Immunological and Molecular Virological Studies on Rotavirus Infection in Animals

轮状病毒(RV)是引起小马驹急性腹泻的病原之一。轮状病毒在动物中的传播方式尚不清楚，尽管已有报道称轮状病毒在动物种群中广泛传播。本研究对轮状病毒感染动物的分子病毒学和免疫学特征进行了研究。(1)1986~1991年，从某轻马场腹泻小马群中分离到一系列马房车。各年所有代表的RV都显示出相似的基因组RNA和G3型，表明某一株RV在该养殖场持续了很长时间。然而，在1987年，一个分离株(CH3)显示出一种独特的病毒RNA电泳型(EPT)，这与该农场广泛流行的其他病毒不同。毒株CH3的VP7氨基酸序列与G14毒株FI23高度同源，VP4氨基酸序列与H2毒株相似。(2)上述养殖场暴发G3型轮状病毒幼崽腹泻。1989年疫情期间，所有的马驹都接种了牛初乳免疫球蛋白(Ig)粉，发病率低于1987年没有给马驹注射Ig粉时的发病率。这表明，免疫球蛋白粉剂可以部分预防马驹腹泻。(3)从新生犊牛流行性腹泻粪便中分离到8株轮状病毒。分离株的病毒RNA分为5个EPTs。然而，有些菌株并不是单一的EPTs，而是两个或三个EPTs的混合构象。这些数据表明，不同的轮状病毒在一头犊牛中的混合感染导致了菌株间基因组片段的重新排列。(4)在封闭奶牛场，从1990-93年出生的59头犊牛的222份粪便标本中分离到35份牛轮状病毒，分离率为16%。发病犊牛的IgA和Ig G抗体水平显著高于3周龄正常犊牛(P&lt；0.05)。35个菌株中的大多数是从2到6岁的小牛身上分离出来的

Rotavirus (RV) is one of the causative agents of acute diarrhea in foals and calves. The mode of RV transmission among animals is still unclear, although RV has been reported to be wide-spreading in the animal populations. The present study is concerned with molecular virologic and immunologic features of RV infection in the animals. (1) A series of equine RVs was isolated from diarrheal foals in a light-horse farm from 1986 to 91. All the represented RVs in each year showed similar genomic RNA and serotype G3, suggesting the persistence of a particular RV strain in this farm for long time. In 1987, however, one isolate (CH3) showed a unique electropherotype (EPT) of viral RNA which differed from the others that widely prevailed on this farm. The VP7 amino acid sequence of strain CH3 also showed a high homology to that of G14 strain FI23, and the VP4 sequence, similar to that of strain H2, respectively. (2) Foal diarrhea with G3 RV broke out on the above-mentioned farm. In 1989, all of the foals received bovine colostral immunoglobulin (Ig) powder during the epidemic, and their morbidity was lower than that observed in 1987, when the Ig powder was not administered to foals. This suggests that the administration of Ig powder might partially prevent foal diarrhea. (3) Eight RV strains were isolated from fecal samples in epidemic diarrhea of new-born calves. Viral RNAs of the strains were classified into 5 EPTs. However, some strains presented not a single but mixed-up conformations of dual or triple EPTs. These data suggest that the mixed infection of distinct RVs in one calf cause the rearrengement of genomic segments among the strains. (4) In a closed dairy farm, bovine RV was isolated from 35 (16%) of 222 fecal specimens repeatedly collected from 59 calves born during the years 1990-93. The affected calves had IgA and IgG coproantibody levels much higher than those of normal calves 3 weeks old (P<0.05). Most of the 35 strains were isolated from calves aged 2 to 6