If a cat is diagnosed with FeLV in a multi-cat household, all cats in that household should be tested to determine their status. If other positive cats are identified in the same household the test and removal system should be applied. That involves periodic testing of cats and removal of positive cats until all of the cats test negative. The best method of preventing spread of infection is to isolate the infected individuals and to prevent interaction with uninfected housemates. Although protection conferred by FeLV vaccines is very good in most situations, the ABCD panel does not recommend reliance solely on vaccination to protect negative cats living together with FeLV positive cats.
There appears to be marked geographical differences in the prevalence of FeLV in rescue cats
in Europe. The prevalence may influence policies on testing and vaccination. In some
countries the prevalence is very low (e.g. the UK) whilst in other countries the prevalence is
noticeably higher, although regional differences may exist within countries.
Sick shelter cats which are confirmed as FeLV positive should be euthanised. Some rescue
shelters are successful in adopting confirmed FeLV-positive, healthy cats to selectedhouseholds, but there is a strong responsibility to ensure that such cats do not pose any risk as
a potential source of infection to uninfected cats. This may require positive cats being rehomed
to households where they will live in isolation or just with other infected cats.
The possibility of transmission of FeLV between cats within a shelter should be avoided.
Ideally, cats are housed individually to avoid disease transmission. If cats are housed in
groups, they should be tested and positive and negative cats should be segregated.
Vaccination may be considered.
The prevalence of FeLV infection is now very low in pedigree breeding catteries in some European countries, largely as a result of routine testing and removal of positive cats. It is recommended that routine testing is maintained once or twice a year in such catteries. Contact should be limited to other cats from establishments that implement a similar routine screening programme. If any cats are allowed access outside and the opportunity of contact with neighbouring cats of uncertain FeLV status, (discouraged for pedigree breeding cats) they should be vaccinated.
The vaccination of FeLV-positive cats against FeLV is of no benefit whatsoever.
In a long-term study where FIV infected cats were experimentally vaccinated against FeLV infection, FeLV vaccinated cats benefited greatly from vaccination compared with the nonvaccinated cats [Hofmann-Lehmann et al., 1995]. From these observations it is concluded that also under field conditions immune compromised cats with FIV infection should be vaccinated against FeLV infection, but only if they are at risk (indoor-only FIV-positive cats should not be vaccinated against FeLV). As the immune response in immunocompromised cats is decreased, more frequent boosters may be considered (in asymptomatic cats).
There is general agreement that cats with acute illness should not be vaccinated but cats with chronic illness such as renal disease, diabetes mellitus or hyperthyroidism should be vaccinated regularly if they are at risk of infection.
Vaccination should be considered carefully in these cats. Depending on the dosage and duration of treatment, corticosteroids may suppress the immune response, particularly the cell-mediated immune response. Concurrent use of corticosteroids at the time of vaccination should therefore be avoided.