Ocular Manifestations of Canine Parvovirus in Juvenile Dogs: Tear Production, Intraocular Pressure, Fundoscopic...

Canine parvovirus (CPV) is a major cause of haemorrhagic enteritis in juvenile dogs, yet its potential ocular effects have not been systematically investigated.

To evaluate whether naturally acquired CPV infection in juvenile dogs is associated with alterations in tear production, intraocular pressure, corneal integrity, fundoscopic findings, and ocular ultrasonographic measurements.

Seventy client-owned dogs under 6 months of age were included: 35 with confirmed CPV infection and 35 healthy controls. Before treatment, all animals underwent standardised ophthalmic examination including Schirmer tear test-I (STT-I), intraocular pressure (IOP) measurement, fluorescein staining, fundoscopic examination, and ocular ultrasonography. In CPV-infected dogs, dehydration severity (mild 5%-8%, moderate 8%-10%, severe ≥10%) was graded clinically for exploratory analyses. Continuous variables were compared using Student's t-test or Mann-Whitney U test, and categorical variables using χ² or Fisher's exact tests.

CPV-infected dogs had significantly lower STT-I and IOP values than controls. Fluorescein staining was positive in 27/35 (77.1%) infected dogs and absent in controls. Fundoscopic abnormalities, including retinal vessel beading, chorioretinitis, and optic neuritis, were detected in 28/35 (80%) infected dogs, whereas all controls had normal findings. Ocular ultrasonographic parameters did not differ between groups. Dehydration severity did not significantly affect STT-I, IOP, or fluorescein results.

CPV infection in juvenile dogs is associated with reduced tear production, ocular hypotony, frequent corneal epithelial defects, and posterior segment abnormalities, indicating that CPV may involve both the ocular surface and fundus in addition to the gastrointestinal system.