Abstract
Purpose :
Canine herpesvirus-1 (CHV-1) and feline herpesvirus-1 (FHV-1) infections represent natural-host, large animal models of ocular herpes simplex virus infection. Cellular changes in the cornea of patients with herpes simplex virus keratitis are described using in vivo confocal microscopy (IVCM), but these alterations have not been characterized in dogs and cats with herpetic keratitis. We tested the hypothesis that IVCM would detect morphological alterations in the cornea of dogs and cats with naturally-acquired herpetic dendritic ulcerative keratitis using a prospective observational clinical study.
Methods :
Laser scanning IVCM examination of the cornea was performed in 6 dogs and 8 cats with naturally-acquired dendritic ulcerative keratitis diagnostically confirmed to be associated with CHV-1 or FHV-1 infection, respectively. The IVCM examination findings were statistically compared to findings from examinations performed in 10 laboratory beagles and 10 laboratory cats with normal ophthalmic examinations.
Results :
Epithelial and stromal changes identified by IVCM were similar for both CHV-1 and FHV-1 keratitis. Morphological alterations were identified in the corneal epithelium of all dogs and cats with herpetic keratitis, but not the control groups (p=0.0001). The epithelial changes included abnormal cellular morphologies characterized by hyperreflective, irregularly-shaped cells in the epithelium immediately adjacent to the areas of dendritic ulceration. Hyperreflective punctate opacities and occasional inflammatory cells were present within all layers of the epithelium. Langerhans cells and anterior stromal dendritic cells were also frequently present within corneas of all dogs and cats with herpetic keratitis, but not the control groups (p=0.0001). Stromal changes distinct from the control groups were less consistent in the affected dogs and cats and included hyperreflective keratocyte nuclei with visible cytoplasmic processes (n=4 dogs, n=6 cats, p≤0.008), inflammatory cells in the anterior stroma (n=3 dogs, n=7 cats, p≤0.04), and abnormal corneal nerve morphologies (n=2 dogs, n=4 cats, p=0.02 cats only).
Conclusions :
Naturally-acquired herpetic dendritic ulcerative keratitis in dogs and cats is associated with numerous microanatomical epithelial and stromal abnormalities that can be detected by IVCM.
This is a 2020 Imaging in the Eye Conference abstract.