VACCINATING AGAINST FELINE LEUKAEMIA VIRUS The Feline Leukaemia Virus (FeLV) has been the subject of research world-wide since its discovery in 1964, much of it at Glasgow University. A lot has been learnt about both the structure of the virus, and how these components cause disease in the cat. This leaflet is intended to give you an overview of what is known about the virus, and help you make an informed decision about vaccinating your cat against FeLV. There is a wealth of further information available, so please feel free to ask for further details if you are interested. THE VIRUS The FeLV virus is an oncornavirus, that belongs to the Retrovirus family. In English this means FeLV is a virus capable of causing cancer, and describes the method by which the viral genetic material replicates itself after invading the nucleus of the host cat's cell. THE DISEASE FeLV may be transmitted through shared food bowls, mutual grooming or fight wounds. After initial exposure the virus infects the tonsils, from where it spreads via the blood stream to the spleen and lymph nodes where there is a massive replication of the FeLV Virus. THE CONSEQUENCES There are three possible outcomes from this stage: 1. Recovery: Some cats may produce antibodies and throw off the infection. Only 40% of cats are capable of producing sufficient antibodies to eliminate FeLV at this stage. 2. Latent infection: The virus may remain latent in the cat's bone marrow. Some of these cats will go on to gradually eliminate the virus (40%), others remain as latent carriers (50%) and the rest (10%) will develop fatal infection after any sort of stress in later life such as accidents, fight wound etc. About 30% of cats will develop a latent infection. 3. Full blown disease: If the virus replicates unchecked it then invades the blood forming cells in the bone marrow. The progression of the disease varies with individuals, and also what form of the disease they develop. About 85% of cats that reach this stage will develop fatal complications within 3 years. After the bone marrow is infected, the FeLV may go on to cause various types of disease, depending which strain is involved : - cancer of the bone marrow or lymph glands, - anaemias and other blood disorders, - immune-suppression, leading to an inability to fight trivial infections, - chronic kidney, joint or eye disease, - reproductive problems in breeding cats - predisposition to other viruses, - and a variety of recurrent ailments, from weight loss to chronic diarrhoea or gum disease. AFTER EXPOSURE TO THE VIRUS Some cats develop an overwhelming bone marrow infection [ 30%] Some cats throw the virus off [40%] Some cats develop latent bone marrow infections [ 30%] LONG TERM OUTCOME recovery [50%] latent infection [17%] various felv diseases, cancers, immune suppression and death [33%] THE VACCINE Safe and reliable vaccines have been available in the UK since 1992, and the one used in this practice relies upon the use of a specific FeLV component protein called p45 to stimulate antibody production. This p45 is closely bound to another protein called p15E, which is responsible for the immunosuppression caused in FeLV infections. Some of the early vaccines produced in the early 1980s by traditional vaccine production methods were found to contain high levels of this p15E, and new methods were researched. The product used in this practice has been produced by genetic engineering to ensure that only p45 protein appears in the vaccine and is thus a completely safe vaccine. No vaccine can claim 100% efficacy, but in clinical and field trials it has been shown to provide between 92-97.5% protection VACCINATING YOUR CAT We advise that all cats, including kittens, should have a screening FeLV test before they are vaccinated. This currently costs xx.xx including VAT. We have FeLV testing kits and are usually able to produce results within a few minutes. Just a small blood sample is required, but kittens, and some cats, will need light sedation first. There is no extra charge for this. The initial course is two injections given at a 15-21 day interval, and may be worked in to coincide with your cat or kitten's vaccinations against 'flu and enteritis. The cost for both injections in the primary Leukaemia vaccination course is xx.xx including VAT. A single annual booster is required to maintain your cat's immunity, and this can be done at the same time as the usual boosters for 'flu and enteritis. The only reported side effects are occasionally a swelling at the site of injection, and sometimes your cat may appear 'tired' for a few days. Please contact the surgery if you would like to make an appointment to have your cat vaccinated against Feline Leukaemia Virus.