Recent animal disease outbreaks and their impact on human populations.

Over the past 20 years, headlines have documented an increasing number of emerging diseases; most have an animal source (zoonoses). Recent examples include West Nile virus, severe acute respiratory syndrome (SARS), avian influenza, and monkeypox. While some emerging diseases occur among both humans and animals, others affect only animals or only humans. Nevertheless, all these new or reemerging infections have societal implications, often tied to local and national economies. It is important to understand the implications of emerging animal diseases and encourage stronger collaboration of veterinary and medical practitioners, especially in rural areas. Illnesses in agricultural workers may be the index cases for newly emerging diseases.