What is feline herpes virus
Feline herpes virus is an upper respiratory virus of cats. It is also known as
rhinotracheitis virus. It is very common among cats, especially in environments
where there are multiple cats or new cats are constantly interacting. The virus
is spread through the air and replicates in the upper respiratory tract (nasal
area, tonsils). The conjunctiva of the eye is also affected during the primary
infection. Clinical signs of infection include sneezing and ocular and nasal discharge.
In most cases the primary infection resolves with no residual ocular lesions.
However, depending on the age when the cat is affected, the serotype of the virus
(infectivity or strength of infection), and other factors, there may be various
ocular signs. In very young cats, adhesions of the eyelids to each other or to
the cornea may occur. Adult cats may experience recurrent conjunctivitis or corneal
ulcers. The virus remains latent in the nerves that serve the eyes. When a cat
is stressed or exposed to new serotypes (different strains) of herpes virus, the
ocular disease can recur. There is some evidence that eosinophilic keratitis,
plasmacytic-lymphocytic keratitis, corneal sequestrum, and some cases of anterior
uveitis may be associated with feline herpes virus infection.
How do cats get feline herpes virus
Most cats are affected as kittens, contracting the infection from their mothers.
Stray cats, multi-cat households, and cats from households where new cats are
constantly introduced are more likely to suffer infection. Feline herpes virus
is not contagious to dogs or to humans but only affects cats.
How is feline herpes virus diagnosed
History and clinical signs can diagnose ocular diseases caused by feline herpes
virus. Aside from history and clinical signs, diagnostic tests for feline herpes
virus include virus isolation, immunofluorescent antibody testing, polymerase
chain reaction testing, serology, and cytology. Testing can be expensive and
is generally reserved for specific cases. Tests that may not specifically detect
the presence of herpes may be used to detect ocular disease caused by herpes.
These tests include a Schirmer tear test (measuring tear production), corneal
staining, and conjunctival biopsy.
How is feline herpes virus treated
Treatment for feline herpes virus infections is nonspecific and generally directed
at controlling secondary bacterial infection. A topical antibiotic such as tetracycline
or erythromycin may be prescribed for use in the eye. Systemic antibiotics may
also be prescribed. Oral L-Lysine is recommended by many veterinary ophthalmologists
at a dose of 250-500 mg twice daily. Lysine competes with another amino acid,
arginine, that herpes virus must have in order to reproduce. Lysine has been
demonstrated to decrease the severity of ocular symptoms associated with herpes
virus infection (1) and reduce viral shedding during periods of disease recurrence
(2). Depending on symptoms, other medications such as topical antiviral drugs,
topical polysulfated glycosaminoglycans, topical nonsteroidal anti-inflammatory
drugs or topical interferon may be used. In some cases the ocular diseases resulting
from feline herpes virus may require surgical intervention. The key to managing
the clinical signs associated with feline herpes virus is controlling the cat's
environment. Cats exposed to multiple cats (indoor-outdoor cats), cats in multiple
cat households, or cats that are frequently introduced to new cats are difficult
to keep disease free. Reducing stress by maintaining a stable routine is helpful
in preventing recurrences of disease. Keep in mind that it is the nature of
the virus to see recurrences of the disease and periodic treatment is often
DOSAGE: Each 1/4 teaspoon contains 250 mg of L-Lysine in a palatable
base. The suggested dose for cats over 6 months of age is 1/4 teaspoon given
orally twice daily. The suggested dose for kittens under 6 months of age is
1/8 teaspoon given orally twice daily. Adjust dosage as needed.
Store at room temperature.