In this article, we’ll try to address the common questions that people have about the herpes virus and its effects on cats. We’ll talk about the virus itself, how it is spread, things to watch out for, and how to care of a cat that has a herpes infection.

Herpes – It’s More Than Just a Cold Sore!

When most people hear, “herpes”, they tend to think of either two things – those pesky cold sores people can get on their lips or the sexually-transmitted disease that humans can get via unprotected sex.

Feline breed of cat

Humans aren’t the only animals that can be affected by herpes. Cats and many other animals are susceptible to the herpes virus as well.

Many of these strains can affect a cat’s different organ systems and body parts. For our four-legged friends, a herpes infection usually can lead to a few mild signs that you can spot.

In cats, herpes is one of the three main infectious agents that veterinarians have termed the Feline Upper Respiratory Tract Syndrome. This syndrome is a common infection of the airways in a cat’s respiratory systems that cause disease. This disease, for a cat, would resemble a cold that humans are known to sometimes get.

In case you were wondering, the other two infectious agents that comprise the syndrome are the Feline Calicivirus and the bacteria Chlamydophila Felis.

cat infected with chlamydiosis lost eye

What Exactly is a Herpes?

Herpes is unique in that the virus is able to avoid the host’s immune system. This leads to a state in which the host is infected for life.

The virus can reappear and cause illness again with varying frequency. This makes a herpes infection a frustrating disease to treat as there is currently no medicine available to permanently cure a cat of this virus.

While that may sound a little scary, often, the symptoms of feline herpes aren’t serious and you can help your cat recover with some basic care.

Most cats infected with herpes come from crowded boarding facilities, catteries, and shelters. Any place where there are a lot of cats living in close proximity to one another allows the virus to jump between hosts easily.

Other groups of cats at risk of herpes infection are young kittens due to the immature nature of their immune system. Similarly, cats of any age that are sick from diseases such as FIV or cancer are at risk too.

We classify these types of patients as being immunocompromised, which means that their body’s ability to ward off and fight infection is decreased due to other morbidities.

What are Some Signs That My Cat May be Infected?

The clinical signs that are associated with a herpes virus are generally mild and can include any combination of the following:

Common signs:

  • Sneezing
  • Conjunctivitis
  • Nasal and ocular discharge; usually bilateral
    • Initially, the discharge is classified as serious – it has a more clear, thin, and watery appearance
    • This can progress to a thick and white/yellow discharge referred to as mucoid or mucopurulent discharge
    • Occasionally, this discharge can appear with a reddish color, from a tiny amount of blood
    • Increased breathing sounds (You may hear sounds similar to snoring, gurgling, or gagging. This is due to the airways being partially obstructed by the discharge noted above)

Less commonly seen signs:

  • An increase in salivation
  • Tiny reddish sores (ulcers) in your cat’s mouth
  • Fever
  • Depression
  • Drooling
  • Lethargy

The herpes virus can also cause complications that can be diagnosed by your vet. The most common complication would involve inflammation to the tissues and membranes surrounding the eye like corneal ulceration or herpes-induced cornea infections which may be difficult to treat.

The virus may also have larger, systemic effects that could affect the following systems:

  • The reproductive system: abortions have been reported in pregnant cats that are infected with herpes.
  • The nervous system: facial spasms and twitching (from damaged nerves), changes in pupil size, and increased sensitivity to light.
  • Dermatologic changes: skin ulcers are occasionally seen around the cat’s mouth and face. These appear as crusty and reddish scabs around the eyes or nose.

That’s a long list of complications that herpes can cause and some of them are pretty scary!

Fortunately, the more severe herpes complications are pretty rare but it’s important to be aware. With any disease, early intervention leads to higher success rates and less chance for complications to develop.

Your job as a cat owner isn’t to be able to identify all of those things on the list. Your vet has specialized tools and tests to be able to diagnose the more serious of these infections.

The main signs that you should look for are discharge around the eyes or nose and changes to breathing sounds and patterns. While discharge around the eyes or nose is not an emergency, cats that appear to have difficulty breathing as well should be taken to your vet as soon as possible.

Open mouth breathing for cats is never normal and should be considered an emergency.

If you are comfortable with taking your cat’s temperature, a reading over 102.5 °F (39.2 ) is considered high.

Are cats and people affected by the same virus?

Herpes contains over 100 different viruses that share a lot of characteristics in terms of how they infect different animals and how they’re able to evade the immune system of each infected animal.

Herpes is thought to be ineffective in all of the birds and mammals on the planet. Each species of the herpes family can only infect a specific range of animals that is unique to that particular virus.

That means that the type of herpes virus that infects your cat CANNOT infect you and likewise, humans can not pass herpes to cats or other animals.

One thing that is common among all the herpes strains out there is that once they infect a given animal, they have the potential to cause latent infections in certain types of nerve cells. This means that the virus will remain with the animal for life.

The trademark of this type of virus is that it remains dormant in the body for a period of time and does not cause any signs or symptoms of the disease. If this happens, cats become lifetime carriers of the virus and may shed it from time to time.

The awakening of the virus may be caused by stress or weakening of the immune system. And when the conditions are right for the virus, it can re-emerge and cause disease all over again.

A stressful event at home or something else can be enough to trigger the virus to come out of hiding and even start infecting more cells which could result in another bout of a herpes-related illness.

In medicine, the term recrudescence is used to describe an illness that re-emerges from a period of dormancy.

adult cat with herpesvirus infecion and purulent conjunctivitis
adult cat with herpesvirus infecion and purulent conjunctivitis

How does a cat become infected?

Transmission of this virus in cats, which is caused by Feline Herpesvirus type-1, may either be thru direct or indirect contact. In direct contact, generally, an unaffected cat must be within close proximity of the infected cat to get the virus. Infected cats shed the virus through their saliva, sneezing, and discharge that can come from their eyes.

Additionally, a pregnant cat that is a carrier of the virus can pass it to her kittens.

Indirect contact, on the other hand, may be thru food or water bowls, toys or litter boxes that are being shared by two felines where one is already infected despite the virus itself being somewhat fragile in the environment. It can also be transmitted from the handling and clothing of pet owners.

This type of illness is common in multi-cat households or animal shelters that are overcrowded. If there is poor ventilation, nutrition, and sanitation, then, the cats are at a higher risk of getting the disease.

Once the virus enters the cat, it begins infecting the cells lining the upper respiratory tract, the tonsils, and conjunctiva which is the tissue that covers part of the eyeball and the eyelid. Once the virus begins replicating in those tissues, the clinical signs of a herpes infection begin to surface.

A fomite is a technical term for an object in the environment that can transmit the disease to another animal. In the above example, the toy or water bowl would be considered the fomite for passing the herpes virus to an unaffected cat.

I think my cat may have a herpes infection, what will my vet do?

This one might be a little unsatisfying for owners, but the actual diagnosis for herpes will often not be performed by your vet. Remember that we touched on respiratory syndrome earlier?


Well, any of the infectious causes of the syndrome could be responsible for a respiratory infection in your kitty. They can all cause similar symptoms!

There are some clues your vet will look for to allow a presumptive diagnosis which is a diagnosis of a certain disease or condition that is based on the presentation, history, and clinical signs seen in a patient, not via a confirmatory diagnostic test.

Respiratory disease in cats is relatively common and most veterinarians can differentiate between causative agents of respiratory infections with relative confidence. A thorough physical exam is oftentimes all it takes for a vet to feel comfortable to start the treatment.

It is not until a cat is roughly symptomatic for at least ten days where certain laboratory tests may be ordered to differentiate between the viruses. If your cat is sick for that long, it then becomes more important to know exactly what is making it sick so that treatment and therapy can be tailored more precisely.

Empirical treatment is the therapy that starts from an educated medical guess in the absence of a perfect diagnosis. Clinicians must always weigh the risks of starting treatment for a presumed disease versus waiting and withholding therapy until the diagnosis is known!

What are the treatments available?

Viral infection has no conclusive treatment so the main goal is to give supportive care, manage the symptoms, and stop the virus from replicating. Most cats usually have a good prognosis or are predicted to overcome the cat herpes symptoms, but a different story occurs in kittens and senior cats.

When cats recover from the feline viral rhinotracheitis, it is estimated that 80% of them become a carrier of the virus.

The treatment for cats with symptoms resembling a viral respiratory infection is largely symptomatic.

Symptomatic treatment involves giving medications designed to alleviate the clinical signs a patient shows and not treat the actual cause of the disease. This is because there are few antiviral medications on the market for cats that are effective against the herpes virus.

Some examples of symptomatic treatment include:

  • Fluid therapy for dehydrated patients – Most cats afflicted with feline herpes get dehydrated due to loss of appetite. It is essential that they are given proper nutrition or the veterinarian will suggest that an intravenous fluid should be administered to support your cat’s body system.

This is usually administered at the clinic but your vet may give you a bag of fluids to give your cat at home in some cases.

  • Cleaning discharge from around the eyes and nose – Your vet can show you how you can do this. So at home, you can try to keep the nasal passages from becoming too obstructed. Some cats with obstructed nasal cavities may have less interest in food or refuse to eat at all.
  • Nutritional support for anorexic cats – We want to keep our feline patients eating, even when they may not have much of an appetite when they are ill. Appetite stimulants for our feline friends work pretty well and are available at most veterinary pharmacies.

In more severe cases, a temporary feeding tube can be used to ensure your cat is getting adequate nutrition while it is sick.

  • Use of Humidifier – If you have a humidifier at home, the moist air can feel soothing and keep the respiratory tract moist. You can set it up in a room that they sleep in to help relieve nasal congestion.

If you don’t have one, even placing your cat in the bathroom while you take a hot shower can help relieve some of its congestion! You can turn on the hot shower in your bathroom until steamy, then you may leave your cat inside for 10 – 15 minutes. Also, observe their breathing pattern once in a while to make sure they are breathing normally.

Some vets may also advise that you give L-lysine – a nutraceutical amino acid for your cats to suppress the virus. This has been largely popular among veterinarians to help combat the recurrence of the feline herpes virus for years.

But in recent studies, there has been no consistent pattern of effective results while some even made the infection worse. You may want to ask your vet for an alternative supplement.

Home care is important to shorten the duration of FHV symptoms. First and foremost, give all the medications to your cat as prescribed by the veterinarian. Ensure that proper nutrition is given to your cats during this time as it is critical in boosting their immune system.

For eye infections, make sure that you help them remove the crusting around their eyes by using a gauze dipped in a warm salt solution.

Are there other treatment options, and what about antibiotics?

Antibiotics are typically not given to patients with respiratory disease as they maintain a normal appetite and behavior. This is because the majority of respiratory disease is caused by a virus and antibiotics are not effective against viral diseases.

With symptomatic treatment, the cat’s immune system will usually be able to clear the disease on its own over the course of five to ten days.

While symptomatic support is usually sufficient, there are a few cases where an antibiotic may be indicated. Cats that have a fever, loss of appetite or lethargy may benefit from antibiotics as these signs can indicate a bacterial component of infection.

These infections are deemed as opportunistic meaning, they don’t cause disease when your cat is normal and healthy. But they can cause health problems when your cat is already sick from something else like the herpes virus.

There are different types of antibiotics that may be prescribed for varying lengths of time. It is up to your vet to determine whether or not your cat would benefit from them.

There is one more type of drug an antiviral agent that is formulated to act against the herpes virus itself called Famciclovir. It is a medication used mainly for humans to treat herpes infections but has seen increasing use for cat treatment.


Famciclovir is a newer drug available to veterinarians. Evidence shows it can prevent the herpes virus from replicating within the cat and reduce clinical signs.

However, there isn’t any published and peer-reviewed data available that proves its effectiveness. Still, it has been used with anecdotal success by some veterinarians.

It wouldn’t hurt to ask your vet about their drug and see if it is something they have had success with.

How can I prevent my cat from getting herpes?

While there is no way to fully protect your cat from the virus, the vaccines available against herpes work similarly to the flu vaccine in people. This vaccine is not used to completely eliminate the probability but is instead used to increase the immune system of the feline.

This also usually lessens the severity of symptoms that arise from infection and decreases time those symptoms last.

The initial vaccine is usually given around 6 weeks of age and boosters are needed at intervals to lower the risk of infection. Ask your local veterinarian about vaccinations so your cat is updated.

If your cat starts to show signs of herpes, some vets may recommend boosting your kitty with an intranasal vaccine. This vaccine works like an inhaler in that it is sprayed into your cat’s nose.

While it is not routinely given as part of the recommended core of vaccines, the intranasal mechanism works to stimulate a different kind of immune response to help cats clear an active infection quicker than they would have otherwise.

If you have multiple cats in your home and one begins to show signs of a respiratory infection, it’s not a bad idea to try and keep your cats separated so they do not pass the virus on to the other members in your furry family. Try to make sure they eat and drink out of separate containers and set up a separate litter box for the cats – even brushes – to use if at all possible.

A good habit of washing your hands before petting your other cats will also help reduce an outbreak at home.

The recuperating stage is critical for your cat’s health. It needs a quiet place where it can rest securely; away from outside noises or even other pets. Reduce the stress levels of your cat as much as you can since this can aggravate the illness and increase the risk of shedding.

House sanitation is important to deactivate the virus. The virus is susceptible to commercial disinfectants and detergents, so house disinfection is a must. The virus is also deactivated at a temperature of 37oC so you may also want to keep your cats warm.

Finally, try to minimize stress in your household. Not only will this contribute to a cat’s general well-being, but you can also lessen the chance that a latent infection resurfaces when your cat is subjected to stress.

Some tips to minimize stress for your cat include:

  • Anticipate stressful events that might perturb your cat. Shy cats may benefit from being isolated in your home if you have visitors over, for example.
  • Always make sure your cat has a secluded and clean area that they can retreat to and feel safe in. If it begins to feel overwhelmed by activity in your home, it knows that it has an accessible place to go hang out in until the commotion passes.
  • If there is a persistent dog barking in your neighborhood or construction nearby your home, leaving a radio on as a source of white noise can help drown out potentially spooky sounds to your cat.
  • Clean litter boxes in a quiet location in your house can do wonders for your cat’s sense of wellness.
  • Consider a few well-placed cat perches around your home. A high vantage point where cats can survey their “kingdom” can help them feel comfortable knowing they are out of reach of children or the family dog.
  • Mental enrichment plays a huge role in a cat’s overall sense of well-being. New and interesting toys, food puzzles, and a little bit of exercise all contribute to its comfort level.
  • Don’t forget the cuddles! All cats need is a little bit of TLC every day to keep the bond between you and your purring pal strong.

So my cat now has herpes forever?

Many cats with upper respiratory infections including those caused by herpes are able to clear the infection in couple of weeks. As mentioned, cats with herpes remain infected for life. While this sounds bad, in reality, it’s a minor complication that you’ll just have to be aware of.

Once your cat begins to clear a herpes infection, some of the viral particles are able to hide out in nerve cells and wait to come out later. We haven’t really figured out how the virus is able to hide from the immune system or what triggers it to come out of hiding. But we do know that it can reappear during times of stress or other illness.

When this happens, your cat may begin to show signs of infection again. Usually, the illness isn’t as bad as it was the first time around. The illness also usually doesn’t last as long either. Be mindful that your cat can infect other cats if you think the virus reappeared.

Cats can actively shed viral particles through their saliva and secretions when the virus becomes reactivated, so be aware that if you have an immunocompromised cat in the household or a cat that is naive (never been exposed) to the herpes virus.

Wrapping It Up

While your mind may conjure scary images when it comes to herpes and your cat, hopefully, this article has relieved some of your concerns and given you a few things to watch out for in your own cats.


While herpes can lead to some serious complications if left unchecked, the vast majority of cats will recover fine with a little prevention and timely intervention.

To sum it all up…

  • While all cats are susceptible to herpes, those at particular risk include kittens and immunocompromised cats.
  • Cats can’t pass their version of herpes to people.
  • Cats that are infected will remain so for life. The virus can reappear and cause mild respiratory issues, similar to the common cold that people have from time to time. These episodes are usually brought on by stressful events or another illness that your cat may have.
  • Vaccines against the virus are safe and commonly used. They help to lessen the symptoms displayed by an infected cat and decrease the amount of time the cat is sick.
  • A cat with clinical signs of an infection is shedding the virus through their saliva, sneezes, and other secretions. Try and keep the affected and unaffected cats separated during this time.
  • Environmental enrichment and providing safe spaces for your cat to go can go a long way in decreasing its stress and lessening the chance for flare-ups.
  • Herpes virus boosters and some human antiviral medications may be beneficial in helping your cat fight an infection. It’s never a bad idea to bring your cat to the family veterinarian if it appears to be particularly affected by an upper respiratory infection. Early intervention leads to the best outcomes for all animals!

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