Dog Cat Love

Understanding FeLV: Loving and Living With FeLV Cats

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Guest post by Joni Gallo

We asked Joni to share her knowledge and understanding of cats with the Feline Leukemia Virus with us. Joni is a lifelong cat lover who has had several FeLV cats in recent years, without planning to. She has learned about the condition and about living with and caring for cats who carry the virus. Despite well-meaning recommendations and advice encouraging her to euthanize her cats upon diagnosis, Joni chose to let them live and give them the love and care they deserved.  She has a mission now, to encourage others to give FeLV kitties a chance at life and happiness.

Sienna, who was discovered to have the virus as a kitten

As I hung up the phone, I began to cry. The vet had just told me that the new kitten I’d brought home had tested positive for the feline leukemia virus. She told me I shouldn’t keep him. I had five other cats. I was torn. Little 3 month old Sienna had been found in an abandoned house with his mother and had nowhere else to go. He would have been “euthanized” at a kill shelter. He would have been spared at a no-kill shelter but would most likely never get adopted. I couldn’t give him to anyone. No one would want him.

Fortunately, as it turned out, I did keep Sienna because I found out a month later, that he was not the only cat I had that carried the feline leukemia virus.

What is the Feline Leukemia virus and why is it so feared? FeLV is a retrovirus that only infects cats. The virus spreads by inserting copies of its own genetic material into the host cat’s cells. The cells are then transformed into cancer cells or cells which do not function the way that they should. (

FeLV is passed along from cat to cat through bodily fluids and requires repeat exposure such as that which occurs in cats sharing a household or living together in the same room at a shelter. Mutual grooming, sneezing, the sharing of dishes and litter pans can all spread the virus. FeLV is sometimes confused with FIV, which is more like human HIV. With FIV, white blood cells called T helper cells are destroyed, leading to a depression of the cat’s immune system. FIV is mostly spread through bite wounds and so is more common in unneutered males. (


When a cat tests positive for feline leukemia and has been exposed to other cats, all the cats should be tested immediately. I made the mistake of only having one other cat tested, Colt, the one that had spent the most time with Sienna. When his test turned up negative, I stopped there. A little over a month later, it was discovered that my two girls, Dharma and Karma, both carried the virus.

Retests are important with FeLV. The test that is performed at the vet’s office is called the ELISA test. This test checks for the presence of a protein component of the virus as it circulates in the bloodstream. ( Since it is possible for the cat to produce an immune response that sheds the virus, another ELISA test should be done a few weeks later. There is also a second test called the IFA test which is sent out to a diagnostic laboratory. This test can be used to confirm the cat’s FeLV status.

40% of the cats exposed to FeLV will successfully shed the virus from their systems. ( This occurrence is more common with an adult cat, then it is for a kitten. If the virus is not shed, there are two other outcomes. 30% of the time, the cat will become persistently infected. In this case, both the ELISA test and IFA test will be positive for feline leukemia and remain positive for the cat’s whole life. Cats that are infected will typically remain healthy two to three years after exposure and then eventually succumb to a FeLV-related disease such as lymphoma, leukemia, or an untreatable infection. 15% of FeLV+ cats do, however, make it past the four year mark.


In the second outcome, 30% of cats exposed to FeLV will become latent carriers of the virus. When the virus moves into the cat’s bone marrow, it becomes undetectable in tests. At a later date, the cat will either shed the virus or become persistently infected. ( This last scenario is how a cat that was previously negative can become positive even without new exposure to the virus. Most likely, my cats, Dharma and Karma, were latent carriers. Sienna, being so tiny, was unlikely to spread the virus to adult cats and although there is a small chance that Dharma and Karma passed the virus to Sienna, it’s more likely he got the virus from his mother. (Sienna’s mother was taken into another home and had not been tested the last I heard.)


When you have a household of both feline leukemia negative and positive cats as I do, you can do two things. First, you can keep the cats separated. In other words, the positive cats can be kept in one room or on a separate floor to prevent exposing the negative cats to the virus. This is the safest option. Second, you can have the cats that tested negative vaccinated against feline leukemia. This is what I opted to do and it has, so far, been successful. Those cats that are negative stayed negative. The vaccine is not considered 100% effective but it can work by creating an immune response to the virus that will protect the exposed cats.

Some vets will suggest euthanizing a cat that carries FeLV, though not all vets do. If you opt to euthanize, you must realize that you are destroying a cat that only has the potential to be ill but is not necessarily currently ill or in any distress. Doing this is not giving the cat’s immune system the chance to possibly shed the virus. Also, if you euthanize, you will never know if the cat could have been one of the 15% that may have lived a long, healthy life.


There are people who believe that euthanizing cats that are positive for FeLV is helping to prevent an epidemic against the whole feline population. This is incorrect. An epidemic of feline leukemia would only be likely to happen in a hoarding situation. Cats that live outside (even in feral colonies) do not live in close enough proximity to each other to spread the virus. For instance, it is estimated that only 2-3% of cats in the United States carry the virus at any given time. (

If you decide to keep your FeLV+ cat, know that you are doing a very noble thing. You are giving a chance to a cat that doesn’t have much of a chance. Although the cat’s lifespan may be shorter than that of a normal cat, that life can be filled with happiness for both you and the cat. Good care is important. Feed the cat a high quality diet and try to find a vet who is knowledgeable about the feline leukemia virus, which you would be more likely to find in a “cat’s only” practice.

FeLV+ cats should always be kept indoors for their own safety and for the safety of any strays that may wander onto your property. Due to their weakened immune system, it is important to treat an infection in a FeLV+ cat immediately with antibiotics. Eye and gum diseases can be especially common and should be watched for. An immune booster such as interferon is sometimes given which can help protect against the growth of tumors. In a controlled research study (Weiss et al. 1991) found that feline leukemia positive cats that were given interferon had a 75 percent reduction in symptoms. (

Sadly, the story with my cats that carried FeLV did not end well. Sienna was euthanized at 6 months old after developing spinal lymphoma. Dharma and Karma were healthy for about 3 years after testing positive for the virus, they both then succumbed to a mixture of cancer and bacterial infections. Colt, unfortunately, tested positive for the virus before he could be vaccinated. He is coming up on the three year mark but is so far still healthy. He now has an FeLV+ companion, Gabriel.

Although it was hard watching Sienna, Karma, and Dharma go, and it is sad that their time with me was cut so short, I could not imagine having lived without them. Their joyful, loving spirits endured until the end and I’m glad that I gave them the chance to live out their lives.

Cats with the feline leukemia virus face a tough struggle. They do not need the added burden of people’s ignorance and fear. If you ever find yourself in my situation, please do what I did and get all the facts before making a decision. That way at least you know, that whatever decision you make, you have thought it through and did not just cave into the hysteria that usually accompanies any discussion involving the feline leukemia virus. These cats deserve no less than our full consideration and respect.

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