Feline herpesvirus, or FHV-1, is a widespread and highly contagious virus responsible for upper respiratory infections in cats, a condition often called feline viral rhinotracheitis (FVR). The virus is a frequent cause of respiratory and eye-related disease, especially in environments with many cats like shelters.
Transmission and Clinical Signs
Feline herpesvirus spreads primarily through direct contact with secretions from an infected cat. The virus is present in saliva and in discharge from the nose and eyes. An infected cat will shed the virus for up to three weeks after the initial infection. Contaminated objects also play a role in transmission; shared food and water bowls, litter boxes, and bedding can harbor the virus and spread it to another cat.
Once infected, a cat becomes a lifelong carrier of the virus, which remains latent in the body. The virus can reactivate and be shed intermittently, particularly during periods of stress, even if the cat is not showing active signs of illness. This means a seemingly healthy cat can still be a source of infection for other felines. FHV-1 is species-specific and cannot be transmitted to humans or other animals like dogs.
Clinical signs of an active infection typically appear within two to six days of exposure. One of the most common signs is sneezing fits, often accompanied by nasal discharge. Cats frequently develop eye issues, including conjunctivitis, which involves inflammation of the eye tissues, and discharge that can be clear or thick. In some cases, the virus causes keratitis, an inflammation of the cornea that can lead to painful corneal ulcers.
Other symptoms include fever, lethargy, and a loss of appetite. Some cats may also develop sores in their mouths or experience coughing. The severity of these signs can vary, but kittens are often more seriously affected than adult cats. Chronic cases might lead to persistent nasal congestion and secondary bacterial infections.
Veterinary Diagnosis and Treatment
A veterinarian often makes a presumptive diagnosis of feline herpesvirus based on the distinct clinical signs present during a physical examination. To confirm the diagnosis, especially in severe or atypical cases, a veterinarian may collect samples from the cat’s eyes, nose, or throat. The most sensitive method for detection is a polymerase chain reaction (PCR) test, which can identify the virus’s DNA.
There is no cure for FHV-1, so treatment focuses on managing the symptoms and improving the cat’s comfort. For cats with eye involvement, a veterinarian may prescribe topical antiviral eye drops. In severe cases, oral antiviral medications like famciclovir might be used. Since the viral infection can lead to secondary bacterial infections, broad-spectrum antibiotics are often prescribed to address these complications.
Supportive care is a component of treatment. The amino acid supplement L-lysine is sometimes recommended to help reduce the severity of symptoms, though its effectiveness is debated. Good nursing care, such as keeping the cat’s face clean and ensuring they are eating, is also a part of the management plan.
Managing Flare-Ups at Home
During a flare-up, owners can provide supportive care at home to help alleviate their cat’s discomfort. To ease nasal congestion, using a humidifier or bringing the cat into a bathroom while a hot shower is running can help. The steam helps to loosen mucus in the nasal passages. Gently wiping the cat’s eyes and nose with a warm, damp cloth can remove discharge and keep the area clean.
Loss of appetite is common during an infection, partly because nasal congestion can diminish a cat’s sense of smell. Owners can encourage eating by offering highly palatable and strong-smelling foods, such as warmed canned or wet food. Ensuring the cat remains hydrated and nourished is an important part of recovery.
Prevention Through Vaccination and Management
The core FVRCP vaccine is a standard part of feline preventative care and protects against feline viral rhinotracheitis (the “FVR” component caused by herpesvirus). This vaccine is effective at reducing the severity of disease caused by FHV-1. It is important to understand that while the vaccine lessens clinical signs, it does not always prevent a cat from becoming infected or developing a latent carrier state.
For all cats, but especially those already carrying the virus, long-term management strategies are centered on minimizing stress to prevent flare-ups. Maintaining a consistent daily routine for feeding, playtime, and cleaning can provide a sense of security. In households with multiple cats, preventing social conflict and providing ample resources like litter boxes, food bowls, and resting spots can reduce stress.
Environmental enrichment supports a cat’s well-being. Providing toys, scratching posts, and climbing structures can help keep a cat mentally stimulated and reduce boredom-related stress. For cats known to be carriers of FHV-1, minimizing exposure to other cats, particularly in high-density situations like boarding facilities, can help prevent transmission. A stable and enriching environment is a component of long-term health for a cat with feline herpesvirus.