Feline herpesvirus (FHV-1 or feline rhinotracheitis virus) is a highly contagious virus of both domestic and wild cats.
Herpesvirus is part of the feline upper respiratory infection complex. This is a group of viral and bacterial infections, also including calicivirus and chlamydiosis, which cause sneezing and discharge from the eyes and nose. Cats often have two or more of the upper respiratory infections at the same time, and feline herpesvirus is one of the most common.
What are the common clinical symptoms of feline herpesvirus infection?
- Respiratory symptoms, including sneezing and nasal discharge and inflammation
- Conjunctivitis (inflammation of the tissues surrounding the eyes). Feline herpesvirus is the most common cause of conjunctivitis in cats. Conjunctivitis is manifested as:
- Squinting or closing of the eye
- Red, swollen tissue surrounding the eye and eyelids
- Eye discharge that may range from clear to yellow-greenish in color
- Reproductive abnormalities, causing complications during pregnancy
Clinical signs often appear suddenly and are especially common after stressful situations such as travel, boarding, surgery, or illness.
In young kittens, clinical signs can be much more severe. They can produce so much eye discharge that their eyes gum closed, sealing the infected secretions around the eye. It is important that the eyelids be opened to allow drainage of secretions as well as application of medicine. The swelling in the lining of the eyelid can be so severe that the eye itself is not visible, and in severe cases the eye can rupture, causing permanent blindness.
Severely affected kittens may also experience more severe respiratory signs, developing life-threatening loss of appetite, and dehydration. It is important that these kittens be seen by a veterinarian as soon as possible.
Who is at risk for catching this disease?
Cats of all ages and breeds are susceptible, although it is most common in the following:
- Kittens, especially those born to infected mothers
- Multi-cat households, catteries and pet shelters
- Pregnant cats
- Sick cats
- Unvaccinated cats
What happens once my pet is infected?
The infection begins with an initial phase, which is usually the most severe. This phase resolves but, much like herpes virus in people, the virus itself does not go away. Instead, it retreats into the patient’s nerves where it remains (latent), trapped by the patient’s immune system. In times of stress (e.g. during boarding, travel, big household changes, or illness) the immune system is taxed, and the virus is able to escape, leading to return of symptoms.
For this reason, many cats are infected with feline herpesvirus and do not show any signs of clinical illness (i.e. they have a latent infection). Fortunately, less than 45% of adult cats with latent herpesvirus infection develop recurrent signs of disease. In most cases, the clinical signs, when they occur, resolve within a few weeks.
What diagnostic testing is indicated for feline herpesvirus?
Diagnosis is based primarily on medical history and physical examination. Staining of the eye with a special dye is often performed to look for any ulcers that may have developed. Special laboratory testing is available to identify feline herpesvirus. This testing may be utilized in patients with chronic or severe signs. Unfortunately, diagnostic testing is usually not rewarding during times of viral latency or in the absence of clinical signs. Since decreased tear film production has been associated with FHV-1 conjunctivitis, specific tests to assess the tear production may be recommended.
What is the treatment for feline herpesvirus?
Treatment is determined by your cat’s specific clinical signs and problems. It is important to remember that these infections are usually mild and self-limiting. However, if there are corneal ulcers or if signs are severe, it is important to treat these appropriately. The following is a list of common treatment regimens used in treating recurrent feline herpesviral conjunctivitis:
- Topical and / or oral antibiotics
These stop secondary bacterial invaders and are helpful in controlling initial infections or severe recurring infections. It is important to realize that antibiotics do not affect the herpes virus itself; they will only work on secondary bacteria. - Topical antivirals
There are several eye drops available (Idoxuridine, vidarabine, Trifluorothymidine) that act directly against the herpes virus. These medications are relatively expensive and typically require administration several times daily. - Oral Interferon
This oral solution uses a natural immune system modulator to suppress herpesvirus symptoms. Though interferon use has not been scientifically tested, it has been in use for many years as something that seems to help shorten the course of infection. - L-lysine
L-Lysine helps suppress reproduction of the herpes virus. Lysine is relatively inexpensive and readily available. A month or so of supplementation is required in order to determine if supplementation has been helpful.
What is the prognosis for a cat diagnosed with herpesvirus?
There is no cure. The therapeutic goal is to reduce the frequency and severity of recurrences. Most cats respond well to medical management and lead relatively normal lives. Minimizing the chance of infection, feeding a premium diet, supplementing the diet with L-lysine daily, reducing stressful situations, and proper vaccination against preventable causes are your cat’s best defense.
How can I prevent my cat from becoming infected?
The best method of protecting your cat against feline herpesvirus is proper vaccination. All kittens receive a series of vaccinations 3-4 weeks apart (starting at 6-8 weeks of age). These vaccination boosters are typically administered as part of an HCP (herpesvirus, calicivirus, panleukopenia) combination vaccine. After the initial series of vaccinations, your veterinarian will discuss with you an appropriate schedule of revaccination.
Can humans get feline herpes? Can cats get human herpes?
Happily, humans and cats cannot share their herpes infections. Feline herpes is contagious among cats only and human herpes is contagious among humans only.