Etiologic and viral gene analysis on a case of human rabies caused by the wounding of a dog inGuizhou province

Abstract

Objective To confirm the death of a child injured by a dog was due to rabies and to understand the molecular biologic features of rabies virus in Kaili, Guizhou province. Methods Brain tissue samples of patient and dog were collected to detect the rabies virus by direct immunofluorescence assay （DFA） and RT-nested PCR assay. Homology and phylogenetic tree were analyzed based on the whole nueleotide and deduced amino acid sequence of N gene of rabies virus followed by molecular epidemiological analysis. Results Both the human and dog brain tissue samples were confirmed positive by DFA and RT-nested PCR assay. The homology analysis of N gene sequences among GZH, GZD and other epidemic and vaccine rabies strains isolated from other provinces and other countries indicated that the detected samples shared the highest homology with the strain detected in Anlong prefecture in Guizhou in the year of 2006, and the homology between GZH and GZD was as high as 100%. Besides, among the vaccine strains, GZH and GZD showed the highest homology with strain CNT. Phylogenetic analysis indicated that the two samples were very close and belonged to genetype 1 lyssavirus, with the closest relationship between samples reported in Guizhou and Beijing. Conclusion It was confirmed on the viral molecular level that both the human and dog in Kaili were suffered from rabies, and the pathogens were genetype 1 lyssavirus. The prevalent strains in Kaili city was probably imported from other prefectures of Guizhou province, suggesting that prevention and control measures on rabies in Guizhou province should be strengthened. Key words: Rabies/virus ; N gene ; Homology ; Phylogenetic tree