Feline calicivirus infection in cats with virulent systemic disease, Italy

• Published in: Research in veterinary science 2019-06, Vol.124, p.46-51
• Main Authors: Caringella, Francesca, Elia, Gabriella, Decaro, Nicola, Martella, Vito, Lanave, Gianvito, Varello, Katia, Catella, Cristiana, Diakoudi, Georgia, Carelli, Grazia, Colaianni, Maria Loredana, Bo, Stefano, Buonavoglia, Canio
• Format: Article
• Language: English
• Subjects: Amino acid sequence; Antigens; Bone marrow; Calicivirus; Conflicts of interest; Disease control; Disseminated infection; Dyspnea; Edema; Feline panleukopenia; Histopathology; Hospitalization; Immunohistochemistry; Infections; Kidneys; Laboratories; Lungs; Lymphatic system; Molecular investigation; Mortality; Organs; Pathogens; Phylogeny; Pneumonia; Respiratory diseases; Spleen; Strains (organisms); Systemic diseases; Systemic infection; Ulcers; Veterinary medicine; Viral RNA; Viruses
• ISSN: 0034-5288; 1532-2661
• DOI: 10.1016/j.rvsc.2019.02.008

Feline calicivirus (FCV) is a contagious viral pathogen that usually causes a mild, self-limiting respiratory disease. More recently, highly virulent FCV strains have emerged and have been associated with severe systemic infection, referred to as virulent systemic disease (VSD). The objective of this study is to report VSD cases in Italian cats along with the molecular characterization of two detected FCV strains. Three client-owned cats showed clinical signs resembling to those described for VSD cases. The cats were subjected to molecular investigations for detection of FCV and other feline pathogens. Histopathology and immunohistochemistry were performed on internal organs of one cat; molecular characterization of two detected FCV strains was obtained through sequence and phylogenetic analyses. Putative VS-FCV strains were detected in all three cats, which were co-infected with feline panleukopenia virus. The cat submitted to histopathology and immunohistochemistry displayed severe histological changes and FCV antigens in internal organs. Two Italian FCV strains, for which amplification of ORF2 was successful, were strictly related and formed a unique phylogenetic cluster. These viruses did not show consistent changes in the amino acid sequences with respect to reference VS-FCVs. The results of our study confirm that VS-FCV strains are circulating in Italy and that VSD diagnosis is complicated since both genetic and clinical markers have not been identified so far. •Virulent systemic disease (VSD) caused by highly virulent feline calicivirus (FCV) was reported in Italy.•FCV antigens were detected in internal organs of one cat.•Two virulent systemic (VS) FCV strains were characterized at molecular level, displaying no specific genetic markers.•Our study confirms that VS-FCV strains are circulating in Italy.