OCW Zoological Medicine 2008
Conservation Medicine in Practice (2009)
M. Pokras, DVM
Cummings School of Veterinary Medicine at Tufts University
1. Conservation Medicine in Practice – why veterinary medicine belongs
1.1. Focus on Ecosystem Health
1.1.1. How do we define health?
Absence of disease
Having the capability to achieve one's fullest potential
Some three decades before the Rio Summit ('92), human health was defined by the World Health Organization as, "...a complete state of physical, mental and social well-being, and not merely the absence of disease or infirmity." Therefore, the metaphorical concept of ecosystem health must incorporate the dynamic interrelations among natural systems, human activity, and social organization, not merely focus on ecosystem deterioration or human health risks, manifested in the resurgence and spread of old epidemics and the emergence of new ones.
1.1.2. Defining Ecosystem Health
More than half a century ago, Aldo Leopold suggested the notion of "land sickness," referring to the breakdown of regional terrestrial (and aquatic) ecosystems to whole landscapes by human activities. He drew attention to specific signs (e.g., erosion, loss of soil fertility, hydrological abnormalities, occasional irruption of certain species, mysterious local extinction of others, and qualitative deterioration in farm and forest products) by which this condition might be recognized.
Healthy Ecosystems are ..."Sustainable and stable state of ecological systems capable of maintaining organization, autonomy and resistance to stress" - Costanza et al. 1992.
David Rapport : ('85) - Identified that stressed ecosystems are characterized by reduced biodiversity and altered primary and secondary productivity but also by increased disease prevalence, reduced efficiency of nutrient cycling, increased dominance of exotic species, and increased dominance by smaller, shorter-lived opportunistic species.
126.96.36.199. Ecosystem Distress Syndrome (EDS) – (Rapport, 1999)
"A high prevalence of diseases is one of the key indicators of the pathology of ecosystems, and a sick ecological system increases the health risks of its components."
"…a collection of symptoms signaling that an ecosystem is being pushed to its limits. EDS Presages the transformation of an ecosystems into something different, usually something less productive, something less useful to humans."
Biological impoverishment: loss of biodiversity & disruption of ecological processes
Global toxification: contaminants, hazardous waste and endocrine disruptors
Global climate change/ ozone depletion
Human ecological footprint expands as a result of population growth
Overloaded air -- clarity, ozone, chemicals, effects on plant growth & wildlife health, etc.
Overloaded water -- loss of wetlands, decreased water quality, sediments, contaminants, decr. health of organisms
Overloaded soils -- loss of biodiversity & productivity of communities, loss of functions of soil (absorption, transformation & recycling), erosion (affects water) -- septic systems, storm drains, pavement effects
Loss of biodiversity -- shift in dominance of biota from the larger, longer-lived life forms that are specialists in their food requirements to smaller, shorter-lived forms that are generalists
Loss of biological productivity
1.1.3. Ecosystem Fragmentation – edge effect
1.1.5. Diagnostic tools for assessing health
Surveillance studies -- quality of air, water, & soils, density of grazing animals, pollutants, productivity & diversity of biological systems, etc.
1.1.6. Defining solutions and treatments
The Precautionary Principle
Evaluation of remediation strategies
1.2. Emerging disease & developing zoonoses
Human demographic & behavior shifts
International travel and commerce
Technology and industry
Microbial adaptation and change
Breakdown in public health measures
Cumulative & Synergistic - effects of multiple stressors
1.2.1. Consequences of Emerging Infectious Diseases
EIDs causing mass mortality events
EIDs causing subtle population loses
death, decreased reproduction, deformities, etc.
1.2.2. Basic Concepts in Disease Emergence
Mary Wilson, 1995
Emergence of EIDs is complex
Infectious diseases are dynamic
Most new infections not caused by genuinely new pathogens
The concept of the microbe as the cause of the disease is incomplete and inadequate
Human factors are the most potent factors driving disease emergence
The current global situation favors disease emergence
Daszak et al. 2000
from domestic animals
from imported wildlife
Pathogen pollution - translocation of host, vector and/or pathogens
for agriculture & food
for pet trade
for fashion, whim, ethos
Passive emergence - no "overt" human involvement, e.g. Climate change
Ozone thinning & UV
Origin of Hantavirus Pulmonary Syndrome in USA
Six year drought
1.3. Climate change
Shifts of species & food sources
1.4. Medical geology
Hg pollution in fish eating birds & humans
1.5. Toxics & interactions with disease
1.6. Animal movements
Exotic species, including pets, invertebrates & plants
Direct ecologic effects
Examples: plague, rabies, monkeypox
1.7. Agricultural impacts
Nutrients & runoff
open space preservation
2. What are the roles for veterinarians?
Eyes & ears - reportable, networking, integrative health issues
Be educators in your practice & community
Be part of solution, NOT problem
Important research & policy opportunities
Veterinary means ALL animals... but can't ignore plants
Surveillance & epidemiology
Greening Veterinary Medicine
Changes in human attitudes
towards wildlife & exotic species
towards human population
towards achieving a balance
3. References and Resources
3.1. Organizations and websites
Aquatic Ecosystem Health & Management Society P.O. Box 85388, Brant Plaza Postal Outlet Burlington, Ontario CANADA L7R 4K5. http://aehms.org/
Millennium Ecosystem Assessment: strengthening capacity to manage ecosystems sustainably for human well-being. http://www.millenniumassessment.org/en/index.aspx
ProMED-mail web site at http://www.promedmail.org
Emerging Infectious Disease journal (CDC) http://www.cdc.gov/ncidod/eid/index.htm
WHO Rabies Network http://www.who.int/rabies/rabnet/en/
AHEAD Emerging Animal Disease (Fed. of Amer. Sci.) http://www.fas.org/ahead/
USGS--National Wildlife Health Center http://www.nwhc.usgs.gov/
Aguirre, Alonso, et al. (ed.) Conservation Medicine: Ecological Health in Practice . Oxford University Press, 2002.
Calder WA III. Size, function and life history . Cambridge,MA:Harvard Univ. Press.1984.
Carson, R., 1962. Silent spring . Houghton Mifflin Pub. Boston, MA
Colburn, T. et al. 1996. Our stolen future . Dutton Pub.NY
Costanza, R (ed). 1992. Ecosystem Health: New Goals for Environmental Management . Island Press, Washington, DC.
DeSalle, R. (ed). 1999. Epidemic! The world of infectious disease . The New Press, NY.
Disease Emergence and Resurgence : The Wildlife-Human Connection. U.S. Geological Survery, National Wildlife Health Center.
Furness, RW and JJD Greenwood. 1993. Birds as monitors of environmental change . Chapman & Hall. London.
Garrett, L. 1994. The coming plagues . Farrar, Strauss and Giroux. New York.
Graham, F. 1970. Since silent spring . Houghton Mifflin Pub. Boston, MA
Leopold, Aldo. A Sand county almanac . Ballantine Books, reissue 1986.
McCormick, JB and S Fisher-Hoch. 1996. Level 4: Virus hunters of the CDC . Turner Pub. Atlanta
Moeller, DW. 1992. Environmental Health . Harvard Univ. Press.
Peters,R.H. The ecological implications of body size . New York: Cambridge Univ. Press. 1983.
Rapport, D, et al. 1998. Ecosystem Health: Principles and Practice . Blackwell Science.
Ryan, F. 1997. Virus X: tracking the new killer plagues . Little, Brown & Co.
GeoYearbook: an overview of our changing environment 2004/5. United National Environment Programme. http://www.unep.org/geo/pdfs/GEO%20YEARBOOK%202004%20%28ENG%29.pdf
Wilson EO.1992. The diversity of life . Press, Cambridge, MA.
3.3. Journal articles
The domestic animal/wildlife interface: issues for disease control, conservation, sustainable food production, and emerging diseases . Annals of the New York Academy of Sciences . 2002. Volume 969.
Burkholder, J M. 1999. The Lurking perils of Pfiesteria. Scientific American , Aug. pp. 42-49.
Callicot, JB et al. 1999. Current normative concepts in conservation. Cons. Biol . 13(1): 22-35.
Daszak, P, Cunningham, AA and AD Hyatt. 2000. Emerging infectious diseases of wildlife. Science , 287(5452):443-449.
Dobson AP, May RM.1982. Disease and conservation. In: Soule, M (ed) Conservation biology . Sinauer Assoc., MA pp: 345-365.
Epstein, PA. 1999. Climate and health. Science , Vol. 285, 16 July, pp. 347 -348.
Epstein, PA. 1995. Emerging disease and ecosystem instabilities: new threats to public health . Am J Pub Health 85 (2):168-172.
Harvell, CD et al.1999. Emerging marine disease: climate links and anthropogenic factors. Science , 285 (5433):1505
Koch M.1996. Wildlife, people and development: veterinary contributions to wildlife health and resource management in Africa. Trop. Anim. Hlth. Prod ., 28: 68-80.
Kruess A, Tscharntke T.1994. Habitat fragmentation, species loss and biological control. Science . 264 (5165):1581-1584.
Landres, PB, Verner, J and JW Thomas. 1988. Ecological uses of vertebrate indicator species: a critique. Cons. Biol . 2(4):316-328.
LeBlanc, Gerald. Are Environmental Sentinels Signaling? Environmental Health Perspectives , volume 103, number 10, October 1995.
Nisbet. ICT. 1994. Effects of pollution on marine birds. In: Nettleship, DN et al (eds).
Seabirds on islands. BirdLife International . Cambridge, England: 8-25
Patz, J. et al. 1996. Global climate change and emerging infectious diseases. JAMA. 275 (3):217-223.
Pimentel, David et al. 1998. Ecology of increasing disease. Bioscience, Oct.
Pokras, MA,Tabor, G, Pearl,M, Sherman, D, and P Epstein. 2000.Conservation medicine: an emerging field. In: Nature and human society: the quest for a sustainable world . National Academy Press. Washington, DC. pp: 551-556.
Rapport, DJ and WG Whitford. 1999. How ecosystems respond to stress. BioSci . 49(3):193-203.
Sherman, DM, Pokras, MA and AW English. 1999. Preparing veterinarians for meaningful participation in wildlife conservation. J Vet Med Educ . 26(1):26-29.
Silva, M and JA Downing.1998. Allometric scaling of minimal mammal densities. Cons. Biol . 8(3):732-743.
Steidinger KA, Burkholder JM, Smith SA.1996.Pfiesteria piscida gen. et sp. nov.: a new toxic dinoflagellate with a complex life cycle and behavior. J. Phycol . 1996; 32(1):157-161.
Thorne, ET, Williams ES.1988. Disease and endangered species: the black-footed ferret as a recent example. Cons.Biol . 2(1):66-74.
Walker, DH. et al. 1996. Emerging bacterial zoonotic and vector-borne diseases: ecological and epidemiological factors. JAMA 275(6): 463-469.
Walters, Mark Jerome. 2003. Six Modern Plagues and How We are Causing Them . Washington, Island Press.