Environews Focus

Environmental Health Perspectives • VOLUME 111 | NUMBER 10 | August 2003 A 525

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Focus | Conservation Medicine

A third-grader can figure out

the easy labels: someone

who practices biology is a biologist;

ecology, an ecologist. But what do you

call a practitioner in the fledgling field of

conservation medicine? “I don’t know,” says

Peter Daszak, executive director of the

Palisades, New York–based Consortium for

Conservation Medicine, laughing at yet

another small hurdle for his new field. “A con-

servation medic?”

Creating nomenclature for the field is just

one of many challenges facing conservation

medicine, which is attempting to pull togeth-

er human health, animal health, and ecosys-

tem health—three fields that are tough

enough on their own in terms of complexity,

lack of data, and other factors. Conservation

medicine—or ecological medicine, or medical

geology, or whatever it may be called by vari-

ous advocates—is rushing headlong against a

decades-long trend of specialization in medi-

cine and the sciences. And many of the essen-

tial data needed to rigorously establish the

links between environmental factors, sick

wildlife, and sick people just don’t exist yet.

Conservation

Combining the Bestof All Worlds

Medicine

However, in the past few decades, agrowing number of professionals havebeen noticing the links between illness—in both humans and wildlife—and ecosys-tem impacts including toxic emissions,land clearing, international travel, and cli-mate changes. One result of these impacts,say conservation medicine advocates, hasbeen the spate of emerging diseases associ-ated with now-familiar names such asLyme, Ebola, Marburg, Pfiesteria,and Cryptosporidium.

Emerging diseases suchas Rift Valley fever, han-tavirus pulmonary syn-drome, Nipah virusencephalitis, severe acuterespiratory syndrome(SARS), HIV, and WestNile virus infection havebecome notorious. Alsoof concern are lesser-known emerging diseasessuch as fibropapillomatosis, amarine turtle disease asso-ciated with heavily pollut-ed coastal areas thatmany suspect could bean indicator portendinghuman health prob-lems. Other researchersare just as concernedabout the pervasive effectsof endocrine disruptors, theinternational airborne spreadof dust, bacteria, and viruses, andthe environmental consequences ofthrongs of well-intentioned ecotourists vis-iting the wild.

All the evidence suggesting strong con-nections between human health, wildlifehealth, and ecosystem health has whettedthe appetite for hundreds of people toedge into conservation medicine. Andwith more than 30 emerging diseases inhumans making headlines in the past threedecades, advocates say even more peopleare becoming interested in the field, par-ticularly the human health angle.“Everybody understands [human health],”says Mary Pearl, president of the nonprof-it conservation organization WildlifeTrust and a primary catalyst behind theconsortium, which is housed in WildlifeTrust offices. “You don’t want to get sick,or have your family get sick.”

What’s in a Name?The general concept of looking at the linksbetween sickness in the environment,wildlife, and people is centuries old. Asrecently as the 19th century, health carepractitioners were expected to have trainingin both the medical and natural sciences.

But as 20th century science unveiled anincreasingly complex world and specializa-tion became the norm, those connectionshave become murky. “Some physicians lookat you with a blank stare when you mentionmercury and other environmental issues,”says Ted Schettler, a physician and sciencedirector for the Science and EnvironmentalHealth Network (SEHN), an Ames,Iowa–based advocacy organization.

But individual disease, pollution, andenvironmental disruption scenarios havebegun to merge in the minds of a few peo-ple. To begin to capture the conceptsbehind the potential linkages, the term“conservation medicine” was first floatedin a 1996 article, “Wildlife, People, andDevelopment,” in the journal TropicalAnimal Health and Production. Picking upon that and other threads, Pearl, alongwith Tufts University’s David Sherman(then an associate professor of environ-mental and population health) and MarkPokras (director of the Center forConservation Medicine at the TuftsSchool of Veterinary Medicine), pushedfor an organization that would cover thefields of both animal and ecosystem

health. The human health element wasadded later, says Pokras.

The end result was the Consortium forConservation Medicine. Consortium part-ners include Wildlife Trust, the TuftsCenter for Conservation Medicine, theU.S. Geological Survey (USGS) NationalWildlife Health Center, the HarvardMedical School Center for Health and theGlobal Environment, and the BloombergSchool of Public Health of The JohnsHopkins University. The nonprofit con-sortium advocates for and conducts

research, develops interdisciplinaryeducation and training programs,

informs policy makers, andis trying to formulate prag-

matic solutions to conser-vation medicine–relatedproblems identified todate. Individuals canjoin, and about 25 havedone so.

After much ponder-ing over what to callthis new field, the con-sortium adopted the

term “conservation medi-cine.” But it isn’t married

to the term, says AlonsoAguirre, director for conserva-

tion medicine at Wildlife Trustand senior editor of the first book

covering the issue, ConservationMedicine: Ecological Health in Practice,published in October 2002.

Schettler isn’t sold on the term “con-servation medicine.” “The word ‘conser-vation’ carries a lot of historical baggage,”he says. Over the past century, the termhas been widely used in arenas such aswildlife management, drinking water pro-tection, and environmental advocacy.Schettler prefers SEHN’s adopted term“ecological medicine,” but concedes that“we probably are talking about mostly thesame thing.”

A third term being used is “medical geol-ogy.” One of medical geology’s primaryadvocates, USGS research chemist RobertFinkelman, says the field covers human andwildlife health issues linked with either geo-logical processes or the tools that geoscien-tists use, such as satellites and subsurfacemonitors. However, Finkelman acknowl-edges that some of the several hundred peo-ple who are becoming medical geologyadherents don’t like adding the twist aboutthe tools of the trade, charging that thisaddition may dilute the field. Some propo-nents would prefer to deal only with naturalgeological processes, not human-inducedlinkages. But a 2003 book about the field,Geology and Health: Closing the Gap, edited

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Focus | Conservation Medicine

Fibropapillomatosis, a marine turtle

disease associated with heavily

polluted coastal areas, could be an

indicator portending human health

problems.

Environmental Health Perspectives • VOLUME 111 | NUMBER 10 | August 2003 A 527

by geologists H. Catherine W. Skinner andAntony R. Berger, covers all these angles.

A loosely organized Madison, Wis-consin, group has solved the problem forthe moment by calling itself theConservation Health Consortium. Thisgroup performs some functions similar tothose of the Consortium for ConservationMedicine, such as education and research,but is local and regional in focus. One of itsmembers, veterinary medical officer JoshuaDein of the USGS National WildlifeHealth Center, says the term “health”seemed to cover a broader spectrumthan “medicine,” which in a strictsense is associated solely withphysician-related activities.

Including an even broad-er spectrum than the tripar-tite environmental health(with its largely humanfocus), wildlife health,and ecosystem healthmight help create betterterminology, says AndrewBrown, associate dean forplanning and develop-ment at the University ofTexas School of PublicHealth in Houston. He wouldadd sociology, economics, andpolitics to the mix, because thosedisciplines prominently influence andare influenced by human behavior, andhuman behavior shapes our environment,which then shapes our health. “What’sneeded is a science of sustainability,” hesays. “‘Sustainability’ is just another wordfor health.”

“Whatever term is used, please just tryto work together,” Aguirre urges. Andthere should be plenty of work to goaround. “Once you grab hold of the con-cept, there are almost too many things todo,” Dein says.

Suspicious ScenariosOne of the first hurdles in the field is todefine what is meant by health in people,in wildlife, and in ecosystems. In people,one broad definition adopted by the WorldHealth Organization is “a state of completephysical, mental, and social well-being andnot merely the absence of disease and infir-mity,” notes Conservation Medicine. That’sa tall order, but given current knowledge,at least there are some ways to measurehealth in those terms in people. Forwildlife, vast portions of the data for deter-mining what a healthy porpoise, snail, oreagle should look like are missing. And theproblem becomes even more complexwhen looking at all the possible perturba-tions of a constantly fluctuating ecosystem.

But some health impacts are obvious, atleast in people and wildlife. Two of thoseimpacts are death and acute harm causedby infectious diseases. People are vulnera-ble to at least 1,415 species of infectiousorganisms, concluded Louise Taylor andothers from the U.K. Centre for TropicalVeterinary Medicine in the 29 July 2001issue of Philosophical Transactions:Biological Sciences. Those organisms, more

than 60% of which can be transmittedbetween people and other animals, areresponsible for about one-quarter of theworld’s deaths. About 175 of the species arelinked with emerging diseases that areappearing in people for the first time or areincreasing substantially in incidence orgeographic occurrence. Included under the“emerging” label, along with others alreadymentioned, are infection with avianinfluenza A strains H5N1 and H9N2,Hendra virus disease, East and WestAfrican trypanosomiasis (sleeping sick-ness), Escherichia coli O157:H7 infection,and monkeypox.

According to Conservation Medicine,there are at least 63 emerging diseases amongmarine creatures, such as campylobacteriosis

in New Zealand sea lions, tuberculosis in furseals, chlamydiosis in sea turtles and somemarine mammals, and herpes in northernfur seals and other animals. In terrestrialwildlife, dozens of diseases have come to thefore in the past few decades, includingcanine distemper, a virally caused kangarooblindness, ranavirus infection in amphibians,and mycoplasmal conjunctivitis in somebirds. Plants have suffered their own emerg-

ing diseases, such as chestnut blight,dogwood anthracnose, and sud-

den oak death syndrome.Conservation medicine

advocates and some otherscientists, politicians, andactivists blame a range offactors for the world-wide disease increases.Chief among them are

human population growthand its sequelae: continued

encroachment of humansinto relatively undeveloped

land, biodiversity loss, andpoverty. Also contributingare behavioral changeslarge and small, such assubstantial alterationsinternationally in thefood and livestock indus-

tries and increased con-sumption of bushmeat in

Africa (this practice, againspurred by pressures such as

population growth and diminishedfood supply, contributes to disease largely

through blood contact during butchering).More than 2 million people cross interna-tional borders every day, along with untoldquantities of agricultural products, live ani-mals, plants, topsoil, ballast water—andpathogens. For a variety of reasons, includ-ing flat or diminishing funding, there hasalso been a significant drop-off in govern-ment public health capacity. Other factorsinclude climate change and microbial adap-tation (pathogens jumping from wildlife tohumans, as in the case of monkeypox).

With emerging diseases such as SARS,major sociological, economic, and politicalfallout can occur on a much broader scale.It’s still too early to evaluate the full impactof the SARS outbreak, but the costs ofother emerging diseases have already beenexamined. The Maryland Sea Grant pro-gram estimated that the combined lossesto tourism, seafood, and other industriesfrom a summer 1997 Pfiesteria piscicidaoutbreak cost that state nearly $50 mil-lion. Economies can shrink by billions ofdollars when trade and travel to affectedareas slow to a crawl, and local govern-ments have to contend with panic, evenC

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nFocus | Conservation Medicine

I ncreased consumption of bushmeat

in Africa, spurred by pressures such

as population growth and diminished

food supply, contributed to the spread

of HIV from chimpanzees to humans.

riots, as residents try to cope with anunknown new villain.

Ultimately, says Schettler, the field willneed to be practiced and not just described.“We could spend many decades deciding tostudy certain phenomena in a cross-disci-plinary way,” he says, “but from the stand-point of health or medicine, there will needto be debate and decisions aboutwhat to do with the informa-tion. My fear is that thisentire area will fail to rec-ognize that ecologicalanalyses are and willalways be characterizedby fundamental uncer-tainties because of thecomplexity of the sys-tems being studied, andthat the practice of ecolog-ical medicine will never takehold because people will al-ways want more research.”

Grabbing the Bullby the HornsMany individual prob-lems relevant to conser-vation medicine havebeen identified. Butfinding appropriate solu-tions will be difficult. Onebasic pitfall is that humansenses and memory just aren’tdesigned to readily detect or recall thesubtle climate, land use, behavioral, andpolitical changes that evolve over a fewdecades, says Brown. Problems becomeapparent with a crisis, but then it is oftentoo late to prevent much of the damage,and affected governments may try todownplay or conceal problems, fearingeconomic or political repercussions. Untila crisis does occur, politicians usuallydon’t allocate much money toward a prob-lem. “We [humans] are a reactive society,but it costs a lot more than being proac-tive,” says Daszak.

But with conservation medicine–relat-ed crises becoming more common anddirectly affecting tens of millions of peo-ple worldwide, the major economic andhealth consequences are grabbing theattention of governments and the generalpublic. Funding for conservation medi-cine projects is still tiny, but is beginningto increase. There have been substantialresponses to recent funding competitionsrun by the NIH and the National ScienceFoundation (NSF) for studies on topicsincluding the ecology of emerging infec-tious diseases—one major focus of con-servation medicine. “We got an enormous

number of applications,” says JoshuaRosenthal, deputy director of the Divisionof International Training and Research atthe John E. Fogarty International Center,a branch of the NIH. “We tapped a nerveout there.”

The funding for these competitionshas jumped from about $4 million in the

beginning to about $13 million each forfiscal years 2003 and 2004, says SamuelScheiner, program director for the NSFDivision of Environmental Biology. Thecompetitions are designed to investigateproblems that Scheiner says “had fallenbetween the cracks” of previous NIH andNSF efforts—current winners are inves-tigating issues such as bat-transmitteddiseases in Malaysia and canine distem-per in dogs, lions, and other mammals inEast Africa’s Serengeti region. The proj-ects have drawn about 55–75 competi-tors each year for 10–12 awards,although diminished NIH funding fornew projects means only about 7–8awards will be available in the future.The competition is scheduled to run forat least three more years.

Awards for another competition thatadds economic development issues to thehuman–wildlife–environment mix areexpected to be announced in the fall of2003, Rosenthal says. Planning grants ofa little under $1 million, funded largelyby the NIH with some potential contri-butions from the NSF and the USGS,will be converted into research grants fol-lowing another competition in abouttwo years.

The USGS has paid more atten-tion to conservation medicine

issues in the past few years,says Dein, although the con-

cept is still not well-recog-nized. General interestwas heightened by theonset and rapid spreadin the United States ofWest Nile virus, whichhas been documentedin about 85% of thestates and now infectspeople as well as about

230 bird, mammal, andreptile species.

There is no line item inthe USGS fiscal year 2004

budget for conservation medi-cine, Dein says, but programs such

as the new Wildlife Disease InformationNode—part of the USGS NationalBiological Information Infrastructure—can be considered to fall under the con-servation medicine umbrella. The infor-mation node is an online national track-ing system for problems such as harmfulalgal blooms and chronic wasting disease(an animal disease suspected of being ableto cross to humans), for most of whichthere have been few national data.

In another effort, the USGS is begin-ning to look at wildlife disease sentinels, atopic also being pursued by Aguirre. He isinvestigating species such as manatees,dolphins, oysters, and clams to see if fac-tors that affect their health can accuratelybe extrapolated to predict human healthimpacts.

Private veterinary hospitals also canplay a role in building the database by col-lecting and reporting data on animal dis-eases, says Jonathan Sleeman, director ofveterinary services at the Wildlife Centerof Virginia in Waynesboro. However, inorder to make the data credible, heacknowledges that the data gatherers willneed to adopt standardized practices.

At the university level, interested pro-fessionals have developed curricula atinstitutions such as Harvard, JohnsHopkins, the Tufts School of Veterinary

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Focus | Conservation Medicine

Desertification caused by overgra-

zing and deforestation creates a

loss of habitat for animals and ex-

acerbates shortages of fuel, shelter,

and water for people.

Environmental Health Perspectives • VOLUME 111 | NUMBER 10 | August 2003 A 529

Medicine, the London School of Hygieneand Tropical Medicine, and Canada’sUniversity of Western Ontario. Harvardhas even exported the contents of oneclass, Global Environmental Change andHuman Health, to 44 other medicalschools, colleges, and universities, andmade it available free on its website, saysEric Chivian, director of the HarvardMedical School Center for Health andthe Global Environment. Jonathan Patz,director of the Program on Health Effectsof Global Environmental Change atJohns Hopkins, says that school, in part-nership with the Consortium forConservation Medicine, also hopes tobegin a special Ph.D. training track inglobal environmental health this fall.

In addition, numerous conferencesheld around the world in 2003 by variousgroups have incorporated conservationmedicine–related sessions. At least fourhave been geared at a wide range of atten-dees: Natural Science and HumanHealth: Prescription for a BetterEnvironment (held April 1–3), theInternational Forum on EcosystemApproaches to Human Health (held May18–23), the Chapman Conference onEcosystem Interactions with Land UseChange (held June 14–18), and the 5thOpen Meeting of the HumanDimensions of Global EnvironmentalChange Research Community (scheduledfor October 16–18). And to reach out toyounger generations about conservationmedicine, Patz has led an effort to createa Johns Hopkins website directed at mid-dle school children, with sections on cli-mate change, biodiversity, food and waterscarcity, and other topics coming onlinethroughout 2003.

People outside the traditional educa-tional channels are also being exposed tothe idea of conservation medicine.Chivian’s team at Harvard annually holdssymposia for U.S. congressional stafffrom across the political spectrum on var-ious conservation medicine issues, reach-ing about 120–140 people over the pastfive years.

The Next WaveDespite the tentative nature of the field,many related efforts are under way.Public health networks are slowly begin-ning to rebuild following the terroristattacks in the United States in 2001.Improvements in those networks—enhanced communication, better recog-nition of the need for interdisciplinarywork, and increased willingness to sharedata—were instrumental in the rapid

identification of the coronavirus respon-sible for SARS. U.S. agencies such as theCenters for Disease Control andPrevention and the USGS continue toexpand their disease and pollution moni-toring programs, and the NationalAeronautics and Space Administration isusing its satellite equipment to greatlyexpand knowledge of worldwide pollu-tion circulation patterns [see “MODISOperandi for Mapping Haze,” EHP111:A458 (2003)].

The United Nations, the World Bank,the World Resources Institute, and otherorganizations anticipate that their study,the Millennium Ecosystem Assessment,should add much more knowledge to thefield. This study is being conducted bymore than 500 natural and social scientistsfrom 70 countries, with results scheduledto be released over two years beginning inSeptember 2003. The assessment will pro-vide what the World Resources Institutecalled in a 5 June 2003 press release “themost extensive study ever of the linkagesbetween the world’s ecosystems andhuman well-being.”

A predecessor to the MillenniumEcosystem Assessment known as the PilotAnalysis of Global Ecosystems was com-pleted in late 2000. But it received littleattention, in part because the pilot analysiswas developed by a relatively narrow rangeof participants and did not have widerecognition in the scientific community[see “Where Do We Stand? GlobalEcosystem Assessments Ask the BigQuestion,” EHP 109:A588–A592 (2001)].Organizers of the Millennium EcosystemAssessment have tried to eliminate thisproblem by involving hundreds of scien-tists, though there is still a risk that thefinal reports will gather dust on shelves,especially if the problems appear over-whelming, costs and benefits are unclearor perceived as inaccurately assessed, orremedies require extensive social changes.

Small studies whose researchers maynot put themselves under the conserva-tion medicine umbrella are also develop-ing applicable findings. In a study ofIsrael’s heavily polluted Kishon River,researchers reported in the April 2003issue of EHP that wildlife declines thatbegan in the 1950s, following develop-ment of many nearby industries, were akey predictor of subsequent high cancerrates in naval divers who used the water-way extensively in ensuing decades.

As interest in wildlife monitoringgrows, new noninvasive techniques areunder development to make the job easierand more accurate. In the case of gorillas,

Michele Goldsmith, an assistant profes-sor with the Tufts Center for Con-servation Medicine who has been study-ing mountain gorillas in Uganda forseveral years, says such techniques caninclude fecal analysis to evaluate bothdiet- and stress-related hormones. Othereffective strategies include hair analysisand hiring locals to discreetly track theanimals, she says.

To help expand conservation medi-cine efforts across the world, WildlifeTrust and the Consortium forConservation Medicine have plans forcooperative ventures in Australia,Mexico, Brazil, Chile, Venezuela, India,and Indonesia. Finkelman says a group ofhis colleagues, now operating as theSpecial Initiative on Medical Geology,have plans to set up medical geology cen-ters in China, South Africa, SouthAmerica, Eastern Europe, India, and theMiddle East during the next 10–15 years.These centers will conduct research andmonitoring to gather data more on a parwith what is available in the UnitedStates, with one aim being to build alinked system that could provide earlywarning of impending problems. Thegroup also hopes to set up a professionalsociety at some point, and will expand itseducational efforts with the publicationof a second book, Medical Geology, at theend of 2003.

The Consortium for ConservationMedicine, the International Society forEcosystem Health, and five other groupsare supporting the launch of a new jour-nal, Ecology & Health, scheduled to startup in early 2004, and Daszak says thatthoughts of accreditation and a profes-sional society are bubbling about. Theconsortium’s annual funding of about $1million has been on the rise since itsfounding, and is transitioning from itsprivate base to more government support,which now accounts for about 30% ofthe total.

Pokras points to the need not just forfocusing on scientific issues critical toconservation medicine but also for train-ing what he calls a new kind of student—“people who can bridge disciplines andcreate those fertile links that we reallyneed for tomorrow’s creative problemsolving.” Whether they end up beingcalled conservation medics, medical geol-ogists, or some other term remains to beseen. But, says Patz, “We all know whatwe’re referring to. There’s definitely amovement afoot.”

Bob Weinhold

Focus | Conservation Medicine