Current unprecedented declines in biodiversity mitigate the ability of ecological neighborhoods to carry out many basic ecosystem services. Here we evaluate evidence that decreased biodiversity affects the transmission of contagious diseases of human beings, other animals and plants. In principle, loss of biodiversity can either increase or decrease condition transmission. However before, mounting proof indicates that biodiversity loss frequently increases illness transmission. In contrast, areas of normally high biodiversity might serve as a resource pool for brand-new pathogens. Overall, despite many continuing to be questions, present evidence suggests that maintaining undamaged ecosystems and also their endemic biodiversity should primarily minimize the ubiquity of contagious diseases.
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In June 2010, a brand-new organization, the Intergovernmental Science-Policy Platform on Biodiversity and also Ecosystem Services (IPBES)—patterned after the Intergovernmental Panel on Climate Change (IPCC)—was establiburned to assess alters to the diversity of life on the Planet and how these transforms will certainly affect humale well-being1. Human well-being would be adversely affected by biodiversity losses if ecounits through decreased biodiversity are less able to provide the ecodevice services—such as carbon sequestration, nutrient cycling and resistance to drought—on which people count. In current years, a agreement has actually emerged that ecosystem attributes decrease as biodiversity is lost2. Here we study just how biodiversity affects the transmission and introduction of infectious conditions and also evaluate the proof that diminished condition transmission is a crucial ecosystem business offered by high biodiversity.
Biodiversity includes the diversity of genes, species and also ecosystems. Increases in huguy populaces have actually resulted in an extraordinary and also precipitous loss of biodiversity3. Current extinction prices are approximated to be at leastern 100–1,000 times background extinction prices and also future extinction rates (over the next 50 years) are estimated to be 10 to 100 times present extinction rates3. A huge propercentage of species in all assessed taxa are presently threatened with extinction (12% of birds, 23% of mammals, 32% of amphibians; 31% of gymnosperms; 33% of corals4) and the finest estimate of population fads of birds, mammals, amphibians, reptiles and also fish suggests that given that 1970 worldwide populace sizes have decreased by virtually 30% (ref. 5). Global and also neighborhood extinction rates of some taxa, particularly microbes, have actually not been well defined. For the many kind of organisms that are symbionts of other organisms, extinction of their hosts deserve to cause their extinction too6. Collectively, these declines and also extinctions are brought about by transforming the Earth’s ecosystems to accomplish flourishing demands for food, fresh water, fibre, hardwood and also fuel, and also by climate change.
Changes in biodiversity have the potential to impact the hazard of transmittable illness expocertain in plants and also animals—consisting of humans—bereason transmittable diseases by definition involve interactions among species. At a minimum, these species encompass a host and also a pathogen; regularly many even more species are involved, including extra hosts, vectors and also other organisms with which these species connect. Intriguingly, biodiversity may play a double function in the introduction and also transmission of infectious diseases. On the one hand, high biodiversity might carry out a bigger potential resource of novel pathogens, however on the other hand also, biodiversity have the right to mitigate even more pathogen transmission for both long-establiburned and also recently emerging conditions. We initially testimonial the impacts of biodiversity on the transmission of establimelted conditions and also then rotate to condition appearance.
Transmission of pathogens in between species
Biodiversity loss could influence illness transmission with a number of mechanisms (Box 1). If the result of each species on pathogen transmission were totally idiosyncratic, one would mean that diversity declines would be equally likely to reason a decrease or an increase in disease transmission in the continuing to be species. However, in recent years, a continuous picture has actually emerged—biodiversity loss has a tendency to rise pathogen transmission and disease incidence. This pattern occurs across eco-friendly devices that vary in form of pathogen, organize, ecomechanism and also transmission mode (Table 1). As an example, West Nile virus is a mosquito-transmitted virus for which several species of passerine birds act as hosts. Three recent research studies detected solid corconnections in between low bird diversity and increased huguy risk or incidence of West Nile encephalitis in the United States7,8,9. Communities with low avian diversity tend to be overcame by species that amplify the virus, inducing high infection prevalence in mosquitoes and also human being, while neighborhoods with high avian diversity contain many type of species that are less skilled hosts. For hantavirus pulmonary syndrome, a directly transmitted zoonotic condition, correlational and also experimental researches have shown that a reduced diversity of tiny mammals rises the pervasiveness of hantaviroffers in their hosts, thereby boosting danger to human beings (Box 2). Diversity has a comparable result for plant illness, with species losses increasing the transmission of two fungal rust pathogens that infect perennial rye grass and also various other plant species10.
Recent attention has focused on assessing the mechanisms through which decreased biodiversity boosts pathogen transmission (Box 1). Biodiversity loss have the right to plainly increase transmission if it reduces predation and competition on reservoir hosts, thereby raising their density. However, debate has centred around whether the loss of species ca rise transmission in various other ways11. This is bereason field research studies choose those on West Nile virus, hantavirsupplies and also rye grass have frequently not controlled for changes in hold thickness that have the right to result from changes in ‘species richness’ (the variety of species present in a neighborhood, which is a measure of taxonomic diversity). As a repercussion, it has actually been challenging to separate the effects of higher density from those of lessened diversity. Recent experiments confirm that rises in condition transmission have the right to occur when species richness declines also if hold thickness stays constant. One of the ideal examples originates from a research of Schistosoma mansoni, a trematode that reasons schistosomiasis in humans. The parasite alternately infects snails and also people by means of free-living contagious stages. Host snails were put in tanks at a constant thickness either alone or through one or two other species of non-host snails and then exposed to the parasite12. In single-species treatments, host snails were 30% more most likely to be infected bereason parasites in multi-species treatments frequently finished up in dead-finish hosts. Increased parasite–hold enrespond to prices resulted in by lessened diversity are enough to rise illness transmission for Schistosoma.
The loss of species ca rise enrespond to rates between pathogens and hosts, as in the Schistosoma example, as soon as the shed species are not hosts for the pathogen. But if the shed species are indeed hosts qualified of transmission, this decreasing diversity could likewise mitigate the total variety of hosts, thereby decreasing transmission if all else continues to be equal13,14. Undoubtedly reductions in the variety of hosts deserve to mitigate the variety of vectors15 and also additionally their infection prevalence16,17, yet empirical examples are fairly rare, in part because the problem has actually been neglected, and likewise bereason all else hardly ever stays equal. For example, the loss of hosts deserve to reason compensatory increases in the abundances of other hosts, such that full organize abundance alters little bit loved one to full organize abundance in more varied communities. Even once full hold abundance does decrease in less varied devices, differences in organize high quality among species can transform simple correlations in between hold abundance and infection risk18.
Pathogen transmission is not always a function of hold density. For example, the variety of transmittable bites ceded by very mobile vectors like mosquitoes deserve to be independent of the thickness of the hold population14. Transmission of straight transmitted pathogens choose hantavirsupplies deserve to likewise be independent of host thickness if transmission entails behavioral encounters, for instance, aggressive interactions in between rodents, and also if the frequency of these encounters does not differ a lot through hold density14,19. In units like these, the loss of organize species deserve to actually rise transmission if the shed hosts are suboptimal for parasite advance and also reproduction; this is bereason these suboptimal hosts absorb pathogens however are poor at transmitting them.
In amount, reducing biodiversity can increase disease transmission once the shed species are either not hosts for the pathogen or are suboptimal ones. For pathogens for which transmission is a role of organize density, loss of diversity is a lot of most likely to increase transmission if the loss causes an increase in the density of proficient hosts. The number and also diversity of examples of pathogens for which species loss leads to increases in total transmission suggests that these problems are generally met (Table 1). More researches in other disease systems would certainly better develop the generality of these relationships.
The loss of biodiversity have the right to influence the transmission of contagious diseases65 by changing:
(1) The abundance of the organize or vector. For plants, seeding experimental fields through plant species that are not hosts for fungal pathogens reduced threefold the pathogen fill of species that are hosts, reportedly by reducing host thickness via competition66. On the other hand also, a higher diversity of host species deserve to occasionally increase pathogen transmission by boosting the abundance of vectors67.
(2) The behaviour of the host, vector or parasite. In a much more varied neighborhood, among the parasitic worms that reasons schistosomiasis (which infects 200 million people worldwide) is even more most likely to finish up in an unsuitable intermediate host. This deserve to minimize the probcapacity of subsequent infection of human beings by 25–99% (ref. 68). For hantavirus in Utah, USA, rodent hosts on even more varied plots are more likely to come in contact with heterocertain mammals and less likely to come in contact via conspecifics, reducing the probcapacity of transmission of the virus55. In principle, better diversity could influence behaviours with a resulting rise in condition transmission65 or might transform the evolutionary dynamics of virulence and transmission pathmethods.
(3) The condition of the hold or vector. In experimental rice areas in China, rice plants in genetically varied mixtures had actually drier leaves bereason the mixture readjusted microclimatic conditions69. As a repercussion, infection with rice blast fungus was much less prevalent in varied areas. Genetically diverse plantings can additionally lead to induced resistance in host plants bereason they are exposed to equivalent pathogens that are experts on the various other cultivars70.
For some illness systems (for instance, Lyme disease), multiple mechanisms run in concert, causing a compounding impact of biodiversity loss on boosted disease transmission (Table 1).
Hantaviroffers are a team of negative-stranded RNA virsupplies connected via murid rodents. They deserve to reason significant morbidity and also mortality in people, via case-fatality prices close to 40% (ref. 71). Infected rodents melted hantavirus in saliva, urine and also faeces; transmission to humans occurs via inhalation of aerosolized excreta and with rodent bites72. The danger of huguy expocertain boosts as the thickness and also infection pervasiveness of rodent reservoirs increase72.
In a field study in Oregon, USA, the only variable significantly attached to infection pervasiveness in deer mouse host populaces was mammalian species diversity, through the prevalence of the hantavirus Sin Nombre virus climbing from 2% to 14% as diversity decreased. Deer computer mouse populace thickness was not statistically associated through Sin Nombre virus infection prevalence, saying that high diversity lessened intraspecific encounters rather than hold abundance56. A research in Utah, USA55, additionally uncovered a negative correlation between small-mammal diversity and Sin Nombre virus infection prevalence in deer mice. As in Oregon, high diversity lessened infection prevalence supposedly by reducing intraparticular encounters fairly than by reducing hold thickness, a result sustained by experiments19.
The conclusions of these researches were supported by an speculative research of hantaviruses in little mammal neighborhoods of Panamá23. In replicated plots, small-mammal diversity was reduced by trapping and removing species that are not hosts for the virus; infection pervasiveness in hosts was compared on manipulated and unmanipulated plots (Box 2 figure). Experimentally decreased small-mammal diversity brought about a rise in the thickness of hold species and also also in seroconversion rates and also seropervasiveness within hosts (Box 2 figure).
Species diversity versus species identityThe loss of certain species in a area clearly has the potential to increase condition transmission. But does reducing diversity itself rise transmission, or is increased transmission the consequence of the removal of specific species? The answer depends on exactly how species composition transforms as richness changes20,21. For example, if those hold species the majority of responsible for amplifying the pathogen tend to persist or also flourish as biodiversity is shed, then illness danger will certainly repetitively increase as biodiversity declines. On the other hand, if amplifying species tfinish to disappear as biodiversity declines, then biodiversity loss will tend to alleviate disease risk. These hypothetical possibilities suggest the prestige of understanding both the non-random sequences by which species are shed from areas, and also whether the species that tend to occur just in even more species-well-off areas tfinish to amplify or buffer pathogen transmission.
In several situation researches, the species a lot of likely to be shed from ecological communities as diversity declines are those the majority of likely to minimize pathogen transmission. In the Lyme condition mechanism of eastern The United States and Canada, for example, the white-footed computer mouse is concurrently the a lot of numerous host species, the many experienced host for the Lyme bacterium, and also the highest-top quality host for immature tick vectors18 (Fig. 1). As a repercussion, this hold species infects a high propercentage of the ticks within woodland communities. The white-footed computer mouse is also an ecologically sturdy species, present in both species-wealthy and species-poor communities22. In contrast, Virginia opossums are bad hosts for the pathogen, kill the vast majority of ticks that attempt to feed on them, and also are absent from many type of low-diversity woodland pieces and also degraded forests wbelow mice are abundant18,22. Because of this, as biodiversity is shed, the host via a strong buffering effect—the opossum—disshows up, while the host via a solid amplifying effect—the mouse—stays. The major hosts for the pathogens that reason West Nile encephalitis, hantavirus pulmonary syndrome, and also bartonellosis also appear to be long lasting species that rise in abundance as biodiversity is lost7,23,24.
Lyme disease is transmitted to humans by the bite of an infected blacklegged tick (Ixodes scapularis). Immature ticks have the right to get the infection if they feed on an infected host and also deserve to end up being transmittable to human beings if they subsequently survive to the following life phase. White-footed mice are abundant in northeastern forests and feed many kind of ticks18. Ticks that attempt to feed on Virginia opossums are likely to be groomed off and eliminated. Green-and-yellow circles display the suppose variety of ticks per hectare fed by mice or opossums; yellow shading reflects the propercentage of ticks infected after feeding. Blue circles display the suppose variety of ticks per hectare groomed off and also killed. Ticks that feed on mice are highly most likely to become infected with the bacterium that causes Lyme disease, whereas those that feed on opossums are not.
Whether an organism’s hold competence and its resilience to factors that mitigate biodiversity are causally connected is an unreresolved but critical concern. Traits that make a organize durable to biodiversity loss might likewise make them vulnerable to pathogen infection and transmission. Such a connection would certainly describe the frequency via which the attach in between diversity loss and illness transmission has actually been observed in lutz-heilmann.info (Table 1). For plants, species that are fast-thriving and nutrient-well-off through relatively high metabolic rates—attributes of ‘weedy’ species—have the right to be even more experienced hosts for arthropod vectors and also plant pathogens than those via less weedy traits25. Plants through these weedy traits are additionally more likely to end up being more abundant as soon as plant diversity declines26. Consequently, the exceptionally species that have actually traits permitting persistence in degraded and also species-poor ecounits are additionally more likely to lug high pathogen and also vector burdens. A comparable pattern may happen in vertebrates—resilience in the confront of disturbances that cause biodiversity loss, such as habitat destruction and fragmentation, is assisted in by life-history attributes such as high refertile output and also intrinsic prices of increase27. Vertebrates with these features tfinish to invest minimally in some aspects of adaptive immunity28,29,30; we hypothesize that this may make them more competent hosts for pathogens and also vectors. Understanding the interrelationships among pathogen transmission, biodiversity loss and also interparticular distinctions in immune feature is an essential location for future research study. Such researches would illuminate just how frequently sturdy species are also those that increase pathogen transmission, and also can administer basic rules about the affect of biodiversity loss on condition transmission.
Diversity within individual hosts
Could alters in biodiversity within the bodies of organisms additionally change pathogen transmission? Recent renovations in the capacity of researchers to detect unculturable microbial species have allowed documentation of the tremendous diversity of microbes upon and also within plants and pets. In huguy bodies, for instance, 90% of all cells are microbial31. A number of research studies have actually begun to display web links in between diseases and also the diversity of an organism’s ‘microbiome’.
Changes in the composition of microbiomes are generally connected with infection and also disease. For example, corals suffering from white plague illness have microbial communities distinctly various from those in healthy corals32. In humans, bacterial vaginosis results from changes in the composition of the vaginal microbial community33, and also this consequently boosts the threat of HIV infection34. Although changes in microbial species composition connected with infection are well-recorded, few researches have actually investigated the effects of changes in diversity itself. In a current investigation, patients with reexisting episodes of infection caused by the bacterium Clostridium difficile had actually considerably reduced diversity of intestinal microbes than did control patients35. Correlational research studies such as these, though intriguing, make it difficult to determine whether transforms in microbial neighborhoods are the cause or the consequence of infections. But some speculative studies clearly show that boosting microbial biodiversity have the right to safeguard versus infection. For example, kids through a history of ear infections given a mixture of 5 strains of Streptococcus were less likely to build subsequent infections compared to a control group36. Similarly, reducing microbial diversity within a hold can increase transmission. When mice through persistent infections of C. difficile were treated with antibiotics that decreased the diversity of intestinal microbes, they started shedding C. difficile spores at high rates37.
In some of these examples, a affluent microbial neighborhood appears to control the abundance of endemic microbial species that have the right to become pathogenic once overly abundant35. In various other instances, high microbial species diversity can proccasion colonization by invasive pathogenic species. For example, the more varied the microbiome surrounding the roots of wheat plants, the even more safeguarded the plants were against intrusion by the pathogenic bacterium Pseudomonas aeruginosa38. Similarly, pigallows elevated in organic environments sustaining a high diversity of microbes were even more resistant to intrusion by pathogenic gut microbes than those elevated in more sterile environments39.
The effects of microbial diversity within and also upon organize bodies present intriguing similarities to the effects of macroscopic species diversity on illness transmission in aquatic and also terrestrial ecosystems. Additional exploration of these similarities, and especially the particular mechanisms operating within hosts, is an important research study frontier because alters in microbial diversity might acagency biodiversity loss in their hosts.
For pathogens already establimelted within eco-friendly communities, we have shown that biodiversity loss typically rises the price of transmission. But what function, if any kind of, does biodiversity have in the procedures by which new pathogens emerge? Between 1940 and also 2004, over 300 emerging illness occasions were determined in human beings roughly the world40. Concomitantly, other emerging contagious diseases also showed up in wildlife, trained animals, and chop and wild plants. Emerging transmittable diseases encompass those in which the pathogen has actually progressed into a new strain within the same organize species, for instance, through the development of drug resistance (methicillin-resistant Staphylococcus aureus or MRSA) or switched to new hold species (for instance, humale immunodeficiency virus or HIV, major acute respiratory syndrome or SARS). In some situations, the switch to new organize species is accompanied by a readjust in geographical selection (for instance, West Nile virus in the Americas).
For pathogens that establish in brand-new species, the introduction process involves multiple measures, including the initial intrusion into the brand-new organize (‘spillover’), the production of transmission steras within the brand-new organize, and also the establishment of the pathogen in the organize populace as a whole41,42. The impact of biodiversity might differ for each of these measures. For the initial intrusion, biodiversity may act as a source pool. This hypothesis is sustained by surveys of arising conditions of humans: a lot of are zoonotic—jumping to human beings from other vertebrate animals43. In one recent analysis, the probcapacity of emergence of pathogens from wildlife to humans was positively associated with mammalian wildlife species richness when data were corrected for reporting bias40. Other eco-friendly and also sociofinancial factors that carry humans into closer call with perhaps new pathogens (for instance, woodland clearing for farming, wildlife hunting) may also add to this pattern. Indeed, virtually fifty percent of the zoonotic illness that have arised in human beings because 1940 resulted from transforms in land also usage, from changes in agricultural or other food manufacturing techniques, or from wildlife hunting (Fig. 2). These huguy tasks increase rates of call in between human beings and also animals, which may be a crucial factor underlying spillover.
Figure 2: Drivers and also areas of introduction occasions for zoonotic infectious illness in human beings from 1940–2005.
a, Worldwide percentage of emergence events caused by each driver; b, Countries in which the emergence occasions took place, and also the chauffeurs of development. The dimension of the circle represents the variety of development events: for scale, the variety of occasions in the United States was 59. Globally, almost fifty percent of these diseases resulted from changes in land usage, transforms in farming and also other food manufacturing practices, or through wildlife hunting, which suggests that call rates in between people and various other pets are an essential underlying cause of zoonotic illness emergence. ‘Other’ includes global take a trip and also commerce, alters in human demographics and behaviour, alters in the clinical industry, climate and also weather, breakdvery own of public wellness steps, and also unmentioned causes. Analysed from data in ref. 40.
Once spillover of the pathogen right into a brand-new host has actually arisen, high densities of that host species might facilitate pathogen establishment and transmission within the brand-new host41. For example, Nipah virus spilled over from wild fruit bats to residential pigs in Malaysia; high densities of pigs in local ranches show up to have actually promoted establishment of pig-to-pig transmission, and the pathogen then spilled over from pigs to humans44. Such high densities of domesticated species are virtually always connected through low biodiversity.
In comparison to development with host-switching, 20% of development events in between 1940 and 2004 arose with the advancement of drug resistance40. For these situations, biodiversity of microbial areas within hosts might have a protective effect; humale use of antibiotics is thmust select for resistant microbes by eliminating the good diversity of non-resistant microbial strains and also species that suppush resistant strains in the lack of antibiotics. Investigations using recent advancements in microbial detection support this idea45,46. Therefore, diminished microbial diversity may be an important underlying reason of the development of drug-resistant pathogens; this as well requires further examination.
The addition of certain species—for example, natural opponents or competitors—deserve to alleviate the effects of establimelted pathogens. For example, experimental enhancement of a naturally emerging bacterium, Janthinobacterium lividum, to the skin of the endangered frog Rana mucosa eliminated frog mortality from experimental infection through chytridiomycosis, which is terrible amphibian populaces worldwide47. For corals, application of phperiods isolated from organic neighborhoods can manage the spread of bacterial infections48. The growing interest in ‘probiotics’ for people and also harvested species offers one more example of this approach49.
More generally, biodiversity itself appears to protect organisms, including people, from transmission of infectious illness in many type of instances (Table 1). Preserving biodiversity in these cases, and maybe generally, may alleviate the incidence of establiburned pathogens. To maintain high diversity in lutz-heilmann.info, conservation scientists have developed robust approaches that reflect the crucial principle that bigger locations sustain bigger numbers of species50. Methods of conserving microbial diversity within and also upon bodies or in the setting are less well occurred, however avoiding the overusage of antimicrobial compounds is crucial. Critically, future research study on the relationship between biodiversity and also condition need to prevent conflating the results of biogeographic patterns of biodiversity (for example, greater diversity in lower latitudes) via those of anthropogenic reductions in extant biodiversity, bereason policy and management alternatives have the right to far more readily affect the latter than the previous.
For arising diseases, the observation that a much more diverse microbiome within a host suppresses strains that are resistant to antimicrobial compounds suggests that avoiding the over-use of these compounds in medication and farming have the right to proccasion the emergence of resistant strains. For pathogens that arise by switching organize species, 3 administration viewpoints are warranted. First, potential development ‘hotspots’ could be predictable on the basis of land-use change and also underlying biodiversity patterns; these locations should be targeted for surveillance of endemic wildlife pathogens that have the potential to jump hold species40,51. 2nd, keeping and protecting intact habitats in these hotspots provides a straightforward, direct method of reducing human–animal contact and reduces the likelihood of introduction of brand-new pathogens, although techniques for achieving lessened contact are not constantly straightforward51. And 3rd, to reduce the probability that pathogens come to be establiburned and transmissible within a brand-new organize population as soon as spillover occurs, the husbandry of high-density monosocieties of residential animals, particularly in areas at high danger of spillover, have to be subject both to even more intensive monitoring and to steps that minimize contact in between wildlife and livestock. Managing potential appearance hotspots by attempting to eliminate them is most likely to backfire bereason the species many long lasting to habitat destruction and destruction might be those that amplify pathogen transmission.
Despite many type of current advancements in our understanding of biodiversity and also condition, a lot stays to be learned. First, we need to increase the variety of condition devices for which we understand the effects of biodiversity loss on disease transmission across a selection of spatial and also tempdental scales. We must likewise emphasis on just how to implement certain plans informed by this scientific research. Future research study, for instance, should monitor transforms in public health in areas in which conservation measures are enforced compared to recommendation sites. A significant obstacle will be to untangle the complex methods in which other international anthropogenic trends—such as climate change, biotic exreadjust, nutrient pollution, armed dispute and financial collapse—communicate via biodiversity loss to affect disease dynamics, and also which of these patterns have the best impacts upon humale health. Regardless of continuing to be concerns, connections in between biodiversity and disease are currently sufficiently clear to rise the urgency of local, regional, and also global efforts to preserve organic ecosystems and the biodiversity they contain.
Marris, E. New UN science body to monitor biosphere. lutz-heilmann.info 10.1038/news.2010.297 (2010)25
Cronin, J. P., Welsh, M. E., Dekkers, M. G., Abercrombie, S. T. & Mitchell, C. E. Host physiological phenoform explains pathogen reservoir potential. Ecol. Lett. 10.1111/j.1461–0248.2010.01513.x (2010)71
CDC. Hantavirus pulmonary syndrome in 5 pediatric patients—4 states, 2009. Morbidity Mortality Week. Rep. 58, 1409–1412 (2009)
We acunderstanding the assistance of the joint NSF-NIH Ecology of Infectious Disease programme and the EPA Biodiversity and also Person Health programme. M. Gillespie provided help in the preparation of the manuscript.
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Department of Biology, Bard College, Annandale, 12504, New York, USA
Department of Biological Sciences, Virginia Tech, Blacksburg, 24061, Virginia, USA
Lisa K. Belden
EcoHealth Alliance, New York, 10001, New York, USA
Peter Daszak & Tiffany kind of Bogich
EEB, Eno Hall, Princeton University, Princeton, 08544-3417, New Jersey, USA
Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, 14853, New York, USA
C. Drew Harvell
Department of Biology, College of Florida, Gainesville, 32611, Florida, USA
Robert D. Holt
Center for Infectious Disease Dynamics, Pennsylvania State University, College Station, 16802, Pennsylvania, USA
College of Veterinary Medicine, Oregon State University, Corvallis, 97331-4801, Oregon, USA
Institute of Zoology, Zoological Society of London, London, NW1 4RY, UK
Kate E. Jones
Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, 27599, North Carolina, USA
Charles E. Mitchell
Harvard Medical School, Harvard University, Cambridge, 02138, Massachusetts, USA
Samuel S. Myers
Cary Institute of Ecosystem Studies, Millbrook, 12545, New York, USA
Richard S. Ostfeld
F.K. and R.S.O. conceived the evaluation. F.K., L.K.B., P.D., A.D., C.D.H., R.D.H., P.H., A.J., K.E.J., C.E.M., S.S.M. and also R.S.O. composed and edited the text. T.B. prepared Fig. 2.