Ananlysis on the molecular characteristics of CVA9 virus in Tibet

Objective To study thegenetic and molecula repid emiological characteristics of ECHO29 virusVP1 region coding in Tibet under 5-year-old children in 1999-2000. Method 7 strains of ECHO29 viruses isolated from 659 stool specimens of AFP cases and under 5-year-old patients and some healthy children in Tibet in 1999-2002 were used to extract ribonucleic acid (RNA) while VP1 coding area were amplified by reverse transcription - polymerase chain reaction (RT-PCR) and the nucleotide sequence of PCR products were determined and analyzed. Result A total of 7 strains ECHO29 viruses were isolated from the stool specimens and identified. 5 strains were isolated from specimens in 1999 while the other 2 strains isolated from samples in 2000. The complete nucleotides sequence of VP1 region of 7 strains ECHO29 viruses were 876nt coding 292 amino acids. The sequence homology of 7 strains detected ECHO29 viruses was between 75.41%-99.3% while amino acid homology was between 71.26%-79.69%.The phylogenetic tree of ECHO29 viruses showed 4 genotypes which the isolates from Tibet were belong to Genotype A and C. Conclusion It was first reported that the popular ECHO29 viruses in children in Tibet were proposed to 2 different genotypes in 1999 and 2000. The popular ECHO29 virus epidemic in 1999 was belong to Genotype C, while popular ECHO29 virus in 2000 belong to Genotype A. ECHO29 virus increasingly popular was not found in 2001 and 2002. Key words: Enterovirus; Genes; Genotype; Polivmyelitis