In recent years, zoonoses and communicable diseases common to man and animals have gained increasing attention worldwide. Human diseases that have their
origins in infected animals, such as AIDS or Creutzfeldt-Jakob, have highlighted the
need for a better understanding of animal diseases in terms of their epidemiology,
mechanism of transmission to man, diagnosis, prevention, and control. Social and
demographic changes have also contributed to the importance of gaining and disseminating knowledge about zoonoses. For instance, as people encroach further and
further on ecological areas with which they had little contact and whose fauna may
not be well known, their exposure to animals—and the infections they transmit—
has increased. New knowledge is also being developed in the area of urban ecology.
The ease and speed of modern travel also facilitates the spread of diseases once confined to specific geographic areas, as recently occurred with severe acute respiratory
syndrome (SARS). Animal migration and trade pose a similar threat, as was shown
by the outbreaks in the United States of West Nile fever, and most recently, monkeypox—two diseases not previously known in the Western Hemisphere. Each of
these examples highlights the need for improved knowledge and surveillance of and
response to zoonoses.