Upper respiratory infections are among the most common illnesses in cats, causing significant discomfort, and are particularly devastating in shelter populations where they spread rapidly.
URI causes cats significant discomfort - nasal congestion means they cannot smell food, often leading to complete anorexia that compounds illness. Mouth ulcers from calicivirus are painful and prevent eating. Eye infections can cause corneal ulcers and permanent vision damage if untreated. In shelters, sick cats are isolated in small enclosures during a frightening time, compounding psychological stress. The combination of physical illness and shelter stress creates a welfare crisis that affects millions of cats annually.