Feline caliciviruses (FCVs) isolated from cats with virulent systemic disease possess in vitro phenotypes distinct from those of other FCV isolates

Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Journal of General Virology (Impact Factor: 3.18). 03/2007; 88(Pt 2):506-17. DOI: 10.1099/vir.0.82488-0
Source: PubMed


During the past decade, several outbreaks of severe systemic disease associated with Feline calicivirus (FCV) have occurred in the USA and the UK. This new disease has caused high mortality in the affected animals and has been termed virulent systemic (VS)-FCV disease. Currently, there are no genetic or in vitro diagnostic methods to distinguish viruses isolated from cases of VS-FCV disease from other isolates. Here, five in vitro properties, as well as the capsid and proteinase-polymerase (pro-pol) sequences, of a set of FCV isolates that included seven isolates from five distinct VS-FCV outbreaks ('VS isolates') were investigated. Although all of the FCV isolates investigated had similar kinetics of growth under single-cycle conditions, VS isolates infected tissue-culture cells more efficiently under multiple-cycle growth conditions. Moreover, it was found that cells infected with VS isolates showed cytopathic effects earlier than cells infected with non-VS isolates, although no difference in relative ATP levels were noted at times when morphological changes were first seen. Both VS- and other (non-VS) isolates of FCV demonstrated similar temperature stabilities. Phylogenetic analyses and alignments of the capsid and pro-pol regions of the genome did not reveal any conserved changes that correlated with virulence, and the VS isolates did not segregate into a unique clade. These results suggest that VS isolates have arisen independently several times since first being described and can spread more efficiently in tissue culture than other isolates when infected at low multiplicity.

Download full-text


Available from: Justine Shotton, Jan 12, 2014
43 Reads
  • Source
    • "vaccines for FCV have been employed for over 20 years, a high incidence of mortality can occur in isolated outbreaks (Hurley et al., 2004; Ossiboff et al., 2007). Vaccine failure has been attributed to the absence of sterilizing immunity, occasional vaccine breakdowns, and in the case of the live vaccine, occasional vaccine-induced disease (Radford et al., 2006). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Caliciviruses are non-enveloped, icosahedral viruses with a single-stranded, positive sense RNA genome. Transposon-mediated insertional mutagenesis was used to insert a transprimer sequence into random sites of an infectious full-length cDNA clone of the feline calicivirus (FCV) genome. A site in the LC gene (encoding the capsid leader protein) of the FCV genome was identified that could tolerate foreign insertions, and two viable recombinant FCV variants expressing LC fused either to AcGFP, or DsRedFP were recovered. The effects of the insertions on LC processing, RNA replication, and stability of the viral genome were analyzed, and the progression of a calicivirus single infection and co-infection were captured by real-time imaging fluorescent microscopy. The ability to engineer viable recombinant caliciviruses expressing foreign markers enables new approaches to investigate virus and host cell interactions, as well as studies of viral recombination, one of the driving forces of calicivirus evolution.
    Virology 02/2010; 400(1):18-31. DOI:10.1016/j.virol.2009.12.035 · 3.32 Impact Factor
  • Source
    • "VSD has been experimentally reproduced with four independent isolates of VS-FCV [15] [31] (Patricia A. Pesavento, unpublished data, 2005 and 2008). Analysis of the genomic sequences has shown that VS-FCV isolates seem to have arisen independently from different genetic backgrounds, however [32]. As yet, no genetic signature has been identified that can discriminate VS- FCV isolates from other FCV isolates. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Caliciviridae are small, nonenveloped, positive-stranded RNA viruses. Much of our understanding of the molecular biology of the caliciviruses has come from the study of the naturally occurring animal caliciviruses. In particular, many studies have focused on the molecular virology of feline calicivirus (FCV), which reflects its importance as a natural pathogen of cats. FCVs demonstrate a remarkable capacity for high genetic, antigenic, and clinical diversity; "outbreak" vaccine resistant strains occur frequently. This article updates the reader on the current status of clinical behavior and pathogenesis of FCV.
    Veterinary Clinics of North America Small Animal Practice 08/2008; 38(4):775-86, vii. DOI:10.1016/j.cvsm.2008.03.002 · 0.82 Impact Factor

  • International Journal of Trauma Nursing 08/2000; 6(3):111-112. DOI:10.1067/mtn.2000.108476
Show more