Sammels L M, Coelen R J, Lindsay M D, Mackenzie J S
Department of Microbiology, University of Western Australia, Nedlands.
Virology. 1995 Sep 10;212(1):20-9. doi: 10.1006/viro.1995.1449.
We examined the molecular epidemiology and evolution of Ross River (RR) virus in Australia and the Pacific Islands. Nucleotide sequences of the E2 and E3 genes of five RR virus strains revealed remarkable conservation between 1959 and 1989 with a maximum divergence of only 3.3%. Sequence data from a 505-base pair fragment of the E2 gene from 51 additional strains showed that RR virus has diverged genetically into three separate groups although at least 95% sequence homology was still maintained between all 56 strains. Each genetic type predominates in a particular geographic region of Australia and can be broadly defined as occurring in the western, northeastern, and southeastern regions of Australia. However, some RR virus strains did not follow this pattern of geographic distribution indicating movement of virus by the travel of viremic humans or livestock across the continent. The Pacific Islands isolates all belong to the southeastern genotype. These findings suggest genetic divergence and independent evolution of RR virus within geographically isolated enzootic foci; however, selective pressures maintain high nucleotide conservation in nature.
我们研究了澳大利亚和太平洋岛屿罗斯河（RR）病毒的分子流行病学和进化情况。五个RR病毒株的E2和E3基因的核苷酸序列显示，在1959年至1989年期间具有显著的保守性，最大差异仅为3.3%。来自另外51个病毒株的E2基因505个碱基对片段的序列数据表明，RR病毒在基因上已分化为三个独立的组，尽管所有56个病毒株之间仍保持至少95%的序列同源性。每种基因类型在澳大利亚的特定地理区域占主导地位，大致可定义为在澳大利亚的西部、东北部和东南部地区出现。然而，一些RR病毒株并不遵循这种地理分布模式，这表明病毒通过病毒血症患者或牲畜在大陆上的移动而传播。太平洋岛屿的分离株均属于东南部基因型。这些发现表明RR病毒在地理上隔离的动物疫源地内发生了基因分化和独立进化；然而，自然选择压力在自然界中保持了较高的核苷酸保守性。
