Feline Herpesvirus (FHV-1) in Cats: Symptoms and Flare-Ups
Feline herpesvirus (FHV-1) is a lifelong viral infection and one of the leading causes of upper respiratory disease, sneezing, and recurring eye problems in cats. Care focuses on reducing and managing flare-ups rather than removing the virus, because FHV-1 stays in the body for life. If your cat has repeated bouts of sneezing, runny eyes, or squinting, feline herpesvirus is a common reason, and your veterinarian can confirm it and guide treatment.
This guide is written for cat caregivers in Australia and New Zealand who want a clear, honest picture of what feline herpes is, how it behaves, and what you can realistically do. We are direct about what the evidence supports and what it does not.
A cat resting comfortably at home.
What is feline herpesvirus (FHV-1)?
Feline herpesvirus (FHV-1) is a highly contagious virus that causes feline viral rhinotracheitis, often called "cat flu". It is one of the two main causes of upper respiratory infection in cats, alongside feline calicivirus (FCV).
FHV-1 spreads through direct contact with an infected cat's saliva, eye discharge, and nasal secretions, as well as shared bowls, bedding, and hands. Kittens, cats in multi-cat homes, and cats in shelters or catteries are at higher risk.
Once a cat is infected, feline herpesvirus becomes a lifelong resident in the nerve tissue. The cat may look completely healthy between episodes, then flare up again when stressed or unwell. This pattern of recurrence is the defining feature of feline herpes infection.
What are the symptoms of feline herpesvirus in cats?
The most common signs of feline herpesvirus are sneezing, nasal discharge, watery or gunky eyes, squinting, and conjunctivitis. Some cats also develop corneal ulcers, and occasionally mouth ulcers, especially during a strong flare-up.
Typical FHV-1 signs to watch for include:
Repeated sneezing and a runny or blocked nose
Clear or coloured nasal discharge
Watery eyes, eye discharge, or crusting around the eyes
Squinting or holding an eye partly closed
Conjunctivitis, where the tissue around the eye looks red and swollen
Corneal ulcers, which can make an eye painful and cloudy
Reduced appetite, low energy, and sometimes a mild fever
Eye involvement is a hallmark of feline herpes, and it is one of the biggest reasons owners seek help. A cat that is pawing at an eye, keeping it shut, or showing a cloudy surface needs prompt veterinary attention, because corneal ulcers can worsen quickly. You can read more about the ocular signs in our overview of feline herpesvirus symptoms and eye discharge.
Why does feline herpesvirus keep coming back?
Feline herpesvirus keeps coming back because it is a lifelong infection that lies dormant in the nerves and reactivates during periods of stress or illness. The virus is never fully removed from the body, so flare-ups are a normal part of living with FHV-1.
Common flare-up triggers include:
Rehoming, boarding, or travel
A new pet or new baby in the household
Changes to routine, territory, or furniture
Other illnesses or surgery
Pregnancy and nursing in queens
Overcrowding in multi-cat homes
Because stress is such a strong trigger, a large part of managing feline herpes is keeping your cat's environment calm, predictable, and low in conflict. Reducing stress will not remove the virus, but it can lower how often and how severely your cat flares.
How is feline herpesvirus diagnosed?
Feline herpesvirus is usually diagnosed by your veterinarian based on the pattern of signs, the cat's history of recurring respiratory or eye problems, and a physical examination. In some cases, laboratory tests such as PCR swabs are used to confirm the virus, particularly in shelters, breeding catteries, or complex cases.
Your veterinarian may also examine the eye closely, sometimes using a special stain, to check for corneal ulcers. This matters because the presence and depth of an ulcer changes how the eye is treated.
Diagnosis is also about ruling other things in or out. Feline herpesvirus and feline calicivirus (FCV) both cause cat flu, but they are different viruses with different tendencies, and telling them apart helps guide care.
Feline herpesvirus vs feline calicivirus: how are they different?
Feline herpesvirus (FHV-1) and feline calicivirus (FCV) are both major causes of upper respiratory infection in cats, but they are distinct viruses with different typical signs. FHV-1 tends to cause more eye and nasal disease, while FCV is more associated with mouth ulcers and oral disease.
Feature | Feline herpesvirus (FHV-1) | Feline calicivirus (FCV) |
Common name | Feline viral rhinotracheitis, cat flu | Cat flu |
Signature signs | Sneezing, eye discharge, conjunctivitis, corneal ulcers | Mouth ulcers, gingivitis, stomatitis, drooling |
Course | Lifelong infection with recurring flare-ups | Can persist or shed for a period; oral disease can be chronic |
Antiviral direction | Famciclovir may be prescribed by a veterinarian | EIDD-1931 is used for FCV oral disease |
If your cat's main problem is mouth ulcers or severe gum inflammation rather than eyes and nose, feline calicivirus may be involved instead. Our guide to feline calicivirus symptoms and mouth ulcers explains that picture in more detail, and vaccination is covered in our article on the feline calicivirus vaccine in Australia.
What is the treatment for feline herpesvirus?
There is no treatment that removes feline herpesvirus from the body, so feline herpesvirus treatment focuses on shortening and easing flare-ups, protecting the eyes, and supporting the immune system. An antiviral called famciclovir is one option a veterinarian may prescribe to help manage active episodes.
HerpX is CureFIP's FHV-1 product line, and its active ingredient is famciclovir. It is an antiviral aimed at supporting cats through herpesvirus flare-ups. Any dosing decision must come from your veterinarian, who will set the right approach for your individual cat, so we do not publish dose figures here.
Supportive care during a flare-up often includes:
Keeping the eyes and nose gently clean of discharge
Encouraging eating with warm, aromatic food
Making sure your cat stays hydrated
Reducing stress and keeping the home calm
Following any eye medication plan your veterinarian sets for conjunctivitis or corneal ulcers
It is important to understand what antivirals and antibiotics each do. Antivirals target the virus itself. Antibiotics do not treat feline herpesvirus at all, and are only used when a secondary bacterial infection develops on top of the viral illness. Your veterinarian will decide whether either is appropriate.
For a fuller picture of what a management plan can look like locally, see our companion piece on feline herpesvirus treatment in Australia.
How can Australian and New Zealand owners manage flare-ups at home?
Australian and New Zealand owners can manage feline herpesvirus flare-ups by lowering stress, supporting good nutrition and hydration, keeping the eyes clean, and working closely with a veterinarian on any medication. Consistency between episodes matters as much as treatment during them.
Practical steps you can take:
Keep routines steady, with predictable feeding, play, and rest.
Provide enough separate resources in multi-cat homes: bowls, litter trays, beds, and high resting spots.
Introduce new pets, people, or changes slowly and calmly.
Wipe away eye and nose discharge gently with a clean, damp cloth.
Watch appetite closely, because a blocked nose can dull a cat's sense of smell and reduce eating.
Book a veterinary visit early when a flare starts, especially if an eye looks painful, cloudy, or shut.
Good husbandry does not eliminate feline herpes, but it gives your cat the best chance of longer, calmer stretches between flare-ups. Many caregivers find that once they know their cat's triggers, they can anticipate difficult periods and act sooner.
Can feline herpesvirus be prevented?
Feline herpesvirus cannot be completely prevented, but vaccination and good hygiene reduce the risk and severity of disease. The core vaccine given to cats in Australia and New Zealand includes protection against feline herpesvirus and feline calicivirus.
Vaccination does not guarantee your cat will never be infected or never flare, but it helps lower how severe the illness tends to be. In multi-cat environments, cleaning shared items, isolating sick cats, and washing hands between cats all help limit spread. Talk to your veterinarian about the right vaccination schedule for your cat's age and lifestyle.
FAQ: Feline Herpesvirus (FHV-1) in Cats
Is feline herpesvirus contagious to other cats?
Yes, feline herpesvirus is highly contagious between cats, spreading through saliva, eye and nasal discharge, and shared items like bowls and bedding. It does not infect humans or dogs. Isolating a flaring cat and cleaning shared items helps reduce spread in multi-cat homes.
Can feline herpesvirus be cured?
No. Feline herpesvirus is a lifelong infection that stays in the body, so it cannot be cleared or eliminated. Care focuses on managing and reducing flare-ups and protecting the eyes, and many cats live full, comfortable lives with good management and veterinary support.
Do antibiotics treat feline herpesvirus?
No, antibiotics do not treat the herpesvirus itself, because it is a virus and not a bacterium. Antibiotics are only used when a secondary bacterial infection develops alongside the viral illness. Your veterinarian will decide whether antibiotics or an antiviral such as famciclovir is appropriate.
How long do feline herpesvirus flare-ups last?
Most feline herpesvirus flare-ups last from several days to a couple of weeks, though this varies with the individual cat and how quickly care begins. Early supportive care and reducing stress can help shorten and ease an episode. See your veterinarian promptly if the eyes are affected.
Is feline herpesvirus the same as feline calicivirus?
No, they are different viruses. Feline herpesvirus (FHV-1) more often causes eye discharge, conjunctivitis, and corneal ulcers, while feline calicivirus (FCV) is more linked to mouth ulcers and oral disease. Both cause cat flu, and your veterinarian can tell them apart.
If your cat is showing signs of feline herpesvirus, the best next step is a conversation with your own veterinarian, who can confirm the diagnosis and tailor a plan. To learn more about the care options and to reach our team, visit CureFIP Oceania and talk through what might suit your cat. Every medical decision should be made together with your veterinarian.
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