Epidemiology of Feline Leukemia Virus (FeLV) and Structure of Domestic Cat Populations

Abstract

The spatial structure of host populations may affect parasite transmission and effect. Our interest focused on feline leukemia virus (FeLV), a lethal retrovirus affecting both domestic cats (Felis catus) and wildcats (Felis silvestris). We assessed presence and epidemiology of FeLV in a long-term study of 3 domestic cat populations in France. All 3 populations shared a common pattern based on matrilinear groups, but they differed in population size, cat density, connections among cat groups (i.e., human shelters) and connections with adjacent feline populations. The prevalence of FeLV was different among populations (P <0.001). Other at-risk categories for FeLV infection included nonneutered cats (P = 0.010), cats living with a single conspecific in the same house (P = 0.020), and cats allowed to roam freely (P = 0.048). The best model for the prediction of FeLV prevalence included effects of population, reproductive status, and group size, but the effect of roaming habit was confounding. The virus did not persist in 1 of the 3 populations, and we hypothesized that this extinction is linked to small population size and isolation. These conclusions raise new perspectives for management of endangered populations of wildcats. Although wildcat populations have been declining in size, keeping small populations isolated from each other and from domestic cats could help prevent the spread and persistence of FeLV infection.