Genetic diversity of human and animal rotaviruses from the perspective of genome homology

轮状病毒被认为是婴幼儿急性腹泻病的一种最重要的病原体。对于开发用于预防轮状病毒引起的腹泻疾病的有效疫苗的基础是更好地理解轮状病毒经历广泛遗传多样性的机制。本研究采用RNA-RNA杂交技术对8年来收集的24份粪便轮状病毒进行了基因组分析。当从这些粪便轮状病毒的基因组RNA杂交的探针制备的原型代表三个人轮状病毒基因组，任何一个分离株表现出高度的同源性，只有一个的三个探针，这些结果证实并扩展了我们以前的观察存在三个不同的基因组之间的人轮状病毒。还通过RNA-RNA杂交试验检查了人和动物轮状病毒之间的遗传关系，其中来自7种不同宿主物种的14种轮状病毒株的基因组RNA与从代表这7种宿主物种的11种轮状病毒株制备的探针杂交。一般而言，从相同动物种属回收的轮状病毒之间共享允许分类为相同基因组的较高水平的同源性，但在来自不同宿主种属的轮状病毒之间未发现这种水平的同源性。然而，在猫轮状病毒株和犬轮状病毒株之间以及在人轮状病毒株和另一种猫轮状病毒株之间观察到如此高水平的同源性。轮状病毒基因组的共享被认为是在自然条件下由一种动物传播到另一种动物的结果。

Rotaviruses are implicated as a single most important causative agent of acute diarrheal illness in infants and young children. Fundamental to the development of effective vaccines for the prevention of diarrheal diseases caused by rotaviruses is a better understanding of the mechanisms by which rotaviruses undergo extensive genetic diversity. This study was undertaken to elucidate such mechanisms by analyzing with RNA-RNA hybridization tests clinical specimens collected over an eight year period.Twenty four stool rotaviruses that comprised 22 distinct electropherotypes were selected for genome analysis. When the genomic RNAs from these stool rotaviruses were hybridized to the probes prepared from prototypes representing three human rotavirus genogroups, any one of the isolates showed a high degree of homology only with one of the three probes ; these results confirmed and extended our previous observation on the existence of three distinct genogroups among human rotaviruses. Genetic relationships among human and animal rotaviruses were also examined by RNA-RNA hybridization assays in which genomic RNAs from 14 rotavirus strains derived from seven different host species were hybridized with the probes prepared from 11 strains representing rotaviruses from those seven host species. In general, higher level of homology that allowed classification into the same genogroup was shared among rotaviruses recovered from the same animal species but this level of homology was not found among rotaviruses derived from different host species. However, such a high level of homology was observed between a feline rotavirus strain and a canine rotavirus strain as well as between a human rotavirus strain and another feline rotavirus strain. The sharing of genogroup is considered to be resulted from interspecies transmission of rotaviruses from one animal species to ano therunder natural conditions.