# Isolation and identification of a genotype F bovine enterovirus in western China

## TL;DR

A new bovine enterovirus strain was isolated and studied in western China, providing insights into its characteristics and potential for vaccine development.

## Contribution

The study presents the first isolation and comprehensive characterization of a genotype F bovine enterovirus strain from western China.

## Key findings

- The virus replicates in Madin-Darby bovine kidney cells, peaking at 48 hours post-infection with a high titer.
- The virus is inactivated at 55°C for 12 minutes and shows tissue tropism in the spleen, liver, and small intestine.
- Pathological changes were observed in the spleen, with no lesions in other organs.

## Abstract

This study successfully isolated a novel bovine enterovirus strain from a bovine fecal sample, which was designated as Sichuan/SQ/20. The isolate showed typical enterovirus morphology under electron microscopy. Phylogenetic analysis showed that this strain exhibits the closest genetic relationship with the HeN-YR91 and JPN/TottoriU-31 strains, and all three belong to the BEV-F1 genosubtype. Subsequently, comprehensive investigations were conducted on the biological characteristics of this virus, both in vivo and in vitro. In vitro characterization revealed that viral replication commenced at 3 h post-infection (hpi) in Madin-Darby bovine kidney cells, reaching peak at 48 hpi with a virus titer of 1 × 108.73 TCID50/0.1 mL. Cytopathic effects initially appeared at 12 hpi. A 12-minute treatment at 55°C was sufficient to completely inactivate the virus. In vivo analysis revealed that significant pathological changes were specifically observed in the spleen, with no lesions observed in other organs. Immunofluorescence assay detected specific fluorescent signals in the liver, spleen, and small intestine, which were consistent with the PCR results. These findings provide a scientific foundation for vaccine design and antiviral drug screening, as well as for the development of effective prevention and control strategies.

Bovine enterovirus (BEV) is an important pathogen causing calf diarrhea and has been detected in the feces of calves with diarrhea, although its pathogenicity remains unclear. This study systematically established an isolation and identification protocol for BEV, characterized its physicochemical properties, and further investigated the pathogenicity and tissue tropism of the isolated strain in mice. These findings establish crucial baseline data for future vaccine development and therapeutic intervention strategies.