The Feline Herpes Virus in Cats

Group of tuxedo kittens looking up at the camera

Feline herpes virus is a very common illness in cats. Although it is never truly curable once contracted, it can usually be managed well with the right treatment and there are steps you can take to prevent the spread of viral particles.

What is Feline Herpes Virus?

Sometimes called Feline Viral Rhinotracheatitis (FVR), feline herpes virus is a major cause of upper respiratory disease and conjunctivitis in cats. It is caused by feline herpesvirus type-1 (FHV-1) and cats become infected through direct contact with the virus. Viral particles will be shed via your cat's saliva as well as any nasal or ocular secretions.

Any cat can become infected with feline herpes virus, but young cats and kittens and those already battling a chronic disease can be more susceptible. Feline herpes virus can also be passed from mother to kitten.

The good news is that the virus doesn't survive long in the environment and can also be easily removed with good cleaning practices. Once secretions are dry, shared bedding, bowls, toys, or litterboxes are no longer considered to be infectious.

Symptoms of Feline Herpes Virus in Cats

  • Sneezing
  • Nasal discharge
  • Nasal congestion
  • Conjunctivitis
  • Ocular discharge

Cats that become infected with feline herpes virus will usually begin to show symptoms of an upper respiratory infection.

The nasal and ocular discharge can range from something that is clear and watery to something that is yellow-green and thick. In severe cases, your cat's cornea may become so inflamed (a condition knows as keratitis) that your cat may develop corneal scarring or chronic dry eye (a condition known as keratoconjunctivitis sicca).

Symptoms will usually arise two to five days after infection. Once your cat starts showing symptoms of the virus they may remain actively infected for 10-20 days. During this time they will be infectious to other cats.

All cats that are infected with feline herpes virus will become carriers of the virus. Most cats will become latent carriers. This means that inactive forms of the virus will survive in your cat's body. During this latent period, your cat isn't considered to be infectious, but if your cat becomes ill or if they are undergoing a period of stress the virus may become reactivated. If this happens your cat will once again become infectious and may become symptomatic.

Diagnosing Feline Herpes Virus

Although it's one of the most common causes of upper respiratory disease in cats, feline herpes virus isn't the only thing that can cause upper respiratory signs in your cat. There are subtle differences, though, and you vet will hone in on a diagnosis of feline herpes virus based on your cat's symptoms, history, and physical exam.

Your vet may perform a test called a fluorescein stain to check for a corneal ulcer caused by severe keratitis. They may also perform a Schirmer tear test to see if your cat's tear production is abnormally low.

If you want a definitive diagnosis of feline herpes virus, your vet will need to take swabs of your cat's ocular discharge, nasal discharge, and/or of the back of their throat. These swabs will be sent to a lab where they will undergo a specialized test called a Polymerase Chain Reaction (PCR). This test allows the viral particles to be amplified and thus isolated and identified. However, if your cat isn't in an active stage of infection, there won't be any viral particles being shed and this PCR test will be inconclusive.

Treatment of Feline Herpes Virus

Cats with an active flare-up of herpes virus will be treated symptomatically. The most common treatment is topical ointment or drops for your cat's eyes. Your vet will also recommend you start your cat on the supplement L-lysine. This is an amino acid that works to boost your cat's immune system and it is something your cat can safely take long term. There are antiviral medications out there, but they can be hard on your cat's kidney and liver enzymes, so they aren't prescribed as often.

Feline herpes virus is quite common in cats, but that doesn't mean you can't have a herpes positive cat living with herpes negative cats. Also, with the right treatment, a herpes positive cat can still have a long and healthy life.

How to Prevent Feline Herpes Virus

Good hygiene practices are the best defence against this virus. All bedding and blankets should be laundered with detergent and warm water. Shared bowls, toys, and litterboxes should also be cleaned with warm, soapy water.

You should also make sure to properly wash your hands with warm soapy water after handling a cat with feline herpes virus.

If you have questions or concerns about your cat's risk of contracting feline herpes virus speak to your veterinarian.