Feline Herpesvirus

January 20, 2026

A Fact of Life … 

Nancy Kerr

Has your cat ever had discharge from the eyes and nose along with sneezing and conjunctivitis (pink eye)? If so, chances are that your cat has “feline herpesvirus, also known as feline viral rhinotracheitis (FVR), an infectious disease caused by feline herpesvirus type-1 (FHV-1). It is only known to cause infections in domestic and wild cats and can infect cats of all ages. It 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).”¹ Since “it is globally widespread and common – exposure rates >90% have been reported.”² Chances are that your cat has the virus (exposure typically happens as kittens) and is a carrier for life whether they manifest clinical signs of disease or not.

Infection

So how did the virus get so widespread? It is transmitted by the saliva and other discharge from an infected cat. As long as it stays moist, the virus can survive. Discharge usually dries up in a short time and the virus dies (generally in a few hours). “Viral particles that get onto hands or other skin surfaces usually remain infective (infectious) for about half an hour, while contaminated items such as food or water bowls, litter boxes, blankets, cleaning cloths, and cat toys will be infective for up to 18 hours if the secretions on them remain moist.”¹

It should be noted that cats recovering from infection may harbor the virus for many months. While feline calicivirus (FCV) “is shed continually, infectious FVR virus is released intermittently. Stress may precipitate a secondary course of illness. The incubation period is 2–6 days for FVR and FCV. Unfortunately, a cat can infect other cats during this incubation period.”³

“The active infection will last about 10–20 days. All cats that have been infected with FVR will become carriers of this virus; most carriers will be latent, meaning that the virus will survive in an inactive form within the cat’s body. Stress and illness can cause the virus to become reactivated, and, if the virus becomes reactivated, the cat will again be infectious. In most cases, the cat will show symptoms of a respiratory infection when the virus is reactivated. However, not all cats with a reactivated FVR infection will show symptoms of the disease. All cats that are actively shedding the virus present a risk to other cats.”¹

Symptoms

The more common symptoms of the virus include “sneezing, nasal congestion, conjunctivitis, excessive blinking, squinting, and discharge from the eyes and nose that range from clear and watery to thick and purulent (containing yellow/green pus).”¹ “Besides the conjunctivitis, the virus may also cause “keratitis, or inflammation and infection of the cornea, leading to corneal ulcers. In chronic or severe infections, keratitis can lead to corneal scarring or chronic ‘dry eye.’ Other non-specific symptoms may include fever, lethargy (tiredness), anorexia (poor appetite), and enlarged lymph nodes.”¹

“The characteristic lesion caused by FCV is ulceration of the oral mucosa. Lesions on the tongue or hard palate initially may appear as vesicles, which subsequently rupture. Ulcerations are occasionally found on the epithelium covering the median nasal septum.”³

Diagnosing

How do you determine if a cat has an active infection? The veterinarian will diagnose the virus based on a cat’s medical history, clinical signs, physical examination results, and evidence of a corneal infection. “FVR is usually diagnosed by recognizing upper respiratory signs in young or unvaccinated cats, or recurring conjunctivitis or keratitis in older cats. Tests the veterinarian may also perform include a polymerase chain reaction (PCR), which identifies viral DNA, and virus isolation tests that detect herpes by culturing the virus from clinical samples.”⁴ Unfortunately, if the virus is in a latent (dormant) state, diagnostic testing is usually not productive nor indicates that the virus is present. “Corneal staining with fluorescein dye is often performed to look for any ulcers that may have developed. A Schirmer tear test may be used to assess tear production since decreased tear production has been associated with FVR conjunctivitis.”¹

For adult cats who are up to date on their vaccinations, the incidence of severe viral upper respiratory disease is rare. “They should be tested for other upper respiratory diseases and, less commonly, concurrent immunodeficiency diseases, including feline leukemia virus and feline immunodeficiency virus.”³

Treatment

So how should this virus be treated and kept under control? Treatment is usually determined by the specific medical symptoms and problems that the cat is showing. Cats with an uncomplicated infection are usually treated based on the symptoms present. This generally involves appropriate supportive care, such as maintaining adequate nutrition and hydration. The veterinarian may recommend supplementing with L-lysine, an amino acid that may help reduce the severity of the disease and decrease the spread of the infection.

“Infection involving the eyes may be treated with topical eye medications. Corneal ulcers should be treated aggressively to prevent permanent damage to the eyes. Antibiotics are often prescribed to control secondary bacterial infections, particularly in kittens.”¹ “In acute cases of infection in young cats, antiviral drugs may help treat lesions on the cornea and upper respiratory signs. Systemic antibiotics can also be used to control the secondary bacterial infections that commonly occur with FVR.”⁴

At home, you can try cleaning the discharge away from the cat’s face or eyes with a warm moist face cloth to minimize irritation. Since cats with a respiratory infection will have a decreased sense of smell, their appetite may also be decreased. To encourage them to eat, try feeding a highly palatable and strong-smelling canned food. You can also try warming the food; this will also increase the aroma. If that doesn’t work, an appetite stimulant may be prescribed. In severe cases, the veterinarian may recommend hospitalization for more intensive treatment, including intravenous fluids and other supportive efforts.

Disinfecting Your Home

It important to sanitize your home: the virus can be killed by disinfectants if used on all contaminated surfaces. It is especially important to do this during an active infection.

“A bleach solution (1:32 bleach to water) is an effective disinfectant for surfaces and objects that can be bleached. Contaminated objects should be soaked in bleach solution for a minimum of five minutes. Blankets or toys can also be disinfected by regular machine washing using hot water and detergent. Objects that cannot be bleached may be decontaminated by thorough washing with plenty of soap and water. Upholstered furniture may be decontaminated with upholstery shampoo, although in most cases, furniture only serves as a source of virus for a short time after being contaminated by an infected cat.”¹

Since the virus can be spread by contact between humans and cats it is important to establish and follow a protocol. After touching an infected cat, sanitize your hands (including under fingernails) by washing with soap and water, then use an alcohol-based hand sanitizer.

Other Cats

It is important to remember that a cat that has an acute (serious) infection will be infectious “to other cats during the incubation period and for up to three weeks after developing symptoms. A cat that is a carrier may always be infective (infectious) to other cats.”¹ Affected cats must be isolated from other cats to avoid further spread of disease. “The risk of infection increases in cats that are unvaccinated, are young, or have chronic underlying problems. Adult cats that have been adequately vaccinated will likely only develop a mild case of illness, which may resolve without treatment.”¹ It is a good idea to isolate any new cat from the other cats in your household for at least one to two weeks to minimize transmission of any infectious diseases.

Your Family

Can humans get the virus from a cat? “FVR and caliciviruses are host-specific and pose no known human risk.”³ “However, upper respiratory infections in cats can be caused by or complicated by bacterial infections, some of which might be contagious to humans.”¹ You can reduce your chances of getting sick by properly washing your hands after handling any infected cat. Consult your doctor if anyone appears to develop health issues while a cat is sick or recovering.

Prevention

Can I prevent my cat from getting the virus? The best prevention is to vaccinate before the cat is exposed. While “the FVR vaccine will not completely prevent an infection if your cat is exposed to the virus, but it will significantly reduce the severity of the infection and will shorten the length of the illness. Immunity is not long-term, and may be overcome by exposure to a high dose of virus, so cats must receive a booster regularly.”¹ This is beneficial to other susceptible cats, particularly those living with the cat being vaccinated.

“A cat that is a carrier of FVR may benefit from periodic boosters with the intranasal herpes and calicivirus vaccine (up to two to three times per year). Boarding facilities, humane societies, animal shelters, and cat shows are all places where susceptible cats can be readily exposed to these infectious diseases. If you plan to board or show your cat, consult your veterinarian about the need for a booster vaccine at least two weeks before the planned event.”¹ Try to avoid contact with other infected cats, and ensure good sanitation and hygiene protocols, such as washing hands thoroughly before and after petting other cats. Infected cats should be kept indoors to avoid spreading infection to other cats in the area. What goes around, comes around.

Prognosis

So, what does this mean for my cat? While the prognosis for recovery is good, recurrence of the disease is common. Lifelong infection may require repeated treatments that can be expensive. Check with your pet insurance to see if this is covered. While there is no cure for herpes virus infections, things can be done to reduce the frequency and severity of recurrences. Most cats respond well to medical management of the condition and lead normal lives. To defend against this disease, it is important to minimize the chances of infection, ensure excellent nutritional diet, try to reduce stressful situations, and make sure your cat is vaccinated regularly.

Sources

1. Courtney Barnes, BSc, DVM; Malcolm Weir, DVM, MSc, MPH; Krista Williams, BSc, DVM; and Cheryl Yuill, DVM, MSc, CVH , Herpesvirus Infection in Cats (Feline Viral Rhinotracheitis), Accessed 11/09/2025, https://vcahospitals.com/know-your-pet/feline-herpesvirus-infection-or-feline-viral-rhinotracheitis

 

2. Feline herpesvirus disease, Accessed 11/09/2025, https://www.vetlexicon.com/felis/internal-medicine/articles/feline-herpesvirus-disease/

 

3. Caroline C. Tonozzi, DVM, DACVECC, Mission Veterinary Partners , Feline Respiratory Disease Complex, Nov 2024, Accessed 11/09/2025, https://www.merckvetmanual.com/respiratory-system/respiratory-diseases-of-small-animals/feline-respiratory-disease-complex

 

4. Respiratory Infections, June 2018, Accessed 11/09/2025, https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/respiratory-infections