Development of a Reverse Transcriptase Polymerase Chain Reaction to Detect Feline Herpesvirus 1 Latency Associated Transcripts in the Trigeminal Ganglia and Corneas of Clinically Asymptomatic Cats

Abstract

Abstract: : Feline herpesvirus 1 (FHV-1) is a frequent cause of recurrent corneal and conjunctival disease in cats. Herpesviral DNA can be detected using a PCR assay in clinically normal corneas. However, the replication status of the virus in these corneas is not known. Purpose: Develop a reverse transcriptase PCR assay to evaluate the corneas and trigeminal ganglia of clinically asymptomatic cats for the presence of FHV-1 latency associated transcripts. Methods: Both corneas and trigeminal ganglia were harvested from 21 cats necropsied at the Purdue Animal Disease Diagnostic Laboratory and 25 cats euthanized at a humane shelter. Cats had no recent history of respiratory or ocular disease and normal ophthalmic examinations. The initial PCR assay detected FHV-1 DNA in the corneas and trigeminal ganglia. RNA was then isolated from the samples positive for FHV-1 DNA and an RT-PCR assay was used to detect latency associated transcripts. Results: FHV-1 DNA was detected in 45/92 (48.9%) corneas and 38/92 (41.3%) trigeminal ganglia. In many samples the RNA had degraded and RT-PCR was not possible. Of the samples subjected to RT-PCR, no (0/39) corneas, but 4/16 (25%) of trigeminal ganglia were positive for FHV-1 latency associated transcripts. Conclusions: Results suggest that a high percentage of clinically asymptomatic cats have detectable FHV-1 DNA in the corneas and trigeminal ganglia. The RT-PCR assay was successful in identifying latency associated transcripts and may serve as a tool to differentiate active and latent FHV-1 infections.

Keywords: gene/expression • animal model