Animal diseases affecting human welfare in developing countries: impacts and control.

Animal diseases adversely affect human populations by reducing the amount and quality of food and fiber, and draft power. Epizootics of diseases such as rinderpest have caused massive mortality among domestic and wild animals. Extensive outbreaks of Venezuelan equine encephalltis have caused massive mortality in equines, and significant morbidity among people. Foot-and-mouth disease can cause high morbidity and great direct economic loss, and loss of markets as a trade barrier. Old diseases such as yellow fever and Rift Valley fever are still with us, and diseases such as the viral haemorrhagic fevers have suddenly appeared for the first time. The transmission of some of these diseases has been facilitated inadvertently by ecological change resulting from development projects. Animal disease control must be based on dealing with disease agents, and their hosts and vectors, as part of ecosystems and farming systems. Better disease surveiliance, diagnosis and reporting is needed. The economics of disease loss and the benefits of interventions must become part of the decision-making process.