Some years ago, concern was raised when infectious RD-114 virus was detected in commercially available live attenuated vaccines for cats and dogs produced on certain feline cell lines, such as CRFK cells (Miyazawa et al., 2010). Feline cells are not susceptible to infection with the RD-114 virus, and it is not pathogenic for cats (Barbacid et al., 1977).
The RD-114 virus is of primate origin, replication competent, and thought to have originated hundred thousands of years ago from an ancestor cat that had preyed on an early primate infected with this virus.
The enFeLV genome is incomplete and therefore does not replicate (Soe et al., 1983). The amount of enFeLV varies between breeds of cats, including Felis silvestris, suggesting that this recombination with MuLVs is a continuing phenomenon (Tandon et al., 2007). This MuLV was then inherited by all offspring. The enFeLV is thought to have originated hundred thousands of years ago in cats that had eaten mice viraemic with a murine leukaemia virus (MuLV), which was able to incorporate its genome into the germ line DNA of the predator. The retroviral genome, its transcription into mRNA and reverse transcription into proviral DNAīesides this “exogenous” FeLV, in the domestic cat two forms of endogenous gamma retroviruses are known: the endogenous feline leukaemia virus (enFeLV Soe et al., 1983) and the RD-114 virus (Sarma et al., 1973). 3): the group specific antigen (gag) gene, including p27 the polymerase (pol) gene coding for the reverse transcriptase, protease and integrase and the envelope (env) gene coding for the glycoprotein gp70 and the transmembrane protein p15 E (Coffin, 1979).įig.3. The FeLV genome contains three genes coding for the structural proteins of the virus (Fig. FeLV also infects small wild cats including Felis silvestris and European and Iberian lynxes, Florida panthers, the Chilean wildcat ( Leopardus Guigna) and Jaguarundis ( Puma yagouaroundi) of Central and South America (Leutenegger et al., 1999 Cunningham et al., 2008 Meli et al., 2009 Filoni et al., 2012 Mora et al., 2015 Silva et al., 2016). 1), after experimental transmission of cell-free material (Jarrett et al., 1964). Virusįeline leukaemia virus (FeLV) is a gamma retrovirus affecting domestic cats worldwide it was first detected in 1964 by electron microscopy (Fig. In order to avoid “vaccine failures” and unnecessary vaccinations any cat should be tested for antigenaemia and preferably also for FeLV provirus before vaccination. All cats at risk of exposure should be vaccinated, kittens at the age of 8 or 9 weeks and again at 12 weeks, together with core vaccine components. Infection management includes separation measures following laboratory diagnosis (detection of viraemia), treatment and vaccination.
The cat’s age at the time of the virus exposure is the most important determinant of the susceptibility for infection and clinical outcome, with kittens being most susceptible. However, with proper care and an indoor-lifestyle, some cats may live much longer. Transmission occurs mainly through friendly contacts like grooming.Ĭommon disease consequences of progressive infection (=persistent viraemia) are immune suppression, anaemia, and lymphoma prognosis in these cats is poor, and most will have died within three years. Risk factors are young age, high population density and poor hygiene. Viraemic cats are the source of infection, with shedding in saliva, nasal secretions, faeces, and milk. Infections occur worldwide, but the prevalence and importance of FeLV in Europe have decreased thanks to reliable tests, programmes to segregate viraemic carriers, understanding of FeLV pathogenesis and the introduction of effective vaccines. Though transmission via fomites is unlikely, it will retain infectivity if kept moist at room temperature ( cave: iatrogenic transmission!). Synopsisįeline leukaemia virus (FeLV), a retrovirus, does not survive for long outside the host and is readily inactivated by disinfectants, soap, heating and drying.
#Abcd cartoon update#
This update has been compiled by Regina Hofmann-Lehmann et al. The feline leukaemia guidelines were published in J Feline Med Surg 2009, 11: 565-574 and updated in J Feline Med Surg 2013, 15: 534-535 and in J Feline Med Surg 2015, 17, 570-58.
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