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Feline Viral Rhinotracheitis PDF Print E-mail

Feline viral rhinotracheitis (FVR) is an upper respiratory infection of cats caused by feline herpesvirus 1, of the family Herpesviridae. It is also known as feline influenza and feline coryza. Viral respiratory diseases in cats can be serious, especially in catteries and kennels. Causing one-half of the respiratory diseases in cats,[1] FVR is the most important of these diseases and is found worldwide. The other important cause of feline respiratory disease is feline calicivirus.

FVR is very contagious and can cause severe disease, including death from pneumonia in young kittens. All members of the Felidae family are susceptible to FVR, in fact FHV-1 has caused a fatal encephalitis in lions in Germany. 

Transmission

FVR is transmitted through the air and direct contact. It replicates in the nasal and nasopharyngeal tissues and the tonsils. Viremia (the presence of the virus in the blood) is rare. The virus is shed in saliva and eye and nasal secretions, and can also be spread by fomites. FVR has a two to five day incubation period. The virus is shed for one to three weeks postinfection.  Latently infected cats (carriers) will shed FHV-1 intermittently for life, with the virus persisting within the trigeminal ganglion. Stress and use of corticosteroids precipitate shedding.

Symptoms

Chronic epiphora in a carrier of FVRChronic epiphora in a carrier of FVR

Initial symptoms of FVR include coughing, sneezing, nasal discharge, conjunctivitis, and sometimes fever and loss of appetite. The symptoms usually resolve within four to seven days, but secondary bacterial infections can cause persistence of symptoms for weeks. Frontal sinusitis and empyema can also result.

FHV-1 also has a predilection for corneal epithelium, resulting in corneal ulcers, often pinpoint or dendritic in shape. Other ocular symptoms of FHV-1 infection include conjunctivitis, keratitis, keratoconjunctivitis sicca (decreased tear production), and corneal sequestra. Infection of the nasolacrimal duct can result in chronic epiphora (excess tearing). Ulcerative skin disease can also result from FHV-1 infection.  FHV-1 can also cause abortion in pregnant queens, usually at the sixth week of gestation, although this may be due to systemic effects of the infection rather than the virus directly.

In chronic nasal and sinus disease of cats, FHV-1 may play more of an initiating role than an ongoing cause. Infection at an early age may permanently damage nasal and sinus tissue, causing a disruption of ciliary clearance of mucus and bacteria, and predispose these cats to chronic bacterial infections.