Cat Herpes – Diagnosis And Treatment of Feline Herpesvirus

cat herpes

Could your fur-friend have cat herpes, without you knowing?

Feline herpesvirus is a surprisingly common infection. Also known as feline rhinotracheitis, this is an important cause of recurring sore eyes in cats.

But it’s also a sneaky virus, which enters a carrier state.

This means cats may appear healthy but at times of stress shed virus and pose an infection risk to others.

Some common questions people ask about feline herpes include:

This article answers all these questions and more.

How Do Cats Catch Feline Herpesvirus?

In much the same way we catch flu, so cats catch feline herpesvirus.

The virus is present in secretions (for this read sneeze droplets, runny eyes, and saliva).

cat herpes

Contact with the virus in sneeze droplets causes infection.

Thus contaminated food bowls, bedding, or clothing pose a small risk.

But, the biggest source of infection is direct contact between a sneezing sick or carrier cat and a healthy one.

Previously infected cats act as a reservoir of feline herpesvirus that can infect healthy cats.

Like a wolf in sheep’s clothing, herpes virus latent within any cat is then able to get into the company of other cats.

The Cattery Scenario

Think of the cattery scenario.

A cat stressed by being away from home, starts to shed feline herpesvirus.

It takes around a week for a carrier cat to start seeding the environment with cat herpes.

The other cats in the cattery are also stressed, which means their immune system isn’t so good at fighting infection.

Now that sneaky ol’ herpesvirus has a whole new population of kitties ripe for infecting.

Herpesvirus in Cats Symptoms

Herpesvirus in cats symptoms is similar to flu in people.

The signs include fever, sneezing, runny eyes, and a snotty nose. These cats feel rough and stop eating.

This leads to a downward spiral where the cat feels worse and declines further.

But feline herpesvirus is a sneaky virus. When a cat is nursed through the worst and appears to recover, the virus goes into hiding.

It lurks in the nerves, ready to cause a flare-up of symptoms when the cat is stressed.

Examples of stress include boarding at a cattery, surgery, or having kittens. All of which can make a seemingly healthy cat develop sneezes, snuffles, and a snotty nose.

In vet speak this is known as ‘recrudescent disease,’ and it’s typical of cat herpes.

Another long-term consequence of feline herpesvirus is a snotty nose. More politely called ‘rhinitis’, the symptoms include a bunged up nose and a yellow-green discharge from one or both nostrils.

Herpesvirus in cats’ eyes is the most common cause of conjunctivitis in cats. Symptoms include red, angry eyes that weep or have a yellow-green discharge.

And last but not least, cat herpes is part of ‘fading kitten syndrome’. This causes 2 – 4-week old kittens to stop thriving and slowly waste away. Sadly, the source of infection is the mother.

How is Cat Herpes Diagnosed?

In many cases, the cat’s symptoms give the vet a fair idea of what’s going on.

Indeed, a definitive diagnosis of ‘cat herpes’ isn’t always necessary because it doesn’t change the treatment.

But when a diagnosis is required, swabbing the surface of the eye or the back of throat can give an answer. These swabs are sent to a specialist lab that’s capable of isolating feline herpesvirus.

However, even a negative swab result doesn’t automatically mean the cat is in the clear. A carrier cat doesn’t shed virus all the time, so positive case of cat herpes is easy to miss.

Herpes Virus in Cats Treatment

Antibiotics can’t kill viruses, that job is up to the cat’s immune system.

Therefore herpes virus in cats treatment targets secondary infections (such as infected sinuses or pneumonia) and supporting the cat until their immune system steps up.

Antibiotics are given to sick cats that aren’t eating, as they may well have a secondary bacterial infection.

Herpesvirus can cause nasty corneal ulcers. In severe cases, the vet may prescribe antiviral eye drops, containing ganciclovir or trifluorothymidine. These are applied to the eye, four to six times a day.

Again, severely ill cats may benefit from antiviral medications, such as famciclovir or interferon. These are given for two to three weeks to decrease the amount of virus in the body.

A popular holistic remedy is L-lysine tablets. However, there is no evidence that these are effective, and there’s a risk they might worsen things.

Nursing a Cat with Feline Herpesvirus

If you’ve seen a cat-flu kitten with their eyes gummed shut, you’ll realize the importance of nursing.

The dedicated owner, who bathes the kitten’s eyes open, every hour, can save that kitten’s eyesight.

Indeed, a snotty nose inhibits appetite because the cat can’t smell her food. Simple things such as wiping the cat’s nose can help.

If that fails, tempt the cat with strong smelling foods such as sardines or mackerel. And warm the food up for added appetite ‘Oomph.’

Sick cats often don’t groom, but they also hate looking scruffy. Therefore, gently brushing the cat does her spirits no end of good.

Stress hobbles the immune system, so reducing stress indirectly helps the cat to recover.

Settle her in a safe, quiet place. Ensure other cats can’t bully her, and all her needs (food, water, and a litter box) are close to paw.

And never underestimate how fusses and strokes help cats to recover.

The Special Case of Kittens

Feline herpesvirus is especially concerning in kittens.

If you’re planning to breed a female cat, make sure she’s vaccinated against cat herpes.

This protects her and passes protective antibodies onto the kittens.

Then, in the later stages of pregnancy, keep the mother away from other cats who may be herpesvirus carriers.

Once the kittens are old enough, vaccinate them against feline herpesvirus too.

What’s the Outlook for Cats with Feline Herpesvirus?

Feline herpesvirus life expectancy varies a lot, depending on the cat’s age and how sick they get.

Especially vulnerable are kittens, with their weak immune systems and lack of resilience.

This is where nursing can make a life and death difference.

Adult cats often fair better and throw off the infection within 2 – 3 weeks.

But these cats become carriers and pose a risk to their fur-friends.

Felines Herpesvirus Vaccination

Happily, we have a great way to protect our cats: vaccination.

Vaccination against feline herpesvirus and calicivirus (combined as cat flu) are considered ‘core’ or essential.

When given to healthy cats, it primes up the immune system to protect against naturally encountered virus.

Cats require two doses of vaccine initially, given 3 -4 weeks apart. Then immunity is boosted by a top-up injection once every two to four years.

Kittens can be vaccinated from 8 – 9 weeks of age, followed by 3-4 week top-ups until they are 16 weeks old.

This regime is necessary because maternal antibodies from the mother’s milk, try to disarm the vaccine.

How long this maternal protection lasts is unpredictable, so several shots can be needed to bridge the gap.

Reducing the Risk of Infection

Feline herpesvirus only survives for 18 hours in a damp environment or 12 hours in the dry.

It’s also killed by common disinfectants, including dilute bleach. Simple precautions such as cleaning floors and washing food bowls reduce the infection risk.

However, the main route of infection is cat to cat. If a cat shows symptoms, isolate that kitty. And make sure all in-contact cats are vaccinated.

Carrier cats don’t shed virus all the time, but stress triggers them to start shedding.

Make your home a stress-free cat haven by providing plenty of high perches, hiding places, and individual litter trays and bowls for each cat.

Cat Herpes Summary

Feline herpesvirus is common, with many cats becoming healthy carriers.

Infection poses a greater risk to those with weak immune systems, such as kittens or elderly cats.

Signs of cat herpes include sneezing, sore eyes, and a runny nose.

With good nursing, many cats do recover but go on to be carriers.

But the best plan is to vaccinate, which protects the cat and prevents illness in the first instance.

Has Your Cat Had Herpes?

What adjustments have you made to protect them (and your other cats if you have them) since?

We hope they’re full of health again now, and we’d love to hear their story in the comments box.


Ward, Conjunctivitis: Feline Herpes Virus, VCA Hospitals, 2004.

Hurley, Feline infectious disease control in shelters, Vet Clinics, Small Animal, 2005.

Freshman, Fading Puppy and Kitten Syndrome, DVM360, 2005.

Radford, Antivirals in Cats: What works and what doesn’t, World Small Animal Veterinary Association congress proceedings, 2006.

Day et al, Guidelines for Vaccination of Cats and Dogs, World Small Animal Veterinary Association, 2016.

Thiry, Feline Herpesvirus Infection, Advisory Board on Cat Diseases, 2017.

Lysine doesn’t help cats with viral upper respiratory disease, The SkeptVet, 2015.


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