Cat flu in kittens - Symptoms, Causes and Treatment

“Cat flu” (or kitten flu) is a general term used to describe upper respiratory tract infections in cats. It is highly contagious and the signs can be particularly serious in kittens. It is typically transmitted by direct or close contact between kittens or cats, e.g., in sneezed droplets. 

Despite the name, cat flu is not actually caused by a feline influenza virus (or feline flu virus). There are several infectious organisms that can be involved, but it is mainly caused by two viruses, feline herpesvirus (also known as feline rhinotracheitis virus) and feline calicivirus. 

Cat flu signs and symptoms in kittens can be particularly serious due to their immature immune systems. In some cases it may look like a kitten “cold” (e.g., a kitten with a snotty nose) but in other cases the signs can be much more serious. The signs can vary depending on which infectious organism is involved.

Symptoms of cat flu may include:
•    Sneezing and/or coughing
•    Discharge from the eyes
•    Discharge from the nose
•    Mouth ulcers causing drooling
•    Low energy levels
•    Decreased appetite
•    Fever 
•    Difficulty breathing
•    Joint pain, stiffness, and limping

If a kitten or cat is infected with feline herpesvirus, the virus can persist in their bodies and they may experience ongoing signs or recurrent flare ups of cat flu. 

If your kitten exhibits symptoms of cat flu, it is important to contact your vet. Delaying treatment can lead to worsening of the signs. Most cases of cat flu can be treated at home, although hospitalisation may be required in severe cases. Please see some examples of medicines your vet may prescribe or a home remedy they may recommend below. 

Depending on the type and severity of the signs, and the results of diagnostic tests, veterinarians may prescribe medicines for cat flu treatment at home. You should never give any medications to your cat unless directed to by your veterinarian.  It is important to avoid giving any human medication as many are unsafe for kittens or cats. Medicines prescribed by vets to help reduce recovery time may include:

•    Antibiotics
•    Antivirals 
•    Topical eye ointment or drops

Just as is the case for people with an upper respiratory tract infection, supportive care is important to get your cat back to full health as quickly as possible.  This can include:
•    Hydration: Encourage your cat to drink plenty of water. Feeding a wet diet rather than dry food can help to increase their water intake.  
•    Purée Favourite Foods: Purée your cat’s favourite food to make it easier to swallow.
•    Warm-Up Food: Heat up the food to stimulate your kitten’s appetite.
•    Clean Nose and Eyes: Use a damp, warm cloth to gently wipe any discharge away from the eyes and nose.

The mortality rate of cat flu is low, but it can cause serious illness and discomfort to kittens and cats. Young kittens and immunocompromised cats are at higher risk of severe complications such as pneumonia which can be fatal.

•    Carrier State and Flare-ups: Feline herpesvirus causes a lifelong infection which can cause flare-ups of illness (e.g., during times of stress). 
•    Chronic Rhinitis: Severe cases of cat flu can lead to chronic rhinitis (inflammation of the nasal passages), characterised by a persistent runny nose and congestion due to damaged nasal linings. 
•    Gingivitis: Feline calicivirus is believed to be a potential cause of long-term inflammation of the gums (gingivitis), which may require medication or even tooth extraction in severe cases.
•    Eye Damage: Feline herpesevirus can cause ulcers of the cornea (the surface of the eye) which can lead to permanent damage to the eye.

Thankfully, of the potential causes of cat flu, most, including the two most common causes, feline herpesvirus and feline calicivirus, do not infect people. One of the potential causes of cat flu, Chlamydia felis, can infect people, so it is important to maintain good hygiene when looking after a cat with cat flu.

Although most cats recover from cat flu, in a small percentage there may be long-term consequences, so you should be prepared for this (and the associated veterinary expenses) if you are considering buying a kitten with cat flu. Ensure the kitten receives immediate medical attention to manage symptoms and reduce the risk of complications.