Clinical Signs

Kitten with Feline Herpes

In susceptible animals, feline herpesvirus-1 causes rhinotracheitis, which is a severe upper respiratory disease.  Clinical signs of this include coughing, sneezing, discharge from the nose and eyes, loss of appetite, fever, and depression. Accompanying these initial signs may be drooling due to excessive salivation.  Abortions may also occur around the 6th week of gestation in pregnant queens.  Not all of these signs need to be present during an infection to be considered a feline viral rhinotracheitis infection.  Conjunctivitis, which is inflammation of the conjunctiva around the eye, typically develops along with the nasal and ocular discharges, which progress from a clear fluid to a thicker discharge.  This thicker discharge of pus and mucous can end up crusting over the eyelids and nostrils, leading to breathing problems.  Secondary bacterial infections may also play a role in disease by taking advantage of an immune system already at war.

Before showing any signs of their first infection, cats will be in an incubation period for 2-6 or more days in which the virus is replicating but not overwhelming the cat's defences yet.  During this period, the cat may be infectious to other cats.  Cats can also become chronically infected and have recurrences of clinical signs throughout their lifetime, especially when exposed to stress.  This is due to the virus becoming latently infective after travelling up the trigeminal nerve to come to rest in the trigeminal ganglia until called into action at a later time.