Your cat starts sneezing, their eyes look gluggy and weepy, and suddenly they’re turning their nose up at dinner. Sound familiar? There’s a fair chance you’re looking at cat flu — one of the most common illnesses we see in Aussie cats, and one of the most misunderstood. The good news is that with a bit of know-how, most cats bounce back well. Here’s what every owner should understand about spotting it, managing it, and keeping it out of your home.
What Cat Flu Actually Is
“Cat flu” is an umbrella term for a feline upper respiratory infection — think of it as a heavy head cold for cats. Around 80–90% of cases are caused by two viruses: feline herpesvirus (FHV-1) and feline calicivirus (FCV). Both are widespread in the Australian cat population. Sometimes bacteria pile on top, which is why a clear runny nose can turn thick and yellow-green.
It’s Not Really a “Winter” Illness
Plenty of owners assume cat flu surges in the cold months the way human colds seem to. In reality, the virus doesn’t care much about the temperature — it spreads through contact and stress, not chilly weather. Winter just happens to bunch cats together: holiday boarding, more time indoors, and busier shelters all create the close contact and stress that let the virus move. Many recovered cats stay lifelong carriers, and herpesvirus tends to flare up again during stressful patches like rehoming, a new pet, or a stay at the cattery.
Symptoms to Watch For
Cat flu looks a lot like a human cold, but signs range from mild sniffles to a genuinely unwell cat. Keep an eye out for:
- Sneezing and a runny or blocked nose
- Red, weepy or gluey eyes (conjunctivitis)
- Nasal or eye discharge that turns yellow or green
- Ulcers on the mouth or tongue, dribbling, or pawing at the face
- Fever, low energy, and going off their food
Why “Off Their Food” Is the Big Red Flag
A blocked nose means a cat can’t smell — and cats that can’t smell their food often stop eating altogether. That matters more than it sounds: a cat that goes without food for even a day or two can develop serious liver problems. Kittens and senior cats are hit hardest because their immune systems have less in reserve. If your cat isn’t eating, is breathing with effort, or seems flat and dehydrated, that’s your cue to ring the vet rather than wait it out. A sudden change in thirst can be telling too — our guide on warning signs when a cat drinks more water is worth a read.
How It Spreads Around the House
Cat flu passes directly through saliva and the discharge from an infected cat’s eyes and nose, and indirectly via shared food bowls, bedding, litter trays — even your hands. That makes multi-cat homes, shelters and breeders the highest-risk settings. Because so many cats become carriers, an apparently healthy cat can still pass it on when stressed, which is exactly why prevention beats cure.
Treatment: Supportive Care Wins
There’s no magic pill that kills the virus, so treatment is about supporting your cat while their body does the work. Your vet may prescribe pain relief, eye drops, antibiotics for a secondary bacterial infection, or fluids if your cat is dehydrated. At home you can make a real difference:
- Gently wipe away eye and nose discharge with a warm, damp cloth
- Sit with them in a steamy bathroom for a few minutes to loosen a blocked nose
- Tempt the appetite with warmed, strong-smelling food
- Keep them warm, quiet and rested — our tips on keeping a cat warm through an Aussie winter help here
- Keep a sick cat separate from other cats for about two weeks, with their own bowls and litter
One firm rule: never give human cold or flu medicines. Many common painkillers and decongestants are toxic to cats — see our rundown of foods and substances toxic to cats before reaching for anything in the cupboard.
When to See a Vet Straight Away
- Not eating for more than 24 hours
- Laboured or open-mouth breathing
- Very lethargic, weak or dehydrated
- A young kitten or elderly cat showing any symptoms
Prevention: Your Best Tools
Vaccination is the cornerstone. In Australia the core F3 vaccine protects against feline panleukopenia, herpesvirus and calicivirus. It won’t guarantee your cat never catches a sniffle, but it dramatically reduces how severe the illness gets. Kittens usually start their course around 8 weeks, with boosters at 12 and 16 weeks, then a booster every one to three years — your vet will tailor this to your cat’s lifestyle.
Beyond the needle, a few simple habits go a long way:
- Keep stress low around boarding, moving house or introducing new pets
- Wash shared bowls, bedding and litter trays regularly
- Quarantine new cats for a couple of weeks before they mingle
- Wash your hands between handling different cats
- Keep indoor cats busy and content — our indoor cat enrichment guide helps lower stress
Key Takeaways
- Cat flu is a viral upper respiratory infection, mostly from feline herpesvirus and calicivirus
- It spreads through contact and stress — not cold weather itself
- A cat that stops eating needs a vet, not a wait-and-see approach
- Treatment is supportive: rest, warmth, hydration and vet-guided care
- The F3 vaccine and good hygiene are your strongest defences
The Bottom Line
Cat flu is common, but it doesn’t have to be scary. Catch the early signs, keep your cat eating, warm and rested, and lean on your vet when symptoms tip past a simple sniffle. Stay on top of the F3 vaccine and a bit of everyday hygiene, and you’ll give your cat the best shot at shrugging it off — this winter and every season after. Dogs have their own contagious cousin worth knowing about too: read up on kennel cough in dogs if you share your home with both.
