Feline leukemia (FeLV) is the most common cause of serious disease in young cats. It is caused by a retrovirus that is spread from cat to cat through prolonged contact, bites and from parent to offspring. This virus, and its cousin retrovirus, Feline Immunodeficiency Virus (FIV), cause a slow, generalized decline in your cat's health.

Feline leukemia is a misnomer in that fewer than half the cats infected with FeLV develop cancer. When they do, it is not actually the FeLV virus that is the cause. It is that the cat’s own cancer-fighting mechanisms have been crippled by the virus.

Estimates are that 2-4% of the cats in the United States carry this disease. However, the incidence is likely to be greater in urban areas where cats live in high density than in rural areas where they do not.

How Did My Cat Catch This Disease?

If your cat is over eight months old, it was probably bitten by an infected cat.The feline leukemia virus was present in the saliva and other secretions of that infected cats.

If you have several cats, there is a slight chance this pet it caught the virus from another one of your pets through mutual grooming or other intimate contact.

If your cat is younger than six months old, its infection was probably passed down from its mother before it was born or while it was nursing. Basically ,the younger a cat is, the more easily it can become infected.

The Leukemia virus does not survive outside of the cat's body for more than a few minutes. So unless you own another infected cat, this pet did not catch FeLV from contact with contaminated places or objects.

Most cats that become infected with Feline Leukemia conquer the virus and recover. Their bodies mount an immune attack against the virus, producing antibodies that cure them or keep the virus in check. In some of these cats the virus is completely eliminated from the body. In others it is held in check throughout their normal lives.

But in a few cats, the virus spreads to their bone marrow and persists. These cats develop a fatal disease at a period in their life when stress or a compromised immune system allows the virus to proliferate.

What Are The Signs Of Feline Leukemia?

In the earliest stage, the pet will usually not show any signs that it has been infected. But anywhere from a month to years later, owners will notice that the cat's health is in decline. At first, the cat's health problems appear to be minor - perhaps less appetite, some weight loss, less time spent grooming, more time spent sleeping.

I often notice that the third eyelid of these cats is extended farther over the eye than normal. Some of these cats develop enlarged lymph nodes that one can feel as lumps under the skin. Many develop abscesses or run unexplainable fevers. Ear infections, bad breath and mouth infections are common - as is a persistent anemia.

Some cats develop persistent or reoccurring respiratory tract infections or relapses of previous respiratory virus (Herpes 1). Some of these cat develop persistent or intermittent diarrhea. A few even develop inexplicable neurological problems, personality changes or seizures.

How Is Feline Leukemia Diagnosed?

Alarms that the FeLV virus may be present go off when healthy cats begin to have too many minor medical problems or when problems do not respond as they should to treatment.

There are two very accurate tests for the presence of the virus.

The first is an ELISA blood test (Idexx Snap Test) that can be performed in a few minutes in your veterinarian' office. (This test also detects the FIV virus.)

If that test is positive, your veterinarian may send off a blood sample for an IFA test. The IFA test will determine if your cat is in an early stage of the disease when it might still conquer the virus, or in the later stages when it will probably not.

Along with those tests, they may send out or run some blood chemistry and blood cell tests to see what damage the virus has already caused. Sometimes, more complicated tests like bone marrow biopsies are also indicated.

What Does A Negative SNAP test mean?

Cats that have a negative SNAP result have either:

1) Not been exposed to FeLV

2) Were just exposed but it is too early to find the virus

3) Have been exposed but have conquered the virus

Most cats that have been bitten or exposed to an infected cat will test positive within 1-2 months of the incident. But to be certain, 90 days need to pass before a negative SNAP result can be relied on.

What Does A Positive SNAP Test Mean?

Cats that have a positive SNAP result are either:

1) Early in the disease and may still overcome and eliminate the virus.

2) Able to live indefinitely or for a long period with the virus but without disease.

3) Later in the disease and will not overcome the virus. If cats show signs of ill health , they are most likely in this group.

What Does An Inconclusive Test Mean?

Occasionally, the test results will be somewhere between positive and negative. When that occurs, a blood sample needs to be sent to an outside laboratory for an IFA test. That test usually resolves the question. It is also possible to just re-run the SNAPs test in a few months. Many owners decide to have any positive SNAPs results confirmed by an outside laboratory using the IFA test.

Vaccination for FeLV does not influence the test results.

What About Testing Kittens?

The SNAP test can be used on cats of any age. However, little kittens may give a false negative test result for many months - even when they are infected. For you to feel entirely safe, the test should be re-run on kittens that test negative when they are 6 months old.

Is There Any Treatments That Will Help My Cat?

There is no scientifically proven treatment for the feline leukemia virus. No medication has been found that kills it.

What veterinarians can do is give your cat general support. That includes antibiotics, steroids, transfusions and other supportive care as it is required. Good nutrition and vitamin supplementation help cats that no longer eat well. A low-stress, indoor lifestyle that minimizes stress, is also important.

Cancer (lymphoma) caused by the FeLV virus responds better to treatment. It can often be held in check with chemotherapy and cortisones.

Alternative Medicine:

Rumors abound that one or another novel herb or medication cures or helps FeLV cats. If those rumors were true, word would spread very rapidly and every caring veterinarian would be using these treatments immediately.

How Long Will My Cat Live?

Even with treatment, 85% of positive cats die within 3 years. However, your cat might be among the fortunate 15%. Fortunate cats can live indefinitely without symptoms but with the virus. But if it is already showing symptoms, it is very unlikely that it will achieve that status.

What Steps Can I Take To Keep My Cat From Catching Feline Leukemia?

1) Unless your cat was unfortunate enough to arrive with the feline leukemia virus, the most certain way to protect your pet is to keep it indoors. It is fine to take cats out-of-doors on a leash, or confine them to a wire-mesh folding kennel while you are in the area.

2) Even indoors cats can escape. So you should also have your cat vaccinated against feline leukemia. But before the initial vaccinations, your pet should be tested to be sure it does not have feline leukemia.

If you have obtained a kitten, give the first of two feline leukemia vaccinations when the kitten is 12 -14 weeks of age. It needs a second booster vaccination 3-4 weeks later.

Because tumors have been associated with leukemia vaccines, many veterinarians now prefer using the Purevax non-adjuvant leukemia vaccine. This vaccine was specially designed to try to avoid some of the factors that we think are responsible for these tumors. This includes a new needle-less transdermal administration. This vaccine has not been available long enough for us to know if it will actually reduce the frequency of these tumors. If it does, other vaccine producers will offer similar products soon.

As cats get older, they develop a natural resistance to feline leukemia. So after the two vaccinations they receive as a kitten and a vaccination a year from that date, many veterinarians only give a booster vaccination against feline leukemia every three years. Some veterinarians give booster leukemia vaccinations to adult cats even less frequently - or never. Others only give the boosters to cats that live with FeLV positive cats or roam outdoors. It is likely that in the past, we gave these vaccinations too frequently.

Can The Leukemia Virus Survive In My House Or Yard?

The virus can not live for more than a few minutes outside of the cat.

To be prudent, you can wash everything that was in contact with an infected cat and then dip the cleaned objects into ordinary household bleach diluted one part bleach in twenty parts water.

Can The Feline Leukemia Virus Infect Me?

Feline leukemia does not affect human beings and is not related to the leukemias that affect man. It does not affect dogs. It has been reported in lions, tigers and other large cats.

What Are The Special Care Needs Of My Feline Leukemia-positive Cat?

Things You Can Do To Help FeLV Positive Cats:

The most important thing you can do for FLV-positive cats is to minimize stress in their lives.

FeLV-positive cats do best in single-cat households. They do better as strictly indoor cats rather than cats that are allowed to roam out of doors. They also do better when they are fed a high quality diet that is not based on fish.

Cats with feline leukemia should receive a vitamin supplement when their appetite is poor or they are loosing weight.

The toenails of your cat should be clipped blunt with a human finger nail clipper and then smoothed with an emery board. This is because scratch wounds in FeLV-positive cats tend to become infected.

FeLV-positive cats are also more susceptible to ear , gum and eye infections. So you need to check these areas regularly and have any problems checked out with your veterinarian.

Your pet's body temperature should be monitored periodically with a pet or child's ear thermometer. If the cat's temperature is persistently above 102.4 F when it is resting and unstressed, tests or antibiotics may be warranted. It is important that antibiotics not be given for less than 7 - 14 days or they will loose their effectiveness the next time they are needed.

Do not feed your pet uncooked foods like raw or poorly cooked meat, eggs or fish. Uncooked foods contain bacteria that are more likely to cause problems in your cat because of its weakened immune system.

As frequently as every six months, your veterinarian can examine your pet for any new problems that might have occurred. Sending a blood sample off for analysis will also catch problems before they get out of hand. If your cat's condition changes for the worse, set an appointment immediately.

When Should I Have My Cat Euthanized?

Clients frequently ask their veterinarian when is it time to euthanize their pet? It is a difficult question that is never the same in any two cases. I tell them - let the cat be, as long as the cat appears happy. Many of my client’s cats remain healthy for a long time when they are kept in a sheltered environment and provided with good nutrition and health care.

There will always be veterinarians, herbalists, chiropractors, naturopaths, homeopaths, nutritionists, acupuncturists and practitioners of other obscure arts who will claim to be able to cure your cat when it is dying of feline leukemia. They will get up your hopes by telling you what you wish to hear. I do not suggest you use them.

Antibiotic Resistant Bacteria:

Antibiotics can often prolong the lives of cats with FeLV. But long term use of antibiotics in a household, produces races of bacteria immune to antibiotics. If these bacteria should later infect you, the infections may be difficult to control. This is a rare occurrence - but I have seen it happen. This is particularly true if you yourself are not in good health.

Cats with FeLV often have unhealthy mouths. Should these cats bite you when you are attempting to medicate them, these bite wounds can become infected. So be careful when you do so.