Modified-live feline calicivirus vaccination reduces viral RNA loads, duration of RNAemia, and the severity of clinical signs after heterologous feline calicivirus challenge

Spiri, A. M., Riond, B., Stirn, M., Novacco, M., Meli, M. L., Boretti, F. S., Herbert, I., Hosie, M. J. and Hofmann-Lehmann, R. (2021) Modified-live feline calicivirus vaccination reduces viral RNA loads, duration of RNAemia, and the severity of clinical signs after heterologous feline calicivirus challenge. Viruses, 13(8), 1505. (doi: 10.3390/v13081505)

Abstract

Feline calicivirus (FCV) is a common cat virus causing clinical signs such as oral ulcerations, fever, reduced general condition, pneumonia, limping and occasionally virulent-systemic disease. Efficacious FCV vaccines protect against severe disease but not against infection. FCV is a highly mutagenic RNA virus whose high genetic diversity poses a challenge in vaccine design. The use of only one modified-live FCV strain over several decades might have driven the viral evolution towards more vaccine-resistant variants. The present study investigated the clinical signs, duration, and amount of FCV shedding, RNAemia, haematological changes and acute phase protein reaction in SPF cats after subcutaneous modified-live single strain FCV vaccination or placebo injection and two subsequent oronasal heterologous FCV challenge infections with two different field strains. Neither clinical signs nor FCV shedding from the oropharynx and FCV RNAemia were detected after vaccination. After the first experimental infection, vaccinated cats had significantly lower clinical scores, less increased body temperature and lower acute phase protein levels than control cats. The viral RNA loads from the oropharynx and duration and amount of RNAemia were significantly lower in the vaccinated animals. No clinical signs were observed in any of the cats after the second experimental infection. In conclusion, FCV vaccination was beneficial for protecting cats from severe clinical signs, reducing viral loads and inflammation after FCV challenge.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hosie, Professor Margaret and Herbert, Miss Imogen

Creator Roles

Herbert, I.: Methodology, Writing – review and editing
Hosie, M. J.: Methodology, Writing – review and editing

• Authors: Spiri, A. M., Riond, B., Stirn, M., Novacco, M., Meli, M. L., Boretti, F. S., Herbert, I., Hosie, M. J., and Hofmann-Lehmann, R.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity; College of Medical Veterinary and Life Sciences > School of Infection & Immunity > Centre for Virus Research
• Journal Name: Viruses
• Publisher: MDPI
• ISSN: 1999-4915
• ISSN (Online): 1999-4915
• Published Online: 30 July 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Viruses 13(8): 1505
• Publisher Policy: Reproduced under a Creative Commons License