Examining the Links Between Biodiversity and Human Health: A Multidisciplinary Approach. 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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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
Biodiversity loss is accelerating
From WWF, “Living Planet Report,” 2004.
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.
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
As provided by the diversity of life on earth
as provided by the diversity of life on earth
Wood and fiber
Adapted from the Millennium Ecosystem Assessment, 2005.
Chemical Diversity: The Imaginative Leap
60% of cancer drugs from natural compounds
75% of drugs for infectious diseases from natural compounds
The bryozoan Bugula neritina has anticancer properties. With most of the world’s phyla, the oceans may be the medicine chest of 21st century
African liana, Ancistrocladus korupensis, from Cameroon produces a novel anti-HIV compound. Significant amounts needed for preclinical investigation.
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
New infectious diseases appear to be emerging
and re-emerging at a faster rate
75% of new infectious diseases are zoonotic in origin
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
Vector-borne diseases, with much of their life cycle outside of the human host, may be most sensitive to change in environmental conditions
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.
Infection rates of Culex mosquitoes declined with increase of nonpasserine species richness
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
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
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
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
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
Biodiversity change in forest systems
Bat populations deprived of their
primary food sources sought alternative hosts:
In rural areas, shift occurred when pigs and cattle were
Massive attacks occurred in gold mining camps of
Amazon when food sources were depleted because
of overhunting and noise (Confalonieri 2001)
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
Global Warming and Spread of Vector-Borne Disease
Projected spread of Ae aegyptii, dengue vector, in Australia by 2050
McMichael et al. 2006
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
Yale Center for EcoEpidemiology
Institute of Ecosystem Studies
Asia-Pacific Institute of Tropical Medicine and Infectious
National Oceanic and Atmospheric Administration
NASA Ames Research Center
World Federation of Public Health Associations
American Public Health Association (APHA)
World Health Organization (WHO)
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