European molecular epidemiology and strain diversity of feline calicivirus

Abstract

Feline calicivirus (FCV) causes a variable syndrome of upper respiratory tract disease, mouth ulcers and lameness. A convenience-based prospective sample of oropharyngeal swabs (n=426) was obtained from five countries (France, Germany, Greece, Portugal and the UK). The prevalence of FCV by virus isolation was 22.2 per cent. Multivariable analysis found that animals presenting with lymphoplasmacytic gingivitis stomatitis complex were more likely to test positive for FCV infection. Furthermore, vaccinated cats up to 48 months of age were significantly less likely to be infected with FCV than unvaccinated animals of similar ages. Phylogenetic analysis based on consensus sequences for the immunodominant region of the capsid gene from 72 FCV isolates identified 46 strains. Thirteen of the 14 strains with more than one sequence were restricted to individual regions or sites in individual countries; the exception was a strain present in two sites close to each other in France. Four strains were present in more than one household. Five colonies, four of which were rescue shelters, had multiple strains within them. Polymerase sequence suggested possible rare recombination events. These locally, nationally and internationally diverse FCV populations maintain a continuous challenge to the control of FCV infection and disease.

Comparative efficacy of the Leucofeligen™ FeLV/RCP and Purevax™ RCP FeLV vaccines against infection with circulating feline Calicivirus

“…The FCV-FR4_01 strain (Genbank accession number MF882991) was isolated during the field epidemiology study performed by Hou et al [ 3 ]. This strain was chosen for the challenge since it was identified as a single isolate (unique sequence) with a high titration from a single cat presenting various clinical signs typical of a calicivirus infection.…”

“…Feline calicivirus shows a high antigen variability and can evolve quickly [ 3 , 4 ]. In a recent study conducted in Europe, 46 strains (pairwise genetic distance >20%) were identified from 72 FCV isolates [ 3 ].…”

“…Feline calicivirus shows a high antigen variability and can evolve quickly [ 3 , 4 ]. In a recent study conducted in Europe, 46 strains (pairwise genetic distance >20%) were identified from 72 FCV isolates [ 3 ]. However, the phylogenetic analysis of partial variable regions of polymerase or capsid sequences showed that the different strains found in the field had a median uncorrected nucleotide distance of around 40% when compared pairwise or when compared with the F9 strain, currently used in some live vaccines [ 3 ].…”

Feline calicivirus strain diversity in Europe — the ‘star‐like’ tree

“…Apart from the identification of a genogroup in Japan (Sato and others 2002), none of the research, including the study by Hou and others (2016), was able to find clear evidence of geographical clustering. Strain diversity is mainly the result of the evolution of local strains with the occasional geographical spread (cats are territorial animals and do not travel).…”

“…Another challenge is technical: FCV vaccines, regardless of the technology, protect cats by reducing clinical signs and sometimes excretion (Poulet and others 2008) but do not prevent infection. Finally, as explained by Hou and others (2016), the key challenge is the high genetic diversity of FCV. Unfortunately, vaccines cannot protect against all circulating strains (Willi and others 2016).…”