INTENDED USE

Herpesvirus infection, also known as feline viral rhinotracheitis (FVR), is an infectious disease caused by feline herpesvirus type-1 (FHV-1). As with other herpes viruses, the virus is very species-specific and is only known to cause infections in domestic and wild cats. The virus can infect cats of all ages.

FVR is a major cause of upper respiratory disease in cats and is the most common cause of conjunctivitis (inflammation of the tissues surrounding the eye, especially the lining of the lids and the third eyelid).

BACKGROUND

Feline respiratory disease complex is a group of respiratory illnesses caused by a number of organisms that can cause infection alone or together. It includes those illnesses with signs including inflammation of the nasal and sinus linings, inflammation of the eye lining (conjunctivitis), excessive tear production, salivation, and mouth sores. The principal diseases are feline viral rhinotracheitis (also called feline herpesvirus type 1; FHV-1) and feline calicivirus, although other diseases may also be involved, including feline infectious peritonitis virus (Kuehn, 2020).

The majority of feline upper respiratory infections are caused by feline viral rhinotracheitis (FVR), although the incidence of feline calicivirus may be higher in some populations of cats. Natural transmission of these agents occurs via aerosol droplets and fomites. The onset of FVR is characterised by fever, frequent sneezing, inflamed eyes (conjunctivitis), inflammation of the lining of the nose (rhinitis), and often salivation. Severely affected cats may develop mouth inflammation with sores, and inflammation of the cornea. Symptoms may last for 5-10 days in milder cases and up to 6 weeks in severe cases. The occurrence of severe viral upper respiratory disease is rare in adult, properly vaccinated cats. The outlook is generally good except for young kittens and older cats (Povey, 1979; Maes et al., 1984; Kuehn, 2020). Antiviral drugs developed for the treatment of humans infected with herpesviruses have been used to treat cats infected with FVR, with varying degrees of success (Thomasy & Maggs, 2016). Several intranasal modified-live virus FVR-FCV vaccines are available.