Feline calicivirus: a neglected cause of feline ocular surface infections?

To investigate the prevalence of feline calicivirus (FCV) infection in relation to ocular surface lesions in cats with upper respiratory tract diseases (URTD).

Ninety-nine cats with ocular surface infection and symptoms or recent history of URTD were examined at various rescue shelters and hospitals.

A complete general and ophthalmic examination was performed including Schirmer tear test, slit-lamp biomicroscopy, fluorescein and lissamine green staining. Clinical and ocular symptoms were scored and recorded. Conjunctival samples were collected using a cytobrush, and nucleic acid extraction using RT-PCR was carried out to analyze for the presence of various infectious agents.

RT-PCR detected either FCV, feline herpes virus type 1 (FHV-1), Chlamydophila felis or Mycoplasma spp. in 63/99 samples. 30/63 samples were positive for FCV, 23/63 for C. felis, 21/63 for Mycoplasma spp., and 16/63 for FHV-1. Out of the 30 FCV-positive samples, 11 were positive only for FCV and in 19 samples FCV was seen in combination with other agents. FCV infection was highest in animals examined at the rescue centers and in the age group of 0-2 months. Erosive conjunctivitis was an important ocular finding. Oral ulcers were detected in all FCV-infected cats.

Results indicate that FCV is highly prevalent in cats with URTD either as a sole infectious agent or in combination with other pathogens and therefore is a potential cause for ocular surface lesions during the URTD.