There is a
long incubation period (months to years) from infection with FeLV to development
of disease. However 85 out of 100 FeLV infected cats die within 3.5 years
of becoming infected.
Anaemia: all
anaemic cats should be tested for FeLV. FeLV suppresses the bone marrow,
where red blood cells are produced.
Immunosuppression:
One effect of FeLV infection is to suppress the immune response, leaving
the cat more susceptible to other infections. Whenever a young to middle
aged cat keeps getting ill or doesn’t recover in a normal time, or gets
a fever and is listless for no apparent reason, it should be tested for
FeLV (and feline immunodeficiency virus (FIV)).
A suppressed
immune response leads to death of 80% of FeLV positive cats, the remainder
die of FeLV associated cancers. The most common cancers associated with
FeLV are solid tumours called lymphosarcomas.
Thymic lymphosarcoma
is a tumour which generally affects young cats up to two years of age.
The tumour grows in the thymus, an organ in the chest in front of the heart.
As it grows, it causes fluid to accumulate which gradually fills the chest,
pressing on the lungs and causing the cat difficulty in breathing. Often
the difficulty in breathing is sudden in onset: in cats difficulty breathing
is manifest by the cat showing rapid breathing or breathing through the
mouth. The tumour can usually be seen on X-ray. Over 90% of cats with thymic
lymphosarcoma are FeLV positive.
Multicentric
lymphosarcoma generally occurs in young to middle-aged cats. The tumours
arise in the lymph nodes and can often be detected even by untrained fingers
under the chin, behind the knees and in front of the shoulder. Only two
cats out of three with multicentric lymphosarcoma are FeLV positive.
Alimentary lymphosarcoma
usually affects middle-aged to older cats. The tumour grows in the small
intestine or colon, causing weight loss and diarrhoea. Only one third of
cats with alimentary lymphosarcoma are FeLV positive.
The reason that
some cats with lymphosarcoma are FeLV negative is unknown but, since lymphosarcomas
are more common in houses where FeLV is endemic, all cats in contact with
a cat which has a lymphosarcoma, whether or not it is FeLV positive, should
be FeLV tested. FIV is also associated with tumours of the cat.
Lymphosarcomas
can arise in any organ: the kidney, nervous system and eye are the next
commonest organs to be affected.
Lymphosarcoma
is the commonest tumour of the eye of the cat.
Leukaemia: despite
the name, ‘leukaemia virus’, leukaemia is less commonly diagnosed, often
requiring a trained haematologist for accurate diagnosis. Nearly half of
all FeLV infected cats are anaemic.
FeLV is also
associated with liver failure, enteritis, infertility, abortion, resorption
of kittens and stillbirths.
--
Information Provided By
http://www.gla.ac.uk
--
|
