Cat Flu ~ Pawprints and Purrs, Inc.

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Cat Flu - Upper Respiratory Infections (URI)

Cat flu is a common disease in cats of all ages despite widespread vaccination, but tends to be particularly severe in young and old cats. A number of infectious agents have been found to cause cat flu, but the vast majority of cases will be caused by one of two viruses, feline herpes virus type 1 (FHV-1) and feline calicivirus (FCV). FHV-1 is also known as feline rhinotracheitis virus.

What are the clinical signs of cat flu?

Signs of cat flu are similar to colds and flu in people. FHV-1 tends to cause more severe disease, the major signs are inflammation of the lining around the eye (conjunctivitis) and nose (rhinitis). This causes a clear discharge from the nose and eyes which becomes thickened and purulent as the disease progresses due to secondary bacterial infection. Cats tend to be dull and depressed with a raised temperature, sneezing and are reluctant to eat. Coughing is also a feature in some cases. Rarely the virus will cause skin lesions and invade the lungs causing pneumonia. Without treatment signs usually resolve in 2-3 weeks but some cats are left with a chronic, intermittent nasal discharge or eye disease.

FCV tends to cause less serious disease, but clinical signs are dependent on the strain of virus that is involved. Mouth ulceration can be a prominent feature of the disease causing severe inappetance. Ulcers may also sometimes occur on the tongue, nose and hard palate. Some strains of FCV cause a lameness and fever syndrome in young kittens. FCV is commonly isolated from cats with long-standing (chronic) inflammation of the gums (gingivitis) but the precise role of the virus remains unclear.

Deaths following respiratory virus infections are rare, usually occurring in young kittens or old cats that have advanced disease before being presented for treatment.

How is cat flu diagnosed?

In most cases the diagnosis is made on clinical signs but in cases where there is recurrent disease or in vaccinated cats a specific diagnosis may be required. This can be achieved by swabbing the cat's mouth and sending the swab in viral transport medium to a laboratory where the virus can be grown in culture and identified.

What treatments are available?

As for colds and flu, specific antiviral treatments are not generally available. Treatment is aimed at controlling secondary bacterial infection (with antibiotics) and stimulating eating and drinking as, particularly dehydration, is a major cause of worsening disease. Antiviral ointment (e.g., acyclovir) used to treat herpes virus infections in people (cold sores, fever blisters) has been used in cats, generally the response is not as good and the drug needs to be used early in the course of infection. Its use tends to be restricted to treatment of FHV-1 outbreaks in colonies of cats. Topical antivirals include Idoxuridine and Betadine eye drops. L-lysine (an amino acid) works to prevent future attacks in some cats. L-lysine can be purchased over-the-counter at health nutrition stores.

What can be done to help treatment?

Your cat can be encouraged to eat and drink using drugs such as multivitamins and mucolytics (helps dissolve secretions) but good nursing plays a crucial role. The eyes and nose can be kept clear of secretions by gently bathing the area with cotton wool and by steaming. Steaming needs to be undertaken carefully. The cat is placed into the bathroom, with the shower as hot as it will go, then the is filled sink with equally hot water. Since the running water sounds may be very upsetting to the cat, stay in the room, grooming and softly speaking to him to keep him calm. The steam acts to loosen secretions making the cat feel better. Your cat can be encouraged to eating by providing highly flavored foods e.g. sardines warmed to body temperature. Hand feeding can also help.

Severely ill cats may need additional care at your veterinarian's hospital; this allows rehydration with intravenous fluids and feeding by naso-esophagal tube.

How can cat flu be prevented and controlled?

For most households with a few cats, vaccination is sufficient. Vaccination will not usually prevent your cat becoming infected but will drastically reduce the severity of the disease, often to the point that all that is noticed is mild lethargy and inappetance for a few days. A variety of vaccines are available depending on the circumstances (see speak with your veterinarian). Neither virus is very hardy, FHV-1 will survive for a maximum of 48 hours in the environment, FCV lasting 7-10 days.

In multicat households, particularly where new cats are continually arriving (such as in rescuing or at shelters), vaccination alone may not be sufficient to control the problem. In these households isolation and quarantine is also required. Disinfection, while an important part of disease control generally, is of limited value in respiratory virus control as most cats become infected by aerosol droplets sneezed or coughed out by infected cats. Clinically ill cats or those suspected of being carriers should be isolated and handled last. Their food bowls and litter boxes disinfected and your hands, face, clothing and shoes washed before handling other cats. If at all possible, separate clothing should be worn. New arrivals to the group should be quarantined for 7-10 days in case they are incubating cat flu. Unfortunately, quarantine will not identify carrier cats. In households where cat flu is endemic, queens should be kittened in isolation from other cats and, where possible, the kittens remain in isolation until vaccinated.

What are carrier cats?

Carriers are animals that are infected with cat flu but are not showing any clinical signs. Carriers are only infectious to other animals when shedding the virus. Viral shedding can be continual or intermittent. Around 80% of cats that have been infected with FHV-1 become carriers. They shed the virus intermittently usually during periods of stress (e.g. rehousing, lactation) and remain carriers for life. About 50% of cats infected with FCV are still excreting virus 3 months after they were originally unwell. Some of these cats continue to excrete for up to 18 months. FCV carriers excrete continually so are always potentially infectious to unvaccinated cats.

Can I check to see if my cat is a carrier?

In some special circumstances it may be helpful to identify carriers but this is not usually important for pet cats. A swab can be taken from your cat's mouth which will show if he is a FCV carrier. FHV-1 carriers are only diagnosed if they are excreting the virus at the time the swab is taken, which is unlikely.

What should I do if my cat is a carrier?

Nothing can be done to change the carrier status of your cat. It is important that your cat does not come into contact with unvaccinated cats or kittens. All cats that have had FHV-1 infection should be assumed to be carriers.

My cat has had cat flu. Should I bother to vaccinate him?

Yes. Your cat is likely to have been infected with only one of the viruses so will still be susceptible to infection with the other.

Additional Info:

Upper Respiratory Infections (URI)

Page URL: http://www.sniksnak.com/cathealth/catflu.html

Resource References:
Much, much appreciation to Dr. Raymond Van Lienden, DVM of Clifton, VA USA for his extensive research in locating the material found on this page. Thank you, dear Doctor!