Epidemiological methods for investigating wild animal reservoirs of animal disease

The epidemiological and ecological methodologies used to investigate tuberculosis in badgers (Meles meles) in Great Britain are reviewed. The objectives of these studies have been, on the one hand, to investigate the causal association between Mycobacterium bovis infection in badgers and the occurrence of tuberculosis in cattle and, on the other, to acquire knowledge of the population biology of badgers and the dynamics of infection in order to identify, formulate and assess potential strategies. The studies provide examples of the possible approaches and the practical difficulties that investigations of wild animal populations present; the importance of a multi-disciplinary team which can be maintained for the protracted periods necessary for prospective studies is also highlighted. The most successful components of the research programme have been specific prospective studies of populations, as they provide the only means of understanding the dynamic aspects of the population biology and the epidemiology of infection and disease. Expedient, cross-sectional studies have, however, proved valuable in supplementing the main long-term studies.