Emerging and reemerging infectious diseases: the perpetual challenge.

Public health officials once suggested that it might someday be possible to "close the book" on the study and treatment of infectious diseases. However, it is now clear that endemic diseases as well as newly emerging ones (e.g., severe acute respiratory syndrome [SARS]), reemerging ones (e.g., West Nile virus), and even deliberately disseminated infectious diseases (e.g., anthrax from bioterrorism) continue to pose a substantial threat throughout the world. Over the past several decades, the global effort to identify and characterize infectious agents, decipher the underlying pathways by which they cause disease, and develop preventive measures and treatments for many of the world's most dangerous pathogens has helped control many endemic diseases. But despite considerable progress, infectious diseases continue to present significant challenges as new microbial threats emerge and reemerge. HIV/AIDS, malaria, tuberculosis, influenza, SARS, West Nile virus, Marburg virus, and bioterrorism are examples of some of the emerging and reemerging threats. In responding to these ongoing challenges, a new paradigm in countermeasure development is needed. In the past, U.S. government-sponsored biomedical researchers have focused on basic research and concept development, leaving product development to the pharmaceutical industry. Increasingly, however, the government has become involved in more targeted countermeasure development efforts. In this regard, partnerships between government, industry, and academia are necessary as we struggle to maintain and update our armamentarium in the struggle to outwit the microbes that pose a never-ending threat to mankind.