Those classic cold symptoms of sneezing, runny eyes, and runny nose, often classified under the general term “upper respiratory disease" (URD) are very common in our cat population.
What causes URD?
Upper respiratory diseases are typically caused by cat-specific viruses (feline herpesvirus or calicivius) and rarely by primary bacterial infection (eg. Chlamydophila spp.). Other species of bacteria will take advantage of an immune system, weakened by viral infection, to cause secondary bacterial infection. The good thing is that these viruses are cat specific and cannot be spread to people.
How would my cat catch URD?
The viruses that cause URD are very common, and can live for long periods of time in our environment, so infection can be spread by casual contact (such as petting a stray cat and then having the virus linger on our hands and clothes). Because the virus tends to be shed during times of stress, any areas that are considered high stress, where lots of cats are together, can lead to infection. Animal shelters, pet stores, boarding facilities, cat shows, and grooming salons are all areas where your cat can catch a cold.
What are the symptoms of URD?
URV symptoms are generally divided into both acute and chronic forms.
Acute disease: In the acute disease, sneezing is generally the first symptom to appear and last to resolve. Depending on the severity of infection, other signs can include eye/nose discharge, ulcers in the mouth, and fever. As this is a systemic infection, your cat can also be lethargic, dull, or show a decreased appetite.
Chronic form: Because some of these viruses persist for long periods of time in the body (and in the case of herpesvirus infection life long), infection flare-ups are possible. Signs of flare-up can include watery eye discharge (in one or both ears), nose ulceration, and chronic nasal discharge. Chronic infection is possible because the viruses that cause infection can survive for very long periods of time in the body in a dormant state and become re-activated in times of stress (such as people with Herpes-induced cold sores that experience flare-ups).
How do we diagnose URD?
On physical examination, your veterinarian may presumptively diagnose URD based on clinical symptoms. The only way to determine the exact cause of a URD is to take a sample (usually nasal or eye discharge) and run several laboratory tests (such as culture), if bacteria are suspected, or other tests (such as PCR) can be run to identify the type of virus.
How do we treat URD?
Unfortunately, as the main cause of URD is viral, then we are more limited in our treatment options and antibiotics are only helpful if bacterial infection is present. Therefore our treatment plan generally focuses on treating the appropriate symptoms, controlling secondary bacterial infection (if present), and boosting the immune system. This is a disease of management, not of curing.
With appropriate treatment, we should begin to see improvement of clinical symptoms within 24 to 48hrs. Sneezing is often the last symptom to resolve. Although we can treat clinical symptoms in an acute flare-up, obtaining a cure is often difficult as these viruses can cause lifelong, asymptomatic, infection. Some cats that are chronically infected may show recurrent eye infection, cloudy nasal discharge, chronic sneezing, or nose ulcers. In these cases, a cure is almost impossible and management of clinical symptoms is important.
How can I prevent URD?
Vaccination can help prevent infection. However it is important to remember that just like catching the flu is possible despite a flu vaccine, no vaccine provides perfect protection. Because these viruses can be spread by casual contact, all cats, including strictly indoor cats, should be protected.