Afonso Maria M, Pinchbeck Gina L, Smith Shirley L, Daly Janet M, Gaskell Rosalind M, Dawson Susan, Radford Alan D
Institute of Infection and Global Health, University of Liverpool, Leahurst Campus, Chester High Road, Neston, S. Wirral CH64 7TE, UK.
University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire LE12 5RD, UK.
Vaccine. 2017 May 9;35(20):2753-2760. doi: 10.1016/j.vaccine.2017.03.030. Epub 2017 Apr 5.
Feline calicivirus (FCV) is an important pathogen of cats for which vaccination is regularly practised. Long-term use of established vaccine antigens raises the theoretical possibility that field viruses could become resistant. This study aimed to assess the current ability of the FCV-F9 vaccine strain to neutralise a randomly collected contemporary panel of FCV field strains collected prospectively in six European countries.
Veterinary practices (64) were randomly selected from six countries (UK, Sweden, Netherlands, Germany, France and Italy). Oropharyngeal swabs were requested from 30 (UK) and 40 (other countries) cats attending each practice. Presence of FCV was determined by virus isolation, and risk factors for FCV shedding assessed by multivariable logistic regression. Phylogenetic analyses were used to describe the FCV population structure. In vitro virus neutralisation assays were performed to evaluate FCV-F9 cross-reactivity using plasma from four vaccinated cats.
The overall prevalence of FCV was 9.2%. Risk factors positively associated with FCV shedding included multi-cat households, chronic gingivostomatitis, younger age, not being neutered, as well as residing in certain countries. Phylogenetic analysis showed extensive variability and no countrywide clusters. Despite being first isolated in the 1950s, FCV-F9 clustered with contemporary field isolates. Plasma raised to FCV-F9 neutralized 97% of tested isolates (titres 1:4 to 1:5792), with 26.5%, 35.7% and 50% of isolates being neutralized by 5, 10 and 20 antibody units respectively.
This study represents the largest prospective analysis of FCV diversity and antigenic cross-reactivity at a European level. The scale and random nature of sampling used gives confidence that the FCV isolates used are broadly representative of FCVs that cats are exposed to in these countries. The in vitro neutralisation results suggest that antibodies raised to FCV-F9 remain broadly cross-reactive to contemporary FCV isolates across the European countries sampled.
猫杯状病毒（FCV）是猫的一种重要病原体，目前经常进行疫苗接种。长期使用既定的疫苗抗原有可能使野外病毒产生抗性。本研究旨在评估FCV - F9疫苗株目前对前瞻性收集的来自六个欧洲国家的一组随机选取的当代FCV野外毒株的中和能力。
从六个国家（英国、瑞典、荷兰、德国、法国和意大利）随机选择64家兽医诊所。要求每家诊所就诊的30只（英国）和40只（其他国家）猫提供口咽拭子。通过病毒分离确定FCV的存在，并通过多变量逻辑回归评估FCV排毒的危险因素。系统发育分析用于描述FCV的种群结构。使用来自四只接种疫苗的猫的血浆进行体外病毒中和试验，以评估FCV - F9的交叉反应性。
FCV的总体患病率为9.2%。与FCV排毒呈正相关的危险因素包括多猫家庭、慢性龈口炎、年龄较小、未绝育以及居住在某些国家。系统发育分析显示出广泛的变异性，且没有全国性的聚类。尽管FCV - F9最早于20世纪50年代分离出来，但它与当代野外分离株聚类在一起。针对FCV - F9产生的血浆中和了97%的测试分离株（滴度为1:4至1:5792），分别有26.5%、35.7%和50%的分离株被5、10和20个抗体单位中和。
本研究是欧洲层面关于FCV多样性和抗原交叉反应性的最大规模前瞻性分析。所采用的抽样规模和随机性让人相信所使用的FCV分离株广泛代表了这些国家猫所接触到的FCV。体外中和结果表明，针对FCV - F9产生的抗体对所采样的欧洲国家的当代FCV分离株仍具有广泛的交叉反应性。
