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. Almost half of all upper respiratory infections in cats are related to a feline herpesvirus infection. It is spread through contact with secretions from infected cats, or through inhalation of the virus that has been released into the air from an infected cat’s sneeze. It is a highly contagious virus, but there is a vaccine that will protect cats and kittens from the disease.
How Feline Herpesvirus Infection Affects Cats
Feline herpesvirus (FHV) infection, also called feline viral rhinotracheitis (FVR), is an acute upper respiratory tract disease that affects both domestic and wild cats. FHV is highly contagious among cats and tends to attacks animals with weakened immune function. It is most frequently diagnosed in multi-cat households and in cats kept in crowded, unsanitary conditions.
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.
Symptoms of Feline Herpesvirus Infection
The most common initial sign of FHV infection is the sudden onset of sneezing fits, accompanied by eyelid spasms or squinting (blepharospasm), conjunctivitis (inflammation and redness of the membrane lining the inner surface of both eyelids) and ocular discharge. Nasal discharge and inflammation of the mucous membrane of the nose (rhinitis) is also quite common. These initial symptoms frequently are closely followed by anorexia, fever, cough, overall malaise and, if the affected feline is pregnant, abortion. The clinical signs of feline herpesvirus infection can resemble flu-like symptoms, and for this reason FHV infection is sometimes referred to as “feline influenza.” The initial symptoms generally last for about one week.
After the initial signs of feline herpesvirus infection resolve, many cats develop secondary bacterial or other infections. These infections tend to localize to the eyes, nose and mouth and can persist for weeks. Corneal ulceration can also occur. Many of these infections wax and wane, usually recurring during times of stress or immunosuppression. Others become chronic and can stabilize or worsen with time.
Like other herpesvirus infections, FHV typically remains latent in an infected cat’s system for life. Future outbreaks of clinical disease may or may not occur. Cats that become pregnant or experience other stressful medical, emotional or environmental conditions, are predisposed to recurrence of clinical disease.
Causes & Preventing 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.
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.
Treating Feline Herpesvirus
The treatment goals for cats with FHV infection are to stop viral replication, prevent or resolve secondary bacterial infections, relieve pain and minimize recurrence of clinical disease. This highly contagious disease can become life-threatening, especially in kittens. While there currently is no cure for FHV infection, there are treatments that can alleviate the painful symptoms and resolve any secondary bacterial infections that develop.
Many cases of FHV infection are self-limiting and resolve with little treatment other than supportive care. Affected cats often need nutritional and fluid support and may need to be force-fed and/or given intravenous or subcutaneous fluids. Dried nasal and ocular discharge should be removed gently with a warm, moist cloth. Topical broad spectrum antibiotic ointments are often prescribed to treat or prevent secondary bacterial infections. Affected cats should be isolated from other cats due to the highly contagious nature of this viral infection. They should be fed a highly palatable diet to prevent anorexia, subsequent weight loss and weakness. If possible, a humidifier or vaporizer should be placed in the isolation room to increase the moisture in the air. The cat’s environment should be kept calm and quiet so that rest is encouraged. Children in the household should be instructed to leave the cat alone until it is well. Recurrent infections should be treated swiftly and aggressively.
A number of new and promising treatments for FHV infections are under development. Talk with your veterinarian about appropriate treatment protocols if your cat is affected by this condition.
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.