Did you know there are specific viruses that only affect cats? Feline Leukemia Virus (FeLV) and Feline Immunodeficiency Virus (FIV) are retroviruses found in cat populations around the world. Both viral infections compromise the immune system, but differ in how they spread and impact your cat's health. Once exposed, your cat can have subsequent health complications for the rest of its life. Screening for these viruses through specific blood testing is important to make appropriate health decisions with your veterinarian. Knowing the status of a cat directs future planning to inhibit spreading the virus and subsequent disease to other cats. Early detection and management will make an impact on the quality of life for your pet and allow you to protect others.
What Are FeLV and FIV?
FeLV and FIV are retroviruses that progressively weaken the immune system. Retroviruses form viral DNA that permanently integrates itself into your cat's genome, making it a fixture of their genetic makeup. FeLV, in its progressive state, can lead to anemia or lymphoma and is much more contagious. It tends to be more aggressive and consequential to your cat's health. FIV affects the immune defense but generally progresses much more slowly and is not as aggressive.
How Do Cats Get FeLV and FIV?
FeLV and FIV are feline-specific viruses that do not spread to humans or any other species, including dogs. So yes, even African Lions have documented cases of FeLV and FIV present in their wild populations! Sometimes called the "friendly cat disease," FeLV is easily spread between cats. While infectious, cats shed viral particles in their saliva, nasal discharge, feces, urine, and milk. Pregnant cats can also spread the virus to their developing kittens. Shared litterboxes, food and water bowls, mutual grooming, bite wounds, and breeding are all common modes of transmission of Feline Leukemia. Feline Immunodeficiency Virus is less contagious than FeLV. The primary mode of infection is through bite wounds. It is commonly seen in fighting cats with unstable social structures. Luckily, mutual grooming, shared water and food bowls, and shared litter boxes are not an efficient route of spreading the FIV (Cornell). What does this mean? Cats who are positive for FIV can live in a household with other cats who are negative for FeLV and FIV as long as they get along with each other!
Common Signs and Symptoms of FeLV and FIV in Cats
FeLV and FIV share some common symptoms like fever, loss of appetite, weight loss, and diarrhea, along with a high risk for secondary infections due to immune compromise (Illinois College of Veterinary Medicine). In FIV, there are three phases: the acute phase, the asymptomatic (latent) phase, and the progressive phase. According to Dr. Jennifer Reinhard DVM DACVIM, most cats with FIV will not progress to a clinical stage and go on to live a normal life. FeLV also has three types of infections: abortive, regressive, and progressive infections. Cats with abortive infections are able to clear the virus before it is incorporated into their genome. These cats will never test positive or be able to spread the virus to other cats. Cats with a regressive infection mount a partial immune response and slow the progression of the disease to an inactivated state. Unfortunately, this can be reactivated if the cat experiences immune compromise when ill with another disease or with certain medications like steroids. Progressive infections carry the poorest prognosis. These cats are at the highest risk for developing secondary infections, having blood disorders, and developing cancers such as lymphoma.
Living with FeLV and FIV
Even though some cats succumb to illness, others exposed to FeLV and FIV have the potential to live normal lives. These cats need additional care achieved with regular wellness examinations, screening bloodwork, an exclusive indoor lifestyle, feeding a high-quality diet with supplements, and using monthly parasite prevention. Cats positive for FIV can live in households with FIV-negative cats as long as they have a stable social system and do not fight. In contrast, because of the contagious nature of FeLV, cats who are FeLV positive should only live with other cats who are also positive.
When to Talk to Your Vet
Knowing the viral status of a new cat before introducing them to your household is essential to keeping your established cats safe. An in-clinic point-of-care test for FeLV and FIV can be done at all three of our locations. Additional testing can be sent out if indicated. The Feline Veterinary Medical Association (FelineVMA) recommends that all kittens and any negative cat with potential exposure to the outdoors or FeLV-positive cats be vaccinated for this virus. Initially, a series of two will be given with subsequent vaccines based on future potential exposure. This is an important conversation to have with your veterinarian at your cat's yearly wellness examination. Currently, there are no vaccines for FIV in the United States. For those cats with a known positive status, notify your vet at the first sign of illness.
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