Twenty‐year lifetime histories of FIV‐ and FeLV‐infected cats in a sanctuary in the UK indicate an effect of retroviral infection on longevity

Abstract Background Feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) are retroviruses that affect cat longevity and health. This study aimed to assess the impact of retroviral status on life expectancy in a feline sanctuary population, which includes cats with behavioural issues and retroviral infections. Method A retrospective cohort analysis was conducted on 132 cats, including 22 uninfected, 82 FIV + , 24 FeLV + and four FeLV/FIV + individuals. Lifetime clinical records were analysed, lifespan analysis estimates were calculated using Kaplan‒Meier analysis and common clinical conditions were assessed. Results The median life expectancies were 160.3 months for uninfected cats, 149.1 months for FIV + , 41.5 months for FeLV + and 74.2 months for FeLV/FIV + . Both FeLV and FIV infections significantly reduced longevity ( p < 0.001 for FeLV and p = 0.037 for FIV), although this reduction was less marked for FIV. Neoplasia, especially lymphoma (76.9%), was strongly associated with FeLV ( p < 0.001), and oral disease was significantly linked to FIV ( p = 0.004). Limitations The study is limited by the low number of animals, particularly in the FeLV/FIV + and uninfected cohorts. Statistical analysis of these groups should therefore be considered with caution. Conclusion FeLV infection markedly shortens lifespan and increases the risk of lymphoma, whereas FIV‐infected cats are less likely to live to extremely old age.