Feline infectious respiratory diseases are the upper respiratory infections that are most commonly associated with two viruses, feline herpesvirus, also known as feline viral rhinotracheitis, and feline calicivirus. A possible non-viral cause of an upper respiratory infection is Chlamydia psittaci, although this organism is associated more frequently with persistent conjunctivitis.
Upper respiratory infections are highly contagious and can be spread from one cat to another through sneezing, coughing, or via objects contaminated with saliva or secretions, such as food and water bowls. Once exposed to infection, the animal usually will show signs of disease within one to five days. Generally, the symptoms are more severe in young kittens.
Most upper respiratory infections improve on their own within five to seven days. Unfortunately, about 80 percent of cats that recover from these viruses remain carriers of the disease for months to years. Feline calicivirus can be shed constantly for months to years. Typically, times of stress result in the shedding of the feline herpesvirus and mild clinical signs in the carrier cat. For example, the nursing mother cat that can infect her kittens with herpesvirus during the nursing period.
