Feline herpesvirus type 1 (FHV1) is an important pathogenic agent that causes feline viral rhinotracheitis, which is a highly infectious upper respiratory tract infection of felids. The virus is readily transmitted between cats through: direct contact (through contact with saliva, ocular or nasal secretions), inhalation of sneeze droplets, sharing or food bowls and litter trays, and a contaminated environment (including bedding and grooming aids). This infection is often fatal to kittens, but adult cats usually survive and exhibit lifelong latency. Rapid test for the detection of FHV Ag in feline eye mucus and nasal discharge.

Feline calicivirus (FCV) is one of the most frequently reported pathogens causing upper respiratory tract and oral disease in cats. Following FCV infection, most cats develop acute respiratory disease and oral ulceration.