Background
In the early 1990s, the concept of "emerging infections" gained a firm footing in American science, medicine and public health at the same time becoming popularized among the general public through best selling books (e.g., "The Coming Plague" by Laurie Garrett, "Hot Zone" by Richard Preston), movies (e.g., "Outbreak" with Dustin Hoffman) and mass media coverage. The dogma that infectious diseases are not stagnant but rather wax and wane attained wide acceptance. Many factors, such as climatic conditions, human social behavior, genetic recombination, and immunization coverage, affect the emergence and re-emergence of these diseases.
Human population expansion and migration, civil and regional wars, and international travel enhance the dissemination of newly introduced pathogens, as do climate changes, animal husbandry practices and the widespread trade of food across national borders. Human activity also impacts disease spread. Irrigation canals and reservoirs alter the ecology of insect vectors, while widespread inappropriate use of antibiotics encourages the emergence of drug resistance. Blood transfusions, the use of shared needles by drug abusers, degradation of public health care systems in many parts of the world, and now, bioterrorism, are all factors that can make difficult problems even more acute or result in the re-emergence of deadly biological agents.
Moreover, scientists, health professionals and the public have come to recognize that the world’s human population comprises a global village, and most pathogens have global reservoirs that do not respect national borders. During the 1990s, the U.S. public accepted that protecting the U.S. population from infectious diseases often requires supporting surveillance and control activities including vaccine development on an international level, particularly in developing countries. Many infectious diseases, such as malaria, typhoid fever, tuberculosis and dengue fever, pose notable risks for travelers including deployed U.S. military personnel. These constitute major endemic disease problems facing populations in developing countries. Lastly, groups representing diverse ideologies and agendas may contemplate the release of pathogenic agents within the U.S. to cause disease outbreaks, civil disruption, and changes in government policy.