Detection and molecular characterization of bovine enterovirus E2 from dairy calves with respiratory disease in Urumqi, Xinjiang, China.

Introduction: Bovine enterovirus (BEV) is a contagious viral agent that can cause respiratory infections and disease outbreaks among calves. This study reports an outbreak that occurred in a population of dairy calves in northern Xinjiang in November 2024. Methods: Nasal swab samples were collected from 58 clinically symptomatic calves and analyzed for some bovine respiratory viruses using RT-PCR and viral metagenomic sequencing. Results: Viral metagenomic analysis annotated only one bovine pathogen, BEV, in respiratory disease samples. RT-PCR further confirmed that BEV was detected in all nasal swab samples from symptomatic dairy calves, while it was not detected in samples from healthy dairy cattle, suggesting that BEV may be the etiological agent of this respiratory disease. One BEV strain, designated XJ-FHT, was successfully isolated and found to be responsible for respiratory illness in calves. Comparative analysis of the whole genome, the encoded polyprotein, and the nucleotide and amino acid sequences of VP1 and P1, along with phylogenetic analysis of VP1 amino acid sequences, classified this isolate as belonging to the E2 subtype. Discussion: This study provides the first identification of a BEV-associated respiratory disease among calves in Xinjiang, China, in 2024. Molecular characterization and phylogenetic analysis identified the isolated strain as belonging to the E2 subtype. These findings highlight the potential role of BEV in bovine respiratory infections and emphasize the need for continued surveillance and preventive measures.