Objective: This study was to explore the differences in the nucleoprotein gene between rabies virus (RABV) and its vaccine strains in Guizhou province from year 2005 to 2010.
Methods: Samples from 4 rabies patients and cerebral tissue samples of 28 rabies infected dogs were collected from different districts in Guizhou province between year 2005 and 2010. Direct Immunofluorescence Assay (DFA) and RT-nested PCR assay were applied to detect the overall length of N gene sequence. Meanwhile, based on the comparison between the homology and phylogenetic tree, the differences in N gene sequence between the prevalent RABV and the RABV vaccine strains collected from NCBI database in these years.
Results: According to DFA and RT-nested PCR assay, the antigen and nucleic acid of the 21 dogs and 4 human samples were both confirmed positive; whose full length of N gene sequences were both 1353 bp. The homological analysis showed that the 25 strains of RABV virus and the RABV type I virus stored by GenBank database shared a high homology in N gene nucleotide and amino acid sequences, which were 89%-100% and 98%-100%, respectively. Besides, the homology between the 25 strains of RABV virus and its vaccines in nucleotide and amino acid sequences were separately 86%-95% and 96%-100%. The N gene of vaccines for livestock shared the highest homology with HEP-Flury strain in the nucleotide and amino acid, which were 88%-89% and 98%-99%, respectively. The vaccines for human use showed its greatest homology with the CTN strain in nucleotide (86%-100%) and amino acid (96%-100%). The phylogenetic tree analysis indicated that the 25 strains of RABV virus, RABV type I virus and the CTN vaccine strains constituted one individual cluster, which was least different from the CTN vaccine for human use.
Conclusion: The prevalent RABV virus, the vaccine HEP-Flury for livestock and the vaccine CTN for human use were found to be highly similar in N gene expression in Guizhou province from 2005 to 2010.