Feline Leukemia Virus

Feline Leukemia Virus (FeLV) is a retrovirus that invades a cat’s cells and causes them to have a weaker immune system. This makes FeLV+ cats more susceptible to common infections, illness, and disease. Unfortunately, because Feline Leukemia continuously replicates itself within living cells, it’s impossible to cure. It can, however, be managed, and it’s important to know that cats infected with FeLV can still live long, happy and fulfilling lives.

Feline Leukemia Virus is mainly spread through the exchange of saliva when cats groom each other, or when fighting is involved. It can also spread from mother to kitten, or when food and water bowls are shared with an infected cat. About 4% of tested cats here in North America are shown to be FeLV-positive. It’s important to note that Feline Leukemia cannot be spread to any other species, including humans. If you have other non-feline pets in your home, there is no need to worry about cross-contamination.

Cats infected with Feline Leukemia virus will require a little extra care and attention. The best thing for an FeLV+ cat is to live exclusively indoors in a clean, calm environment. They should also be the only cat in your home. Maintaining a high-quality and nutritionally rich diet is also important to keep an FeLV+ cat healthy. Canned food is usually best because of the higher water content. Lastly, having a good preventative healthcare routine is essential to keeping an FeLV+ cat happy and healthy. Visiting the vet once a year for routine vaccinations, regular deworming, and an overall health check for potential infections or illness is a must. All FeLV+ cats should also be spayed or neutered.

There are three different forms of FeLV with different prognoses for each. Abortive
infections are when the cat tests positive for FeLV, but is able to mount an effective immune response against the virus and kill it naturally. After they clear the virus, cats infected with this form will be FeLV-negative and live normal, healthy lifespans. Regressive infections mean the virus has been eliminated from the bloodstream but has integrated into the cat’s genome. There is a lower risk for developing FeLV-associated diseases with this form, and infected cats will have a higher chance of living normal lifespans. Progressive infections mean the virus was not contained during early stages of infection and can be found reproducing throughout the cat’s body, including in the bloodstream. Cats infected with this form of the virus tend to live shorter lives and are more likely to
succumb to FeLV-associated diseases.

In order to determine what form of Feline Leukemia Virus a cat has, veterinarians must first look for the virus inside the blood cells of an infected cat using polymerase chain reaction (PCR), a laboratory technique used to amplify and study DNA. Simply put, veterinarians can determine if a cat has an abortive, regressive or progressive infection by seeing how much (or how little) of the virus exists in the cat’s blood. Please note that in some cases, it will be impossible to determine what form of FeLV a cat has. It’s also entirely possible for a regressive form of the virus to advance to the progressive form.

Feline Leukemia Virus can sound scary and seem overwhelming at times. It’s crucial to remember, however, that giving a cat a loving home is what’s most important. We can’t predict the lifespan of your cat and there is always ambiguity
when choosing to love and care for an FeLV-infected cat. However, there is also something special, rewarding, and unique about the experience. Many adopters find comfort in knowing that they have given a cat in need a loving and happy home, regardless of how much time it has left.  FeLV+ cats have so much love to give and whether they live for many years or only months, they deserve a home and a family to call their own.

Learn more about Feline Leukemia Virus.