APPENDIX D

Abstracts of Conference Presentations

GEORGE ALLEYNE, M.D.

The reemergence in the Americas of infectious disease that had been controlled in the past, such as cholera, plague, and dengue, as well as the emergence of new infectious agents, such as Hanta and Guanarito viruses, E. coli:0:157, and cryptosporidia, have had a direct impact on health policy and the prevention of disease. Over the past several years, governmental and nongovernmental organizations have been working closely to modify health policy in order to place more emphasis on disease prevention. A major concern is the changing dynamics of disease transmission, which is influenced by migration, land use, and environmental degradation. Many lines of action are being perused to prevent infectious diseases. One requirement is flexible management within the health sector, which is close to the population and that can adapt to the changing patterns of disease. In addition, the wide impact of infectious diseases, such as AIDS, mandates a policy of increased intersectorial cooperation. There must be fluid communication and management of health problems among the sectors of health, environment, and agriculture, supported by competent research based on policy analysis. It is believed that policy reform, combined with broad public support gained by effective use of the mass media, will allow us to confront the health problems caused by climate change and environmental degradation.

J. BRIAN ATWOOD

Climate change is believed to cause a wide variety of deleterious effects, including desertification, change in agricultural patterns, and disease. The effect is both direct and indirect; the causes may be either natural or manmade. To the extent that climate change and its impacts are influenced by human activity, methods must be found to mitigate, adapt, or respond. The U.S. government is obligated to exercise leadership at home and abroad to ensure that responses are appropriate and timely.

Who is at risk? Every human being is vulnerable but the citizens of developing countries and regions face the most immediate dangers. In those nations, climatic change and the necessary responses may be greatest, but available resources are most limited. Clearly, the



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Conference on Human Health and Global Climate Change: Summary of the Proceedings APPENDIX D Abstracts of Conference Presentations GEORGE ALLEYNE, M.D. The reemergence in the Americas of infectious disease that had been controlled in the past, such as cholera, plague, and dengue, as well as the emergence of new infectious agents, such as Hanta and Guanarito viruses, E. coli:0:157, and cryptosporidia, have had a direct impact on health policy and the prevention of disease. Over the past several years, governmental and nongovernmental organizations have been working closely to modify health policy in order to place more emphasis on disease prevention. A major concern is the changing dynamics of disease transmission, which is influenced by migration, land use, and environmental degradation. Many lines of action are being perused to prevent infectious diseases. One requirement is flexible management within the health sector, which is close to the population and that can adapt to the changing patterns of disease. In addition, the wide impact of infectious diseases, such as AIDS, mandates a policy of increased intersectorial cooperation. There must be fluid communication and management of health problems among the sectors of health, environment, and agriculture, supported by competent research based on policy analysis. It is believed that policy reform, combined with broad public support gained by effective use of the mass media, will allow us to confront the health problems caused by climate change and environmental degradation. J. BRIAN ATWOOD Climate change is believed to cause a wide variety of deleterious effects, including desertification, change in agricultural patterns, and disease. The effect is both direct and indirect; the causes may be either natural or manmade. To the extent that climate change and its impacts are influenced by human activity, methods must be found to mitigate, adapt, or respond. The U.S. government is obligated to exercise leadership at home and abroad to ensure that responses are appropriate and timely. Who is at risk? Every human being is vulnerable but the citizens of developing countries and regions face the most immediate dangers. In those nations, climatic change and the necessary responses may be greatest, but available resources are most limited. Clearly, the

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Conference on Human Health and Global Climate Change: Summary of the Proceedings preventive and responsive measures we employ to deal with climate change and its effects must involve every affected person and operate society-wide. ERIC CHIVIAN, M.D. Despite increasing evidence that climate change and ozone depletion may have disastrous consequences for human health, there is little understanding, either among policy-makers or the public, of the extent of the possible threat to human life. Physicians and public health professionals should be central figures in helping to promote this understanding, but they are by and large uniformed, as their education does not in general cover the relationship of global environmental change to human health. This presentation shall look at the role of the medical and public health communities in global environmental issues, such as climate change and ozone depletion, and shall address the growing need for their education and involvement. RITA R. COLWELL, Ph.D The origin and cyclical nature of cholera has intrigued scientists and public health officials. Robert Koch postulated environmental origins of cholera, but proof was not established until the tools of molecular biology and immunology were available. Work on environmental aspects of cholera during the past 20 years has revealed an association of Vibrio cholerae with zooplankton and marine and estuarine systems. Furthermore, the capability of V. cholerae to enter a dormant, that is, viable but nonculturable state, has offered an explanation for the inability to isolate it between epidemics. With fluorescent monoclonal antibody and gene probes, coupled with PCR amplification, it has been possible to detect and monitor V. cholerae in the environment. Furthermore, it has been shown that plankton blooms are correlated with increased incidence of V. cholerae. Studies carried out in Bangladesh provided the link between cholera outbreaks and plankton populations. Studies in progress, employing satellite imagery, will permit retrospective and prospective analyses of marine plankton and the cholera outbreak in Latin America during 1991–1992. The El Niño event appears to be closely associated with this cholera outbreak. Perturbations of the marine ecosystem may be the key to the eratic, cyclical nature of cholera epidemics. STEPHEN C. JOSEPH, M.D., M.P.H. Global surveillance is critical to national security and plays a vital role in the mission of the Department of Defense (DoD). Military forces can be deployed to virtually any area of the world on short notice; knowledge of emerging diseases and their potential impact on military operations greatly assist us in preparing countermeasures to avoid such threats, reduce their impact, and provide a rapid response to outbreaks. At present, three things need to be

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Conference on Human Health and Global Climate Change: Summary of the Proceedings accomplished. First, DoD—using existing resources—will establish a surveillance and response capability in its overseas laboratories. Second, along with other U.S. government agencies, DoD will link international and host-nation training of field epidemiologists and researchers to existing DoD laboratories, creating regional networks. Third, U.S. government agencies in international partnerships need to establish a functional surveillance system on the Internet, of which PROMED is an excellent early prototype. LAURENCE KALKSTEIN, Ph.D Direct weather impacts, such as heat waves, have a profound effect upon human health; during unusually hot conditions, deaths from all causes can rise over 50 percent above average levels. The elderly, poor, and very young appear disproportionately stressed. The impact of climate change could exacerbate the situation, as more extreme hot weather, and a greater frequency of oppressive air masses could cause the number of heat-related deaths to rise significantly. Although developing nations could suffer inordinately, it is quite obvious that extreme heat can cause havoc in American cities, as evidenced by the recent Chicago heat wave. There are a number of unanswered or disputed questions involving the impact of climate change on mortality and morbidity. Will increasing winter warmth compensate somewhat for hotter summers by decreasing winter mortality? What will be the impact of increasing accessibility to air conditioning? Would many of the people who die of excess heat represent deaths that would have occurred shortly afterward, regardless of the weather? What is the acclimatization potential of the population if future temperatures rise? Can excessive deaths be mitigated with the development of watch/warning systems that provide the appropriate agencies with advance notice about impending dangerous weather conditions? Finally, how does the combination of hot weather and air pollution contribute to increasing human mortality, and what are the implications of a global warming on weather or pollution impacts? MARGARET L. KRIPKE, Ph.D The amount of ultraviolet-B (UV-B) radiation in natural sunlight is dependent on the concentration of ozone in the atmosphere. A reduction in ozone will increase the amount of UV-B radiation reaching the earth's surface. Even a small increase in UV-B radiation is likely to have important consequences for human health. Although a small amount of UV-B is necessary for production of vitamin D, excessive exposure causes squamous and basal cell skin cancers and contributes to the incidence of melanoma skin cancer. Ocular changes that lead to certain types of cataract are also a consequence of excessive exposure to UV-B radiation. UV-B radiation can also interfere with the body's immune system; this constitutes one of the most potentially dangerous effects of UV-B because of the possibility that immunity to infectious diseases may be compromised. Unfortunately, too little is know about the immunology consequences of UV-B radiation to make predictions about the impact of ozone depletion on human diseases.

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Conference on Human Health and Global Climate Change: Summary of the Proceedings ANTHONY J. McMICHAEL, M.D., Ph.D Three things about this topic need emphasis: scale, context, and uncertainty. First, the anticipated health risks are not of a localized kind; they are of large scale, impinging at population level, and transcending national boundaries. Second, the risks are not just “more of the same” (more heatwaves, air pollution, etc). Rather, they would arise substantially via indirect pathways (by disturbance of natural systems, e.g., the ecology of infective agents, food production, and freshwater supplies). Third, forecasting them entails complexity, uncertainty, and a long time horizon. It is tempting to focus on the more familiar risks; increased deaths from heatwaves (especially in the very young, frail, and elderly), trauma from floods and storms, and—from stratospheric ozone depletion—more cases of skin cancer. However, in the long term, sustained changes in climate and in climate-dependent natural systems (particularly if also subjected to other environmental or ecological stresses) would result in: (a) altered patterns of infectious diseases, especially vector-borne diseases (malaria, dengue, etc); (b) some regional declines in food production; and (c) population displacement (rising seas, declining agriculture, food shortages, and weather disasters) and its many public health consequences. Combinations of mobile infections, malnutrition, and social stress—especially in displaced and migrating groups—could amplify the health impacts of climate change. STEPHEN S. MORSE, Ph.D “Emerging infectious diseases” are those that are newly appeared in the population or are rapidly increasing their incidence or geographic range (e.g., HIV/AIDS, cholera in South America and Africa, Ebola in Africa, and Hantavirus pulmonary syndrome and Lyme disease in the United States). Most emerging infections are caused by pathogens that are present in the environment but are newly introduced into humans, often from another species as a result of changing ecological or environmental conditions that increase the chance of human contact, or are infections that were once geographically isolated but now have an opportunity to reach larger human populations. Climate may often be a factor. For example, with Hantavirus pulmonary syndrome in the southwestern United States in 1993, the virus probably was long present in local rodent populations, but unusual local weather conditions led to an exceptionally large rodent population, with greater opportunities for people to come in contact with infected rodents (and, hence, with the virus); the weather anomaly itself may have been due to large-scale climatic effects. Human population movements, which can introduce remote infections to a large population, also are often a factor in the emergence of disease. The mass movement of workers from rural areas to cities, largely driven by economic conditions, can allow a previously isolated infection to reach larger numbers of people (this probably happened with HIV). Climate changes, by potentially decreasing productivity of local rural agriculture, could accelerate this migration. As a final example, epidemiologists have long documented a close relationship between climatic conditions and epidemics of childhood bacterial meningitis (which can also spread globally by travel) in parts of Africa where the disease naturally occurs.

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Conference on Human Health and Global Climate Change: Summary of the Proceedings JOEL SCHWARTZ, Ph.D Increases in temperature in the Northern Hemisphere will result in increased demand for air conditioning, and hence increased emissions from electric power generation, which are the major source of fine particles in much of North America. Increased temperature will also lead to increased ozone formation. While the degree of pollution resulting from climate change is relatively unclear, the effects of particulate air pollution and ozone are becoming increasingly clear. Increased particulate air pollution is associated with increased risk of mortality, decreased life expectancy, and increased hospital admissions for heart and respiratory illness. Ozone is associated with increased hospital admissions for respiratory illness. The magnitude of these risks can now be quantified. ROBERT E. SHOPE, M.D. Some probable effects of global warming are (a) an increase in temperatures especially at night, (b) greater warming in polar than in tropical latitudes, (c) an increase in the frequency of tropical storms, (d) loss of forests, and (e) migration of humans and their domestic animals north in the Northern Hemisphere. These changes will affect the health of people and animals, especially through increased numbers and efficiency of arthropod and rodent vectors of disease. Vector-borne diseases such as dengue, St. Louis encephalitis, Lyme disease, yellow fever, malaria, and Rift Valley fever, as well as bat rabies and Hantaviruses, will be affected. These diseases have in common an ecological component such that climate limits their distribution. Most occur in tropical areas and have either a mosquito, tick, or wild animal as part of their cycle. In many cases the infectious agent multiplies better in the reservoir at high ambient temperature, and often the vector depends on ample rainfall to thrive. In the case of Lyme disease, climate influences both the infectious agent and the hosts that maintain the life-cycle of the vector. Dengue is a tropical virus disease transmitted by Aedes mosquitoes. This disease, with warming, appears to be moving northward to the U.S.-Mexican border. ROBERT T. WATSON, Ph.D The Earth's climate is predicted to change because human activities are altering the chemical composition of the atmosphere. The buildup of greenhouse gases—primarily carbon dioxide, methane, nitrous oxide and chlorofluorocarbons (CFCs)—is changing the radiation balance of the planet. The basic heat-trapping property of these greenhouse gases is essentially undisputed. However, there is considerable scientific uncertainty about exactly how and when the Earth's climate will respond to enhanced greenhouse gases. The direct effects of climate change will include changes in temperature, precipitation, soil moisture, and sea level. Such

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Conference on Human Health and Global Climate Change: Summary of the Proceedings changes could have adverse effects on ecological systems, human health, and socioeconomic sectors. Accumulation of CFCs in the upper atmosphere has already led to world-wide depletion of the ozone layer and an ozone hole in springtime over Antarctica. Ozone filters out harmful ultraviolet radiation and keeps it from reaching the Earth's surface. Recent international agreements to phase out CFCs are beginning to show results; we now expect peak depletion to occur about the turn of the century, and the ozone layer should recover over the next several decades. Ozone depletion and climate change are complex problems that will affect the economy and the quality of life for this and future generations. The lag time between emission of the gases and their impact is on the order of decades to centuries; so, too, is the time needed to reverse any effects. Thus, decisions in the near term will have long-term consequences. M. GORDON “REDS” WOLMAN, Ph.D The geologic record provides clear evidence of climatically induced changes in the quantity and quality of fresh water on the globe. Major fluctuations in climate, in the last 10,000 years and before, have resulted in the creation and demise of lakes and river systems. Temperature perturbations of only a few degrees have also been accompanied by significant increases in the frequency of floods, and similar flood events are associated with El Niño oscillations in some regions. Increasing seasonal runoff at some locations in the United States may be associated with a warning trend during this century, but the record is not consistent. Climate change influences water quality directly and indirectly; directly through changes in water temperature and associated chemical and biochemical phenomena (e.g., dissolved oxygen, algae), and indirectly through alterations of vegetation and the erosional process on land. Sediment yield and accompanying organic and inorganic constituents may alter the quality of ambient flow and the characteristics of the habitat. Human impacts acting on both landscape and climate are often inseparable from the variable behavior of natural processes. DAVID OOT, Ph.D. More than 800 million people, or 15 percent of the world's total population, are food insecure. They lack the economic and physical access to adequate food to meet their dietary needs and to lead healthy and productive lives. Inadequate food consumption is a primary cause of malnutrition along with infection and poor health. For 1993, the UN reports that over 34 percent of all preschool children in developing countries are malnourished. From recent research we know that protein energy malnutrition (PEM), even in its mild-to-moderate forms, contributes to 56 percent of child deaths in 53 developing countries. The terrible burden of PEM on child survival is even greater when the toll of hidden hunger due to micronutrient

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Conference on Human Health and Global Climate Change: Summary of the Proceedings deficiencies—especially of Vitamin A, which leads to blindness; of iron, causing anemia; and of iodine deficiency, which leads to impaired mental performance. Projections through 2020 suggest an increasing number of malnournished people, especially in South Asia. Estimates for the numbers of additional people at risk of hunger range from a conservative 100 million to around 360 million by the year 2060. Cereal prices were estimated to increase dramatically from 25 to 125 percent, with profound implications for the net purchasers of food, the poor. The differential and negative impact in the developing world has implications for the range and types of actions that need to be taken to address the health and nutrition consequences. Early warning and famine mitigation; Institutional strengthening in developing countries to predict and respond to environmental and related emergencies; Development assistance to vulnerable countries for promoting and refining adaptive measures to improve food production and income generation; Increased emphasis on basic health and nutrition services including family planning; Focused and coherent approaches to effective utilization of U.S. food resources targeted to the vulnerable; and Global action and leadership to advance scientific knowledge and its application. ADDITIONAL ABSTRACT OF CONFERENCE PRESENTATIONS J. Michael Hall, Ph.D., and Paul Epstein, M.D., M.P.H. During the past 15 years scientists have made dramatic progress in predicting the El Niño-Southern Oscillation (ENSO) phenomenon and related seasonal to interannual climate variability in many critical areas of the globe, particularly in the tropics and subtropics, where the ENSO signal and impacts are strongest. Current ENSO-forecasting capabilities can predict climate trends for many affected regions of the world with a lead time of up to 1 year. Accurate and timely forecasts allow policy-makers to mitigate the potentially devastating economic impacts of ENSO by adapting planning processes to short-term climate fluctuations. The ability to anticipate an upcoming anomalous wet or dry period is already being used by decision-makers in several tropical countries. Past successes in climate forecasting and impacts modeling in the agriculture and hydrology sectors have set the stage for a new line of investigation and application in the health sector. El Niño events—producing warmer and wetter years periodically in regions around the world—may be associated with upsurges of cholera and other water-borne diseases, new appearances of harmful algal blooms, disease events across taxa in the marine environment, outbreaks of malaria and dengue fever, and the abundance of rodents as pests and pathogen vectors. Multidisciplinary application centers integrating climate forecasting with ecological and social information can provide early warning for multiple sectors including hydroelectric energy,

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Conference on Human Health and Global Climate Change: Summary of the Proceedings water resources management, and agriculture (“Famine Early Warning Systems”). With additional investigation, the potential exists to extend these application efforts to human health (“Health Early Warning Systems”). While climate circumscribes the distribution of many disease vectors, extreme events may determine the timing of outbreaks. In considering El Niño as an analogue for long-term climate change, lessons can be learned from El Niño's effects on extreme events: changes in droughts, floods, and minimum and maximum temperatures. Study of the linkage between ENSO and health is beginning to reveal important threshold effects and provide tools for predicting the impacts of global climate change that can be tested and perfected on verifiable timescales. The significance of ENSO may be greater still, as some scientists believe that global climate change may be experienced in large part through changes in climatic extremes and climate variability. For some diseases, changes in climatic extremes may be even more important than changes in average temperature and average precipitation.