Spread of herpes simplex virus within ocular nerves of the mouse: demonstration of viral antigen in whole mounts of eye tissue.

Spread of herpes simplex virus to and within the mouse eye after inoculation of the cornea or the skin of the snout was examined by peroxidase-antiperoxidase (PAP) staining of viral antigen in flat mounts of the eye and by isolation of virus from nervous tissue. Following inoculation of virus at either site, viral antigen was found in ocular nerves. One to three days later antigen was also found in the iris, ciliary body and choroid/sclera suggesting that virus spread to these tissues occurred via their nerve supply. Viral antigen was also found in the retina of the uninoculated eye after corneal inoculation. After inoculation of the snout, virus was isolated from ophthalmic and maxillary parts of the trigeminal ganglion and the superior cervical ganglion and then from the brainstem, eye and mandibular part of the trigeminal ganglion. This sequence also suggested that virus reached the eye via the nerves and that this may occur indirectly via the brainstem. The PAP method allows rapid determination of the distribution of antigen in various tissues. Our observations suggest that widespread involvement of ocular tissue may occur by spread of virus in nerves within the eye.