FELINE HERPESVIRAL CONJUNCTIVITIS
What is feline herpesviral conjunctivitis?
Conjunctivitis is a medical term used to describe inflammation of the tissues surrounding the eye. These tissues include the lining of the lids and the third eyelid as well as the tissues covering the front part of the eye or globe. Conjunctivitis may be a primary condition (caused by an infection) or may be secondary to an underlying systemic or ocular disease.
Feline herpesviral conjunctivitis is a form of primary conjunctivitis caused by the highly infectious feline herpesvirus (FHV-1). Herpesvirus infection is common in cats (studies show that 80% of cats entering shelters already carry the virus) and is the most common cause of conjunctivitis in cats. Many cats are infected with FHV-1 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 ocular disease such as conjunctivitis. In most cases, herpesvirus conjunctivitis is self-limiting and will resolve within two weeks.
What are the clinical signs of feline herpesviral conjunctivitis?
The most common clinical signs of conjunctivitis are squinting or closing of the eye, red, swollen tissue surrounding the eye and eyelids, ocular discharge that may range from clear to yellow-greenish in color, and upper respiratory infection symptoms such as sneezing or nasal discharge. These signs often appear suddenly and are especially common after stressful situations such as travel, boarding, surgery or illness. Chemosis, a condition in which the membranes that line the eyelids and surface of the eye appear to have fluid in them, is more commonly associated with chlamydial infections.
What diagnostic testing is indicated for feline herpesviral conjunctivitis?
Diagnosis is based primarily on medical history and physical examination. Corneal staining is often performed to look for any ulcers that may have developed. Identification of feline herpesvirus DNA by polymerase chain reaction amplification (PCR testing) is the most sensitive test available for diagnosing infection by FHV-1. 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 herpesviral conjunctivitis?
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, it is important to treat these quickly. Treatment often involves antibiotic and/or antiviral topical eye medications and possibly supplementation with the amino acid L-Lysine, which inhibits viral replication.
What is the prognosis for a cat diagnosed with herpesviral conjunctivitis?
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.
SNEEZING WITH FRIENDS - A REAL LIFE STORY OF HERPES CATS IN MY HOME
By Joan Levergood
In 1999 my husband and I adopted Britton from Tree House. He was a cat who had severely damaged eyes due to having a severe eye infection related to the feline herpes virus as a very young kitten. Sadly for Britton, he did not get the medication that would have helped him in time and the damage to his eyes was so severe that it was estimated that he had only 10 to 20% vision. The virus also had caused him to have chronic congestion, frequent eye infections and one of his tear ducts to become blocked. During his time at Tree House one of his tear ducts needed to be unblocked regularly by our veterinarians. Britton spent his first 2 ? years as a first floor cat at Tree House before coming to our home.
Britton came to live with us and our animal family of 1 dog and 4 cats. He quickly acclimated to his new surroundings and made friends with his new animal brothers and sisters. At the time when Britton was adopted less was known about the feline herpes virus than is now and I was not aware that our other cats could become infected with the virus. Within the first 6 months it became obvious that Britton would not have as many problems in our home as he had at Tree House. He did not need to have his tear duct unblocked, had no eye infections, and his chronic congestion improved.
Britton has been a member of our family for over 6 years now and during that time he has never had to have his tear duct unblocked, nor has he had any eye infections. He still sneezes on a daily basis, but has not needed treatment or medication since shortly after coming to live in our home. I suspect that the stress of living in a shelter with so many cats and continually being exposed to various illnesses was the primary reason for his frequent eye infections and the need for his tear ducts to be drained while he was at Tree House. In all of the years since being exposed to the virus through living, sleeping, wrestling, grooming and playing with Britton, only one of our other cats has had a single an eye infection, which cleared up with medication in a few days. This cat also had a severe eye infection as a very young kitten, which may have made him more susceptible. All of the other cats have had no problems at all. Subsequent to adopting Britton, we adopted 2 more cats from Tree House that had chronic respiratory symptoms. Despite their exposure to the virus, our other cats have had no significant problems.
Although my experience may not be typical, I have concluded that keeping a cat with the herpes virus in a home with other healthy cats does not always result in the other cats becoming infected. In fact I have found that a healthy high quality diet and low stress environment is very likely to lessen outbreaks in a cat who does have herpes, which decreases the likelihood of a cat shedding the virus. I would highly recommend everyone to consider adopting a cat with a history of chronic upper respiratory illness if at all possible. Britton is much loved member of our feline family and is even a friend to our dog.
This client information sheet is based on material written by Ernest Ward, DVM © Copyright 2005 Lifelearn Inc. Used with permission under license. December 14, 2011