Kitten flu (or cat flu) is the common term for feline upper respiratory tract infection, a contagious illness that mainly affects the nose, throat and sometimes the eyes. It is most often seen in unvaccinated cats and kittens and it can spread quickly in places where cats live closely together, such as multi-cat households or rescue centres.
Although most cats recover well, cat flu in kittens can sometimes be more serious. Young kittens are more vulnerable because their immune systems are still developing, which means they may find it harder to fight off infection. In severe cases, kitten flu can make them very unwell and sadly, it can sometimes be fatal.
Knowing the early signs of cat flu in kittens, getting veterinary advice promptly and taking steps to prevent infection can all make an important difference.
What is cat flu (feline upper respiratory infection)?
Cat flu is an infection of the upper respiratory tract. This means it mainly affects the nose, throat and airways, although the eyes and mouth can also be involved. You may sometimes see it referred to as a kitten upper respiratory infection when it affects young cats.
Cat flu is usually caused by one or both of two common viruses:
- Feline herpesvirus
- Feline calicivirus
Some cats are infected with just one of these viruses, while others may have both at the same time. Secondary bacterial infections can also develop, especially when the immune system is already busy dealing with the viral infection. This can make signs (or symptoms) worse and may lead to a kitten feeling much more unwell.
How does cat flu affect kittens?
Cat flu can affect cats of any age, but kittens are often more seriously affected than healthy adult cats. Their immune systems are not yet fully developed, so they may be less able to fight infection effectively.
This is why cat flu in kittens may cause more noticeable illness, including sneezing, a runny nose, eye discharge and reduced appetite. In some cases, kittens can become weak, dehydrated or reluctant to eat, especially if they are very congested and cannot smell their food properly.
Because young kittens have fewer reserves than adult cats, they can deteriorate more quickly. That is why it is important to take kitten flu symptoms seriously, particularly in very young kittens.
What causes kitten flu?
The main kitten flu causes are viral infections, most commonly feline herpesvirus and feline calicivirus.
Feline herpesvirus often causes sneezing, eye discharge and nasal congestion. In some cats, the virus can remain in the body long term and flare up again during times of stress or illness.
Feline calicivirus can also cause respiratory signs, but it is particularly associated with ulcers in the mouth, which can make eating uncomfortable.
Sometimes a kitten with cat flu also develops a secondary bacterial infection. This happens because the viral infection can weaken the normal defences of the respiratory tract, giving bacteria an opportunity to cause further infection. When that happens, signs may become more severe or last longer.
Cat flu spreads from cat to cat, usually through close contact with infected saliva, nasal discharge or eye discharge, as well as through shared bedding, bowls, litter trays or human hands and clothing after handling an infected cat.
Common Kitten Flu Symptoms
The most common kitten flu symptoms are similar to the signs we might associate with a bad cold, including:
- Sneezing
- Runny nose
- Eye discharge
- Lethargy or sleeping more than usual
- Poor appetite
- Mouth ulcers or difficulty eating
- Noisy breathing or congestion
- Fever
- Reduced drinking
In many cases, kittens begin to improve after around a week, but it can take two to three weeks before they are fully back to normal.
Mild and moderate symptoms
Signs of cat flu in kittens can vary from mild to severe. In milder cases, kittens may just seem a little snuffly but remain bright, active and eating well.
Even mild or moderate signs should be monitored carefully, especially in younger kittens. Because they are more vulnerable, what begins as a mild or moderate illness can sometimes become more serious.
Serious symptoms (when to contact a vet)
Contact a vet promptly if your kitten:
- Develops mouth ulcers
- Just seems much more unwell than expected
A kitten that is not eating or drinking is especially concerning. Cats rely heavily on their sense of smell to stimulate appetite, so a blocked nose can quickly lead to poor food intake. Young kittens can become dehydrated and weak much faster than older cats, so it is always safest to seek veterinary advice if they are not themselves.
Treatment for cat flu in kittens
Cat flu kitten treatment is usually supportive. This is because cat flu is most often caused by a virus, so there are no commonly used specific treatments that directly cure the infection itself.
If a secondary bacterial infection is suspected, your vet may prescribe antibiotics - antibiotics do not work against viruses, so they are only useful when bacteria are involved.
Supportive care is the mainstay of treatment and may include:
- Nursing care
- Keeping the kitten hydrated
- Encouraging food intake
- Anti-inflammatory medication prescribed by a vet
- Monitoring for complications
What your vet may recommend
Your vet will usually begin with a thorough examination, checking things such as hydration, gum colour, breathing, temperature and chest sounds.
If your kitten is very unwell, your vet may recommend admission for treatment, especially if they are dehydrated, not eating or need help with feeding and fluids. In milder cases, your vet may prescribe medication for you to give at home, such as anti-inflammatory treatment or other supportive medicines depending on your kitten’s condition.
In some cases, especially if a kitten is severely affected, further tests may be recommended to check for complications.
What you can do at home
Many kittens with flu can be cared for at home and your vet can advise you on the best way to do this. Home care is likely to include gently wiping away eye or nose discharge and keeping the nose as clear as possible. You can also tempt your kitten to eat by offering warm, tasty food. If cats cannot smell their food well, they often lose interest in eating - warming food slightly can help because it enhances the smell.
You can help to ease congestion by putting your kitten in a warm steamy environment, like the bathroom with a hot shower running. However, if your kitten seems to be getting worse rather than better, or is not improving as expected, you should contact your vet.
If one cat in the household has cat flu, it is likely that others may be exposed too, because infected cats can spread the infection before obvious signs appear. Washing your hands between handling cats, cleaning bowls and bedding carefully, and separating affected cats where possible may help reduce spread.
How to prevent kitten flu
Vaccination is one of the most important ways to help prevent cat flu in kittens. The cat flu vaccine forms part of routine kitten vaccinations and is then followed by regular booster vaccinations as recommended by your vet. Vaccination does not always prevent infection completely, but it makes infection less likely and usually helps reduce the severity of illness if a cat does become infected.
Keeping infected cats separate where possible and maintaining good hygiene around bowls, bedding and litter trays may also help reduce the spread of infection.
FAQs
Kitten flu is usually diagnosed based on the typical signs, such as sneezing, nasal discharge, eye discharge and poor appetite. If a kitten is very unwell, your vet may recommend additional tests, such as blood tests, swabs or chest X-rays, to check for complications.
The more severe signs of kitten flu often last around 7 days, but it may take 2 to 3 weeks for a kitten to recover more fully and return to normal.
No. The viruses that cause kitten flu are different from the viruses that cause flu in people, so kittens do not catch human flu from us and we cannot catch flu from them.
Most kittens with mild signs recover with supportive care, but untreated cat flu can become serious, especially in young kittens. There is a risk of dehydration, poor food intake and complications such as secondary bacterial infection. If your kitten seems unwell, stops eating or drinking, or signs worsen, veterinary advice should be sought promptly.
Yes. Cat flu is infectious, so adult and senior cats can catch it from infected kittens. This is why it is important to isolate affected cats where possible and maintain good hygiene.
Purina Editorial Team
