Different virulence of porcine and porcine-like bovine rotavirus strains with genetically nearly identical genomes in piglets and calves

Abstract

Direct interspecies transmissions of group A rotaviruses (RVA) have been reported under natural conditions. However, the pathogenicity of RVA has never been directly compared in homologous and heterologous hosts. The bovine RVA/Cow-tc/KOR/K5/2004/G5P[7] strain, which was shown to possess a typical porcine-like genotype constellation similar to that of the G5P[7] prototype RVA/Pig-tc/USA/OSU/1977/G5P9[7] strain, was examined for its pathogenicity and compared with the porcine G5P[7] RVA/Pig-tc/KOR/K71/2006/G5P[7] strain possessing the same genotype constellation. The bovine K5 strain induced diarrhea and histopathological changes in the small intestine of piglets and calves, whereas the porcine K71 strain caused diarrhea and histopathological changes in the small intestine of piglets, but not in calves. Furthermore, the bovine K5 strain showed extra-intestinal tropisms in both piglets and calves, whereas the porcine K71 strain had extra-intestinal tropisms in piglets, but not in calves. Therefore, we performed comparative genomic analysis of the K71 and K5 RVA strains to determine whether specific mutations could be associated with these distinct clinical and pathological phenotypes. Full-length sequencing analyses for the 11 genomic segments for K71 and K5 revealed that these strains were genetically nearly identical to each other. Two nucleotide mutations were found in the 5′ untranslated region (UTR) of NSP5 and the 3′ UTR of NSP3, and eight amino acid mutations in VP1-VP4 and NSP2. Some of these mutations may be critical molecular determinants for RVA virulence and/or pathogenicity.

Pathogenesis of Korean Sapelovirus A in piglets and chicks

“…All animals were fed with sterilized commercialized milk or feed. After inoculation, clinical signs including diarrhoea, pneumonia and convulsions were evaluated daily as described previously (Park et al , 2013). Animals were euthanized at specified times (Table 1).…”

“…They were immediately placed in 10 % buffered formalin for histological examination. Formalin-fixed samples were embedded in paraffin, sectioned, stained with Mayer’s haematoxylin and eosin and examined microscopically (Park et al , 2013). All samples collected for qRT-PCR analysis were immediately snap-frozen in liquid nitrogen and kept at −80 °C until use.…”

“…SV-A genome RNA levels in the faeces, sera and each organ or tissue were quantified by qRT-PCR as described previously with slight modifications (Chen et al , 2014; Park et al , 2013). Briefly, all tissues and fluid samples collected from experimental animals were individually weighed, homogenized or vortexed at a 1 : 10 dilution in 0.01 M PBS and centrifuged (tissues 13 000 g for 3 min; faecal samples 5000 g for 10 min).…”

Exotic rotaviruses in animals and rotaviruses in exotic animals

“…Partial genomic analysis (VP4 [VP8*], VP6, VP7, NSP4 and NSP5 genes) of the bovine G3P [3] strains provided evidence for multiple reassortment events involving ruminant and simian strains [34]. By whole genomic analysis, bovine G5P [7] strains, isolated from cattle herds in South Korea, was found to be genetically closely related to porcine RVAs, including those from Korea, providing compelling evidence for porcine-to-bovine interspecies transmission events [47,109]. Interestingly, during crossspecies pathogenicity studies, the bovine G5P [7] strain induced diarrhea in calves and piglets, whilst its porcine counterpart caused diarrhea in piglets, but not in calves [109].…”

The General Composition of the Faecal Virome of Pigs Depends on Age, but Not on Feeding with a Probiotic Bacterium

“…Most of them represent widely distributed enteric viruses of pigs [2,10,11]. Whereas rotaviruses are well-known pathogens of piglets, which may lead to diarrhoea [12,13,14], the clinical importance of the other viruses is a subject of controversy [10,[15][16][17][18][19][20][21][22].…”