Bovine Rhinitis Viruses Are Common in U.S. Cattle with Bovine Respiratory Disease

Bovine rhinitis viruses (BRV) are established etiological agents of bovine respiratory disease complex however little research into their epidemiology and ecology has been published for several decades. In the U.S., only bovine rhinitis A virus 1 (BRAV1) has been identified while bovine rhinitis A virus 2 (BRAV2) and bovine rhinitis B virus (BRBV) were previously only identified in England and Japan, respectively. Metagenomic sequencing of a nasal swab from a bovine respiratory disease (BRD) diagnostic submission from Kansas identified contigs with approximately 90% nucleotide similarity to BRAV2 and BRBV. A combination of de novo and templated assemblies using reference genomes yielded near complete BRAV2 and BRBV genomes. The near complete genome of bovine rhinitis A virus 1 (BRAV1) was also determined from a historical isolate to enable further molecular epidemiological studies. A 5'-nuclease reverse transcription PCR assay targeting the 3D polymerase gene was designed and used to screen 204 archived BRD clinical specimens. Thirteen (6.4%) were positive. Metagenomic sequencing of six positive samples identified mixed BRAV1/BRAV2, BRAV1/BRBV and BRAV2/BRBV infections for five samples. One sample showed infection only with BRAV1. Seroprevalence studies using a cell culture adapted BRBV found immunofluorescence assay-reactive antibodies were common in the herds analyzed. Altogether, these results demonstrate that BRV infections are common in cattle with respiratory disease and that BRAV1, BRAV2 and BRBV co-circulate in U.S. cattle and have high similarity to viruses isolated more than 30 years ago from diverse locations.