Genetic variability of respiratory syncytial virus isolated during the last 20 years from Sapporo

对札幌市1980 ~ 1999年19次呼吸道合胞病毒（RSV）A亚群125株和B亚群32株分离株的遗传变异进行了调查。通过对大糖蛋白（G）基因的选定区域进行RT-PCR，然后进行RFLP分析和/或对RT-PCR产物进行直接测序，将分离株分配到谱系中。在RSV亚组A分离株中鉴定出10种不同的遗传谱系。在每次流行中分离出具有相同基因型的菌株，并且在每一个连续的流行之后，优势谱系被其他谱系取代。然而，随着年龄的增长，没有明显的多样性积累，表明渐进的变化。通过对32株RSV B亚群G基因核苷酸序列的系统发育分析，发现近季节分离的RSV毒株分属7个不同的分支。有一种趋势，最近的菌株躺在每个分支的末端，这些线性进化的变化是典型的代表在一个分支包含9个菌株分离在1980年至1986年的6个季节。

The genetic variability of 125 respiratory synsytial virus (RSV) subgroup A and 32 subgroup B isolates over 19 epidemics from 1980 to 1999 in Sapporo city was investigated. Allocation of isolates into lineages was archived by RT-PCR of selected regions of large glycoproteins (G) gene followed by RFLP analysis and/or direct sequencing of RT-PCR product. In RSV subgroup A isolates 10 different genetic lineages were identified. The strains with the same genotypes were isolated in each epidemic and the dominant lineages were replaced by others after every one to three consecutive epidemics. However there was no apparent accumulation of diversity with age to indicate progressive changes. The dominant strains were often closely related to those isolated in other parts of the world at a similar time.Phylogenic analysis of nucleotide sequences of G gene of 32 RSV subgroup B strain revealed seven distinct branches in which strains isoalted during seasons of close proximity were located. There was a tendency for recent isolates to lie at the end of each branch and these linear evolutionary changes were typically represented in a branch containing nine strains isolated during 6 seasons from 1980 to 1986.