FELINE LEUKEMIA VIRUS (FeLV):
Dr T van Egdom BVSc and Dr C N Sparks BVSc
It can cause immunosuppression, severe anaemia and tumours in cats. The virus is present worldwide and in nature FeLV infects domestic cats and a few other members of the Felidae family group.
TRANSMISSION:
Persistently infected cats are the major source of FeLV. These carriers excrete large quantities of virus in the saliva and some in the tears, urine and faeces. Cats smelling / licking each other and their urine ( sharing food and litter trays), is the most likely way of transmitting FeLV between cats. Bite wounds are a more important means of transmission of the virus in outdoor cats.
Young kittens are much more susceptible than adult cats. The virus might be transmitted to kittens through the uterus, or through the mother's milk, saliva, faeces or urine. Prolonged intimate contact between adult cats are nessesary to transmit the disease as the virus is fragile and a large number of viruses is needed for transmission through the mouth or nose.
It takes 2-4 weeks after infection before the virus start circulating in the infected cat's bloodstream (viraemia). The acute stage of the disease is normally not detected and in about 70% of cats, virus shedding only last for 1- 16 weeks. There are a few cats that continue to shed the virus for months after the end of the viraemia. The virus may persist in the bone marrow, but normally disappear within 6 months. About 30 % of cats do not mount an adequate immune response and become permanently viremic and persistent carriers. These cats can appear clinically healthy for many months and even years before developing fatal disease.
DISORDERS EVENTUALLY CAUSED BY FeLV:
- Weight loss and dull coats.
- Immune suppression: Cat can easily get sick from bacterial, fungal and viral diseases eg. enteritis and respiratory infections.
- Lymphoid or myeloid tumours: cats with FeLV are 60x more likely to develop these tumours than FeLV negative cats.
- Anaemia (shortage of red bloodcells)
- Reproductive problems: Infertility and abortions.
- Neurological disorders might also be seen occasionally.
DIAGNOSIS:
A test is available that can be quickly performed (5-10 minutes) on a blood sample. This test can be done in the veterinary clinic while you are waiting.
TREATMENT:
THERE IS UNFORTUNATELY NO SPECIFIC TREATMENT AVAILABLE. Basic treatment is aimed at treating secondary infections.
PREVENTION:
This is one of the diseases where prevention is better than cure. With the increase in FeLV, we advise vaccination of cats against this disease. Cats need to be tested for the disease before they can be vaccinated as there is no point in vaccinating positive cats. Clinically healthy cats that test positive can be retested 6 monts later. Once a uninfected, vaccinated household of cats are established, all new cats and kittens need to be tested and vaccinated before being introduced. Vaccination consist of a primary vaccination, booster 3-4 weeks later and a yearly booster. There is a combination vaccine available that includes the normal 3/1 vaccination. Kittens can be vaccinated from 9 weeks of age.
All cats that test positive must be separated from other cats and use separate feed and water bowls as well as separate sand trays. Infected healthy cats should be sterilised/ neutered to prevent transmission by bite wounds and to prevent kittens from being born with the disease.