Feline Upper Respiratory System Infections Study Guide

Overview and Clinical Importance

Feline upper respiratory infections (URI), commonly referred to as "cat flu" or "feline respiratory disease complex," represent one of the most frequently encountered infectious disease syndromes in feline practice. These infections account for approximately 80-90% of infectious respiratory disease in cats and are a significant source of morbidity in both shelter and household environments.

The two primary viral pathogens, feline herpesvirus-1 (FHV-1) and feline calicivirus (FCV), together cause approximately 80-90% of all feline URI cases. Bacterial agents including Chlamydia felis and Bordetella bronchiseptica may act as primary pathogens or complicate viral infections. Understanding the etiology, clinical presentation, diagnosis, and management of these infections is essential for NAVLE success.

Etiology and Pathogen Characteristics

Feline Herpesvirus-1 (FHV-1)

FHV-1 is a large, enveloped DNA virus belonging to the family Herpesviridae. It is the causative agent of feline viral rhinotracheitis (FVR) and represents the most common cause of infectious conjunctivitis in cats. The virus is highly species-specific and affects only domestic and wild felids.