Feline Herpes Virus (Cat Flu)

What is feline herpes?   How do cats become infected?   How does feline herpes affect your cat?   Symptoms   How is it diagnosed?   How is it treated?   Can I catch herpes from my cat?

Feline herpes at a glance

  • Feline herpes is a highly infectious upper respiratory infection caused by the feline herpes virus (FHV-1). Kittens and senior cats are most at risk.
  • Symptoms include eye and nose discharge, sneezing, fever, loss of appetite, drooling and corneal ulcers.
  • Diagnosis is based on presenting symptoms and a nasal or eye swab sent for PCR testing.
  • Treatment is supportive and may include nutritional and fluid support, removing discharges from the eyes and nose antiviral medications.
  • Feline herpes can be prevented by vaccinating your cat.

cat herpes

What is feline herpes?

Also known as feline viral rhinotracheitis (FVR), feline herpes is a highly contagious upper respiratory disease of cats caused by the feline herpesvirus type 1 (FHV-1). An upper respiratory disease refers to infections in the area of the eyes, nose, throat and sinus areas. It is similar to a cold/flu in humans.

Feline herpesvirus is the most common cause of upper respiratory disease in cats, it is most common in kittens, cats in stressed/overcrowded environments such as animal shelters and multi-cat households.   Kittens and older cats are more at risk than healthy adults and are also at greater risk of dying. Once your cat becomes infected with the feline herpesvirus he will have it for life.

The first outbreak is usually the most severe. Once recovered, in the healthy cat the immune system usually manages to keep the virus in check, but there may be the occasional outbreak at times of stress (pregnancy, lactation, overcrowding, while boarding etc.) or sickness. Corticosteroid injections may also bring on an outbreak in the infected cat.

Feline herpes can be found throughout the world.

How does feline herpes affect your cat?

The virus infects and grows in nose, eyes, sinus, throat, mouth, and tonsils of a cat which causes inflammation and fever. Due to the nasal discharge, the cat’s sense of smell is severely diminished, causing his appetite to wane. While the loss of appetite is dangerous in all cats, it is especially so in kittens.

Due to the damage caused to tissues, it is possible for a secondary bacterial infection to take hold.

If a pregnant cat catches herpes, it may lead to abortion of the kittens.

How do cats become infected with feline herpes?

Feline herpes can be spread by direct or indirect contact. The virus can survive for up to 24 hours in the environment.

Direct contact:

  • In utero: It is possible for feline herpesvirus to be passed on to unborn kittens via the mother.
  • Feline herpesvirus is transmitted in saliva, eye and nasal secretions, as well as airborne particles, sneezed from an infected cat.
  • Asymptomatic/latent carriers may shed the virus. This means that while they are displaying no symptoms themselves, they are actively shedding the virus and other cats can become infected.

Indirect contact (fomites):

  • Food bowls, litter trays, toys, bedding etc., which have been in contact with an infected cat shedding the virus.


The most common symptoms of feline herpes is acute upper respiratory infection including:


Your veterinarian will perform a physical examination of your cat. There are several other diseases with similar flu-like symptoms to feline herpesvirus although there are some slight variations. For example, calicivirus (which is also responsible for upper respiratory infections in cats) typically causes ulcers in the mouth, whereas feline herpesvirus causes ulcers in the eye.

Most cases of feline herpes are diagnosed based on physical signs, especially if your cat has corneal ulcers.

A swab of ocular or nasal secretions may be taken and sent to a laboratory for PCR (polymerase chain reaction) testing. This involves amplifying the virus greatly. It is possible for a negative result, even though the cat has feline herpesvirus.

Other tests he may wish to perform include biochemical profile, complete blood count, and urinalysis.


There is no cure for feline herpes, once a cat is infected he has the virus for life. The goal is to give supportive care, treat the symptoms and try to shorten the duration. Treatment also depends on severity and symptoms and may include:

  • Keeping the nostrils and eyes clear of discharges. Use cotton balls dipped in warm water to wipe away any discharge.
  • Broad-spectrum antibiotics may be prescribed, these are ineffective against the herpes virus but may be used to prevent or treat secondary infections that may occur.
  • Oral antiviral drugs such as acyclovir, famciclovir or ganciclovir may be prescribed to treat severe infections. In cats suffering from corneal ulcers, antiviral eye ointment may be given.
  • L-Lysine is an essential amino acid which has been shown to suppress viral replication and inhibit cytopathogenicity. However, you should always speak to your veterinarian before you supplement your cat’s diet.
  • Cats often lose their appetite if they are suffering from an upper respiratory infection. Offer him highly palatable soft foods such as the gourmet cat foods or poached chicken. Warming it up slightly can help.
  • Ensuring the cat is receiving food and liquid intake. Nutritional support such as offering highly palatable foods, appetite stimulants or if necessary a feeding tube, as well as intravenous or subcutaneous fluids, may be necessary.
  • Ease breathing and discharge with vaporizers. If you don’t have a vaporizer, run a hot shower until the room is steamy and leave your cat in the bathroom for 10-15 minutes.

Uncomplicated feline herpes usually resolves within 7-10 days.

Home care:

Administer all medications as directed by your veterinarian.

If you have other cats in the household, isolate the infected cat until he has recovered.

My vaccinated cat caught cat flu:

If a cat (usually during kittenhood) contracts feline herpes before it has been vaccinated, the virus will remain in your cat for life. Most of the time it lies dormant (known as latent stage), but at times of stress or sickness, the virus can be reactivated, causing symptoms.

Is feline herpes contagious to humans?

No, you can not catch feline herpes from your cat, only domesticated cats and close relatives can catch feline herpesvirus. There are several types of herpes virus to infect humans but they are not the same as feline herpes.

Is feline herpes contagious to other cats?

Yes, feline herpes is extremely contagious, which is why a cat with herpes should be isolated from other cats in the household while he is sick.

Preventing feline herpes:

The best way to prevent feline herpes is to have your cat vaccinated. Kittens should receive their F3 vaccination at 8, 12 and 16 weeks of age. Then receive a booster at 12 months followed by tri-annually after that or as your veterinarian recommends.

Image courtesy of Nottingham Vet School

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