Difficulty in controlling disease in wild animals may lead to the establishment of enzootic diseases and to outbreaks of epizootic diseases, causing great economic losses and the risk of the spread of zoonoses. Difficulty of controlling disease in wild animals may arise through lack of knowledge of the outbreak in the first place, and through the inaccessibility of wild animal populations. Once the disease is recognized, the only means of control so far available is that of mass extermination, which is undesirable from an ecological and cultural point of view, and total extermination of a disease-carrying species (the only certain way in which to ensure that it will not break out again), is largely impracticable. Immunization measures come up against the problem of tracing infected wild animals and of capturing them, inoculating them successfully, and then being able to retrace them to record results.
Several hundred thousand of Australia's feral water buffalo have been shot from helicopters in a government programme to wipe out unmustered feral water buffalo in areas where tests show a rate of around 10% or higher of bovine tuberculosis, a disease which can affect other cattle and humans. This drastic measure is being taken to protect Australia's cattle industry from the possibility of tuberculosis and its reputation from the suggestion that the disease is common in cattle-raising areas.