Herpesvirus infection effects cats exclusively and is not seen in dogs. Specifically, the virus attacks and causes clinical disease in the upper respiratory system, the eyes, or both. With the respiratory form, the patient experiences mild to severe congestion, cough, fever, and inappetance. With the occular form, the patient presents with all or some of the following symptoms in one or both eyes: severe tearing; thickening, swelling, and redness of the inner eyelids; redness of the whiltes of the eyes; spasming closed of the eyelids; and corneal ulcers.
Herpesvirus is most commonly seen in kittens, cats that have spent time in a shelter, cats that go to the groomery, and cats that spend all or part of the time outdoors. Since herpes is a virus, antibiotics are not effective in eliminating the organism. However, antibiotics are commonly used to control secondary bacterial infections that exacerbate the disease. Systemic antibiotics are given orally to help control secondary bacterial invaders of the trachea and nasal cavity. Topical antibiotic ophthalmic preparations are administered to the eye(s) of cats that are affected with the occular form, serving to limit secondary bacterial growth while protecting and allowiing any corneal ulcers to heal. In rare cases, herpesvirus can affect the patient so severely that hospitalization with fluid therapy and other supportive care is necessary.
The most frustrating aspect of herpesvirus is that the organism integrates itself into the host’s DNA, making the patient infected for life, despite having been recovered and cleared of symptoms of disease. This leaves the patient susceptible to future outbreaks in times of stress or other immune system suppressive events. In most cases, as the patient ages and the immune system strengthens, episodes become less severe, become less frequent, and in many cases stop altogether. A small percentage of patients, however, remain chronically afflicted with, or have frequent relapses of clinical disease. In these cases, daily supplementation with the amino acid, Lysine, has shown to often be effective in helping these cats. However, always consult with your vet before doing this, as overdosing can be toxic and even fatal.
Roger L. Welton, DVM
Founder and Chief Editor, Web-DVM.net
President, Maybeck Animal Hospital
Article updated 6/3/2014