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Cat Flu (Upper Respiratory Tract Disease)

What is cat flu?

Cat flu (also known as upper respiratory tract disease) is a general term used to describe common set of symptoms of the upper respiratory tract. The symptoms are similar to that of a cold or flu in humans.

What causes cat flu?

Cat flu is caused by several pathogens (disease causing organisms).

The most common causes are feline herpes virus (FHV), feline calicivirus (FCV), feline reovirus, Bordetella bronchiseptica, and feline Chlamydophila (Chlamydophila felis). FHV and FCV are by far the most common cause of cat flu, being responsible for 80% of cases. FHV typically is the more severe of the two.

How is cat flu spread?

Direct contact: Infection is passed from a sick or carrier cat via eye, nasal, and mouth discharges.

Indirect contact (fomites): Contaminated food bowls, bedding etc. Calicivirus is resistant to many disinfectants and can live in the environment for long periods of time.

What are the symptoms of cat flu?

Many of the causes of cat flu have overlapping symptoms. However, some causes have individual symptoms. For example, mouth ulcers are often seen in a cat with of feline calicivirus, whereas eye ulcers are seen with feline herpes virus. Cats with FCV may also develop a limp.


cat fluA thick, sticky eye discharge also occurs with cat flu. Corneal ulcers may develop. Eyes become red and inflamed (conjunctivitis).


Sneezing and nasal discharge are common symptoms of cat flu.

The virus causes inflammation of the mucus membranes (rhinitis), accompanied by nasal discharge, which may be clear or thick.


When an infection takes hold, the body responds by increasing its temperature. This can make your cat feel generally unwell.


cat mouth ulcersUlcerations of the mouth and tongue may develop, making eating painful.

Loss of appetite:

A cat with the flu will often lose its appetite. This is made worse by the nasal discharge, which affects the cat's sense of smell.

Dehydration is another concern with the sick cat. It feels too poor to drink and thus quickly dehydrates.

How is cat flu diagnosed?

Your veterinarian will perform a physical examination of your cat and may make a diagnosis based on present symptoms. To determine the exact pathogen, he/she may take a throat or eye swab to send off to a laboratory for testing.

How is cat flu treated?

Treatment depends on the cause of the cat flu. There are no drugs to treat viral infections, and supportive care is necessary. This includes keeping the nose clear of discharge. A stuffed up cat will often lose its appetite; therefore, it is of utmost importance that you do everything you can to encourage your cat to eat and drink. If your cat refuses to eat or drink, then seek veterinary advice immediately.

Even if the cause is viral, antibiotics may be prescribed to protect against secondary bacterial infections.

Encouraging your cat to eat and drink is extremely important. If he is not showing an interest in his regular food, try offering him the small "gourmet" canned food. Warming it up a little can help make it more appealing. There are also high-calorie products available from your veterinarian to use with sick and recuperating cats. These are usually in paste form.

Plenty of tender, loving care is required.

Feline Chlamydophila:

Antibiotic eye ointment (usually tetracycline) will be prescribed.

There is an interesting article on the use of another antibiotic known as Zithromax which can be found here.


Supportive care.

Antiviral drugs.

L-lysine has been shown to suppress viral replication and inhibit cytopathogenicity.

Removal of discharge from the nose and eyes will make your cat more comfortable.

If the cat has become anorexic, force feeding may be necessary. Fluids may also be required to treat dehydration.


Supportive care.

Removal of discharge from the nose and eyes will make your cat more comfortable.

If the cat has become anorexic, force feeding may be necessary. Fluids may also be required to treat dehydration.

Antibiotics may be prescribed to treat secondary bacterial infections.

How is cat flu prevented?

Vaccinating your cat will protect it against FHV and FCV. These are covered in the regular F3 vaccination.

There is a vaccination available for Chlamydophila felis. It has side effects associated with a small percentage of cats, including lethargy, lameness, depression, anorexia, and fever, and therefore, it is only recommended for high-risk situations. The American Association of Feline Practitioners do not recommend routine use of this vaccination.

Proper hand washing and changing of your clothing after handling other cats — especially high-risk cats such as those in a shelter — should be practiced before handling your own cats.

Also, as a courtesy, if you are visiting multiple breeders or shelters in one day, advise them beforehand. Some breeders will ask you not to visit them if you have been to another cattery, to reduce the chances of transmitting diseases.

Can I catch colds and flu from my cat?

No, it is not possible to catch a cold or flu from your cat, nor can your cat catch a cold or flu from you.


In the cases of FHV and FCV, once recovered, the cat will be a carrier. This means they will show no outward signs of infection and may shed the virus intermittently or continually, exposing other cats to infection.

There may be the occasional outbreak, at times, of stress (caused by pregnancy, lactation, overcrowding, poor nutrition, new family member etc.) or sickness.

Also see:

Signs of sickness in cats   Cat colds