Ocular lesions in association with upper respiratory tract disease (URTD) are globally recognized in cats. The major pathogens include feline herpes virus 1 (FHV-1), feline calicivirus (FCV), Bordetella bronchiseptica, Chlamydophila felis, and Mycoplasma felis (to a lesser extent). One of the complications of URTD is feline ocular surface lesions, commonly caused by FHV-1. In this study, 99 cats with surface ocular infections and active or recent URTD underwent ocular examinations, clinical and ocular scorings, and samplings for RT-PCR for infectious agents. Cats were selected from shelters or private hospitals. An infectious agent was isolated from 63/99 cats. In 40/63 cats, a single infectious agent was isolated: Chlamydophila spp 16/63 (25%), FCV 11/63 (17%), FHV-1 8/63 (13%), and Mycoplasma spp 5/63 (8%). In the remaining 23/63 cats, multiple infectious agents were isolated, most commonly with some combination of FCV (19 isolates), FHV-1 (8 isolates), and Mycoplasma spp (16 isolates). FCV was isolated most frequently from shelter cats <2 months of age. In cats with FCV ocular lesions, key findings included erosive conjunctivitis. All cats with FCV had oral ulcers.

Commentary
This study showed that FCV could be a more prevalent cause for shelter cats exhibiting URTD and conjunctivitis in Germany and the UK. An equal prevalence of FCV and FHV-1 was reported in shelter cats in the United States.1 However, FHV-1 still remains the primary ocular surface disease pathogen (herpetic keratoconjunctivitis) that general practitioners may see with or without URTD in US cat populations. Recognizing FCV as a more prevalent pathogen in shelter cats with URTD and conjunctivitis is helpful for improving shelter management, treatment/supportive care, and potential improvement for disease control.—Cherlene Delgado, DVM

Source
Feline calicivirus: A neglected cause of feline ocular surface infections? Gerriets W, Joy N, Huebner-Guthardt J, Eule JC. VET OPHTHALMOL 15:172-179, 2012.

1. Epidemiologic evaluation of multiple respiratory pathogens in cats in animal shelters. Bannasch MJ, Foley JE. J Feline Med Surg 7:109-19, 2005.

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