Detection of rat, porcine, and bovine group B rotavirus in fecal specimens by solid-phase enzyme immunoassay

Complete genome characterization of a rotavirus B (RVB) strain identified in Alpine goat kids with enteritis reveals inter-species transmission with RVB bovine strains

Rotavirus B (RVB) has been associated with enteric disease in many animal species. An RVB strain was identified in pooled intestinal samples from Alpine caprine kids (between 2 and 3 days of age) experiencing high (>90 %) morbidity, and the complete caprine RVB genome was characterized. Histology revealed villus atrophy, the samples tested positive for RVB by real-time RT-PCR and metagenomic next-generation sequencing identified only RVB and orf virus. In the VP4 gene segment, the caprine RVB strain had a higher percentage nucleotide identity to the Indian bovine RVB strains than to the Japanese bovine RVB strains, but the VP7, VP6, VP2, NSP1, NSP2 and NSP5 gene segments of the American caprine RVB strain were genetically related to the Japanese bovine RVB strains. The results indicate a lack of RVB sequences to understand reassortment or the evolutionary relationship of RVB strains from cattle and goats.

Longitudinal Surveillance of Porcine Rotavirus B Strains from the United States and Canada and In Silico Identification of Antigenically Important Sites

Rotavirus B (RVB) is an important swine pathogen, but control and prevention strategies are limited without an available vaccine. To develop a subunit RVB vaccine with maximal effect, we characterized the amino acid sequence variability and predicted antigenicity of RVB viral protein 7 (VP7), a major neutralizing antibody target, from clinically infected pigs in the United States and Canada. We identified genotype-specific antigenic sites that may be antibody neutralization targets. While some antigenic sites had high amino acid functional group diversity, nine antigenic sites were completely conserved. Analysis of nucleotide substitution rates at amino acid sites (dN/dS) suggested that negative selection appeared to be playing a larger role in the evolution of the identified antigenic sites when compared to positive selection, and was identified in six of the nine conserved antigenic sites. These results identified important characteristics of RVB VP7 variability and evolution and suggest antigenic residues on RVB VP7 that are negatively selected and highly conserved may be good candidate regions to include in a subunit vaccine design due to their tendency to remain stable.

Detection and characterization of group C rotavirus in Buenos Aires, Argentina, 1997-2003

The role of group C rotaviruses as a cause of diarrhea was examined among children <17 years of age admitted to a Hospital in a suburban area of Buenos Aires, Argentina between 1997 and 2003. A total of 1,579 fecal samples were screened for group A (RVA) and C (RVC) rotaviruses by two in-house ELISA methods at Quilmes University (UNQ-ELISA). Samples positive, doubtful and negative by RVC specific UNQ-ELISA (n = 246) were examined further for RVC by another in-house ELISA (CDC-ELISA), electron microscopy, RT-PCR, nested PCR, and Southern hybridization. Sensitivity, specificity, and predictive values for each test were determined. While the sensitivity was comparable for the nested PCR and CDC-ELISA methods (82.5%), the molecular methods were slightly more specific. Poorly preserved particles were often seen in fecal samples, suggesting that degradation of RNA could be a factor influencing the performance of molecular methods. The incidence of RVC was estimated to be 3% without apparent differences among seasons. RVC infected patients had a significantly (P < 0.001) higher median age (6 years vs. 1 year) than those with RVA infection. Sequence of the RVC VP7 gene from six Argentinean strains and sequences reported previously in different countries showed high nucleotide (94.4-99.9%) sequence identities, indicating a high degree of conservation for human RVC VP7 genes among strains collected on five continents over a period of 17 years. These findings indicate that RVC is a significant cause of diarrhea and it is necessary to develop simple and sensitive serological methods for its detection.

Evidence for interstate transmission and increase in prevalence of bovine group B rotavirus strains with a novel VP7 genotype among diarrhoeic calves in Eastern and Northern states of India

During a surveillance study (2003-2005) in a cattle market in Kolkata city, state of West Bengal, Eastern India, 34 (13.0%) of 260 calves with diarrhoea were positive for group B rotaviruses (GBR) by RNA electrophoresis in polyacrylamide gels. Analysis of the partial VP7 gene sequence of 28 of the 34 GBR strains revealed maximum identities (97.7-99.5% at nucleotide level and 97.8-100% at amino-acid level) with the novel bovine GBR 'Kolkata strains' reported in an earlier surveillance study (1.5%, n=192, 2001-2002) from the same cattle market, and shared low identities of 73.7-78.9% and 80.8-89.6%; 62.6-66.2% and 59.8-65.4%; 58.9-62.2% and 48.6-54.9% at nucleotide and amino-acid level with other bovine, human, and murine GBR. The GBR-infected calves were traced to districts in neighbouring states of West Bengal. Therefore, the present study reports a rapid increase in prevalence (13.0% in 2003-2005 against 1.5% in 2001-2002) of novel GBR strains among calves with diarrhoea, and provides evidence for interstate transmission of GBR.

Sequencing and sequence analysis of VP7 and NSP5 genes reveal emergence of a new genotype of bovine group B rotaviruses in India

Three bovine group B rotavirus strains were detected from diarrheic calves during a surveillance study of rotaviral diarrhea in West Bengal, India. The sequence analysis of VP7 and NSP5 genes of these strains demonstrates a high degree of sequence variation from other group B rotavirus strains, indicating the emergence of a new genotype.

Detection of group B rotaviruses in fecal samples from diarrheic calves and adult cows and characterization of their VP7 genes

Groups A, B, and C rotaviruses have been identified in cattle. Group B rotaviruses are associated with sporadic cases of diarrhea in calves and adult cows. From diagnostic submissions to our laboratory, 90 fecal samples from cases of calf diarrhea, 81 fecal samples from cases of adult cow diarrhea (winter dysentery), and 20 fecal samples from case control normal adult cows were tested for group B rotaviruses by polyacrylamide gel electrophoresis (PAGE), and reverse transcription (RT)-PCR (targeting 279 bp of the VP7 gene). In addition, 53 fecal samples from diarrheic adult cows were tested for group B rotaviruses by immune electron microscopy (IEM). By RT-PCR, five samples from calves were group B rotavirus positive (5.6%). Fifteen samples from adult cows with diarrhea were group B rotavirus positive (18.5%), and none of the control fecal samples from normal cows were positive for group B rotaviruses. By PAGE, one calf sample (RT-PCR positive) was group B rotavirus positive (short electropherotype), but none of the adult cow samples were positive for group B rotaviruses. By IEM, 5 (9.4%) of the 53 fecal samples from diarrheic adult cows were group B positive (all were also RT-PCR positive). The VP7 genes of three strains (WD653 from an adult cow and the ATI and Mebus calf strains) were sequenced. The VP7 genes from the three bovine strains showed high (over 90%) nucleotide and deduced amino acid homologies, but lower homologies (48 to 61%) were seen between these genes and the genes from rodent (IDIR) and human (ADRV) group B rotaviruses. Although there were some differences of degree, all inoculated gnotobiotic calves (n = 6) showed abnormal feces between 1 and 3 days after inoculation with each of three strains of group B bovine rotaviruses, and group B rotaviruse, were detected in the feces for up to 2 weeks by RT-PCR but for shorter periods by PAGE or IEM.