FELINE LEUKAEMIA VIRUS
Feline leukaemia virus (FeLV) is associated with the occurrence
of tumours and anaemia in cats but also causes disease by suppressing
the cat's immune system. This leaves the cat susceptible to
a variety of other problems, which may then be more serious
as the cat is unable to combat disease effectively. This is
similar to the problems seen in man with the AIDS virus and
in cats with Feline Immunodeficiency Virus (FIV).
Which cats are at risk?
The FeLV virus cannot survive for long in the environment, so
spread of infection between cats is reliant on prolonged close
contact. Therefore, infection may be common in environments where
there are a large number of cats. It is estimated that currently
1-2% of cats in this country are infected with FeLV. In multi-cat
households where FeLV is endemic, up to 30% of the cats may be
infected.
Young cats and particularly kittens, are especially vulnerable
to becoming infected. As cats get older their susceptibility
to infection will decline. Nevertheless, vaccination of older
cats is recommended if they are considered ‘at risk’.
How is it spread?
The virus is spread mainly via the saliva from a persistently
infected cat exchanged, for example, by mutual grooming or sharing
of food bowls. In addition, the infection can also be caused
by biting or contact with urine and faeces containing the virus.
The virus can also pass from a queen to her kittens either in
the womb or after the kittens are born, via infected milk.
The majority of cats become infected with the virus entering
the body via the mouth or nose. The virus multiplies at these
sites before spreading in the bloodstream to the rest of the
body and, in particular, to the bone marrow. Not all cats which
are exposed to the virus become persistently infected. If the
cat is able to eliminate the virus, this will occur during the
initial stages (4 - 12 weeks) of infection. Once significant
infection of the bone marrow is present, the cat remains infected
for the rest of its life.
Signs and symptoms
Signs of infection can take months or years to develop and so
infected cats can appear to be totally normal and healthy for
quite some time. The first signs of infection may be vague and
non-specific because of the huge variety of problems that can
occur with FeLV infection.
The cat may appear to be slow to recover from minor infections,
may be off colour and have a poor appetite over a period of time
or may develop chronic or recurring problems such as diarrhoea.
If tumours develop, the signs seen will depend on the site of
the tumour and a variety of different sites may become infected
like the chest, kidneys, gut and spinal cord. Anaemia may result
in pale gums and listlessness.
Prevention and control
There is no treatment to eliminate a FeLV infection, although
interferons are now being used in an attempt to eliminate disease
in some cases. Treatment must therefore be aimed at maintaining
quality of life and managing the effects of infection such as
immunosuppression, anaemia and cancer.
Vaccination
There are several vaccines on the market to protect your cat
against FeLV. Vaccination helps to prevent cats from becoming
persistently infected by helping to stimulate a successful immune
response. Unfortunately, no vaccine is likely to be 100% effective
at protecting against infection. Vaccination is recommended in
situations where cats have a risk of exposure to the virus. This
includes cats that go outdoors and all those in contact with
potentially infected individuals. |
