The Influence of Global Environmental Change on Infectious Disease Dynamics Workshop Summary (2014) / Chapter Skim
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Workshop Overview
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report, Microbial Threats to Health, identified changing ecosystems; economic development and land use; climate 1 The planning committee's role was limited to planning the workshop, and the workshop summary has been prepared by the workshop rapporteurs (with the assistance of Rebekah Hutton, Katherine McClure, and Priyanka Nalamada) as a factual summary of what occurred at the workshop.
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It is likely that bushmeat hunting and the associated trade in wildlife have contributed to the emergence of "novel" infectious diseases such as Ebola and HIV/AIDS. · Dam building and irrigation projects to "manage" the flow of freshwa ter resources have been associated with the emergence and spread of infectious diseases including schistosomiasis, malaria, Rift Valley fever, filariasis, leishmaniasis, dracunculiasis, onchocerciasis, and Japanese en cephalitis.
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Participants examined and discussed the observed and potential influence of environmental factors, acting both individually and in synergy, on infectious disease dynamics, and considered a range of approaches to improve global readiness and capacity for surveillance, detection, and response to emerging microbial threats to plant, animal, and human health in the face of ongoing global environmental change. This meeting served to update two previous Forum workshops, Infectious Disease Movement in a Borderless World (IOM, 2010)
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Such stability may now be under threat. Since the Industrial Revolution, a new era has arisen, the Anthropocene, in which human actions have become the main driver of global environmental change.
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FIGURE WO-1 The increasing rates of change in human activity since the beginning of the Industrial Revolution. Significant increases in rates of change occur around the 1950s in each case and illustrate how the past 50 years have been a period of dramatic and unprecedented change in human history.
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"If one boundary is transgressed, then other boundaries are also under serious risk," they warn. Ecosystems and Disease Dynamics Energy, food, and water crises; climate disruption; declining fisheries; increas ing ocean acidification; emerging diseases; and increasing antibiotic resistance are examples of serious, intertwined global-scale challenges spawned by the accelerating scale of human activity.
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loss of tropical rainforest and woodland, as estimated for tropical Africa, Latin America, and South and Southeast Asia; (xi) amount of land converted to pasture and cropland; and (xii)
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and an additional 800,000 smaller dams around the world, changing flows on roughly 60 percent of the world's rivers. Resource use has also contributed to changes in global nutrient cycles and altered climatic patterns, which in turn may accelerate hydrological cycles and increase the likelihood of extreme weather events, such as droughts, heavy precipitation, heat waves, hurricanes, typhoons, and cyclones.
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Ocean acidification Global mean saturation state 2.75 2.90 3.44 of aragonite in surface sea water Global freshwater use Consumption of freshwater 4,000 2,600 415 by humans (km3 per year) Change in land use Percentage of global land 15 11.7 Low cover converted to cropland Atmospheric aerosol loading Overall particulate concentration in the To be determined atmosphere, on a regional basis Chemical pollution For example, amount emitted to, or To be determined concentration of, persistent organic pollutants, plastics, endocrine disrupters, heavy metals, and nuclear waste in the global environment, or the effects on the ecosystem and functioning of the Earth system NOTE: Boundaries for climate change, rate of biodiversity loss, and nitrogen cycle have been crossed.
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Infectious disease dynamics, according to the WHO, are influenced by "destruction of, or encroachment into, wildlife habitat[s through] logging and road construction; changes in the distribution and availability of surface waters [through dam construction, irrigation and stream diversion]
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Increased use of natural resources will likely be accompanied by severe deterioration of global ecosystems and strain the ecosystem services provided by freshwater re sources, including aquatic habitat, fish production, water for households, industry, and agriculture. · Climate change: Climate change will worsen the outlook for the avail ability of critical resources and is expected to reinforce additional con tributors to infectious disease emergence, including global trade and transportation, land use, and human migration.
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. The profound consequences of human-mediated biological introductions include emerging infectious diseases (EIDs)
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A recent analysis by the National Intelligence Council -- referred to earlier in this chapter -- suggests that several key global trends will further encourage the emergence and spread of infectious diseases over the course of the next two decades (National Intelligence Council, 2012)
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6 The Association of State and Territorial Health Officials (ASTHO) defines Health in All Policies as "a collaborative approach that integrates and articulates health considerations into policymaking across sectors, and at all levels, to improve the health of all communities and people." SOURCE: http://www.astho.org/Programs/Prevention/Implementing-the-National-PreventionStrategy/HiAP-Toolkit (accessed August 6, 2014)
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"Malnutrition risks could double by mid-century." Further focusing on infectious diseases, Patz offered the following examples of diseases showing evidence of influence by the suite of environmental shifts collectively known as climate change: temperature and VBDs; hydrologic extremes and disease risk; and climate and land use synergies. Temperature and Vector-Borne Diseases Patz noted that diseases transmitted by cold-blooded vectors, such as arthropods,7 are especially temperature sensitive.
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"Our results emphasize the importance of considering not just the statistical significance of climate trend, but their biological implications with dynamical models," they wrote. Hydrologic Extremes and Disease Risk As the Earth warms, droughts and flooding rains are expected to become more frequent, raising the risk for a variety of infectious diseases (IOM, 2008)
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. Indeed, the transformation of wild lands through human enterprise is proceeding exponentially around the globe and -- as Andrew Dobson, of Princeton University, argued in his keynote address to the workshop (see the section "Understanding Infectious Disease Dynamics" on page 20)
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. Addressing the Health Consequences of Environmental Changes The multifactorial nature of global environmental change means that the health effects of its components are interdependent, and therefore need to be considered together (Rockström et al., 2009a,b)
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. A convincing business case for addressing the health effects of global environmental change needs to be made, advised Forum member Jeffrey Duchin, of the Seattle and King County Department of Public Health.
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important people that will be involved and invest in changing the world." Understanding Infectious Disease Dynamics Identifying and interpreting how multifactorial, interacting environmental forces influence the emergence and spread of infectious diseases is essential to reducing the harm they cause. Keynote speaker Andrew Dobson, of Princeton University, an ecologist studying infectious disease dynamics, offered a provocative view of this effort by attempting to debunk the following six misconceptions about emerging pathogens, as he described them (Dr.
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"So we have to keep worrying about those if we are worried about the world's economy, and indeed I would say we should be worried about those certainly as much as governments." Their analysis also suggested that the economic effects of vector-borne and parasitic diseases are to some extent buffered by local biodiversity -- a strong argument for protecting it, Dobson concluded. Misconception Two: Climate Will Drive Disease Emergence Climate change will influence infectious disease dynamics, Dobson said, but its significance may be difficult to discern among the multiple, interacting forces underlying global environmental change.
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Eventually, the focus on local governance leads to failures in managing the global commons. Problems like climate change, marine fisheries, and pollution grow worse and global environmental problems intensify.
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Misconception Four: Virus Hunting Is an Effective Strategy for Detecting Emerging Diseases Virus hunters who head for the tropics in search of the next emerging pathogen are, in Dobson's opinion, wasting time and resources for two key reasons related to infectious disease dynamics. First, he observed, "Wherever you go, there is a huge amount of undiscovered bacterial and viral tissue.
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Shouldn't we get there ahead of the curve, go to places where diseases are likely to emerge, and try and at least characterize the diversity of fauna viruses out there so we can do something about it? " Relman observed that while the emerging diseases shown on Daszak's maps constitute overt cases of pathogenicity (parasites receiving benefits by damaging their hosts)
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Misconception Five: Emerging Pathogens Will Evolve to Higher Virulence What happens when an infectious disease spreads rapidly and no one tries to stop it? Does it necessarily gather virulence like a ball rolling down a hill gathers momentum?
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"If we really want to understand emerging diseases we need to move beyond high-tech natural history description of novel components to develop mathematical models that capture the essential dynamics of immunity, and then examine how those things vary as we move from the mammals to the birds to the bats," Dobson concluded. This approach could, among other things, reveal why bats are reservoirs of several emergent pathogens, including the SARS, Nipah, and Hendra viruses (Dobson, 2005)
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. The central point of this exercise is to illustrate that food webs and the vertebrate immune system have a network structure that can be examined using ecological food web models.
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Viruses do not gain particular advantage in "jumping" host species, he observed; spillover is a product of global environmental change. "In the tropics, you have more people, you have more vectors, you have more viruses, and you have more disruptions, and more people making more people more quickly." Upon introduction to a host, pathogens are generally surrounded by communities of diverse indigenous microbes, noted Forum member Margaret McFallNgai.
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Figure WO-7 offers three perspectives on this phenomenon and its intersection with population growth. A central feature of global environmental change, increased human mobility and migration have both caused and resulted from environmental influences (such as deforestation, drought, land use, climate change)
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30 GLOBAL CHANGE AND INFECTIOUS DISEASE DYNAMICS FIGURE WO-7 (A) Travel over four male generations of the same family.
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. A more straightforward relationship exists between the global movement of animals and animal products and the emergence of zoonoses, which are estimated to comprise 60 percent of newly identified infectious diseases (Jones et al., 2008)
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Introducing Plant Pathogens Global pathogen movement -- enabled by international travel and trade, as well as by extreme weather -- has also had a profound effect on plant health, and thereby on food security. Along with anthropogenic introduction, winds, and weather -- including extreme weather events12 -- are associated with the introduction, establishment, and spread of fungal diseases (Anderson et al., 2004)
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These circumstances -- which fueled the Irish Potato Famine in the mid-nineteenth century and the 1970 epidemic of southern corn leaf blight in the United States -- now threaten banana (plantain) , a major food crop in East Africa, Allen noted.
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. Nonhuman primates share several infectious diseases and disease agents with humans, including tuberculosis, viral hemor rhagic fever, herpes B virus, hepatitis A and B viruses, monkeypox, simian immu nodeficiency virus (SIV)
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, and bushmeat (the likely origin of the first human HIV infection, and a known source of Ebola virus, SIV, and SFV, among other infectious diseases)
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. Green arrows indicate periodic migrations of airborne spores in extinction–recolonization cycles (X, XI, XII, XIII, XIV)
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SOURCE: Pautasso et al., 2012. 2001, banana trees in east Africa began showing signs of the emerging disease now called banana Xanthomonas wilt (BXW)
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At the same time, the populations of Latin America, North America, the United States, and Canada -- and even China -- will be relatively aged, and therefore in need of the labor that African and Indian immigrants could provide. Human migration can influence infectious disease dynamics through a variety of mechanisms, according to speaker Chris Beyrer, of Johns Hopkins University (Dr.
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. Recent forced migrations in Zimbabwe caused thousands of people to flee to neighboring countries, where many were considered illegal immigrants; as such, they were unlikely to receive treatment for infectious diseases, or to be recognized in disease surveillance efforts, he observed.
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SOURCE: Figure: Credit Suisse, 2012; Data: Population Division of Department of Economic and Social Affairs of the United Nations Secretariat, Credit Suisse. 9 species and >200 serovars,13 is present in water contaminated by urine from infected animals -- often rats -- and can be transmitted to humans through skin lesions or through mucous membranes.
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In Salvador, a city in Northeast Brazil, as well as in the large urban centers throughout the country, outbreaks of leptospirosis occur annually within the same slum communities and involve a single serovar of the pathogen, for which domestic rats serve as a reservoir (Ko et al., 1999)
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Furthermore, the paradigm of the sanitation revolution in the 1980s may not adequately address the complexities of contemporary slum communities, he observed. Ko asserted that new paradigms need to be constructed which incorporate interdisciplinary approaches to these inherently complex health problems, based on an understanding and linkage of ecological and social drivers for all infectious diseases -- something we have yet to achieve for marginalized urban slum populations, he said (Riley et al., 2007)
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Conflict and Complex Emergencies Following his more general introduction to the ways in which human mobility and migration may directly or indirectly influence infectious disease dynamics, Beyrer focused on two multifaceted phenomena in which human migration and mobility play a central role: conflict and complex humanitarian emergencies, which he defined as a humanitarian challenge, such as a natural disaster, combined with social conflict or political upheaval. Both circumstances are unfortunately common, especially in the context of environmental change, he observed.
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Beyrer recounted his own attempts to gain admittance to the country to assist with recovery, only to be denied because he was deemed "a humanitarian doctor," and therefore, a threat to the dictatorship. Amazingly, no major infectious disease outbreaks occurred in Burma following Cyclone Nargis, Beyrer reported; nevertheless, the population suffered epidemic posttraumatic stress disorder, widespread depression, and impoverishment.
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Temperature increases of just a few degrees can produce rapid growth in several types of bacteria that cause diarrheal diseases, including Salmonella and Vibrio species. In addition, an increase in water temperature coupled with eutrophication has been known to promote dormant strains of cholera,
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The importance of safe water has been expressed in the United Nations Millennium Development Goals (United Nations Millennium Development Goal 7) .15 However, new Sustainable Development Goals are focusing on water quality and sustainable water security.
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. The emergence of these and other waterborne diseases raises an important set of intersecting questions, Rose observed, including 16 Combined sewer systems are sewers that are designed to collect rainwater runoff, domestic sew age, and industrial wastewater in the same pipe.
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The lake system is described through two subsystems: water quality indicators and the ecosystem responses. SOURCE: Adapted from Mavrommati et al., 2013.
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Rose suspects that combined sewer overflows -- from sewers installed in increasing numbers between the 1950s and 1980s -- played a key role in raising fecal pollution rates in Clinton River. With the data they have gathered so far, Rose and coworkers developed a complex causal loop diagram -- a more detailed and specific version of the integrated systems model shown in Figure WO-14 -- to illustrate the interacting forces contributing to fecal pollution in Lake St.
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50 FIGURE WO-14 Causal loop diagram representing two pathways. Pathway 1 is human use of water (residential water demand)
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. Roads as catalysts for diarrheal disease dispersal While past studies have focused on the influence of road construction on the emergence and spread of sexually transmitted diseases, which are largely shaped by social processes, and VBDs, which are driven by ecological factors, Eisenberg's research has focused on the complex transmission patterns of enteric pathogens, which are affected by both social and ecological forces.
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. To explore how social and environmental changes associated with road construction influence the epidemiology of diarrheal diseases, Eisenberg and coworkers compared enteric pathogen infection rates from case-control studies conducted in 21 villages across their study region in northern Ecuador with infection rates in the regions' major population center, Borbón, as well as between those communities that reside close to the road and those that reside far from the road (Eisenberg et al., 2006)
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Climate Change As Patz previously observed (see the section "Health Impacts of Environmental Change" on page 13) , the major features of climate change -- warming and hydrologic extremes -- can profoundly influence infectious disease dynamics.
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This area covers approximately one-eighth of the Earth's surface, but its residents number only about 4 million, of whom about half live in the Russian Federation, and 10 percent are of indigenous ancestry, he stated. Investigations in the Arctic provide an opportunity to study climate-sensitive infectious diseases in isolated human and wildlife populations, according to Parkinson.
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. The presence of a road or roads causes environmental changes (social and ecological)
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. "I think we can learn a lot from outbreaks about climate change and infectious disease emergence," Parkinson concluded.
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Climate shifts, animal migrations, and infectious disease dynamics While the influence of climate change on pathogen dynamics is readily apparent in Arctic wildlife and in some marine ecosystems, detecting such effects in human populations inhabiting temperate regions has proven difficult, noted Altizer. "The wealth of nations; the better infrastructure; and the better health care, surveillance, and control aimed at human pathogens in developed countries, might actually be masking the climate signals," she explained.
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In addition to these effects on disease dynamics, migration can also affect the evolution of pathogen virulence and host resistance in this system, Altizer noted,
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Because many animal migrations are likely to be compromised by climate change and other human activities, she urged greater effort to understand the effects of these losses on infectious disease dynamics.
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introduction of pathogens cause the most plant emerging infectious diseases. SOURCE: Anderson et al., 2004.
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. Allen noted that the emergence of coffee rust in Latin America -- described in Figure WO19 -- offers an opportunity to characterize the influence of climate change on a plant disease epidemic.
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She added, however, that "this is a place where it is worth looking if we are trying to find climate change footprints in plant disease development." Models also provide a way to examine the consequences of climate change for plant disease (see the section "Characterizing the Effects of Environmental Change on Infectious Disease Dynamics" on page 63 for further discussion of ecological models of infectious diseases)
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. Characterizing the Effects of Environmental Change on Infectious Disease Dynamics The previously described case studies illustrate the daunting challenges involved in measuring the effect of individual anthropogenic factors on disease dynamics, host–microbe interactions, and in understanding the interplay of multiple factors that influence these relationships.
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. Spatial models depicting the presence and absence of emerging diseases among susceptible host species can inform strategic responses to these threats, Pautasso observed; he described two such efforts, directed against Phytophthora ramorum (the cause of Sudden Oak Death in North America, and Sudden Larch Death in the United Kingdom)
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. The model integrates data on the distribution of main susceptible hosts and a realistic reconstruction of the plant trade involving ornamental plants susceptible to P
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. If pathogen dispersal is limited, high host susceptibility may matter less, but this scenario is made less realistic by long-distance dispersal due to trade in infected ash saplings, such as to the 21 As Allen noted in discussion, breeding for disease tolerance or resistance has long been con sidered the best way to manage plant disease threats.
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Further dimensions to be considered are the conduciveness of the environment to disease, other pests such as emerald ash borer (which has been reported to be spreading westward from the Moscow region of Russia) , as well as human actions to prevent further worsening of the dieback.
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. This outcome could generate sporadic disease emergence in a naïve population (if extremes in temperature allow only occasional invasion and/or establishment)
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Their analysis suggested that spores released during the late summer and fall persist in the environment and remain infectious for several months, and that the size of the spore "bloom" influences human exposure in the winter and spring. They also determined that exposures end abruptly in mid-summer, coincident with the local rainy season, which may suppress aerosolization of the spores.
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. Global maps of infectious diseases are of potential use to several audiences, including international funding agencies, public health officials responsible for vaccine distribution, ministries of health with inadequate reporting capacity, and travelers in general, according to speaker Jane Messina, of the University of Oxford, England (Dr.
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. Understanding the current distribution of a disease is the first step toward predicting its response to global environmental change, Messina noted.
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72 IGURE WO-24 A schematic of the disease classification process. The classification system results in diseases being categorized into one of five options: (1)
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, which Messina described as "the first step in our niche modeling process," she and FIGURE WO-25 Infectious disease global risk modeling framework: (a) evidence consensus; (b)
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· How do we apply environmental/climate data and models to the study of transmission and disease management? While it is possible to identify hot spots for disease transmission based on current knowledge of disease dynamics (e.g., as demonstrated by Messina's
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Moreover, he added, "We cannot assume that what happens globally is relevant to the local conditions and vice versa. We have to do both, and we have to work on many scales." To begin to approach this challenge, he and coworkers have examined VBDs that persist under changing environmental conditions and/or intensive intervention: malaria and schistosomiasis, which have resisted eradication in known, often rural, hot spots, where they frequently infect the same person.
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While researchers cannot model the long-term impact of current interventions, they are getting better at making connections between interventions and disease dynamics, he said -- and are getting better in making short-term predictions, and even more long-term forecasts, albeit more limited ones, in some situations. Approaches to Identify and Address Factors Contributing to Disease Emergence Presentations in the final session of the workshop offered diverse examples of efforts to address risk factors for infectious disease emergence -- as characterized in earlier sessions -- through strategic prevention, surveillance, intervention, and response.
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. In his workshop presentation, he addressed the following "big questions for pandemic prevention," and in so doing, extended his earlier response to the critique of pandemic prediction presented by Dobson in his keynote address (see the section "Understanding Infectious Disease Dynamics" on page 20)
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By dissecting this process and analyzing the interactions of the underlying drivers with the risk of spillover and spread, development of a more structured approach to pandemic prevention is possible. The ultimate goal of successful pandemic prevention is to move the control point to stage 1.
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. Their map, based on a comprehensive review of all infectious diseases reported between 1960 and 2008, was critiqued by Dobson in his presentation and briefly discussed afterward by Daszak.
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80 FIGURE WO-27 Global emerging disease "hot spots." NOTE: Update of model found in Jones et al., 2008, using driver datasets as of 2009 and events as of 2010. SOURCE: Daszak presentation, 2013 (adapted and updated from Jones et al., 2008)
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WORKSHOP OVERVIEW 81 FIGURE WO-28 Global vulnerability from (A) zoonotic EIDS and (B)
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To learn how people make contact with wildlife, Daszak and coworkers are sampling viral diversity in sites representing pristine forest, fragmented habitats, and rural–urban centers in Borneo, Brazil, and Uganda -- all hot spots for disease emergence. The researchers are examining known reservoir species in these areas for viruses with pandemic potential; they also use questionnaires to learn about residents' contact with local wildlife.
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Daszak agreed with that assessment, noting that the ability for third parties to report outbreaks has increased reporting accuracy for infectious diseases. "One of the things that we will probably see over the next 10 years or so is trying to deal with the underlying drivers of emerging disease," he observed -- an area in which global governance could enable swift and effective interventions to reduce pandemic threats.
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Case-control studies in Bangladesh revealed that people who reported drinking raw date palm sap were significantly more likely to be cases than controls. This led to the suspicion that consumption of raw date palm sap may be an important route for human exposure to Nipah.
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, is often highly profitable. Luby and coworkers designed two types of interventions to address this risk: a campaign to warn people not to drink raw date palm sap, and several versions of protective "skirts," that sap harvesters could manufacture themselves, to keep bats and other animals out of the sap as it is being collected (see Figure WO-29)
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This result appears quite variable from village to village, however, so he and coworkers plan to launch a two-tiered message campaign -- "just say no" and "skirts make sap safer" -- in the hope that this dual messaging effort will reduce outbreaks that are still occurring. Rather than convince sap collectors to use skirts, the key to reducing infection risk "is convincing the date palm sap drinkers that they want to drink sap from a protected tree," Luby observed.
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"I think it is important to recognize that the problem of reducing the risk of emerging disease is not fundamentally a problem of Bangladesh. It is a problem of humanity." Modeling Emerging Infectious Diseases According to speaker Neil Ferguson, of Imperial College, London, mathematical models address several stages of infectious disease emergence.
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This process is highly speculative, because it includes assumptions about the fitness of the viral intermediates. Nevertheless, he observed, "It gives you some ballpark estimate." In the case where a virus has already begun to infect humans, such as the swine influenza variant H3N2v, which has caused limited human cases since it was first reported in 2011, one can use epidemiological data to assess whether this virus is more transmissible in humans than other swine strains, and whether it can generate sustained epidemics in humans, Ferguson stated.
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. Rapid assessment of 2009 H1N1 and MERS "Perhaps the busiest time in the last few years was during the H1N1 pandemic in 2009 where we undertook with collaborators around the world particularly Mexico and the World Health Organization and later with the Centers for Disease Control and Prevention a number of rapid assessments," Ferguson recalled.
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Ferguson noted that as a result, in part, of increased attention from researchers, health officials in Saudi Arabia and other affected countries are more consistently performing follow-up investigations of cases, and increasingly detecting milder cases. "The data collected just in the last few weeks very much validates what I presented," he reported.
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. Failing to recognize that these factors are not static hinders our understanding of disease dynamics, as well as our ability to predict or change them, she observed.
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. Recognizing that labor migration is common in this region, which is economically dependent on agriculture, the researchers attempted to examine the influence of migration patterns on disease dynamics.
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A clear understanding of population dynamics not only helped to explain the mechanism underlying the dynamics of measles transmission in their study area, but also to inform better disease control, Bharti concluded. She noted that a similar approach could prove valuable in other contexts, such as to investigate the contribution of rainy-season migration to malaria transmission dynamics, and the effects of drought on migration patterns, which in turn could affect the transmission of several infectious diseases.
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residents for the first time in several decades. Disease screening programs for immigrants provide opportunities for surveillance of a range of emerging infectious diseases, some of which may be most effectively addressed through intervention in their countries of origin (see Figure WO-30)
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More importantly, this program is building health infrastructure for the ongoing detection, treatment, prevention, and control of infectious diseases, he said. The CDC also provides interventions to control outbreaks of measles and prevent the spread of other infectious diseases among Syrian refugees of civil war living in camps in neighboring countries.
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To help cities and countries worldwide assess their potential for MERS-CoV importation following the 2013 Hajj, the researchers examined Hajj-related travel to the area over the previous decade, along with worldwide flight patterns, to predict population movements out of Saudi Arabia and the broader Middle East. They also compared the magnitude of travel to countries, their capacity for timely detection of imported MERS-CoV, and their ability to mount an effective public health response, as indicated by their economic status and per capita health care expenditures.
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Conclusion Cetron's presentation on BioMosaic brought together many recurring themes of the workshop: · The complex interactions of anthropogenic drivers of infectious disease emergence and spread, · The usefulness and limitations of maps (along with other quantitative and modeling tools) as a means to characterize and predict those interactions, · The importance of local and temporal variation in environmental condi tions and population dynamics, and · And the need to distinguish between correlative and causative observa tions of environmental change and disease dynamics.
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Public health officials can then use the information to detect, respond, and prevent any type of public health emergency. Specifically, BioMosaic can be used for: · Surveillance -- By monitoring multiple data sources to identify outbreaks, emerging diseases, events of public health significance, media reports, or other sources, BioMosaic helps predict health threats.
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SOURCE: CDC, 2013a. The emergence of MERS-CoV requires an internationally coordinated effort to mitigate its potential global health and economic consequences, with particular emphasis on supporting diagnostic and public health response capacity in vul nerable, resource-limited countries.
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2011. Animal migration and infectious disease risk.
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2004. Emerging infectious diseases of plants: Pathogen pollution, climate change and agrotechnology drivers.
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What links bats to emerging infectious diseases? Science 310(5748)
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2006. Environmental change and infectious disease: How new roads affect the transmission of diarrheal pathogens in rural Ecuador.
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American Journal of Tropical Medicine and Hygiene 90(2)
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2008. Global trends in emerging infectious diseases.
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Emerging Infectious Diseases 14(1)
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Emerging Infectious Diseases 14(5)
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1974. The effects of environmental stress on outbreaks of infectious diseases of fishes.
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2010. Emerging infectious diseases of crop plants in developing countries: Impact on agriculture and socio-economic consequences.
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