Bovine rhinitis B virus is highly prevalent in acute bovine respiratory disease and causes upper respiratory tract infection in calves

Discovery and characterization of BRBV-sheep virus in nasal swabs from domestic sheep in China

Introduction

The escalating occurrence of infectious disease outbreaks in humans and animals necessitates innovative, effective, and integrated research to better comprehend their transmission and dynamics. Viral infection in livestock has led to profound economic losses globally. Pneumonia is the prevalent cause of death in sheep. However, very few studies exist regarding virus-related pathogens in sheep. Metagenomics sequencing technologies in livestock research hold significant potential to elucidate these contingencies and enhance our understanding.

Methods

Therefore, this study aims to characterize respiratory viromes in paired nasal swabs from Inner Mongolian feedlot sheep in China using metaviromic sequencing. Through deep sequencing, de novo assembly, and similarity searches using translated protein sequences, several previously uncharacterized and known viruses were identified in this study.

Results

Among these discoveries, a novel Bovine Rhinitis B Virus (BRBV) (BRBV-sheep) strain was serendipitously detected in the nasal swabs of domestic sheep (Ovis aries). To facilitate further molecular epidemiological studies, the entire genome of BRBV-sheep was also determined. Owing to the unique sequence characteristics and phylogenetic position of BRBV-sheep, genetically distinct lineages of BRBV in sheep may exist. A TaqMan-based qRT-PCR assay targeting the 3D polymerase gene was developed and used to screen 592 clinical sheep specimens. The results showed that 44.59% of the samples (264/592) were positive. These findings suggest that BRBV sheep are widespread among Inner Mongolian herds.

Conclusion

This discovery marks the initial identification of BRBV in sheep within Inner Mongolia, China. These findings contribute to our understanding of the epidemiology and genetic evolution of BRBV. Recognizing the presence of BRBV in sheep informs strategies for disease management and surveillance and the potential development of targeted interventions to control its spread.

Bovine Rhinitis B Virus Variant as the Putative Cause of Bronchitis in Goat Kids

A diagnostic investigation into an outbreak of fatal respiratory disease among young goats in Iowa, USA revealed bronchitis lesions of unknown etiology and secondary bacterial bronchopneumonia. Hypothesis-free metagenomics identified a previously unreported picornavirus (USA/IA26017/2023), and further phylogenetic analysis classified USA/IA26017/2023 as an aphthovirus related to bovine rhinitis B virus. Viral nucleic acid was localized to lesions of bronchitis using in situ hybridization. This marks the first report of a picornavirus putatively causing respiratory disease in goats and highlights the potential for cross-species transmission of aphthoviruses.

Co-infecting viruses of species Bovine rhinitis B virus (Picornaviridae) and Bovine nidovirus 1 (Tobaniviridae) identified for the first time from a post-mortem respiratory sample of a sheep (Ovis aries) in Hungary

In this study, a picornavirus and a nidovirus were identified from a single available nasopharyngeal swab (NPS) sample of a freshly deceased sheep, as the only vertebrate viruses found with viral metagenomics and next-generation sequencing methods. The sample was originated from a mixed feedlot farm in Hungary where sheep and cattle were held together but in separate stalls. Most of the sheep had respiratory signs (coughing and increased respiratory effort) at the time of sampling. Other NPS were not, but additional enteric samples were collected from sheep (n = 27) and cattle (n = 11) of the same farm at that time. The complete/nearly complete genomes of the identified viruses were determined using RT-PCR and Nanopore (MinION-Flonge) / Dye-terminator sequencing techniques. The results of detailed genomic and phylogenetic analyses indicate that the identified picornavirus most likely belongs to a type 4 genotype of species Bovine rhinitis B virus (BRBV-4, OR885914) of genus Aphthovirus, family Picornaviridae while the ovine nidovirus (OvNV, OR885915) - as a novel variant - could belong to the recently created Bovine nidovirus 1 (BoNV) species of genus Bostovirus, family Tobaniviridae. None of the identified viruses were detectable in the enteric samples using RT-PCR and generic screening primer pairs. Both viruses are well-known respiratory pathogens of cattle, but their presence was not demonstrated before in other animals, like sheep. Furthermore, neither BRBV-4 nor BoNVs were investigated in European cattle and/or sheep flocks, therefore it cannot be determined whether the presence of these viruses in sheep was a result of a single host species switch/spillover event or these viruses are circulating in not just cattle but sheep populations as well. Further studies required to investigate the spread of these viruses in Hungarian and European sheep and cattle populations and to identify their pathogenic potential in sheep.

Detection and genetic analysis of bovine rhinitis B virus in Japan

Bovine rhinitis B virus (BRBV) (genus Aphthovirus, family Picornaviridae) is a significant etiological agent of the bovine respiratory disease complex. Despite global reports on BRBV, genomic data for Japanese strains are not available. In this study, we aimed to obtain genomic information on BRBV in Japan and analyze its genetic characteristics. In nasal swabs from 66 cattle, BRBV was detected in 6 out of 10 symptomatic and 4 out of 56 asymptomatic cattle. Using metagenomic sequencing and Sanger sequencing, the nearly complete genome sequences of two Japanese BRBV strains, IBA/2211/2 and LAV/238002, from symptomatic and asymptomatic cattle, respectively, were determined. These viruses shared significant genetic similarity with known BRBV strains and exhibited unique mutations and recombination events, indicating dynamic evolution, influenced by regional environmental and biological factors. Notably, the leader gene was only approximately 80% and 90% identical in its nucleotide and amino acid sequence, respectively, to all of the BRBV strains with sequences in the GenBank database, indicating significant genetic divergence in the Japanese BRBV leader gene. These findings provide insights into the genetic makeup of Japanese BRBV strains, enriching our understanding of their genetic diversity and evolutionary mechanisms.

Identification of Astrovirus in the virome of the upper and lower respiratory tracts of calves with acute signs of bronchopneumonia

IMPORTANCE

Astroviruses (AstV) are known suspects of enteric disease in humans and livestock. Recently, AstV have been linked to encephalitis in immunocompromised patients and other animals, such as cattle, minks, and swine. In our study, we also identified AstV in the respiratory samples of calves with signs of bronchopneumonia, suggesting that their tropism could be even broader. We obtained one bovine AstV (BAstV) complete genome sequence by next-generation sequencing and showed that respiratory and enteric AstV from different species formed a divergent genetic cluster with AstV isolated from encephalitis cases, indicating that tropism might be strain-specific. These data provide further insight into understanding the biology of these understudied pathogens and suggest BAstV as a potential new candidate for bovine respiratory disease.

Detection and Genomic Characterization of Bovine Rhinitis Virus in China

Bovine rhinitis virus (BRV) is an etiological agent of bovine respiratory disease complex (BRDC) and can be divided into two genotypes-bovine rhinitis A virus (BRAV) and bovine rhinitis B virus (BRBV). However, knowledge about the prevalence and molecular information of BRV in China is still limited. In this study, 163 deep nasal swabs collected from bovines with BRDC syndrome on 16 farms across nine provinces of China were tested for BRAV and BRBV by a duplex real-time RT-PCR assay. The results showed that 28.22% (46/163) of the samples were BRV-positive, and the positive rates were 22.09% (36/163) for BRAV and 9.2% (15/163) for BRBV. The co-circulation of both BRV genotypes was observed on two farms. Furthermore, five near-complete BRV genomes, including three BRAVs and two BRBVs, were obtained. The phylogenetic analysis showed that the three obtained BRAVs were phylogenetically independent, while the two BRBVs exhibited significant genetic heterogeneity. Recombination analysis revealed that three BRAVs and one BRBV strain obtained in this study were recombinants. The present study confirmed the presence and prevalence of BRAV in China, and it found that both types of BRV are circulating in beef cattle, which contributes to a better understanding of the prevalence and molecular characteristics of BRV.