Feline herpesvirus-1 (FHV-1) is an extremely common viral infection that causes acute upper respiratory disease and establishes lifelong latent infection, with recurrent episodes triggered by stress throughout a cat's life.
FHV-1 creates a welfare burden that extends across a cat's entire lifetime. The initial infection in kittens - often from shelter or multi-cat households - can be severe, causing eye damage, breathing difficulties, and failure to thrive. The chronic consequences are underappreciated: cats with FHV-related rhinosinusitis experience persistent nasal obstruction that disrupts smell (and therefore appetite), breathing during sleep, and overall comfort. Each recurrence - triggered by the stress of rehoming, new animals, or veterinary visits - creates an acute welfare episode. The cyclical nature means that stressful but necessary interventions (like veterinary care) directly worsen a disease that causes chronic suffering.