Genomic sequence and virulence evaluation of MN184A-like porcine reproductive and respiratory syndrome virus in Japan.

In this study, a porcine reproductive and respiratory syndrome virus (PRRSV) that was isolated from a 9-week-old diseased pig on a farm in Japan with a high mortality rate during 2007-2008 was characterized. This unique isolate, designated as Jpn5-37, did not have a high nucleotide identity in open reading frame 5 against any Japanese isolates. Among all available type 2 PRRSV complete genome sequences, Jpn5-37 shared the highest nucleotide identity (93.

Reinfection of adult cattle with rotavirus B during repeated outbreaks of epidemic diarrhea.

Rotavirus B (RVB) infection in cattle is poorly understood. The objective of this study was to describe the epidemiological features of repeated outbreaks of epidemic diarrhea due to RVB infection in adult cattle on a large dairy farm complex in Japan. In October 2002, approximately 550 adult cows and approximately 450 in February 2005 had acute watery diarrhea at several farms on the complex.

Phylogenetic inference of the porcine Rotavirus A origin of the human G1 VP7 gene.

Rotavirus A (RVA) is an important cause of acute gastroenteritis in children worldwide. The most common VP7 genotype of human RVA is G1, but G1 is rarely detected in porcine strains. To understand the evolutionary relationships between human and porcine G1 VP7 genes, we sequenced the VP7 genes of three Japanese G1 porcine strains; the first two (PRV2, S80B) were isolated in 1980 and the third (Kyusyu-14) was isolated in 2001.

Isolation and characterization of a novel type of rotavirus species A in sugar gliders (Petaurus breviceps).

To estimate the risk of interspecies transmission of rotavirus species A (RVA) from exotic pets to other mammalian species, the prevalence of RVA in sugar gliders (Petaurus breviceps) was investigated. RVAs were detected in 10 of 44 sugar gliders by reverse transcription (RT)-semi-nested PCR. These viruses were classified as G27P[3] and G27P[36] genotypes, with G27 and P[36] being new genotypes as assigned by the Rotavirus Classification Working Group.

Pathogenicity of emerging Japanese type 1 porcine reproductive and respiratory syndrome virus in experimentally infected pigs.

To clarify the pathogenicity of Japanese type 1 porcine reproductive and respiratory syndrome virus (PRRSV) isolate in experimentally infected pigs, we evaluated clinical signs and monitored viremia for 21 days post-inoculation (dpi). Lungs were mottled, tanned and reddish in appearance; had lesions predominantly in the cranial, middle and accessory lobes; and failed to collapse at 10 dpi. Although microscopic lesions of lungs were reproduced using the Japanese emerging type 1 PRRSV isolate under experimental conditions, no significant differences were noted between the challenge and control groups regarding mean rectal temperature and daily weight gain.

Persistence of the rotavirus A genome in mesenteric lymph nodes of cattle raised on farms.

Previous studies revealed that rotavirus A (RVA) is present in not only the small intestine but also various organs. It was reported that RVA persisted in mesenteric lymph nodes (MLNs) in experimental models. However, there have been no reports focused on RVA in MLNs of animals under natural conditions.

Whole-genome sequence analysis of G3 and G14 equine group A rotaviruses isolated in the late 1990s and 2009-2010.

Equine group A rotavirus (RVA) G3P[12] and G14P[12] strains cause gastroenteritis in foals worldwide. Both of these strains have been co-circulating in Japan since G14P[12] strains emerged in the late 1990s. Although it is important to comprehensively understand the evolution of RVA strains, whole-genome sequence data on recent equine RVA strains in Japan are lacking.

Analysis of genetic divergence among strains of porcine rotavirus C, with focus on VP4 and VP7 genotypes in Japan.

Porcine rotavirus C (RVC) has been often detected in sporadic cases or outbreaks of diarrhoea in suckling and weaned pigs. Surveillance studies of RVCs have demonstrated high prevalence in the United States, and Japan, and some other countries. To date, the zoonotic impact and pathogenicity of RVCs are not well understood, and only a few complete sequences of RVCs are available.

Detection of avian-like rotavirus A VP4 from a calf in Japan.

A total of 568 normal feces from calves on a beef farm in Fukui Prefecture, Japan, in 2011-2012 were examined by RT-semi-nested PCR for rotavirus A (RVA) VP4 genes. Through partial sequencing and BLAST analyses of 84 VP4-positive specimens, we identified an avian-like RVA strain, N2342, which shares highest nucleotide identity (80.0%) with known avian-like bovine strain 993/83, in one specimen.

Application of a SYBR®Green one step real-time RT-PCR assay to detect type 1 porcine reproductive and respiratory syndrome virus.

The emergence in Japan of field isolates of type 1 porcine reproductive and respiratory syndrome virus (PRRSV) suggests problems with control. We therefore developed a one-step real-time reverse transcription polymerase chain reaction (qRT-PCR) with improved sensitivity that detects as little as 1 × 10(-2) TCID50/ml of viral RNA. We tested serum samples collected in January and September 2008, October 2009 and January 2011 from a farm with an outbreak and found infected pigs between January and September 2008, but not in January 2011.

Surveillance of diarrhea-causing pathogens in dairy and beef cows in Yamagata Prefecture, Japan from 2002 to 2011.

The economic consequences of bovine diarrhea are serious. Few long-term epidemiological data are available concerning the causative pathogens of bovine diarrhea in Japan. From 2002 to 2011, surveillance of enteric pathogens was performed in cows of various breed and age from 302 farms in which diarrhea had occurred in Yamagata Prefecture, Japan.

VP6 genetic diversity, reassortment, intragenic recombination and classification of rotavirus B in American and Japanese pigs.

Rotavirus B (RVB) has been identified as a causative agent of diarrhea in rats, humans, cattle, lambs, and swine. Recently, 20 RVB VP7 genotypes were determined based on an 80% nucleotide percent cut-off value. In this study, we sequenced the RVB VP6 gene segment from 80 RVB positive swine samples from the United States and Japan.

Phylogenetic characterization of VP6 gene (inner capsid) of porcine rotavirus C collected in Japan.

Porcine rotavirus C (RVC) has been often detected in sporadic cases or outbreaks of diarrhea in suckling and weaned pigs. Previous surveillance studies using both enzyme-linked immunosorbent assays and reverse-transcription polymerase chain reaction in some countries including Japan and the United States have demonstrated a high prevalence of porcine RVCs. In order to understand the phylogenetic relatedness of RVCs, we performed genetic analysis of VP6 gene encoding inner capsid protein by using 22 porcine RVC strains collected in Japan from 2002 to 2010.

Concise and broadly applicable method for determining the genomic sequences of North-American-type porcine reproductive and respiratory syndrome viruses in various clusters.

We developed a concise and broadly applicable method for accurate genomic sequencing of North American genotype (NA-type) porcine reproductive and respiratory syndrome viruses (PRRSVs) that overcomes high genetic variability of the viruses. The method, designated "combination of consensus oligonucleotide reverse transcription and multiple displacement amplification" (CORT-MDA), involves reverse-transcription of viral RNA followed by shotgun sequencing after amplification using only 11 degenerate oligonucleotide primers; these primers were designed against consensus regions within the open reading frames of the 124 NA-type PRRSV strains with reported full-length genomic sequences. Sequencing of the 192 shotgun clones generated per virus showed 80% to 94% coverage on the reported PRRSV genomic sequence, such that only 2 or 3 unread regions had to be resequenced after PCR amplification using custom primers.

Experimental teschovirus encephalomyelitis in gnotobiotic pigs.

A central nervous system (CNS) disorder characterized by non-suppurative encephalomyelitis with neurological signs was induced experimentally in gnotobiotic pigs by intravenous and oral or intranasal inoculation of the porcine teschovirus (PTV) Toyama 2002 strain isolated from breeding pigs in Japan. Lesions consisting of perivascular cuffing of mononuclear cells, focal gliosis, neuronal necrosis and neuronophagia were observed in the brainstem, cerebellum and spinal cord. Non-suppurative ganglionitis in the spinal ganglion and neuritis in the spinal root were also observed.

Whole-genome analysis of bovine rotavirus species C isolates obtained in Yamagata, Japan, 2003-2010.

An epidemic of diarrhoea in adult cows occurred at a total of 105 dairy farms in Yamagata Prefecture, Japan, between 2003 and 2010. Reverse transcription-PCR diagnostic tests revealed the presence of bovine rotavirus species C (RVCs) in samples from each of six farms (5.7 %).

Detection of bovine group a rotavirus using rapid antigen detection kits, rt-PCR and next-generation DNA sequencing.

We investigated the sensitivity of human rotavirus rapid antigen detection (RAD) kits, RT-PCR and next-generation DNA sequencing (NGS) for detection of bovine group A rotavirus (RVA). The Dipstick 'Eiken' Rota (Dipstick) showed the highest sensitivity out of the seven RAD kits against all selected strains in limited dilution analyses, which was consistent with the results for equine rotavirus previously reported. RT-PCR had 10⁰-10³-fold higher sensitivity than the Dipstick.

Hemagglutination mediated by the spike protein of cell-adapted bovine torovirus.

Bovine torovirus (BToV)-Aichi, recently isolated in cultured cells, showed hemagglutination (HA) activity, although the virus has a truncated hemagglutinin-esterase (HE) protein, judging from its gene structure, indicating the existence of another viral protein with HA activity. We examined whether the spike (S) protein possesses HA activity. A BToV antiserum used in this study, reactive to S but not to HE, inhibited HA activity.

Annual changes in predominant genotypes of rotavirus A detected in the feces of pigs in various developmental stages raised on a conventional farm.

The goal of the present study was to improve understanding of the ecology of porcine rotavirus A (RVA) infection in pigs raised on a conventional farrow-to-finish farm. We collected 145 fecal samples over a 3-year period from suckling pigs and their dams, and pigs at 30, 60, 90, 120, and 150 days of age. Reverse transcriptase-polymerase chain reaction analysis revealed that 29 samples (20%) were positive for the viral VP7 gene.

Antibody response in vaccinated pregnant mares to recent G3BP[12] and G14P[12] equine rotaviruses.

Background: Both the G3P[12] and the G14P[12] type of equine group A rotavirus (RVA) have recently become predominant in many countries, including Japan. G3 types are classified further into G3A and G3B. The G3A viruses have been circulating in Europe, Australia, and Argentina, and the G3B viruses have been circulating in Japan.

Whole-genome analysis of two bovine rotavirus C strains: Shintoku and Toyama.

Rotavirus C (RVC) has been detected frequently in epidemic cases and/or outbreaks of diarrhoea in humans and animals worldwide. Because it is difficult to cultivate RVCs serially in cell culture, the sequence data available for RVCs are limited, despite their potential economical and epidemiological impact. Although whole-genome sequences of one porcine RVC and seven human RVC strains have been analysed, this has not yet been done for a bovine RVC strain.

Detection of substantial porcine group B rotavirus genetic diversity in the United States, resulting in a modified classification proposal for G genotypes.

Rotavirus (RV) is an important cause of gastrointestinal disease in animals and humans. In this study, we developed an RT-PCR to detect RV group B (RVB) and characterized the VP7 (G) gene segment detected in porcine samples. One hundred seventy three samples were tested for RV group A (RVA), RVB, and C (RVC) by RT-PCR and examined for RV-like lesion using histopathology.

Phylogenetic analysis of nonstructural protein 5 (NSP5) gene sequences in porcine rotavirus B strains.

Porcine rotavirus B (RVB) has frequently been detected in the diarrhea of suckling and weaned pigs. Because it is difficult to propagate RVBs serially in cell culture, little genetic information about RNA segments other than VP7, NSP1 and NSP2 is available for porcine RVBs. We conducted a phylogenetic analysis focusing on nonstructural protein 5 (NSP5) using 22 porcine RVB strains, which were identified in fecal samples collected around Japan.

Analysis of the excretion dynamics and genotypic characteristics of rotavirus A during the lives of pigs raised on farms for meat production.

To determine the excretion dynamics and genotypic characteristics of rotavirus A (RVA), a longitudinal observational study was performed in 10 pigs from 3 litters at a farrow-to-finish farm. A total of 400 fecal samples were directly collected from the rectums of individual pigs (aged 7 to 217 days) at 3- to 14-day intervals. Seventy-one samples (17.

Development and application of one-step multiplex reverse transcription PCR for simultaneous detection of five diarrheal viruses in adult cattle.

A one-step multiplex reverse transcription (RT)-PCR method was developed for the simultaneous detection of five viruses causing diarrhea in adult cattle: bovine group A rotavirus (GAR), bovine group B rotavirus (GBR), bovine group C rotavirus (GCR), bovine coronavirus (BCV), and bovine torovirus (BToV). The detection limit of the one-step multiplex RT-PCR for GAR, GCR, BCV, and BToV was 10(2), 10(0), 10(1), and 10(2) TCID(50)/ml, respectively, and that for GBR was 10(6) copies/ml. The one-step multiplex RT-PCR with newly designed primers to detect GAR had higher sensitivity than a single RT-PCR with conventional primers, with no false-positive reactions observed for ten other kinds of bovine RNA viruses To assess its field applicability, 59 of 60 fecal samples containing one of these five viruses from all 25 epidemic diarrhea outbreaks in adult cattle were positive in the one-step multiplex RT-PCR assay.