FVR is very contagious and can cause severe disease, including death from pneumonia in young kittens.

All members of the family Felidae are susceptible to FVR; in fact, FHV-1 has caused a fatal encephalitis in lions in Germany.

[4] Latently infected cats (carriers) will shed FHV-1 intermittently for life, with the virus persisting within the trigeminal ganglion.

[6] Initial signs of FVR include coughing, sneezing, nasal discharge, conjunctivitis, and sometimes fever (up to 106) and loss of appetite.

Other ocular signs of FHV-1 infection include conjunctivitis, keratitis, keratoconjunctivitis sicca (decreased tear production), and corneal sequestra.

[8] FHV-1 can also cause abortion in pregnant queens, usually at the sixth week of gestation,[3] although this may be due to systemic effects of the infection rather than the virus directly.

However, many healthy cats are subclinical carriers of feline herpes virus, so a positive test for FHV-1 does not necessarily indicate that signs of an upper respiratory tract infection are due to FVR.

There are no specific antiviral drugs in common use at this time for FVR, although one study has shown that ganciclovir, PMEDAP, and cidofovir hold promise for treatment.

[17] The use of serology to demonstrate circulating antibodies to FHV-1 has been shown to have a positive predictive value for indicating protection from this disease.