Scientific Community Recognizing Link Between Ecology And Health

SENSE OF PROPORTION: "more needs to be done relative to the scale of the problem," remarks Stanford ecologist Gretchen Daily. The worldwide spate of emerging and reemerging infectious diseases in the first half of this decade has prompted a growing recognition of the connection between global climate change and human health. Individual researchers from such disparate disciplines as epidemiology and public health, ecology, virology, climatology, nutrition, and biomedicine have directly addressed the link. They have been joined by such esteemed groups as the World Health Organization and the United States' National Academy of Sciences (NAS). The topic has been brought up at international conferences and has been featured in reports and special journal issues. New professional societies and publications have been introduced to explore the subject. But despite the heightened interest in exploring the environment-human health connection, funding for these efforts is difficult to come by. In an era of budget cutbacks, such large, interdisciplinary endeavors tend to be relegated to low-priority status, scientists working in this area note. "The scientific community is excited about working together," says William Sprigg, director of the NAS board on atmospheric sciences and climate. His office is assembling an independent panel and planning two workshops to evaluate links between climate and health and to devise a research plan. "That being said, it takes funding to pull people together, but it's very difficult for the traditional funding agencies to commit to the development of such a thing when they don't have the funds readily available." The 1990s have seen at least a dozen emerging or reemerging infectious diseases -- from the South American outbreak of cholera in 1991 to the reappearance of the Ebola virus in Zaire last year. The factors contributing to these epidemics are as numerous as the epidemics, researchers maintain. Human population growth; improved transportation; redistribution of disease organisms and their vectors; and resistance to pesticides, among others, all play a role, in concert with climatological and environmental factors. Despite the recent attention focused on this area of study, individual researchers say there is still room for improvement in communication via journals and at meetings. "My perception is that much more needs to be done relative to the scale of the problem," remarks ecologist Gretchen Daily, the Bing Interdisciplinary Research Scientist at Stanford University. "From the point of view of ecologists, there isn't much collaboration or interaction." As for biomedical investigators, Jonathan Patz, a physician in occupational and environmental medicine at the Johns Hopkins School of Hygiene and Public Health, remarks that "it should be obvious -- at least to the health community -- that they need to talk to people like ecologists to understand some of the upstream determinants of the causative agents of disease." Patz coauthored a paper in a special issue of the Journal of the American Medical Association in January (J.A. Patz et al., JAMA, 275:217-22, 1996) devoted to emerging microbial threats. Emerging infectious diseases are influenced by three broad factors, explains Paul R. Epstein, a specialist in tropical public health at Harvard Medical School and School of Public Health. These influences are socioeconomics; local and regional ecological changes, such as deforestation; and the climate system, which affects where and when diseases might occur. "Whereas traditional science looks at confounding factors, and how to tease those factors out, we're looking at what factors compound the resurgence of old diseases; emergence of new diseases; and redistribution of old diseases on a global scale," notes Epstein, a coauthor of Patz's 1996 JAMA paper. Climate change has played a role in many infectious-disease cases, agree biomedical researchers familiar with this area of research. "The issue of climate change and associated ecological change is relatively new in public health," notes Patz. "It shouldn't be, but I think it's been forgotten. But of course in public health the most important issue has always been the environment, especially when you talk about sanitation." In fact, a recent review paper by Princeton University ecologist Andrew P. Dobson and Hopkins public-health researcher E. Robin Carper (Bioscience, 46:115-35, 1996) points to three ecological processes essential to understanding the spread of disease: the size and distribution of the human-host population; migrational patterns of hosts and vectors; and the nutritional health of human hosts. TAKING NOTICE: The global climate-change community is starting to become "cognizant" of funding needs, according to the University of Maryland's Rita Colwell. "An aspect of infectious diseases which has not been considered until recently are environmental factors," said Rita Colwell in her president's lecture, "Global Change: Emerging Diseases and New Epidemics," at last month's meeting of the American Association for the Advancement of Science (AAAS) in Baltimore. "In general, since most emerging disease agents are not new, but are existing pathogens of animals or humans that have been given opportunities to infect new host populations, environmental and social changes -- especially those resulting from human activities, which accelerate pathogen traffic -- need to be defined." Patz contends that "these issues are so complex; unless we take an integrated, interdisciplinary approach, we're not going to get very far" in understanding the contribution of the various factors causing infectious-disease outbreaks. ADDITIVE AGENTS: "Whereas traditional science looks at confounding factors, we're looking at what factors compound" the resurgence and emergence of new diseases, explains Harvard's Paul Epstein. Such coordination was apparent in the American Southwest two years ago. After an initial outbreak of hantavirus in the area in the summer of 1993, ecologists and epidemiologists collaborated to seek out climatological and ecological reasons for the epidemic (K.Y. Kreeger, The Scientist, July 11, 1994, page 14; July 25, 1994, page 15). "About the one place in the world where there is the kind of integration of health surveillance and environmental monitoring that's needed" is in this region, says Epstein. Robert Parmenter, a mammologist from the University of New Mexico, has been studying the population dynamics of hantavirus' rodent vector at Sevilleta National Wildlife Refuge in New Mexico for the last six years. He ties a 1993 rodent population explosion to El Nino, an oceanic condition off the U.S. Pacific coast. El Nino caused heavy spring rains in the Southwest, which increased the rodents' food supplies. This in turn led to record mouse populations and, presumably, increased contact with humans. One program that is attempting to create the early-warning system that Epstein is calling for is ProMED -- the Program for Monitoring Emerging Diseases. ProMED is an Internet-based monitoring system in which subscribers -- from biomedicine as well as ecology -- report infectious-disease outbreaks and discuss surveillance and response activities (see accompanying story). Life At The Interface Colwell, as a marine microbiologist, does research with Vibrio cholerae -- a marine microbe responsible for some cholera epidemics -- that sits at the boundary of ecology and biomedicine. "Working in environmental microbiology in the '70s and '80s was rather different because people really didn't take it seriously," recalls Colwell, who is also president of the University of Maryland Biotechnology Institute. "It was a relatively new discipline. It was at the interface of microbiology and ecology, so I found myself perched between oceanography, space sciences, epidemiology, and medicine." She says it was difficult to find journals to publish in because her work "didn't fit into the limnology- oceanography kind of papers," and that it "definitely" didn't fit into the purview of publications like the Journal of Bacteriology, Cell, or Molecular Biology. Journals such as Applied Environmental Microbiology are "receptive" to interdisciplinary papers, she says, but "then you don't reach the audience of physicians or atmospheric scientists. You can publish, but you can't reach everyone you want to address." Being categorized as a conference speaker is no different. "At meetings, it's either feast or famine," says Colwell. "Either you're a plenary lecturer because [your subject's] so unique or you're scheduled on the last day of the last afternoon because they don't know where to put you." Lately there has been more of an attempt by the biomedical and environmental science communities to integrate their broad fields. The special issue of JAMA is one prime example. Most recently, the AAAS conference devoted a daylong session to the subject of biomedicine and global climate change, and last month, officials from a major research university in the northeastern U.S. had their initial meeting to discuss setting up the first medical school-based center to study global change. Earlier this year, the United Nations' Intergovernmental Panel on Climate Change (IPCC) for the first time included a chapter on the growing body of evidence connecting climate change and human health in its "Second Assessment Report of the IPCC." And an international conference on the same subject held last September and sponsored by the Institute of Medicine (IoM) and the President's National Science and Technology Council (NSTC) was the first of its kind. "I think it takes meetings like [the AAAS conference] to bring disparate groups together," remarks virologist Melinda Beck, an assistant professor of pediatrics at the University of North Carolina, Chapel Hill. Beck, a presenter at one of the AAAS global change sessions, studies the contribution of diet to viral diseases. Beck sees value in broad disciplinary groups' informing each other, but notes that the path to integration has not been easy. "When I started working with nutrition, just blending this area with virology was difficult because the two fields normally have nothing to do with each other. Once we saw that nutrition could influence viruses, it was a hard sell to get the virologists to understand the nutritional component because they thought it had nothing to do with virology." "We certainly have a long way to go," acknowledges Patz. However, he is quick to add: "I definitely think the awareness and need for integration and communication is growing. I'm a physician and I'm working with mathematicians, ecologists, economists, and agronomists." Funding for these types of efforts from large governmental agencies is becoming available, albeit slowly. "We are turning to wherever we can to get the necessary funds," says NAS's Sprigg. For example WHO and the World Meteorological Organization have agreed to help where they can. "They can support travel for people from developing countries and host workshops in their facilities." He comments that their involvement in any capacity is good because they are the agencies that would eventually implement international plans. "We're now entertaining nominations for the [proposed] NAS panel [on health and climate change], but can't establish it without the funds," Sprigg notes. He estimates the total cost of the effort to be about $1 million over three years. Epstein lists other prominent efforts in the U.S. The National Aeronautics and Space Administration (NASA) is working on remote sensing and health applications. The Office of Global Programs at the National Oceanographic and Atmospheric Administration (NOAA) is interested in the extent to which climate information can be used to provide an early-warning system for catching the emergence and spread of infectious diseases. But "this is all at a very early stage," reports program manager Claudia Nierenberg. "There's lots of talk about interagency programs, but it's difficult right now with the budget situation." And then there's the U.S. Global Change Research Program Office, which Epstein calls the "most interdisciplinary program" in the country to study global change, and a "model of what science programs can be." The office coordinates the almost $2 billion efforts of 11 agencies, including programs at NOAA, NSF, NASA, the Department of Energy, the Environmental Protection Agency, and NIH. On the international front, Stanford's Daily says, in her experience, "one of the most promising" collaborations is between ecologists and economists. This effort is now poised to bring in biomedical scientists. Along with Stanford colleague Paul Ehrlich, Daily is active in a joint venture with the Beijer Institute of Ecological Economics of the Royal Swedish Academy of Sciences in Stockholm. Daily and Ehrlich have given talks at the institute and have prepared a paper for the upcoming first issue of the academy's new journal, Environment and Development Economics (Cambridge University Press), which will discuss human disease and ecological and economic considerations. Carl Folke, deputy director of the Beijer Institute, is in the midst of coordinating an international meeting in May that will include biomedical scientists. This get-together aims to develop a research agenda for such subjects as changing land-use practices and vector-borne diseases. So far, he says, "the collaboration has been quite successful, with people dropping their own disciplinary approaches to look at the problem mutually." As opportunities and funding for international and interagency communication slowly grow, funds for individual researchers lag behind. Investigators seeking grants for work that crosses disciplinary boundaries maintain that proposal reviewers who are specialists find it hard to see the big picture. "At a time when as few as 10 [percent] to 13 percent of [NIH] proposals are being funded, they certainly are not going to have any space for funds for something that is not going to get a [high-priority] rating," explains Colwell. She adds that interdisciplinary proposals "don't get those ratings because a molecular biologist or someone working in structural biology [who might be reviewing grant proposals] thinks that what you're doing -- simply because he or she has no knowledge of the work -- is out in left field. "Fortunately, the global climate change people are beginning to take cognizance of the fact that these phenomena affect living systems, and therefore need to include those people working in biological systems in the funding process." "There are calls for more interdisciplinary research, and yet, because of funding constraints, most people can only afford to focus on their individual issues," says Patz. Daily says from her perspective in ecology, the best funding sources are mainly private foundations. The situation has been slightly better north of the border. Ecologist David Rapport, who holds the Eco-Research Chair in Ecosystem Health at the University of Guelph in Ontario, Canada, says, "I've been very lucky, particularly in Canada. We've had a program that funds my work at the moment, which is sponsored by the three science councils of Canada. They formed a temporary secretariat to fund a special program that interfaces the three research councils [social, natural, and medical science] and set up five chairs to each cover a facet of that interface. I hold one." With recent budget cuts in Canada, this temporary secretariat was cut. But, Rapport says, "at least it gave us a toehold into doing this work. And, based on that, I've been able to interest other funders like private foundations to carry out special projects." Sense of Proportion: "More needs to be done relative to the scale of the problem," remarks Stanford ecologist Gretchen Daily.

Scientific Community Recognizing Link Between Ecology And Health

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