Feline herpesvirus (FHV) infection, also called feline viral rhinotracheitis (FVR), is an acute and highly contagious viral upper respiratory tract disease that affects both domestic and wild cats, especially those with weak immune systems.
How Feline Herpesvirus Infection Affects Cats
Cats infected by FHV show classic signs of upper respiratory tract disease, including acute onset of sneezing, inflammation and irritation of the membranes lining the eyelids and nasal cavity and increased salivation. A fluxuating fever may be present, and a thick, yellow-ish nasal and ocular discharge usually occur as well. Affected cats tend to lose their appetites because their sense of smell is adversely affected by the inflammation and congestion. Some cats will become depressed, listless and lethargic. In most cases, the initial clinical signs will persist for approximately one week before they subside. However, periodic recurrence of clinical signs is fairly common.
Causes of Feline Herpesvirus Infection
Almost one-half of all feline upper respiratory tract infections involve feline herpesvirus. Infection by this virus is caused by direct contact with secretions from infected cats through oral, nasal or conjunctival exposure. Feline herpesvirus is highly contagious between cats. FHV infection is perpetuated by latent carrier cats that harbor the virus indefinitely.
Preventing Feline Herpesvirus Infection
The best way to prevent severe FHV disease is routine vaccination with a modified live or inactivated virus vaccine. This vaccine can be started in young kittens, with annual boosters. The vaccine does not prevent infection by the virus but does prevent development of severe upper respiratory disease. Owners should also take steps to reduce environmental stressors that may adversely affect their companion cats. Of course, any clinically affected cat should be strictly isolated from all other cats until the infection is resolved.
Feline herpesvirus is infectious and contagious between cats but is not zoonotic and thuys does not present a risk to humans. The prognosis for cats infected by feline herpesvirus is generally quite good, as long as appropriate nutritional support and fluid therapy are provided. Owners should recognize that this disease can recur periodically, particularly during periods of stress, illness or immunosuppression. Young kittens with undeveloped immune systems and older cats with weakened immune systems tend to be affected more severely by the virus and thus have a poorer prognosis.