If your cat has started sneezing, squinting or turning up their nose at dinner as the cold weather sets in, you’re not imagining it. Vets around Australia see a noticeable jump in “cat flu” through the cooler months, when cats spend more time huddled indoors and stress levels quietly creep up. The good news? Most cats recover well with the right care, and a few simple habits can stop the sniffles turning into something serious.
What exactly is cat flu?
Cat flu is the everyday name for an upper respiratory infection in cats. Despite the name, it has nothing to do with human influenza. According to RSPCA Australia, around 90% of cases are caused by two viruses: feline herpesvirus (FHV-1) and feline calicivirus (FCV). Both spread easily between cats but pose no risk to people or dogs.
Here’s the tricky part: cats who catch feline herpesvirus often become lifelong carriers. They can seem perfectly healthy for months, then flare up again during periods of stress — which is exactly why winter can bring the symptoms roaring back.
Why winter tends to make it worse
Cold weather itself doesn’t cause cat flu, but the season creates the perfect conditions for it to spread and resurface:
- More time indoors. Cats kept inside for warmth share bowls, bedding and airspace, giving viruses easy paths between animals in multi-cat homes.
- Higher stress. A change in routine, a new pet, or simply less time in the sun can trigger carrier cats to “shed” the virus again. Stress also has an immunosuppressive effect, lowering a cat’s defences.
- Vulnerable ages. Kittens and older cats have weaker immunity and tend to be hit hardest.
If you’ve recently adopted from a shelter or cattery — common over the winter and school-holiday period — keep a close eye out, as these busy environments are classic flare-up spots.
Signs to watch for
- Sneezing and a runny or blocked nose
- Watery, red or gunky eyes (conjunctivitis)
- Dribbling, mouth ulcers or reluctance to eat
- Fever, low energy and hiding away
- A hoarse or lost meow
A blocked nose is more serious than it sounds. Cats rely heavily on smell to feel hungry, so a stuffy nose can quickly lead to a cat refusing food altogether — and that’s when a mild bug can turn into a real problem.
Caring for a sniffly cat at home
There’s no cure that wipes these viruses out, so treatment focuses on supportive care while your cat’s immune system does the heavy lifting. Your vet may prescribe medication for secondary bacterial infections or, in severe cases, antivirals. At home, many owners find these steps help:
- Gently wipe away eye and nose discharge with a damp, warm cloth.
- Sit your cat in a steamy bathroom for a few minutes to loosen congestion.
- Offer warmed, strong-smelling wet food to tempt a blocked-up nose.
- Keep fresh water within easy reach to prevent dehydration.
- Keep them warm, quiet and separated from other cats.
Consult a licensed veterinarian for diagnosis or treatment specific to your pet, especially if symptoms don’t ease within a few days.
Prevention that actually works
- Stay on top of vaccinations. The standard F3 vaccine covers herpesvirus and calicivirus. RSPCA Australia recommends starting from around eight weeks of age, with boosters as advised by your vet.
- Reduce stress. Predictable routines, quiet hiding spots and gradual introductions help keep carrier cats from flaring.
- Keep things clean. Wash bowls, bedding and litter trays regularly, and wash your hands between handling different cats.
- Isolate new or unwell cats until you’re confident they’re in the clear.
Vaccination won’t always stop infection outright, but vaccinated cats generally develop milder symptoms and shed less virus, which protects the other cats around them too.
When to call the vet
Book a vet visit if your cat stops eating for more than a day, struggles to breathe, has thick green or yellow discharge, or becomes very lethargic. A stubborn case can also mask other winter health problems, so it’s worth getting checked. For kittens and senior cats, don’t wait — these groups can go downhill quickly, so any symptoms deserve a prompt call.
Frequently asked questions
Is cat flu contagious to humans or dogs?
No. Feline herpesvirus and calicivirus only affect cats. You can’t catch it and neither can your dog — though you can carry the virus on your hands or clothes between cats, so wash up between pats.
Can an indoor-only cat still get cat flu?
Yes. Carrier cats can flare up on their own during stress, and the virus can hitch a ride indoors on hands, shoes or shared items. Indoor living lowers the risk but doesn’t remove it entirely.
Does my cat need the vaccine every year?
Booster timing varies. Many cats move to a three-yearly schedule for core vaccines, but your vet may recommend annual boosters depending on your cat’s lifestyle and risk. Follow your vet’s advice.
Will cat flu go away on its own?
Mild cases often improve within one to two weeks with supportive care. But because carrier cats can relapse and symptoms can worsen without warning, it’s still worth checking in with your vet.
Key takeaways
- Cat flu is a viral upper respiratory infection, not human flu, and about 90% of cases come from feline herpesvirus and calicivirus.
- Winter raises the risk through indoor crowding, stress and lower immunity in kittens and seniors.
- There’s no cure, but supportive home care and prompt vet advice help most cats bounce back.
- Vaccination, low stress and good hygiene are your best defences.
