Feline Leukemia – The Facts

What is FeLV (Feline Leukemia)?

Feline Leukemia Virus (FeLV) is a virus that infects only cats and is fairly common. FeLV depresses the immune system and may lead to persistent infection in a cat. FeLV is an predominantly a cause of anemia in cats. It additionally can cause cancers of several types. It is found worldwide. It is transmitted through the exchange of bodily fluids between cats when fighting, grooming, sharing eating stations, and litter boxes. There is no treatment to eliminate the FeLV virus from the body once infected, and thus the disease is ultimately fatal.hypodermic needle and medicine

How Does a Cat Contract Feline Leukemia?

The most common way a feline can contract the disease is through saliva and casual contact with an infected cat such as biting, mutual grooming, sharing bowls, and even touching noses. Since this disease is highly contagious between cats, it is important to completely isolate new cats of unknown viral status. It is also important for humans to wash their hands when handling multiple cats. Kittens are more susceptible to FeLV. Cats who go into the our0of-doors are at greater risk of exposure. The virus can also be transmitted from mother to kittens. Kittens can become infected during fetal development or during the first days of life as their mothers nurse and care for them.

How Does FeLV Cause Disease in its Victims?

The Feline Leukemia Virus can cause bone marrow suppression. As one of the functions of bone marrow is to produce the cells of the immune system that fight off infection, this disease can result in a suppressed immune system. The immune system normally protects the cat from common infectious agents such as bacteria and viruses, that do not generally cause disease in healthy cats. However, if a cat’s immune system is weakened, as with FeLV, these same organisms can cause disease. This is known as secondary or opportunistic infection. Although the disease only affects cats, it is recommended that immunocompromised people such as chemotherapy patients and AIDS patients, not reside with FeLV + cats because these cats are they can infect these patients that are immunocompromised. This viral disease is also associated with the development of certain types of cancer such as lymphoma and leukemia, in affected cats.

What are the Signs?

  • Oral Signs

A cat may develop pale gums and/or a yellow color in the mouth. Some cats also develop stomatitis, meaning their gums become very inflamed and ulcerated.

  • Respiratory Difficulties

It’s easy to spot the warning signs of feline leukemia when the virus is settling in the chest. The cat will cough and have other signs of respiratory problems with gagging on phlegm that is being produced. Wheezing and a runny nose or eyes is also common.

  • Stomach Problems

When the virus settles in the abdomen, a cat may experience bloating and other signs of abdominal problems. The cat will also experience vomiting and/or frequent diarrhea which is usually accompanied by a lack of appetite.

  • Weight Loss

Feline weight loss is common when infected with the virus and appetite changes in a cat are always a reason for concern. In the case of FeLV these changes in eating habits are often the first symptom of the virus.

  • Lethargy and Weakness

Multi-centric (entire body) leukemia can show itself in several ways. Typically, malignant tumors begin to grow in various parts of the body. This causes the immune system to stop working and the cat’s overall health begins to deteriorate. She may show signs of listlessness, sleepiness or personality changes.

Associated Medical Conditions

As a cat’s immune system weakens, other symptoms you will see can include enlarged lymph nodes and an unhealthy appearance to the cat’s skin and coat. Your cat will become susceptible to other conditions which can include:

  • Infections of the bladder, respiratory system and skin, among other systems
  • Infections that are chronic and resistant to treatment
  • Fever
  • Sterility

Recognize the Final Stages of Feline Leukemia

In the final stages of FeLV, the cat’s health will be severely compromised by the infection. This leaves it open to developing other diseases and disorders not related to FeLV. With any of the following symptoms, there is a good chance the feline may be in the final stages of FeLV:

  • Persistent infections, such as in the respiratory system, ears and in the mouth and gums
  • Inflammations in the eyes
  • Weight loss that does not improve and no interest in eating
  • Constant diarrhea
  • Difficulty in mobility
  • Extreme lethargy
  • Bodily tumors and cancer, particularly Lymphoma and Fibrosarcoma
  • Seizures
  • Overall changes in his behavior

Not every cat that becomes infected with FeLV develops clinical signs or long-term complications associated with the virus. The immune system of some cats can eliminate the infection before the cat becomes sick. In other cats, the virus can “hide” in the bone marrow, where it is difficult to detect until it begins to cause problems later in life. Other cats become carriers of the disease or experience various illnesses and immune suppression before eventually dying of FeLV-associated complications.

cat at veterinarianHow is a Cat Tested?

A simple in-house blood test, or “snap” test have been developed to detect the presence of the FeLV. In general, these tests are very reliable, with almost 100% accuracy.

In some situations, a second blood test is needed for confirmation at a veterinarian office. If a cat tests positive for the virus, it could mean that the cat has FeLV or a false positive showed in the results. A positive test should be confirmed by an IFA test, which can be done at a full-service vet clinic.

If the IFA test is negative, it could mean that the cat is:

A) not infected with FeLV at all.

B) recently infected (up to 30 days ago) but won’t test positive yet, in which case a repeat IFA test should be done again approximately four weeks later to confirm.

Protection and Possible Outcomes for a Patient

FeLV positive cats must be kept indoors away from unaffected cats so they don’t spread the disease to other cats.  They should be spayed/neutered, provided with good nutrition, avoid raw diets, and need regular visits to their veterinarian. With proper care many FeLV cats can live months to years in good health.

Cats infected with FeLV have 4 different possible outcomes.cat at veterinarian office

  1. A cat may succumb to the infection and develop FeLV associated diseases. The development of FeLV associated diseases such as bone marrow suppression or cancer poorly affects the cat’s prognosis.
  2. A cat may overcome the virus but the viral “DNA” is incorporated into the cat’s own DNA; these cats may or may not develop illness at some point in their lifetime. Those cats that are infected and have no clinical signs may remain asymptomatic for months to years or for life. These cats should still be considered contagious to other cats.
  3. A cat may completely eliminate the virus from their system
  4. A cat’s system could be confined / localized the virus to a small region of the body, such as a mammary gland. This is rare.

As it helps to keep cats  INDOORS, if they are also outdoors cats, make sure to have them tested and vaccinated.

Vaccinations are highly recommended for kittens and also for adult cats determined to be at risk (i.e. cats that go outdoors or encounter new cats that have not been viral tested).  Vaccinations will NOT interfere with testing for the disease.

Remember to isolate and test kittens or new pets, for FeLV, before allowing them to come into contact with your existing pets.


Feline Leukemia Virus (FELV) is a relatively common viral disease of cats. Some cats acquire this infection at a very young age by being born to an FELV-infected female cat, others contract this disease through direct contact with bodily fluids from another infected cat. Most cats with FELV lead full, normal lives, but these cats do have special environmental and health requirements and are susceptible to some health consequences once infected.

Welcoming a New Cat Family Member

Bringing home a new cat can be exciting and overwhelming. There is so much to buy and do, to get ready. Your new cat may be frightened and confused as she enters a new living space, but you can help to ease her transition by getting everything ready, taking good care of your cat, and considering any special needs she might have before you welcome her into your home for the first time.

Whether your new cat is coming from a shelter, a home, an urban street or a country barn, the first twenty-four hours in your home are special and critical. Before you bring a new cat into your life, it helps to understand a little bit about how cats relate to their world.

You can help make the transition to a new home smoother and easier by providing some privacy for your new cat. If possible, start by preparing your home before you bring in the cat.

First off make sure you have the key supplies ready for your new kitty before bring her/him home for the first time.

  • Food and water bowls
  • Food and treats (age appropriate)
  • Litter boxes (one for each cat in your house plus one extra)
  • Litter (fine grain, unscented, clumping litter is best)
  • A collar and identification tag with your cat’s name plus your name and phone number or address
  • A brush
  • Cat toys
  • Cat bed or furniture
  • Scratching post or cardboard scratching blocks
  • Cat carrier

Upon bringing your cat home choose a room in which to keep your cat. It may be best to confine your cat to one room when you first bring them home. This will allow her to adjust to the smells and sounds of their new home without being overwhelmed. Make sure you provide food, water, a hiding place, litter box and toys. After a few days, when your cat appears more confident, you can leave the door open and allow the cat to explore at their own pace.

cat eating at bowlFeeding Area.  Prepare your cat some food and fresh water as soon as you bring her home. Place the food and water someplace quiet, so that your new cat will not be disturbed. Avoid placing the food and water in a high traffic areas as this may prevent your cat from eating or drinking when she needs to. Make sure that the food and water are appropriate for the cat’s age. and that you change your cat’s water every day and check it often to make sure that your cat always has enough fresh, clean water.

Litter Box Area. Choose a room or section of the home for the litter box. Each cat should have its own litter box. Usually a bathroom works well for placement. Fill the litter box with a subsurface of baking soda and then pour one or two inches of litter over the base surface. There are a variety of litter choices on the market, from plain clay, clumping and scented clay, old pellet newspaper, absorbing plastics, and wood pellets. It will be up to you and your cat to figure out which works best.

Give your cat some toys. Cats love to play, so make sure that you provide your cat with some stimulating toys. Get a variety of toys for your cat, such as wands, ball toys, food dispensing toys, and catnip toys. Having several different options for your cat to play with will help keep her active, happy, and nimble. Add in some catnip to stimulate and help your cat play.

cat sleepingDesignate places for your cat to sleep. Your cat may decide that she prefers to sleep on the windowsill or in the laundry hamper, but you can encourage your cat to sleep in some designated places by providing her with some special bedding. Place a cat bed or some blankets on a comfortable spot where she will not be disturbed. Good places include a shelf, a rarely used chair, a basket in a corner, or a spot on the floor where the sun shines in through a window. Make sure to wash bedding often to prevent it from getting infested with fleas and/or ticks.

Set up scratching stations. Cats need to scratch to remove the outer sheath of their claws. You can trim your cat’s nails every 2-3 weeks to make them less sharp, but your cat will still need to scratch. To help prevent your cat from scratching your furniture, set up some scratching stations for her around your house. Place scratching posts and cardboard scratchers in rooms with furniture to give your cat something else to scratch.

cat in boxCreate a safe haven. Purchase a covered cat bed, but even a cardboard box turned upside down. Provide two “doors” by cutting into the walls. This helps provide more security so that they may have options in “escaping”. The box should be big enough for the cat to stand up, turn around, stretch out and lie down in. Keep it cozy! Place the box next to the wall or in a corner where the cat can see the door to the room to avoid the cat from feeling trapped. Place a sisal, cork or corrugated cardboard scratching post next to the box. Finally, make sure there is a high perch structure for the cat to sit on as felines are arboreal in nature.


Ultimately, the journey and transition for a new cat family member is a stressful experience for the animal. But, it can be made an easy one, for the animal, with the right preparation and thought. A simple, common sense list is needed including a feeding area, a resting area, a litter area and a play area. These will make the best new home for the cat. And of course, lots of love, attention, and long term commitment are required for the animal to feel secure for the duration of its life.