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最重要的单一病原体。开发预防轮状病毒引起的腹泻病的有效疫苗的根本是更好地了解轮状病毒经历广泛遗传多样性的机制。本研究是通过对8年期间收集的临床标本进行RNA-RNA杂交试验来阐明这种机制的。选取了24种包含22种不同电泳型的粪便轮状病毒进行基因组分析。当将这些粪便轮状病毒的基因组rna与代表三种人类轮状病毒基因群的原型制备的探针杂交时，任何一种分离株仅与三种探针中的一种具有高度同源性；这些结果证实并扩展了我们先前关于人类轮状病毒存在三种不同基因群的观察。还通过RNA-RNA杂交试验检验了人类和动物轮状病毒之间的遗传关系，其中将来自7种不同宿主物种的14种轮状病毒株的基因组rna与来自这7种宿主物种的11种轮状病毒株制备的探针进行杂交。一般来说，从同一动物物种中恢复的轮状病毒具有较高的同源性，可以归类为同一基因组，但在来自不同宿主物种的轮状病毒中没有发现这种同源性。然而，在猫轮状病毒毒株和犬轮状病毒毒株之间以及人轮状病毒毒株和另一种猫轮状病毒毒株之间观察到如此高的同源性。基因组的共享被认为是轮状病毒在自然条件下从一个动物物种传播到另一个动物物种的结果。

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.