Cats get herpes almost exclusively from other cats, through direct contact with respiratory secretions like sneezes, shared saliva, or mutual grooming. The virus, called feline herpesvirus type 1 (FHV-1), spreads through the air as droplets or through nose-to-nose contact, and a cat can start passing it to others within two to five days of being infected, before any symptoms appear.
The Main Routes of Transmission
FHV-1 enters a cat’s body through the nose, mouth, or eyes. The most common scenario is straightforward: an infected cat sneezes near another cat, and the virus rides the droplets into the healthy cat’s airways. But transmission doesn’t require something that dramatic. Two cats drinking from the same water bowl, grooming each other, or simply sharing a sleeping spot can be enough. Any exchange of nasal or oral secretions creates an opportunity.
What makes FHV-1 especially efficient at spreading is the timing. A newly infected cat becomes contagious during the incubation period, days before it shows any signs of illness. Once symptoms do appear, the cat remains infectious for up to three weeks. That’s a long window during which an apparently healthy cat, or one that just started sniffling, can silently spread the virus to every cat in the household.
How Mothers Pass It to Kittens
One of the most common transmission routes is from mother to kitten. The virus doesn’t cross the placenta during pregnancy, so kittens aren’t born infected. Instead, the stress of giving birth and nursing triggers a flare-up in mothers who carry the virus, causing them to shed it in their secretions right when their kittens are most vulnerable. The close contact of nursing and grooming makes transmission nearly inevitable. This is why FHV-1 is so widespread in the cat population: many cats are exposed before they’re even old enough for their first vaccine.
Why the Virus Never Leaves
Once a cat is infected, FHV-1 is permanent. After the initial illness clears, the virus retreats into nerve cells near the base of the skull and goes dormant. In this latent state, the virus produces almost none of its usual proteins, essentially hiding from the immune system. It stays there for the rest of the cat’s life.
Virtually all infected cats develop this latent infection. The virus can reactivate at any time, triggered by stress, illness, or changes in the cat’s environment. When it reactivates, the cat begins shedding virus in its nasal and eye secretions again, becoming contagious even if symptoms are mild or absent. This cycle of dormancy and reactivation is the engine that keeps FHV-1 circulating through cat populations. A cat that seemed perfectly healthy for years can suddenly start spreading the virus after a stressful event like a move, a new pet in the home, or a bout of another illness.
Environmental Spread Is Rare
Unlike some viruses that can linger on surfaces for days, FHV-1 is fragile outside the body. In typical home environments, contaminated surfaces don’t play a significant role in transmission. The exception is densely housed settings like catteries or shelters, where many cats share close quarters and contaminated objects are harder to avoid. For most pet owners with one or two cats, the virus spreads cat-to-cat, not through furniture or food dishes sitting around.
Standard household disinfectants can kill the virus on hard surfaces with about 10 minutes of contact time. Diluted bleach (sodium hypochlorite) works, as do products containing chlorine dioxide or potassium peroxymonosulfate. If you’re bringing a new cat into a home where a cat has had a herpes flare-up, wiping down food bowls, litter boxes, and other shared items with one of these solutions adds a reasonable layer of protection.
High-Risk Settings
Shelters, boarding facilities, and multi-cat households are where FHV-1 thrives. Crowding, stress, and constant introduction of new animals create the perfect conditions for both fresh infections and reactivation in carriers. A single stressed cat shedding virus in a room full of unvaccinated cats can spark an outbreak quickly. Kittens and cats with weakened immune systems are hit hardest, often developing severe upper respiratory infections with heavy nasal discharge, eye ulcers, and fever.
What Vaccination Can and Can’t Do
The standard FVRCP vaccine, which most cats receive as kittens, includes a component against FHV-1. But this vaccine doesn’t prevent infection entirely. Its realistic goal is to reduce the severity and duration of symptoms if a cat is exposed. A vaccinated cat can still catch the virus, carry it for life, and shed it during flare-ups. The vaccine simply makes the disease less dangerous.
Research on whether adding an intranasal vaccine on top of the standard injectable version improves protection has produced mixed results. Some studies found modest improvement, while others found no benefit or even a slight increase in upper respiratory illness in shelter cats receiving both. For most pet cats, the standard injectable vaccine given on a routine schedule provides the best-established protection available.
What a Flare-Up Looks Like
The first infection is usually the worst. Symptoms appear two to five days after exposure and typically last 10 to 20 days. You’ll see sneezing, nasal congestion, watery or goopy eyes, and sometimes fever or loss of appetite. In kittens or immunocompromised cats, the infection can become severe enough to cause eye ulcers or secondary bacterial infections.
Later flare-ups tend to be milder but follow the same pattern of sneezing, eye discharge, and congestion. They’re triggered by anything that taxes the immune system: a stressful vet visit, surgery, a new animal in the house, or concurrent illness. During these episodes, the cat is contagious again, so separating it from other cats (especially unvaccinated ones) reduces the chance of spreading the virus further.