World Health Day 1997: Emerging Infectious Diseases1
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Until recently, there was widespread optimism that World Health Day 1997: the struggle against infectious diseases was almost won. This optimism, fueled by progress such as the Emerging infectious global eradication of smallpox and dramatic reduc- 1 tions in the incidence of other diseases, has in some diseases cases led to complacency, allowing diseases like malaria and tuberculosis to make a comeback in many parts of the world. In addition, previously unknown infectious diseases are appearing at an alarming rate: more than 30 in the past 20 years. At the same time, disease-causing organisms have be- come resistant to a wider spectrum of antibiotics. All of this is happening at a time when public health resources are shrinking in both rich and poor countries. In view of the threat posed by these factors, the World Health Organization has selected the theme “Emerging Infectious Diseases—Global Alert, Global Response” for World Health Day 1997. Celebrated on 7 April in observance of the formal adoption of the WHO constitution in 1948, this annual event calls attention to a health topic of global importance. In his World Health Day mes- sage, the Director-General of WHO expresses the hope that this year’s theme will serve as a catalyst for countries to take a realistic look at infectious dis- ease problems and concentrate on rebuilding the foundations of disease surveillance and control. CURRENT PROBLEMS AND RESPONSES Emerging infectious diseases are those caused by newly identified and previously unknown infec- tions. Recent examples include a highly fatal respi- ratory disease caused by a hantavirus, which came to light in the southwestern United States of Amer- ica in 1993; a variant of Creutzfeldt-Jakob disease (a central nervous system affliction), which is sus- pected, though not proven, to be associated with a similar disease in cattle (bovine spongiform encephalopathy, popularly referred to as “mad cow disease”); HIV infection, which causes AIDS; and Ebola hemorrhagic fever. It is not always possible to know if these diseases are new in humans or whether they have been present but unrecognized for a long time. In contrast, re-emerging infectious diseases are those which are once again becoming common after having fallen to levels so low that they were 1 Source: World Health Organization. World Health Day 1997 Infor- no longer considered a public health problem. mation Kit. Geneva: WHO; 1997. These diseases often reappear in epidemic propor- Rev Panam Salud Publica/Pan Am J Public Health 1(5), 1997 405 tions. Tuberculosis is increasing worldwide, in part international initiatives in the past five years to because of its association with HIV infection. restore and improve surveillance and control of Cholera was reintroduced in 1991 into many coun- communicable diseases. The Member States of tries of the Americas after having been absent for WHO expressed their concern in a resolution of the decades from the Western Hemisphere; its spread 48th World Health Assembly in 1995, which urged has been encouraged by deficiencies in water and all Member States to strengthen surveillance for sanitation systems. Epidemics of dengue fever have infectious diseases in order to promptly detect re- recurred in urban areas where mosquito control has emerging diseases and identify new ones. That broken down. same year PAHO prepared a Regional Plan of Action for Combatting New, Emerging, and Re- emerging Infectious Diseases in the Americas, Causes of emergence and re-emergence of which will serve as PAHO’s blueprint for imple- infectious diseases menting programs and initiatives on emerging infections in the Western Hemisphere. Several factors contribute to the emergence The success of efforts to combat infectious and re-emergence of infectious diseases, but most diseases depends on the ability to obtain informa- can be linked to the increasing human population: tion on them and the willingness to communicate rapid and heavy international travel; overcrowding that information nationally and internationally. In in cities with poor sanitation; changes in the way furtherance of the World Health Assembly resolu- large quantities of food are handled and processed; tion, WHO established the Division of Emerging and increased exposure of humans to disease vec- and Other Communicable Diseases Surveillance tors and natural reservoirs. Closer contact of and Control (EMC), whose mission is to strengthen humans with the natural reservoirs of an infectious national and international capacity in these areas in agent sets the stage for the agent to “jump” across order to ensure a timely and effective response to the species barrier from animals to humans. emerging and re-emerging public health problems. These problems are compounded by the A worldwide partnership of countries, non- development and spread of antibiotic-resistant governmental organizations, international organi- microorganisms. Many well-known antibiotics are zations, and individuals is required to respond to no longer effective in treating common infections, the threat of emerging and re-emerging diseases by such as otitis, pneumonia, gonorrhea, and tubercu- ensuring rapid detection and effective containment. losis. At the same time, fewer new antibiotics are The World Health Organization, as one of the part- released on the market, partly because of the high ners in this global effort, is strengthening global cost of developing and licensing them and because monitoring systems to serve as part of the overall microbial resistance reduces the “useful life” of anti- detection system. Three independent systems are biotics. The misuse of antibiotics exacerbates the already in existence, bringing together specialized problem of resistance. laboratories and disease surveillance systems from All of these factors have been observed in the all countries and feeding information electronically past few decades, together with a waning concern to the World Wide Web and other international (and decreased resources) for infectious disease electronic and printed media. control. During the first half of the 20th century, deaths from infectious diseases declined steadily because of improved hygiene and nutrition. This WHO Collaborating Centers. One of these global trend was strengthened with the advent of a grow- systems is the network of WHO Collaborating Cen- ing number of vaccines and antibiotics. Because ters, which include specialized laboratories and infectious diseases appeared to be a decreasing institutions with expertise in infectious disease threat, funds for their control were channeled to- diagnosis and epidemiology. During recent epi- ward other problems, and as experts retired, fewer demics, it has become clear that the WHO system students entered the field. The infrastructure for of Collaborating Centers could no longer fully re- communicable disease control began to crumble spond to global needs. For example, some centers and in many places it has become unable to cope had failed to keep up with changes in technology with the demands imposed by a growing popula- and were unable to provide the diagnostic support tion and new disease threats. necessary to confirm the etiology of disease out- breaks. Other centers did not have sufficient exper- tise in the epidemiology of some of the newer infec- The global response tious diseases. Moreover, there are not enough Collaborating Centers in developing countries to Alarm over emerging and re-emerging dis- ensure self-sufficiency within all regions. WHO eases has resulted in a number of national and is therefore asking governments to provide the 406 Temas de actualidad • Current topics resources necessary to bring the Collaborating Cen- tive preparedness and rapid response to contain ters up-to-date. WHO is also facilitating the epidemics of international importance. exchange of information and reagents among cen- Between the world of today and this vision of ters, increasing the number of centers in developing the 21st century lies a huge gap. The possibility of countries, and ensuring that all centers are linked bridging this gap depends on the forging of com- electronically and regularly exchange information. mitted partnerships among individuals, organiza- tions, and countries, with the backing of PAHO, WHO, and other agencies. The challenges and the Antimicrobial resistance monitoring. The sec- international responses that are required to meet ond global system includes the WHO networks for them are outlined below. monitoring and containing antimicrobial resistance: WHONET, for the monitoring of general antimicro- bial resistance, and GASP, the program for moni- Early detection of epidemics toring gonococcal antibiotic susceptibility. Increas- ing antimicrobial resistance results in higher costs In an environment with poor public health because of the use of more expensive combinations infrastructure, an unusual disease may not be of antibiotics, increased rates of hospitalization for detected until it has become a major threat to the infections once easily treated on an outpatient basis, population and cannot be contained with national and time lost from work or school until cure. resources. Public health laboratories, where they Through WHONET and GASP, WHO regularly exist, are often poorly equipped or unable to diag- obtains standardized and reliable information on nose common diseases and assess their impact on the current state of antimicrobial resistance, helps the community. countries use this information to formulate sound There