Ron Hines DVM PhD 9/14/07

Please also read:

http://www.2ndchance.info/respiratorydiscat.htm
http://www.2ndchance.info/cateye.htm andhttp://www.2ndchance.info/cornealulcer.htmand http://www.2ndchance.info/sneezing.htm

Rhinotracheitis, is caused by the feline herpes virus –1. It is a very common disease of cats. The majority of cats that contract rhinotracheitis show mild symptoms that pass within two weeks when the cats are otherwise healthy. But stressed cats with over-taxed immune systems become much more ill with the disease and more likely to become chronic carriers of the virus. Concurrent infection with the feline leukemia virus, feline aids or poor nutrition make the disease more severe and increase the length of convalescence. Physical and emotional stress also complicates the course of this disease. This is why cats in shelters suffer more common and more severe infections. Genetics also plays a roll in determining the severity of rhinotracheitis. Longhaired and purebred cats seem genetically predisposed to a more serious infection.

Cats become infected with rhinotracheitis in two ways. Pets that approach and sniff infected cats become directly infected. In addition sneezing pets scatter the virus up to ten feet. Cats that sneeze and cough also shower their environment with virus particles. Susceptible cats that come in contact with this material later, become infected indirectly. People can also spread the virus on their hands and clothing. It is also possible for infected mother cats to pass the virus on to their kittens while they re still in the womb.

Rhinotracheitis virus invades the lining of the nose, pharynx, sinuses, throat, windpipe and the membranes that surround the eyes (conjunctiva). A few days after infection, cats begin to sneeze. When the disease affects young cats and kittens they loose their appetite and become depressed. It is quite common for these cats to have nasal and ocular discharges. Interference with the sense of smell probably accounts for their lack of appetite. In severe infections ulcers may form in the mouth as with calicivirus. Other cats develop pneumonia.
These problems usually resolve without treatment during the two or three weeks following infection.
When pregnant cats become infected, the queens may abort their kitten or give birth to kittens in poor health. Infections in these kittens can be fatal.

A common residual effect of rhinotracheitis is persistence of the virus in the corneas of the eye. Periodically, with stress, the virus, which lays dormant in nerves of the face, will reappear forming oval corneal ulcers that are slow to heal. These appear as milky areas on an otherwise clear cornea. When these ulcers are active, blood vessels can be seen entering the area. When they are quiescent, they are in effect scars with no specific blood supply.

Another residual form of the disease is chronic rhinitis (nose inflamation) and sinusitis. In these cats, flare-ups of the virus lead to necrotic tissue within the turbinate and ethmoid bones of the nose. These areas of chronic inflammation harbor bacterial infections that are very hard to eliminate, even with excellent veterinary care,
Approximately eighty percent of the cats that contract the disease harbor the virus in their system for the rest of their lives. This is called a latent infection. When stressed, latently infected cats again shed the virus. Some stressors are moving, boarding, pregnancy, lactation, vaccination, injury, surgery or a new cats in the household.
Overcrowding, poor nutrition, poor sanitation, and lack of vaccination also make the disease more likely. Some pets continue to have low grade, persistent infections with respiratory symptoms, eye drainage and conjunctivitis. These cats are also quite efficient in passing the infection on to other pets

Diagnosis
Although we can be highly suspicious that we are dealing with a case of rhinotracheitis, it is not possible to diagnose the disease with certainty from symptoms alone. This is because infection with calicivirus or mycoplasma are too similar. Typically calicivirus does not affect the eyes and mycoplasma affects primarily the eyes. And typically calicivirus and mycoplasma do not cause depression, malaise and fever.
It is possible to send cotton swabs of nasal secretions and eye drainage to certain laboratories for Herpes-1 virus isolation - but this is rarely done.

Treatment
Good nursing care in a low stress environment is the most important therapy for rhinotracheitis. Antibiotics help prevent secondary bacterial pneumonia and rhinitis and nose drops facilitate breathing .Cats with rhinitis and sinusitis are often reluctant to eat. Pungent tasting foods help tempt cats that are reluctant to eat.

I commonly place cats with rhinotracheitis on trimethoprim/ sulfa( 7.5mg/pound twice a day) or cephalexin (10mg/pound twice a day) oral suspensions.
Nose drops and steam make it easier for the cats to breath.
In severe infections I nebulize gentamycin (0.5ml of 100mg/ml solution) or amikacin (0.5ml of 250mg/ml solution). I also give fasting cats injections of B-complex vitamins (0.25ml).

The amino acid, l-lysine, has been found to help many cases of rhinotracheitis resolve. This amino acid reduces the amount of another amino acid, arginine, that is present in the cat's body. Arginine is thought to be necessary for herpesvirus to reproduce. The suggested lysine dose is 250-500 mg per day sprinkled on canned cat food. I would give this suplement until the acute flare-up has resolved. But many cat owners continue the suplement indefinitely. Lysine can be purchased at health food stores. Pick a brand that is propylene glycol-free.

Prevention
Because natural immunity to rhinotracheitis is poor, reinfection is common. Avoiding keeping large numbers of cats in the same area helps prevent outbreaks. It is next to impossible to prevent cross-transmission of the virus to all cats in a household.
Multivalent vaccines that incorporate rhinotracheitis virus are routinely given to cats. However, many cats are already carriers of the virus before the vaccine can be given. I usually give rhinotracheitis-containing vaccine at 9, 12 and 14 weeks of age and from then on annually even though we know that the effectiveness of the vaccine does not persist much beyond six months.
You can read more about respiratory infection in your cat at: http://www.2ndchance.info/respiratorydiscat.htm

Recently, information has appeared on the Web indicating that the administration of feline omega interferon lessen the symptoms caused by feline herpesvirus. I do not know the acuracy of this information. The links given in the URL, www.poose.de/englisch/fiv/felines_interferon.html , are broken. In the catched article, the interferon treatment was given on five consecutive days. Cats received a subcutaneous injection of 500,000 units per pound body weight. The authors state that it is possible to give 5 million units (the smallest dose used) to an animal weighing eight pounds or to divide the dose into two injections of 2.5 million units each for a six pound cat. The treatment was discontinued after five days.It could, however, be repeated many times if required.

To my knowlege, this product, sold by the Virbac Co for use in dogs only. It. is not yet available in the US but is available in Japan and Europe.

Terms Of Use

Consult With Dr. Hines

More Articles

Home