Global health surveillance.

Awareness of the importance of global health surveillance increased in the latter part of the 20th century with the global emergence of human immunodeficiency virus and novel strains of influenza. In the first decade of the 21st century, several events further highlighted global shared interests in and vulnerability to infectious diseases. Bioterrorist use of anthrax spores in 2001 raised awareness of the value of public health surveillance for national security. The epidemic of severe acute respiratory syndrome (SARS) in 2003, re-emergence of a panzootic of avian influenza A H5N1 in 2005, and the sudden emergence of pandemic H1N1 in North America in 2009 all highlighted the importance of shared global responsibility for surveillance and disease control. In particular, in 2003, SARS precipitated changes in awareness of the world's collective economic vulnerability to epidemic shocks.