Comparison of polymerase chain reaction tests for diagnosis of feline herpesvirus, Chlamydophila fells, and Mycoplasma spp. infection in cats with ocular disease in Canada

This study assessed the value of polymerase chain reaction (PCR) for making a diagnosis of feline herpesvirus (FHV-1) infection, and for differentiating this from Chlamydophila felis and Mycoplasma spp. infection in a clinical setting in Canada. We compared the frequency of positive FHV-1 PCR test results from 48 clinical cases of ocular disease in cats suspected to be due to FHV-1 between 1 research and 2 commercial laboratories in Canada. We also compared PCR results for Chlamydophila felis and Mycoplasma spp. between the 2 commercial laboratories. The prevalence of FHV-1 infection in the cats ranged from 4% to 21%. The prevalence of Chlamydophila felis was 2% and 17% and the prevalence of Mycoplasma spp. was 11% and 27%. Agreement between FHV-1 culture and PCR results at the research laboratory was substantial (kappa = 0.76). There was slight agreement (kappa < 0.20) between the 3 laboratories for FHV-1 PCR and between the 2 commercial laboratories for both Chlamydophila fells (kappa = 0.2) and Mycoplasma spp. (kappa = 0.07) PCR.