Joint Spatio-Temporal Modeling of Mycobacterium bovis Infections in Badgers and Cattle - Results from the Irish Four Area Project

In Ireland and in the UK, bovine tuberculosis(bTB) infects cattle and wildlife badgers (Meles meleslinnaeus) and badgers contribute to the spread of the disease in cattle. Isotropic and anisotropic spatio-temporalmodels are fitted to cattle herd and badger settbTB incidence data from the Four Area Project using sequences of linear geostatistical models. An association was found between the spatial distribution of the disease in cattle and badgers in two of three areas. The limited association may be due to irregularity of sett territories,fragmentation of farms, TB-test insensitivity, temporal lags associated with transmission or non-spatial transmission. A statistical methodology is outlined whereby hypotheses related to spatial correlation structure may be tested.