What are some of the main causes of chronic upper respiratory tract disease?
There are many causes of this relatively common problem in cats. Feline Viral Rhinotracheitis and Caliciviruses were the primary causes of chronic upper respiratory tract disease prior to the development of vaccines in the 1970’s. These viral infections caused such severe mucous membrane damage in some cats that healing was incomplete and left the membranes susceptible to secondary bacterial infection. In addition, these upper respiratory viruses tend to persist in cats (carrier cats) for weeks, months or years. In some, but not all, of these carriers, the chronic virus infection exacerbates the mucous membrane damage and helps the bacterial infection that is the main cause of clinical signs. Even vaccinated cats, without adequate boosters or because of a variety of factors, may still become infected with one or more of these viruses and later show chronic post-viral rhinitis and conjunctivitis. Chlamydia and Bordetella are other respiratory infections that can be prevented by vaccinat
