Viral infections can be extremely debilitating, causing lifelong issues for some cats. These diseases can also cause uveitis, a painful condition that affects your cat’s eyes. Our team at Veterinary Vision Center would like to educate you on what viruses can affect your cat’s eyes, and ways you can protect your cat.
What is uveitis in cats?
Uveitis is inflammation of the uveal tract, which has three main components:
- Iris – The colored tissue in the front of the eye that helps control pupil size
- Ciliary body — The tissue that connects the iris to the choroid
- Choroid — A thin tissue layer between the retina and the sclera
Uveitis often occurs secondary to ocular trauma or a systemic infection, and signs include red eyes, squinting, tearing, cloudy cornea, and rubbing at the eyes.
What viruses cause uveitis in cats?
Four common feline viruses result in uveitis in cats.
- Feline infectious peritonitis (FIP) — FIP is a viral disease caused by a feline coronavirus. Most feline coronavirus strains are feline enteric coronaviruses (FeCV) found in the gastrointestinal tract, and do not result in significant disease. In about 10 percent of cats affected by these strains, the virus will mutate, resulting in FIP, which can occur as a dry or wet form. Uveitis is more prevalent in the dry form. FIP breaks down the blood-ocular barrier, causing uveitis and fibrin leakage into the eye’s front chamber. FIP signs include fever, lethargy, decreased appetite, incoordination, and seizures. Once a cat shows FIP signs, the disease is almost always fatal. A vaccine against FIP exists, but the only way to definitively prevent your cat from FIP infection is to prevent their exposure to cats infected by FeCV.
- Feline leukemia virus (FeLV) — This virus is shed in an infected cat’s saliva, nasal discharge, urine, feces, and milk. Transmission can occur if an infected cat bites another cat, or during mutual grooming. FeLV is the most common cause of cancer, and causes an immune deficiency that limits a cat’s ability to fight off other infections. Uveitis is often the first presenting sign in affected cats, with other signs including weight loss, poor coat condition, fever, enlarged lymph nodes, and inflammation inside the mouth. No definitive cure exists for FeLV, and treatment is focused on therapy for signs exhibited, and isolating affected cats so they cannot contract other diseases. An effective FeLV vaccine is available, but the only definitive way to safeguard your cat is to ensure they are not exposed to cats affected by FeLV.
- Feline immunodeficiency virus (FIV) — FIV attacks the cat’s immune system, making them vulnerable to other infections. FIV is most commonly transmitted through an infected cat’s bite. Uveitis is caused by direct viral damage, or from secondary infections. Other signs include fever, lethargy, decreased appetite, and enlarged lymph nodes. As the disease progresses, and the immune system is further compromised, signs will depend on the secondary infections affecting the cat. No definitive treatment for FIV is available, but if managed appropriately, these cats can live normal lives for many years. No vaccine is available against FIV, so the only way to safeguard your cat is to prevent their exposure to FIV-infected cats.
- Feline herpesvirus-1 (FHV-1) — FHV-1 is transmitted through an infected cat’s respiratory droplets. The virus can cause lifelong infection and signs, including fever, nasal and ocular discharge, lethargy, and ulcers on the cornea and in the mouth, may recur when a cat is stressed. Uveitis can occur from direct damage by the virus, or secondary to a corneal ulcer. Treatment involves supportive care and antiviral drugs. Antibiotics may also be useful to control secondary bacterial infections. An effective vaccine is available against FHV-1, but you should still prevent your cat from contacting infected cats.
What secondary complications can occur in uveitic cats?
Numerous complications that may cause blindness can occur secondary to uveitis in cats.
- Glaucoma — Aqueous humor is produced by the ciliary body, and typically flows from the posterior chamber, through the pupil, and into the anterior chamber, and then exits out the iridocorneal angle. Uveitis impairs this flow, resulting in increased pressure inside the eye, known as glaucoma.
- Cataracts — Uveitis results in inflammatory cells diffusing across the lens capsule, resulting in cataract formation.
- Lens luxation — Uveitis causes an inflammatory breakdown of the lens’ suspensory ligament, resulting in lens luxation.
- Retinal detachment — Uveitis causes the retina to become inflamed, resulting in necrosis and retinal detachment.
How is uveitis treated in cats?
Uveitis management is generally aimed at controlling inflammation and providing pain relief, typically with topical eye medications, such as corticosteroids, and non-steroidal anti-inflammatory drugs. Antiviral medications may be employed if appropriate, and antibiotics may be necessary to control secondary infections. The underlying cause of the uveitis will determine the specific treatment protocol. Uveitis can be difficult to manage, and your cat will likely require frequent veterinary rechecks to assess their treatment response.
Keeping your cat up to date on their vaccines, and ensuring they are not exposed to infected cats are the best ways to safeguard your cat. If your cat is suffering from viral uveitis, do not hesitate to contact our team at Veterinary Vision Center.