# An efficient method for the selective isolation of feline herpesvirus 1(FHV-1) in feline calicivirus (FCV) coinfected specimens

## TL;DR

This study presents a method to isolate feline herpesvirus 1 from coinfected samples with feline calicivirus, improving diagnostic accuracy.

## Contribution

A novel method using FCV polyclonal antibodies to selectively isolate FHV-1 from coinfected specimens.

## Key findings

- FCV polyclonal antibodies with high neutralizing activity were successfully produced.
- FHV-1 was isolated from coinfected samples without cross-contamination.
- The method is potentially applicable to other FCV-related coinfections.

## Abstract

Feline herpesvirus 1 (FHV-1) and feline calicivirus (FCV) are the most common viral pathogens of feline respiratory disease and are highly prevalent in cats worldwide. Coinfection with these viruses is frequent in cats with feline respiratory disease complex (FRDC). It is difficult to isolate pure FHV-1 by conventional laboratory cell culture methods from specimens with FRDC, which brings great trouble to the epidemiological investigation of FHV-1.

FCV polyclonal antibodies were obtained by immunizing rabbits, and the coinfected specimens were neutralized with FCV polyclonal antibodies. Then, virus isolation was performed. After several rounds of neutralization, FHV-1 was finally obtained.

The FCV polyclonal antibody was successfully obtained with neutralizing activities of 1:128, 1:537, and 1:91. After virus neutralization, the FHV-1 was successfully isolated from the coinfected cell culture suspension and confirmed by immunofluorescence and QRT-PCR.

In this study, all FHV-1 present in the coinfection samples were isolated, without any cross-contamination. This method is also theoretically suitable for the isolation and purification of other FCV coinfections or contaminating disease substances.