Examining the Links Between Biodiversity and Human Health: A Multidisciplinary Approach

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Examining the Links Between Biodiversity and
Human Health A Multidisciplinary Approach
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The Biodiversity Crisis Human actions
are causing a biodiversity crisis, with species
extinctions up to 1000 times higher than
background rates --Pimm et al. 1995
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• Biodiversity loss is accelerating

From WWF, Living Planet Report, 2004.
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Global Decline
Proportion of threatened bird species (blue is
highest) Davies et al. 2006
Best predictors of extinction risk are human
impacts, such population density and agricultural
activity. Conservation priorities should focus
on areas of high human density as well as best
remaining habitat.
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Mata Atlântica
Golden-lion tamarin
In Brasil, Mata Atlântica has declined by more
than 90. Intensive deforestation causes massive
species losses because new habitats cannot
sustain viable populations of forest-dependent
species

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Ecosystem Services As provided by the diversity
of life on earth
Ecosystem Services as provided by the diversity
of life on earth
Provisioning Services Food Freshwater Wood
and fiber Fuel Clean Air Medicines
Regulating Services Climate regulation Flood
regulation Disease regulation Water purification
Cultural Services Aesthetic Cultural Recreationa
l Spiritual
Supporting Services
Nutrient cycling Primary
production Soil formation
Adapted from the Millennium Ecosystem
Assessment, 2005.
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Chemical Diversity The Imaginative Leap
60 of cancer drugs from natural compounds 75 of
drugs for infectious diseases from natural
compounds
Bryostatin The bryozoan Bugula neritina has
anticancer properties. With most of the worlds
phyla, the oceans may be the medicine chest of
21st century
Michellamine B African liana, Ancistrocladus
korupensis, from Cameroon produces a novel
anti-HIV compound. Significant amounts needed
for preclinical investigation.
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Chemical Diversity The Imaginative Leap
Vacina de sapo Campinas Indian Reserve, Acre,
Brasil. Shamans administered the kambô remedy,
known as vacina de sapo or frog vaccine.
Collected by catching kambô, tying it spread-
eagled between posts, and collecting slime from
its back. Frog is released and dried poison
is rehydrated before application.
Potential applications include hypertension,
strokes, and other illnesses. Profits to
be shared with traditional users. World Bank
estimates 65 billion potential from
traditional medicines
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The Third Epidemiologic Transition?

• First during transition to agriculture (10,000 yr
  BP)
• Rise in infectious disease
• Emerging zoonotics and increased virulence of
  human pathogens
• Second during Industrial Revolution (19th
  century)
• Shift from infectious to chronic diseases
• Increased water and air pollution linked to
  higher rates of cancer, allergies, birth defects,
  and impeded mental development
• Third during period of globalization and
  ecological collapse
• Rise of emerging and re-emerging diseases and
  antibiotic resistance
• Accelerated globalization of human disease
  ecologies
• Barret at al. 1998

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• New infectious diseases appear to be emerging
• and re-emerging at a faster rate

Fauci 2006
75 of new infectious diseases are zoonotic in
origin
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How can a decline in biodiversity affect human
health? Disease emergence in past 30 years is
primarily the result of social, demographic, and
environmental transformation since World War
II Anthropogenic environmental changes drive
infectious disease emergence throughout the
continuum from humans to wildlife to domestic
animals and within plant host populations Vect
or-borne diseases, with much of their life cycle
outside of the human host, may be most sensitive
to change in environmental conditions
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Biodiversity and West Nile Virus Mosquito-borne
disease wild birds serve as the primary
reservoir hosts Factors accounting for variation
in WNV prevalence are poorly known Ezenwa et al
(2006) examined the diversity of bird reservoirs
in association with West Nile virus infection in
mosquitoes across Louisiana.
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Infection rates of Culex mosquitoes declined with
increase of nonpasserine species richness
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The lower infection rates were correlated with
lower numbers of human cases of West Nile virus.
Links between high biodiversity and reduced
disease risk may help account for distribution
patterns
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Biodiversity and Lyme disease
Nymphal tick infections
Ostfeld and LoGiudice 2003
Reduced reservoir biodiversity correlates with
increased risk of Lyme disease transmission to
humans and may be a general rule of
frequency-dependent transmission
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LoGuidice et al. 2003
Mammalian species from squirrels (Sq) to skunks
(Sk) can reduce the effect of white-footed mice,
the most competent reservoir of Lyme disease, on
tick infection. 90 of ticks feeding on
white-footed mice become infected with Lyme
bacterium Only 15 of ticks feeding on squirrels
become infected with Lyme bacterium Species
richness may be only part of the problem,
abundance also plays a role
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• Conditions for dilution effect
• Generalist vector
• Variation in reservoir competence among hosts
• Positive correlation between reservoir
  competence and percentage of tick meals supplied
  by hosts in the community Logiudice et al. 2003

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Deforestation and Spread of Vector-Borne Diseases
Low biting rate
High biting rate
Forest in 2 x 2 km grid
Vittor et al. 2006
Deforested sites in the Peruvian Amazon had
greater mosquito (A. darlingi) transmission rates
of malaria compared to sites with less habitat
alteration.  Biting rates were 278 times higher
in deforested areas than rates for forests
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Forest fragmentation and disease transmission
Loss of biodiversity increases the frequency of
interspecific interactions, in turn increasing
pathogen transmission Intensity of
gastrointestinal parasite infection is elevated
in red colobus monkeys inhabiting forest
fragments with reduced plant biodiversity and
high rates of human encroachment (Golberg
Gillespie) High levels of antibiotic resistance
in bacteria from chimpanzees in locations where
humans have been encroaching upon their habitats
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Biodiversity change in forest systems

• Bat populations deprived of their
• primary food sources sought alternative hosts
  
• humans
• In rural areas, shift occurred when pigs and
  cattle were
• eliminated
• Massive attacks occurred in gold mining camps
  of
• Amazon when food sources were depleted because
  
• of overhunting and noise (Confalonieri 2001)

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Wildlife Trade and Disease Emergence
Consumption of wild animal meat Central Africa
more that 1 billion kg per year Amazon Basin
67-164 million kg per year approximately 6.4
to 15.7 million animals Outbreaks, including
SARS, have caused hundreds of billions of dollars
of economic damage globally One regulatory
approach is to decrease the rate of contact among
species at this interface created by wildlife
trade Karesh et al 2005
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Global Warming and Spread of Vector-Borne Disease
2050
Present
Projected spread of Ae aegyptii, dengue vector,
in Australia by 2050
McMichael et al. 2006
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Biodiversity-Health Research at US Environmental
Protection Agency

• Exploratory research funding
• How do anthropogenic drivers of changes in
  biodiversity directly affect the transmission of
  human disease?
• What are the mechanisms that connect these
  issues?
• Multidisciplinary approach to exploring root
  causes of disease emergence and spread to assist
  in prevention and mitigation

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Workshop on Biodiversity and Human Health

• Sept. 14-15, 2006, at Smithsonian Institution
  Washington, DC
• Convene interdisciplinary workshop of
  researchers, practitioners, and decision makers
  in ecology, public health, social sciences, and
  remote sensing to discuss
• the state of the science
• important research priorities
• risk analysis and creation of monitoring and
  forecasting network
• types of data and models needed to map the
  relationship between biodiversity decline and EIDs

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Partners and Collaborators

• Yale Center for EcoEpidemiology
• Institute of Ecosystem Studies
• Asia-Pacific Institute of Tropical Medicine and
  Infectious
• Diseases
• National Oceanic and Atmospheric Administration
• (NOAA)
• NASA Ames Research Center
• World Federation of Public Health Associations
• American Public Health Association (APHA)
• World Health Organization (WHO)
• Smithsonian Institution

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Protecting biodiversity, protecting human health

• Environmental factors contribute to emerging
  diseases and environmental approaches can reduce
  their burden
• Develop new tools to integrate data for improved
  understanding of relationships between
  biodiversity and human health
• Use earth observation and field data to track
  and analyze global relationships between habitat
  alteration, biodiversity loss, vector ecology,
  and the emergence and spread of infectious
  disease
• Inform decision-making to benefit society
• Develop new constituency, momentum, and
  approaches for conserving biodiversity and
  protecting endangered species

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