The epidemiology of brucellosis in animals.

The Brucella spp. may infect a wide variety of both domesticated and feral animals. However, classic symptoms are usually limited to hosts typically associated with singular bacterial species. The host-parasite relationship is influenced by many factors such as age, gestation, virulence and number of bacteria. Environmental conditions such as animal density affect exposure to infection. A diagnosis of herd infection is usually simple, but individual diagnoses can be complicated. Influences such as incubation period, vaccine titers, and heterospecific antigenic stimuli must be considered. A wide variety of test methods is available. The control of animal brucellosis is affected by many factors and is made difficult by modern agricultural practices such as increases in herd size and commerce. These and ancient practices such as nomadism may limit the effectiveness of organized programs. The use of vaccines will continue to play a major role in control in most countries. Research will hopefully lead to the development of more accurate and simple diagnostic methods, improved vaccines, and a better understanding of the host-parasite compatibility. New delivery mechanisms may prove beneficial in chemotherapy.