Comparison of pathogenicities and nucleotide changes between porcine and bovine reassortant rotavirus strains possessing the same genotype constellation in piglets and calves.

Although reassortment is one of the most important characteristics of group A rotavirus (RVA) evolution, the host range restriction and/or virulence of reassortant RVAs remain largely unknown. The porcine 174-1 strain isolated from a diarrheic piglet was identified as a reassortant strain, harboring the same genotype constellation as the previously characterized bovine strain KJ56-1. Owing to its same genotype constellation, the pathogenicity of the porcine strain 174-1 in piglets and calves was examined for comparison with that of the bovine reassortant KJ56-1 strain, whose pathogenicity has already been demonstrated in piglets and calves. The porcine 174-1 strain induced diarrhea and histopathological changes in the small intestine of piglets and calves, whereas KJ56-1 had been reported to be virulent only in piglets, but not in calves. Therefore, full genomic sequences of 174-1 and KJ56-1 strains were analyzed to determine whether specific mutations might be associated with clinical and pathological phenotypes. Sequence alignment between the 174-1 and KJ56-1 strains detected one nucleotide substitution at the 3' untranslated region of the NSP3 gene and 16 amino acid substitutions at the VP7, VP4, VP1, VP3, NSP1 and NSP4 genes. These mutations may be critical molecular determinants for different virulence and/or pathogenicity of each strain. This study presents new insights into the host range restriction and/or virulence of RVAs.

Molecular epidemiology of Korean porcine sapeloviruses.

To evaluate the prevalence and genetic diversity of porcine sapeloviruses (PSVs) in Korea, a total of 100 diarrhea fecal samples from pigs were analyzed by RT-PCR and nested PCR assays with primer pairs specific for the VP1 gene. Overall, 34 % of the diarrhea samples tested positive for PSV, and a high proportion of infections occurred along with a variety of other enteric viruses and bacteria. Genomic and phylogenetic analysis of the VP1 genes revealed pronounced genetic diversities between PSVs from Korean and elsewhere. Our results indicate that PSV infections are very common in Korean pigs with diarrhea. The infecting strains are genetically diverse.

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

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.

Azuki bean (Vigna angularis) extract inhibits the development of experimentally induced atopic dermatitis-like skin lesions in NC/Nga mice.

The present study investigated the effects of azuki bean (Vigna angularis) extract (VAE) on the progress of atopic dermatitis (AD)-like skin lesions in NC/Nga mice induced by 1-chloro-2,4-dinitrobenzene. The efficacy of VAE in NC/Nga mice was determined by measuring gross and histological skin lesions, serum IgE levels, eosinophil ratio in peripheral leucocytes, and mRNA expression levels of interleukin (IL)-4, tumour necrosis factor (TNF)-α and interferon (IFN)-γ in splenocytes. Continuous ingestion of VAE inhibited the development of the AD-like skin lesions in a dose-dependent manner. In the VAE-treated mice, the numbers of mast cells in the skin, eosinophil ratio in peripheral leucocytes, relative mRNA expression of inflammatory cytokines in the spleen, and serum IgE levels were significantly reduced. Results suggest that VAE can inhibit the development of AD-like skin lesions in NC/Nga mice by regulating immune mediators and cells, and may be an effective alternative therapy for AD.

Detection and genotyping of Korean porcine rotaviruses.

Porcine group A rotavirus (GARV) is considered to be an important animal pathogen due to their economic impact in the swine industry and its potential to cause heterologous infections in humans. This study examined 475 fecal samples from 143 farms located in 6 provinces across South Korea. RT-PCR and nested PCR utilizing primer pairs specific for the GARV VP6 gene detected GARV-positive reactions in 182 (38.3%) diarrheic fecal samples. A total of 98 porcine GARV strains isolated from the GARV-positive feces were analyzed for G and P genotyping. Based on the sequence and phylogenetic analyses, the most predominant combination of G and P genotypes was G5P[7], found in 63 GARV strains (64.3%). The other combinations of G and P genotypes were G8P[7] (16 strains [16.3%]), G9P[7] (7 strains [7.1%]), G9P[23] (2 strains [2.0%]), and G8P[1] (1 strain [1.0%]). The counterparts of G or P genotypes were not determined in three G5, five P[7], and one P[1] strains. Interestingly, phylogenetic analysis indicated that all Korean G9 strains were more closely related to lineage VI porcine and human viruses than to other lineages (I-V) of GARVs and to Korean human G9 strains (lineage III). These results show that porcine GARV infections are common in diarrheic piglets in South Korea. The infecting strains are genetically diverse, and include homologous (G5P[7]), heterologous (G8P[1]), and reassortant (G8P[7]), as well as emerging G9 GARV strains.