Molecular epidemiology of rabies in Guangxi Province, south of China.

BACKGROUND: Surveillance data for rabies in Guangxi Province in China showed that human rabies cases have gradually increased since 1996. OBJECTIVE: To evaluate the epidemiology of rabies at the molecular level and provide suggestions for effective prevention of rabies in Guangxi. STUDY DESIGN: Since 2000, 1569 brains from suspected rabid animals were collected from different areas of Guangxi. Rabies virus was isolated from 42 samples. RT-PCR was used to amplify a 455 nucleotide segment of the 3'-terminal of the N gene. The sequencing data from that segment was used for phylogenetic analysis. RESULTS: Nucleotide homology comparisons and phylogenetic tree analysis based on this sequence indicated that all the rabies virus isolates from Guangxi belonged to genotype 1 and could be divided into four groups. Groups I, II and IV included 23, 10 and 8 isolates, respectively. These had nucleotide homologies of 97.1-100%, 98.2-100% and 99.1-99.6%, respectively. Only the GXN119 strain belonged to group III. Group I had two group-specific mutations: T90N and E110D. Group II had one group-specific mutation of T42S. CONCLUSIONS: This study showed that rabies virus isolates from Guangxi have a close genetic relationship and topographical distribution.