Feline Viral Respiratory Disease Complex
Feline viral respiratory diseases are highly contagious, often serious illnesses of cats that can spread rapidly through a multicat home, a cattery, or a shelter. They are one of the most common infectious disease problems a cat owner is likely to encounter. Although few adult cats die of upper respiratory disease, the death rate among young kittens approaches 50 percent.
Although these diseases are highly contagious among cats, they cannot be transmitted to humans. Cats also cannot catch our colds. This is because the viruses that attack cats do not affect humans, and vice versa.
Recently, it has been recognized that two major viral groups are responsible for the majority of clinical upper respiratory infections in cats (80 to 90 percent). The first is the herpesvirus group, which includes feline viral rhinotracheitis (FVR). The second is the calicivirus group, which includes feline caliciviral disease.
Other viral agents, especially those of the reovirus group, cause feline viral respiratory illness. They account for a minority of cases.
There are two distinct stages in the feline viral respiratory disease complex. The acute stage is followed by the chronic carrier state.
Acute Viral Respiratory Infection
There is considerable variation in the severity of illness. Some cats have mild symptoms, while in others the disease is rapidly progressive and sometimes fatal.
The disease is transmitted from cat to cat by direct contact with infected discharge from the eyes, nose, mouth; by contaminated litter boxes, water bowls, and human hands; and rarely, by airborne droplets. The virus is stable outside the host for as short as 24 hours or as long as 10 days, depending on conditions.
Clinical signs appear 2 to 17 days after exposure and reach maximum severity 10 days later. Illness begins with severe bouts of sneezing lasting one to two days. This is followed by conjunctivitis and watery discharge from the eyes and nose, which may suggest a cold or flu. By the third to fifth day, a cat exhibits fever, apathy, and loss of appetite. The eye and/or nasal discharge becomes mucoid or purulent. Cats with obstructed nasal passages breathe with their mouths open.
Further signs depend on the particular respiratory virus in question. A cat with herpesvirus develops a spastic cough. If the surface of the eye is severely inflamed, the cat may develop keratitis or corneal ulcerations.
In a cat with calicivirus, you may see ulceration of the mucous membranes of the mouth (stomatitis). This is particularly disabling, because the cat loses his taste for food and refuses to eat and drink. Drooling is common. Shortness of breath and viral pneumonia can occur. Secondary bacterial infection, dehydration, starvation, and rapid weight loss are all complications that can lead to death.
A diagnosis can be suspected from the clinical signs. It can be confirmed by isolating the virus from the throat or by specific serologic blood tests. Because these diseases are highly contagious, these tests are most important when the disease involves a cattery, a shelter, or a multicat household.
Treatment: Cats suspected of having acute viral respiratory infection should be strictly isolated for three to four weeks so as not to infect others. It is important to disinfect any bedding, bowls, cages, or other items the sick cat has come into contact with by washing them thoroughly with a dilute solution of bleach and water. Human caretakers should change their clothing, wear disposable shoe covers, and wash their hands frequently.
For the patient, rest and proper humidification of the atmosphere are important. Confine your cat in a warm room and use a home vaporizer. A cool steam vaporizer offers some advantage over a warm vaporizer because it is less likely to cause additional breathing problems. At the very minimum, keeping the cat in the bathroom while you shower will help.
Clean secretions from the eyes, nose, and mouth with moist cotton balls as often as needed.
Chronic Carrier State
Almost all the cats who have been infected with FVR will become chronic carriers. FVR lives and multiplies in the cells lining the throat. During periods of stress (such as illness, anesthesia, surgery, lactation, medication with steroids, or even emotional stresses), the cat's immunity breaks down and the virus is shed in mouth secretions. At this time, the cat may exhibit signs of a mild upper respiratory illness.
Prevention: The most effective step by far is to vaccinate all cats, but even then, control is not 100 percent. Vaccination will not eliminate the chronic carrier states.
This article is excerpted from “Cat Owner’s Home Veterinary Handbook” with permission from Wiley Publishing, Inc.
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