Temporally separated feline calicivirus isolates do not cluster phylogenetically and are similarly neutralised by high-titre vaccine strain FCV-F9 antisera in vitro

作者：Shirley L. Smith, Maria M. Afonso, Gina Pinchbeck, Rosalind M. Gaskell, Susan Dawson, Alan Radford · 发表于：Journal of Feline Medicine and Surgery · 年份：2019 · DOI：10.1177/1098612x19866521 · 被引用次数：30 · 研究领域：Viral gastroenteritis research and epidemiology、Viral Infections and Immunology Research、Vector-Borne Animal Diseases

OBJECTIVES: Feline calicivirus (FCV) is a highly variable and globally important feline pathogen for which vaccination has been the mainstay of control. Here, we test whether the continued use of FCV-F9, one of the most frequently used vaccine strains globally, is driving the emergence of vaccine-resistant viruses in the field. METHODS: This study made use of two representative panels of field isolates previously collected from cats visiting randomly selected veterinary practices across the UK as part of separate cross-sectional studies from 2001 and 2013/2014. Phylogenetic analysis and in vitro virus neutralisation tests were used to compare the genetic and antigenic relationships between these populations and FCV-F9. RESULTS: Phylogenetic analysis showed a typically radial distribution dominated by 52 distinct strains, with strains from both 2001 and 2013/2014 intermingled. The sequence for FCV-F9 appeared to be integral to this phylogeny and there were no significant differences in the genetic distances within each studied population (intra-population distances), or between them (inter-population distances), or between each population and FCV-F9. A 1 in 8 dilution neutralised 97% and 100% of the 2001 and 2013/14 isolates, respectively, and a 1 in 16 dilution neutralised 87% and 75% of isolates, respectively. There was no significant difference either in variance between the FCV-F9 neutralising titres for the two populations, or in the distribution of neutralisation titres ...