Special Issue Global Surveillance of Communicable Diseases David L. Heymann and Guénaël R. Rodier World Health Organization, Geneva, Switzerland Globalization and Health: The Need for source of communicable diseases such as Global Surveillance hepatitis and other bloodborne infections. Social A recent report of A/Sydney/05/97-like and environmental changes linked to urbaniza- (H3N2) influenza on a cruise ship from New York tion, mobility, and deforestation have created to Montreal demonstrates the ease with which new opportunities for infection, while rapid communicable diseases can be transferred across adaptation of microorganisms has facilitated the international borders (1). In this outbreak 2.7% of return of old communicable diseases and the passengers and 0.5% of crew had acute febrile emergence of new ones. With the rapid evolution respiratory illness during or after the cruise and of antimicrobial resistance, treatments for a wide introduced this antigenic variant of influenza A range of parasitic, bacterial, and viral infections into both Canada and the United States. have become less effective. Today, a communi- Other viral infections and parasitic diseases cable disease in one country is a global concern. are also associated with population movements. In industrialized countries, where deaths due During 1996, fatal yellow fever infections were to communicable diseases have greatly decreased imported into the United States and Switzerland over the past century, the concern is to prevent by tourists who traveled to yellow fever–endemic diseases from entering and causing an outbreak areas without yellow fever vaccination (2,3). or reemergence. In developing countries, the During the same year approximately 10,000 concern is to detect communicable disease cases of malaria were imported into the European outbreaks early and to stop their mortality, Community, one fourth of them from the United spread, and potential harm to trade and tourism. Kingdom (4). Had mosquito vectors been present, When cholera entered Peru in 1991, it spread these diseases could have set up endemic cycles. through the existing sanitation and water Misdiagnosed by an unsuspecting health worker, systems, causing more than 3,000 deaths (9). they could have been fatal. Seafood export embargoes and decreased tourism Bacterial infections such as meningococcal cost an estimated loss of US$770 million to the meningitis and cholera are also spread with ease Peruvian economy in 1 year. Negative economic by international travelers. Among the pilgrims impact can also occur in the more robust for the Haj in 1987, 7.7 per 100,000 returned to industrialized economies, the most recent example their countries of origin with meningitis (5). being bovine spongiform encephalopathy and the Cholera, often associated with religious pilgrim- new variant of Creutzfeldt-Jakob disease in the age and movement of refugees, resulted in 70,000 United Kingdom. cases and a 22% fatality rate in 1995 among Concerns about communicable diseases in recently arrived Rwandese refugees in Goma, both industrialized and developing countries can Democratic Republic of the Congo (formerly best be addressed through strong surveillance Zaire) (6). Rickettsial diseases such as louse- systems, renewed commitment to public health, borne typhus have also recently caused illness and strong international partnerships to and death among refugee and prison populations strengthen national and international coopera- of Burundi and Rwanda (7,8). tion in communicable disease prevention and Population movement is only part of the control. In view of the disparity among national globalization fallout. Expansion in international surveillance systems, partnerships in global travel and commerce in food and medicinal surveillance are a logical starting point in this biologic products provides another potential area of common commitment. Emerging Infectious Diseases 362 Vol. 4, No. 3, July–September 1998 Special Issue Global Surveillance: An Essential Public Refugees and the United Nations Children’s Health Instrument Fund. International military networks such as With globalization, strengthened communi- the U.S. Department of Defense Global Emerging cable disease surveillance at the global level has Infections System, private clinics, individual become an essential public health instrument. In scientists, and public health practitioners complete addition to providing necessary information for the network of formal information sources. monitoring communicable diseases and evaluat- Geographic gaps and deficiencies in expertise ing control measures, global surveillance serves in these networks must be rectified. These as an early warning system for epidemics and networks must develop means of including the provides the rationale for public health interven- private sector as well as other sources of valid tion. Early detection of communicable diseases information such as military and research and immediate public health intervention can laboratories. They must represent both human curtail the numbers of communicable illnesses and and animal infections and provide information deaths and negative effects on international travel on antimicrobial resistance and the environ- and trade. At the close of the 20th century, which ment, including water, insect vectors, and has seen the affairs of all countries become ever animal reservoirs. more intertwined, global communicable disease surveillance and response is a decisive element in Informal Sources of Information controlling communicable disease. Telecommunications, media and Internet Global surveillance provides health advice access, and rapid information exchange across for international travelers and guidance to those the globe permit public health professionals involved in international transport and trade, around the world to communicate more effec- including the food, plant, animal, and animal tively. Many groups, including health profession- products industries. At the same time, it supplies als, nongovernmental organizations, and the crucial data to support the Biological Weapons general public, have access to reports on disease Convention and to prevent or anticipate outbreaks, challenging national disease surveil- bioterrorism. To be effective, global surveillance lance authorities, which were once the sole source must be free of, and be perceived as free of, of such information. Public Internet sites are political bias. Global surveillance requires a dedicated to disease news and include sites for neutral reporting and response environment, and medicine and biology as well as major news the World Health Organization (WHO) is agencies and wire services. strengthening the framework within which it can Such electronic discussion sites, accessible be fostered. through free and unrestricted subscription, are valuable sources of information. Their scope Global Networking may be worldwide (ProMed, TravelMed), regional (PACNET in the Pacific region), or Formal Sources of Information national (Sentiweb in France). They exemplify Government and university centers such as unprecedented potential for increasing public the U.S. Centers for Disease Control and awareness on public health issues. Prevention, the U.K. Public Health Laboratory The Global Public Health Information Service, the French Instituts Pasteur, the global Network is a second generation electronic network of schools of public health, and the surveillance system developed and maintained Training in Epidemiology and Public Health by Health Canada. Its powerful search engines Intervention Network (TEPHINET) provide actively crawl the World-Wide Web looking for confirmed reports of communicable diseases. reports of communicable diseases and communi- Most of these sites are or will become part of the cable disease syndromes in electronic discussion WHO Collaborating Centre network. This groups, news wires, and elsewhere. Searches are network, as well as the WHO Regional Offices, in English and French and will eventually WHO country representatives, and other WHO expand to all official languages of the WHO, to and UNAIDS reporting sites, contributes to which it has created close links for verification. global surveillance along with reporting net- Other network sources for communicable works of other United Nations agencies such as disease reporting include nongovernmental the United Nations High Commissioner for organizations such as the Red Cross and Crescent Vol. 4, No. 3, July–September 1998 363 Emerging Infectious Diseases Special Issue societies, Médecins sans Frontières, and Medical Requirements for monitoring the intentional Emergency Relief International (Merlin), and use of pathogenic microbes have also been Christian religious organizations such as the addressed in the network, specifically in the Catholic and Protestant mission networks. revision of the IHR, in collaboration with the ad hoc Group of States Parties to the Biological Legally Mandated Sources of Information Weapons Convention. The International Health Regulations (IHR) Nonverified information about communi- are a legal instrument that requires WHO cable diseases coming from within the networks, member states to report diseases of international including that from IHR, requires rapid importance: currently plague, cholera, and verification from multiple sources other than the yellow fever. Countries have not uniformly originator. Such “disease intelligence” requires complied, often fearing unwarranted reactions information management