Cat Flu. What Every Owner Needs to Know.
Medically Reviewed by Dr. Romilly Haslam & Dr. Mark Tonzing
It usually starts with a simple sneeze. Then comes the watery eyes, the lethargy, and the untouched food bowl.
If your feline friend is showing these signs, they might be dealing with "cat flu"—one of the most common infectious diseases in domestic cats.
Despite the name, cat flu is not caused by the influenza virus that affects humans. It is a highly contagious upper respiratory infection (URI) that can affect cats of any age, though kittens, senior cats, and those with weakened immune systems are particularly vulnerable.
Here is everything you need to know about spotting, treating, and preventing cat flu.
The Culprits Behind the Cough
In over 80% of cases, cat flu is caused by one of two viruses:
Feline Herpesvirus (FHV-1)
This virus tends to cause more severe symptoms, particularly affecting the eyes. Like human herpesviruses, it remains dormant in a cat’s body for life and can flare up during times of stress.
Feline Calicivirus (FCV)
Generally milder in respiratory symptoms, FCV is notorious for causing painful mouth ulcers, which can stop a cat from eating.
Note: Sometimes, bacteria like Bordetella bronchiseptica or Chlamydia felis join the party as secondary infections, making the symptoms worse.
Signs and Symptoms to Watch For
Because cats are masters at hiding illness, it’s important to catch the early warning signs. Contact us if you notice your cat experiencing:
- Frequent sneezing or coughing
- Discharge from the eyes or nose (clear, yellow, or green)
- Squinting, red, or swollen eyes
- Loss of appetite (often because a blocked nose means they can't smell their food, or mouth ulcers make chewing painful)
- A fever or noticeable lethargy
- Drooling
- Hoarse meow or loss of voice
How Does it Spread?
Cat flu is highly contagious. It spreads rapidly through direct contact with an infected cat's saliva, tears, or nasal discharge.
It also spreads via "fomites"—objects like shared food bowls, bedding, litter trays, and even human hands or clothing.
Because the virus can survive in the environment for up to a week, indoor cats are still at risk if the virus is accidentally tracked inside on your shoes or clothes.
Treatment and Care at Home
While there is no direct "cure" for the viruses that cause cat flu, we can do a lot to support your cat through the illness and treat any secondary bacterial infections.
Veterinary Care
If your cat is diagnosed with cat flu, we may prescribe antibiotics (to clear up secondary bacterial infections), eye drops if their eyes are affected, and pain relief if they have painful mouth ulcers. In severe cases where a cat has stopped eating and drinking, they may need to be admitted for intravenous fluids and nutritional support.
Nursing at Home:
Clear the airways
Gently wipe away eye and nasal discharge with a warm, damp cotton ball.
Encourage eating
Warm up strong-smelling wet food (like sardines or roast chicken) to break through their congested sense of smell.
Steam therapy
Bring your cat into the bathroom while you take a warm shower. The steam helps loosen congestion in their nasal passages.
Reduce stress
Keep them in a quiet, warm, and comfortable room away from loud noises or other pets.
The Power of Prevention
The absolute best defense against cat flu is vaccination. While vaccines don't always prevent infection 100% of the time, they dramatically reduce the severity of the illness and prevent life-threatening complications.
Kittens should receive their core vaccinations starting at 6-8 weeks of age, followed by regular boosters. Even if your cat is strictly indoors, staying up-to-date on their boosters is vital for their long-term protection.
Dealing with "Carrier" Cats
If your cat has recovered from the Feline Herpesvirus, they will likely become a lifelong carrier. Most of the time, they will appear perfectly healthy.
However, stressful events—such as moving house, new additions to the family, or boarding at a cattery—can trigger a flare-up of symptoms. Managing their stress and maintaining a calm environment is key to keeping carrier cats healthy.
Frequently Asked Questions
Can humans or dogs catch cat flu?
No, humans cannot catch cat flu, as it is completely different from the human influenza virus. Dogs are generally safe from the main cat flu viruses (FHV-1 and FCV), though they can share certain secondary bacterial infections like Bordetella.
How long does cat flu last?
Mild cases typically resolve in 1 to 2 weeks with proper care. However, if your cat develops secondary bacterial infections, recovery can take longer. Keep in mind that cats infected with FHV-1 often become lifelong carriers and may experience flare-ups during periods of stress.
Can my strictly indoor cat get cat flu?
Yes. The viruses that cause cat flu can survive in the environment for up to a week. You can accidentally track the virus inside on your shoes, clothing, or unwashed hands after petting a stray or infected cat. This is why keeping indoor cats fully vaccinated is highly recommended.
Is cat flu fatal?
In healthy adult cats, cat flu is rarely fatal, though it can make them feel extremely unwell. However, it can be life-threatening for vulnerable cats, particularly young kittens, unvaccinated felines, seniors, or those with compromised immune systems.
When to Call the Vet
Cat flu can progress from mild sniffles to a severe respiratory issue very quickly, particularly in young kittens. If your cat hasn't eaten in 24 hours, is struggling to breathe, or seems profoundly lethargic, do not wait.