Introduction
The most common infectious disease in domestic cats is feline upper respiratory disease. This disease has many causes, including viruses, fungi, and bacteria. The two most prevalent causes are feline herpesvirus, which is also called feline rhinotracheitis virus, and feline calicivirus. Multi-cat households, shelters, and catteries are extremely vulnerable to the highly contagious nature of both viruses.
Transmission
Upper respiratory disease is generally transmitted to healthy cats by contact with nasal or eye discharge of infected ones. Objects such as litter pans and shared food and water bowls are frequently found to be vectors of infection. Mutual grooming in multi-cat environments is also a major factor leading to transmission. Feline herpesvirus and feline calicivirus can also be transmitted from an infected mother to her newborn kittens through licking and close contact. Although most kittens are infected six to 12 weeks after birth, early neonatal infection can cause sudden death in kittens.
Symptoms
The symptoms of upper respiratory disease will be evident two to 17 days after exposure. Many cats display rhinitis as an initial symptom. Rhinitis is characterized by extreme inflammation of the mucous membranes in the nose. Cats displaying rhinitis will have an increased amount of nasal discharge. This discharge will initially be clear but soon turn to a yellow or green color, which indicates the presence of pus. In some cases, cats will develop blood-tinged nasal discharge. Additional symptoms of upper respiratory disease include:
• Sneezing
• Anorexia
• Fever
• Eye lesions
• Eye discharge
• Oral ulcers (more common with feline calicivirus)
Treatment
As soon as symptoms are observed, the cat should be taken to a veterinarian for a diagnosis. If infected, the cat should be isolated to prevent other cats from being exposed. Discharge of the eyes and nose should be regularly cleaned with a damp, warm cloth. Housing the infected cat in an area that provides rest and humidity is ideal. Cats that seem uninterested in eating should be fed a diet that has a strong aroma and is highly palatable. Cats with severe dehydration may be treated with electrolyte and fluid therapy.
Veterinarians will also prescribe a broad-spectrum antibiotic to treat any secondary bacterial infections. Generally, kittens and cats recover from the acute phase of the disease within four days; however, some cats will exhibit sneezing for several weeks. The longevity of recovery depends on whether feline herpesvirus or feline calicivirus is the underlying cause of the disease. Generally, cats suffering from feline calicivirus recover in a more timely manner, although there is a highly virulent strain of calicivirus that can cause increased disease and mortality.
Cats that recover from upper respiratory disease may become carriers of the condition. These cats do not regularly spread the virus unless they undergo extreme stress, such as moving to a new house or being introduced to a new group of cats. To prevent transmission from carrier cats, it is best to isolate them from a new cat population until you are sure they do not show clinical signs of infection. Owners should also practice good sanitation practices when handling and cleaning areas used by cats. Adult cats with chronic upper respiratory infections should also be tested for feline immunodeficiency virus and feline leukemia.
Vaccinations are available for both feline herpesvirus and feline calicivirus; however, the vaccines are not 100-percent reliable at preventing an infection. These vaccines increase the protection at exposure and result in no disease or a less severe infection. Scientists have found multiple strains of the calicivirus, so vaccinations only protect against a number of these strains. In other words, many strains of the calicivirus will always be resistant to vaccines. Cat owners are urged to follow a regular vaccination schedule to better guard the health of their companion cat.
Amy Fischer, Ph.D - University of Illinois
Amanda Young - University of Nebraska-Lincoln
