94) for Ixodes sinensis, respectively. Phylogenetic analyses of gltA genes detected in ticks indicated that there are two dominating groups of SFGR. Sequences of group one were closely related to Rickettsia monacensis, whereas sequences of group two were closest related to Rickettsia heilongjiangensis and Rickettsia japonica, which are human pathogens. Our findings underline the importance of these ticks in public health surveillance in Zhejiang Province, China.