2023 Volume 42 Pages 3-7
A real-time polymerase chain reaction (PCR) was performed on tear fluid from cats with epithelial keratitis in both eyes caused by an infection feline herpesvirus type 1 (FHV-1). Viral load was simply assessed based on cycle threshold (Ct) values obtained from real-time PCR, and its relationship to corneal ulcers was evaluated over time. Real-time PCR was performed using Schirmer tear test (STT) strip, and corneal ulcers were evaluated with a systematic ophthalmologic examination. Upon initial examination, geographic-like superficial or dendritic corneal ulcers were observed in both eyes. After treatment with oral famciclovir and hyaluronic acid eye drops, the corneal ulcers in both eyes healed as Ct values increased. The Ct values represent the number of PCR cycles required to sufficiently detect the viral genome, with higher values indicating a lower amount of viral genome in a specimen. Thus, an increase in the Ct value implies a reduction in the amount of viral genome at the lesion site. In this case report, the amount of viral genome was simply estimated based on the Ct value from real-time PCR. The results revealed a correlation between the amount of viral genome and the alleviation of corneal ulcers during the course of treatment of epithelial keratitis caused by FHV-1. This approach may offer a valuable strategy to diagnose and treat corneal ulcers caused by an FHV-1 infection.
