Understanding Feline Flu

Over the last week I have received numerous phone calls from concerned cats owners that have read the news about the cat in Calgary who died from H1N1 infection. The Feline Flu or in its professional name, Feline upper respiratory Complex, is a very common disease in cats.

However H1N1 ( Avian Influenza (flu) Virus) is only rarely the cause for these upper respiratory infections in cats.

Upper respiratory complex in cats is wrongly known to most people as Cats Flu. Flu is a disease that is caused by the Influenza virus. Despite its name, the common cats flu, usually does not refer to an infection by an Influenza virus. In fact the Feline upper respiratory infection is caused by a complex of few pathogens, including two viruses Feline Herpes Virus and Feline Calici Virus, and two bacteria: Bordatella Bronchoseptica (similar to dogs Kennel cough) and Chlamidophila Felis.

Feline Upper respiratory Complex in cats is a highly contagious disease.

The initial symptoms of the disease are coughing, sneezing, nasal discharge, eye infections, and sometimes fever and loss of appetite. These symptoms can either resolve within four to seven days, however secondary bacterial infections can cause the persistence of clinical signs for weeks. The infection is primarily located in the upper respiratory tract. However, in very young, old or immunosuppressed animals the infection can spread into the lower part of the respiratory system, and affect the lungs as well. Although in general feline upper respiratory syndrome tends to be mild and transient, in these groups of animals the disease can be fatal. Herpes Virus in particular can also permanently damage the eyes.

Calici Virus can lead to other complications beyond affecting the respiratory system. The most common are chronic ulcers in the mouth and chronic infection of the mouth- stomatitis. In addition to stomatitis, some cats may develop polyarthritis (inflammation of the multiple joints). Stomatitis and polyarthritis can develop without any upper respiratory infection signs, but fever and loss of appetite may occur. Less commonly the cat may develop kidney infection as well. The great variability of clinical signs in individual cases of Feline Calici Virus is related to the relative virulence of different strains of the virus. Diagnosis by your vet is usually based on the typical signs associated with this syndrome and exclusion of other causes. Testing for Calici Virus and Herpes Virus involves collecting a mouth or eye swab which is then sent to a specialized veterinary laboratory where the virus can be identified. Isolating the causative agent is important in more severe cases for the determination of the prognosis and long term outcome.

The treatment focuses mainly on the secondary bacterial infection and is done by a relatively long course of antibiotics. Affected cats are often reluctant to eat – they will have a poor sense of smell and eating may also be uncomfortable. Using soft, highly aromatic foods (for example kitten foods, fish in oil) that are gently warmed will help to tempt an inappetent cat. There are few anti-viral eye drops available to treat the eye infections, if present.
Lysin is an important protein that can be given as a food additive. Adding Lysin to the cat’s diet over a period of few months, can aid with strengthening the cat’s immunity and its ability to fight the viruses.
Most cats that recover from the infection with the upper respiratory viral infection will become ‘carriers’. Carrier cats usually show no sign of illness but, may shed virus in saliva, tears and nasal secretions, and can be a source of infection to other cats.
Similarly to humans that suffer from Herpes virus (cold sores), most cats that have been affected by Herpes virus will carry it for life. The infection may not ever appear again or recur at times of stress or immunosuppression.
As for prevention, fortunately there are vaccines available against Herpes and Calici viruses. These vaccines are recommended for all cats, irrespective of how they are kept (even if kept totally indoors), as the diseases are so ubiquitous. However, although vaccination usually prevents severe disease developing, they cannot always prevent infection from occurring and so mild disease may still develop in some cats. In addition, Calici virus tends to undergo mutations so various different stains are present. This fact makes the vaccination for the disease challenging and can reduce the effectiveness of the vaccine.

If there is more than one cat in a household, it is important to try to minimize the risk of infection being spread to the other cats. This is not always possible, but in addition to ensuring that all cats are vaccinated, where possible, a cat showing clinical signs should be kept isolated from the other cats (e.g., confined to one room). Separate food bowls and litter trays should be used, and ideally the cat should be kept in a room that has very easy to disinfect surfaces (i.e., not soft furnishings and carpet). These viruses are susceptible to most disinfectants, but take care to use any disinfectant carefully – most are irritant to cats if they come into direct contact with the disinfectant.

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About the Author

Dr. Moshe Oz owns Rose Valley Veterinary Hospital, a small animal veterinary practice in West Kelowna.

Dr. Oz has deep love and affection for animals. It was his childhood dream to become a veterinarian, a dream that he has fulfilled when he graduated with honours from KUVM,on 2006. Dr. Oz's special interest is internal medicine and surgery.

In his free time Dr. Oz enjoys training and racing triathlons, including the legendary Penticton's Ironman.

Dr. Oz can be contacted through his website: www.KelownaVet.ca

The views expressed are strictly those of the author and not necessarily those of Castanet. Castanet does not warrant the contents.

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