Feline upper respiratory infection (URI) is a common cause of disease in shelters, and one of the most important diseases faced by shelter veterinarians. Animals with URIs experience a longer stay within a facility, decreased adoption, and can cause the spread of disease among the population, as well as suffer from increased mortality. URIs are encompassed by Feline Respiratory Disease Complex (FRDC), which refers to the presentation of respiratory or ocular disease caused by several pathogens including feline herpesvirus-1 (FHV-1), feline calicivirus (FCV), Chlamydophila felis (C. felis), Mycoplasma sp. and Bordetella bronchiseptica. More recently, feline coronavirus (FCoV) has also come under consideration as part of FRDC and upper respiratory tract infection.