Feline Herpesvirus

By: Lynsey Wagner, DVM

TVMA Member
San Antonio, TX.

Published January 2015

Herpesvirus is one of the most common causes for conjunctivitisInflammation of the conjunctiva (mucous membrane that covers the front of the eye and lines the inside of the eyelids) of the eye. and corneal ulcerationA corneal ulcer is an erosion or open sore in the outer layer of the cornea. It is often caused by infection. in cats. The ocular (eye) clinical signs can be accompanied by upper respiratoryOf, relating to, or affecting respiration or the organs of respiration. disease as well. Many owners mistake the symptoms of herpesvirus for seasonal allergies.

This virus is extremely widespread in the cat population with some studies showing that 90 percent of cats are exposed to herpesvirus. The virus is not contagious to people or other species (e.g., dogs). It is passed to other cats through sneezing, coughing, grooming and generally being in close contact with an infected individual. Routine vaccination by your veterinarian typically includes a herpes virus vaccine. This vaccine will minimize clinical signs of the disease but will not completely protect your cat from infection or future recurrence of herpesvirus.

Signs of Feline Herpesvirus

Herpesvirus can cause a range of signs in the cat population. The mildest of infections lead to conjunctivitis (redness and swelling in the white part of the eye). Other signs include ocularOf or related to the eyes or vision. and nasal discharge, sneezing, coughing and corneal ulcerationA corneal ulcer is an erosion or open sore in the outer layer of the cornea. It is often caused by infection..

Studies show that many cats initially infected with the virus will remain infected long-term. These cats are carriers for herpesvirus and will appear clinically normal after the initial infection. The virus lives in the nerves of the face and can cause recurrence of symptoms throughout life. Just like cold sores in people, these recurrences typically occur during times of stress or illness. Not all cats will experience recurrence of clinical disease.

Treatment for Feline Herpesvirus

Your veterinarian may prescribe antiviral medications to aid in controlling the symptoms of herpesvirus. Antiviral medications slow replication of the virus and allow your cat’s immune system to resolve the infection. These medications can shorten the time period during which your cat is showing signs of herpesvirus infection. The medication will not completely clear herpesvirus from your cat’s system. It is recommended that while a cat is showing signs of herpesvirus, it should be isolated from any other feline housemates.

As viruses predispose animals to secondary bacterial infections, your cat may be placed on an antibiotic to protect against these infections.

Studies have shown that during active herpesvirus infection, the tear film is negatively affected in cats. Thus, topical artificial tear preparations or other lubricants may be prescribed.

Lysine, an amino acid supplement, has been shown to increase the time period between recurrences of herpesvirus symptoms. There are many formulations of lysine, and your veterinarian will discuss which might be best for your cat.

Lynsey Wagner, DVM, DACVO, is a graduate of Texas A&M College of Veterinary Medicine who lives in San Antonio, Texas. Dr. Wagner is a board-certified diplomate of the American College of Veterinary Ophthalmologists who practices at South Texas Veterinary Ophthalmology.