FAQs About Feline
Leukemia Virus (FeLV)
If your cat is diagnosed with FeLV this does not
mean a death sentence!
When a cat or kitten tests positive for feline
leukemia, one of three outcomes may occur, depending on how deeply the leukemia
virus has infected the cat's body and on how strong the cat's immune system is:
Type 1: Transitory Viremia
Known as "transitory viremia", some
cats and kittens with strong and healthy immune systems will manage to clear
the leukemia virus on their own within 3-4 weeks of infection. Though this
rarely occurs, it is worth keeping any healthy-looking leukemia-positive cat in
isolation for a month and then retesting to see if the cat can reject the virus
on its own. After no more than one month, a cat with transitory viremia should
test negative for leukemia. At that time, the cat would be healthy and no
Type 2: The Chronic Carrier
In the "chronic carrier" state, the cat
becomes infected with the feline leukemia virus but does not immediately die or
become ill. A carrier will test positive for leukemia initially, on a follow-up
test and throughout the rest of the cat's life. In carriers, the leukemia virus
infects a part of the cat's body such as the bone marrow, spleen or lymph
nodes, but the cat is able to keep the illness relatively under control. A
carrier will eventually die from leukemia or complications resulting from
leukemia, but in the meantime, the chronic carrier may enjoy many - many years of a
healthy, normal life.
Type 3: Classic Feline Leukemia
Many cats infected with feline leukemia fall into
this category, those that quickly fall gravely ill and pass away within a few
weeks or months of their initial infection. Symptoms of feline leukemia include
anemia, weakness, progressive weight loss, and cancerous tumors.
It’s best to take preventive measures against
this typically fatal disease, because there is no cure for FeLV:
- A vaccine is recommended for all cats at
risk of exposure, but the only sure way to prevent transmission is to
prevent exposure to infected cats.
- Keep your cats indoors, away from
potentially infected cats that might bite them.
- If you do allow your cat outdoors, provide
supervision or place her in a secure enclosure.
The good news is that the
virus will not survive outside a cat for more than a few hours in most
Classic Feline Leukemia
Cats become infected with FeLV in two different
- The unborn kittens are infected while in the
uterus if the mother is carrying the virus. They may also be infected from
her milk. This is different from FIV, where kittens are not infected by
the mother, although they may receive antibodies.
- FeLV is spread through blood, saliva, and
excrement. Outdoor cats are at higher risk of contracting this disease,
due to the increased likelihood of coming into contact with infected cats.
Methods of Infection
The virus occurs in saliva, nasal secretions,
urine, feces and milk from infected cats. It is spread cat-to-cat through:
- bite wounds
- from an infected mother cat to her kittens
- during mutual grooming
- through shared litter boxes and feeding
dishes (although this is rare)
Outdoor cats and indoor/outdoor
cats are at greater risk than indoor-only cats.
In the earliest stage, your 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.
How Is Feline Leukemia Diagnosed?
Two types of FeLV blood tests are in common use.
Both detect a protein component of the virus as it circulates in the
ELISA (enzyme-linked immunosorbent assay) and
similar tests can be performed in your veterinarian's office. ELISA-type tests
detect both primary and secondary stages of viremia.
IFA (indirect immunofluorescent antibody assay)
tests must be sent out to a diagnostic laboratory. IFA tests detect secondary
viremia only, so the majority of positive-testing cats remain infected for
Each testing method has strengths and weaknesses.
Your veterinarian will likely suggest an ELISA-type test first, but in some
cases, both tests must be performed—and perhaps repeated—to clarify a cat's
true infection status.
The symptoms of FeLV are varied, and your cat may
not have all of them:
- Excessive urination
- Excessive thirst
- Loss of appetite
- Poor fur condition (bald patches, etc.)
- Weight loss
- Skin lesions (and wounds fail to heal)
- Pale gums
- Enlarged lymph nodes
- Fluid accumulation
- Difficulty breathing
- Tumors (by palpation or X-ray)
- Progressive weakness; and/or
Can FeLV be
There is no specific treatment for FeLV, so most
of the treatment of FeLV-positive cats involves supportive care.
Although my cat has tested positive, it is
healthy in all other respects. How can I prevent a Feline Leukemia related
disease from becoming active in its system?
There is no sure way to keep your cat healthy. Eventually, a Feline
Leukemia related disease would probably develop no matter what you do.
However, one way in which a disease is likely to develop is if you stress your
cat's system. If a cat's system is stressed, its body can't put as much
energy into fighting off illnesses.
Can FeLV-negative and FeLV-positive cats live
A negative and positive cat could certainly live
in the same house, as long as the negative cat is vaccinated. Remember
that the virus is actually very difficult to pass on to other adult
cats. Simple precautions like separate feeding dishes and cleaning the
litter tray out as soon as it has been used are sensible. If the infected cat
is one of a multi-cat household, the others may either carry the virus or have
Virus Neutralizing antibodies, which means they are immune (this is very likely
if they are all adults) or if they have no intimate contact with the infected
cat, they may have neither. Remember, the highest risk of infection is to
kittens under 4 months.
Can FeLV-positive cats have a good life?
FeLV-positive cats can live perfectly happy
lives, and they deserve to do so. People who have FeLV-positive cats just need
to be aware that they may have a shorter life span and that they need to be
taken to a veterinarian as soon as a problem is noted.
Your veterinarian may recommend the following
- Keep your cat indoors to limit its exposure
to other infections, and to prevent your cat from spreading its illness.
- Keep your cat's environment as stress-free
as possible, providing it with a comfortable place to rest, and limiting
its interaction with people or other pets that may annoy it.
- Provide your cat with plenty of fresh water
at all times.
- Keep your cat on a regular, healthy diet.
- Schedule regular veterinary check-ups to
monitor your cat's condition, and to diagnose and treat any secondary
Information provided by American Association of Feline Practitioners and the Cornell Feline Health Center, Cornell University, College of Veterinary Medicine