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

Abstract

Bovine respiratory disease (BRD) is the most significant cause of cattle morbidity and mortality worldwide. This multifactorial disease has a complex aetiology. Dogma posits a primary viral infection followed by secondary bacterial pneumonia. Bovine rhinitis B virus (BRBV) is an established aetiological agent of BRD, but little is known regarding its pathogenesis. Here, a BRD PCR panel identified 18/153 (11.8 %) lung samples and 20/49 (40.8 %) nasal swabs collected from cattle with respiratory signs as positive for BRBV, which was the most prevalent virus in nasal swabs. Primary bovine tracheal epithelial cells were used to isolate BRBV that was phylogenetically related to contemporary sequences from the USA and Mexico and genetically divergent from the previous sole BRBV isolate. To investigate virus pathogenesis, 1-week-old colostrum-deprived dairy calves were inoculated intranasally with 7.0 log10 TCID50 BRBV. Virus was isolated from nasal swabs, nasal turbinates, trachea and the brain of the challenged animals. Neutralizing antibodies were detected beginning 7 days post-inoculation and peaked at day 14. In situ hybridization (ISH) localized BRBV infection in the upper respiratory ciliated epithelial and goblet cells, occasionally associated with small defects of the superficial cilia lining. Sporadically, pinpoint ISH signals were also detected in cells resembling glial cells in the cerebrum in one calf. Together, these results demonstrate the BRBV infection is highly prevalent in acute BRD samples and while the pathogenicity of BRBV is minimal with infection largely limited to the upper respiratory tract, further research is needed to elucidate a possible initiatory role in BRD.

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

“…By NGS, we also detected BRAV and BRBV in NS and BAL of ill animals, and after in vivo challenge, BRBV was shown to cause upper respiratory tract infection in calves ( 39 ). BAstV could have a similar pathogenesis to BRBV but further samplings in healthy and sick cattle are warranted to better understand their involvement in triggering bovine pneumonia.…”

Detection and Genetic Analysis of Bovine Rhinitis B Virus in Japan

“…Additionally, no respiratory pathogens were exclusively detected in symptomatic cattle among those admitted to Azabu University. BRBV replicates e ciently in the upper respiratory tract but exhibits lower replicative and pathogenic potential in the lungs, typically resulting in asymptomatic infections or mild symptoms in cases of solitary infection [3,7]. This implies that BRBV spreads undetected, contributing to BRDC, similar to most BRDC pathogens.…”

“…Metagenomic analysis of cattle exhibiting symptoms of bovine respiratory disease complex (BRDC) has identi ed BRBV as one of the most frequently detected pathogens [4][5][6]. Although the isolation of BRBV is challenging, reports on the rst successful isolation in 50 years using primary bovine respiratory epithelial cells have emerged [7]. Advances in next-generation sequencing have revealed signi cant genetic diversity within BRBV [8].…”

Detection and Genomic Characterization of Bovine Rhinitis Virus in China

“…BRV can be divided into bovine rhinitis A virus (BRAV) and bovine rhinitis B virus (BRBV) according to the genomic characterization [5]; of these two genotypes, BRAV is reported to be more virulent than BRBV [6]. To date, the virus has been identified in ten countries across five continents, including Germany, England, Japan, USA, Mexico, Canada, Sudan, Sweden, China, and Australia [7], and has caused significant losses in certain countries [6,8].…”