Feline rhinotracheitis is a condition characterized by severe inflammation of the upper respiratory tract, including the nasal passages, the larynx, the pharynx and the trachea--in other words, the nose and throat. The disease itself doesn't usually kill a cat, but if it goes on long enough to cause a weakened state of health, rhinotracheitis can lead to death.

The most common source of rhinotracheitis is a viral infection caused by a calcivirus, a contagious organism that can create acute upper respiratory disease; however, herpes virus, chlamydia and allergies can all lead to rhinotracheitis. The viral and bacterial infections are easily picked up from other cats by either direct contact or fomites--objects that transfer infection without themselves being affected, such as shoes. Allergies can be due to just about anything, but plants, dust and molds are usually the troublemakers. Many viruses come on the scene when a sick kitten is brought to a shelter for adoption or put in a cage at a pet shop with other kittens. Due to their young age and underdeveloped immune systems, kittens fall prey to infections in a way that older, vaccinated cats do not.

The first sign of rhinotracheitis is constant sneezing with a nasal discharge, which can be watery or clouded with mucus. After the conjunctivitis comes redness, excessive and thickening tear production or a mucus discharge. At times the eyes become so inflamed that they remain shut. With progression of the disease a cough develops and breathing becomes labored and noisy. You will know your cat is in trouble if she stops eating and is reluctant to play. Often an infected cat will run a fever--normal cat temperature is between 100 and 103 degrees Fahrenheit. Although there is little we can do to fight viruses with medicine, it is still a good idea to seek medical attention for a kitten or cat showing these signs. More than anything, supportive care will help your pet fight the virus on her own. Here is what we do for cats with URIs (upper respiratory infections):

• Oral antibiotics are used to prevent worsening of the disease by a secondary bacterial invasion. They are generally given twice daily for seven to 10 days.

• Fluid therapy, either by intravenous route or by injection under the skin, combats dehydration and helps drop the body temperature if the fever has gone too high.

• Eye drops or ointments with topical antibiotics help combat bacteria and products with antiviral properties if necessary.

• Force-feeding with so-called recovery diets, which are rich in protein and calories can be fed via a dropper or syringe. We always try to get the cat to eat on their own first by offering foods that have very strong odors like tuna or mackerel cat food. Often they can't smell their food due to all the nasal congestion, so if you offer something with a strong smell, they may develop an appetite.

• For chronic cases, I recommend having your vet perform a trans-tracheal wash, which involves sedating the cat, inserting a sterile solution into the throat through a tube and recollecting the fluid to analyze it for types of cells and to culture for bacteria. Often this helps fine-tune which therapeutic approach you should take. At times we have to do this to select the appropriate antibiotic and may choose to use it for an extended period of time. Often with a tracheal wash we discover allergic conditions and sometimes, sadly, we find cancer affecting the respiratory tract.

Cats who have a chronic respiratory infection may die if they go untreated for too long and the cat goes off his food. Cats, unlike many other species, suffer severe liver degeneration after just four to five days of not eating. If you think your cat has gone a day or two without eating, it is a warning to seek help immediately. In the vast majority of cases, upper respiratory infections affect kittens four months old or younger and are gone with limited therapy within a week or two. If your cat's infection keeps coming back or won't disappear with the treatments I've mentioned, it could mean they have a weakened immune system from other causes. It's important to know if your cat has been exposed to the feline leukemia virus or the feline immunodeficiency virus. A simple blood test when your kitten is at least nine weeks old will tell you if she suffers from either of these illnesses. In either case, if found to be positive, it's a bad sign for the future. Cats with these viruses usually have short lives and are often sick. They should never be allowed contact with healthy cats as these viruses pass only through direct contact.

Dr. Peter Kross, DVM, has had his own veterinary practice, the Rivergate Veterinary Clinic in New York City, since 1989. He lives in Manhattan with his three white boxers, Buchanan, Wilhelmina and Laila.