Transcript Ch. 15.1 + 15.2 slides

Chapter 15.1
Links Between Human Health and the Environment
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emerging diseases (avian flu, SARS, Ebola)
appear as we continue to manipulate the
natural environment and change ecological
relationships
however, old and familiar diseases take the
greatest toll on human life
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malaria, diarrhea, respiratory viruses
risk = hazard x vulnerability
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in the context of environmental health, hazard is
anything that can cause
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injury, disease, or death to humans
damage to personal or public property
deterioration or destruction of environmental components
risk: the probability of suffering injury, disease,
death, or some other loss as a result of exposure to
a hazard
Ex. presence of avian flu in poultry is a hazard that
presents the risk of humans contracting the disease;
people working with poultry are much more
vulnerable
health
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WHO defines as “state of complete mental, physical,
and social well-being”
environmental health focuses on disease; as a
result, health is usually defined as absence of
disease
two measures are used in the study of disease in
societies:
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morbidity—incidence of disease in a population
mortality—incidence of death in a population
epidemiology—study of the presence, distribution,
and prevention of disease in populations
public health
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in U.S., lead agency for protecting the health
and safety of the public is the Centers for
Disease Control and Prevention (CDC)
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agency under Department of Health and Human
Services
other countries normally have a similar
ministry of health
life expectancy
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universal indicator of health
1955 average was 48 years
today, average is 67 years
expected to be 73 years in 2025
progress is result of social, medical, and economic
advances (epidemiologic transition)
20% of annual deaths in the world are children
under the age of 5 in the developing world
infectious diseases responsible for 54% of deaths in
developing countries, but only 7% in developed
countries
environmental hazards
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two ways to consider hazards:
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1. lack of access to necessary resources
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Ex. lack of access to clean water and nourishing food is
harmful to a person
2. exposure to hazards in the environment
cultural hazards
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matter of choice, or at least can be influenced by
choice
examples include eating too much, using harmful
drugs, smoking, sunbathing, choosing hazardous
occupations
environmental hazards
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biological hazards
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history: black plague, smallpox, antibiotics,
immunizations
~25% of global deaths are due to infectious and
parasitic diseases
physical hazards
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hurricanes, tornadoes, floods, forest fires,
earthquakes, landslides, volcanic eruptions
some can be anticipated, others are a
consequence of where people choose to live
environmental hazards
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biological hazards
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history: black plague, smallpox, antibiotics,
immunizations
~25% of global deaths are due to infectious and
parasitic diseases
physical hazards
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hurricanes, tornadoes, floods, forest fires,
earthquakes, landslides, volcanic eruptions
some can be anticipated, others are a
consequence of where people choose to live
environmental hazards
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chemical hazards
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industrialization has brought a host of technologies that
use chemicals such as cleaning agents, pesticides, fuels,
paints, and medicines
manufacture, use, and disposal of these chemicals often
brings humans into contact with them
exposure is either by ingestion of contaminated foods or
drinks, breathing contaminated air, absorption through the
skin, direct use, or by accident
toxicity (condition of being harmful, deadly, or poisonous)
depends not only on exposure, but also on the dose
people have different thresholds of toxicity for given
substances
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Ex. children are often at greater risk; embryos are even more
sensitive
carcinogens
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cancer-causing agents
because cancer often develops over a period of 1040 years, it is often difficult to connect the cause
with the effect
in the U.S., 23% of all deaths in 2003 were traced to
cancer
cancer is a cell line that has lost its normal control
over growth
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at least 3 dozen genes have been studied that can bring
about malignant cancer
two-hit hypothesis
Chapter 15.2
Pathways of Risk
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2002 WHO annual report: Reducing Risks,
Promoting Healthy Life
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shows that a small number of risk factors is
responsible for a vast proportion of premature
deaths and disease
top 10 factors are responsible for more than onethird of all deaths and much of the global disease
burden
risks of being poor
cultural risk of tobacco use
risk and infectious disease
toxic risk
disaster risk