[DNA detection and sequence analysis of spotted fever group Rickettsiae in rodents from Heilongjiang forest region].

ABSTRACT

OBJECTIVE: To investigate the infection in spotted fever group Rickettsiae (SFGR) in wild rodents from Heilongjiang, China. METHODS: Polymerase chain reaction (PCR) was used to detect the OmpA gene of SFGR in rodents collected in Heilongjiang. The PCR products amplified from rodent specimens were sequenced and compared with the corresponding part of the sequences deposited in the GenBank. Phylogenetic trees were constructed with Mega 5.0 software. RESULTS: A total of 514 rodents were collected from Heilongjiang during 2009-2011 and 11 species were included. The infection rate of SFGR in the rodents was 9.3% (95% CI 7.1%-12.2%). Statistical analysis showed a significant difference in different areas of Heilongjiang (P=0.023). The highest prevalence was observed in Mudanjing area (12.42%). There were significant differences in different species of rodents (P=0.002). The infection rate of SFGR determined in Clethrionomys rufocanus was the highest (22.1%). Sequence analysis revealed SFGR belonged to R.heilongjiangensis and a new unknown rickettsia genotype. CONCLUSION: R.heilongjiangensis has been presented in rodents in Heilongjiang, and a new SFGR genotype different from other rickettsiae genotypes may exist in this area.