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Page 9
INTRODUCTION
When fishermen report strange episodes of memory loss associated
with a bloom of the dinoflagellate Pfiesteria or there is an
announcement of a new cancer-fighting drug isolated from a marine
organism, the public becomes aware of the potential of the ocean
both to threaten and benefit human health. Attention is then
directed to the scientific experts to interpret these events and to
make the appropriate policy recommendations. However, this requires
an active research community that recognizes the links between
human health and ocean processes and nurtures cooperative studies
in fields as diverse as physical oceanography, public health,
epidemiology, marine biology, and medicine. There is clearly a need
for scientific exchange among these fields to ensure an integrated
approach to issues where human health and ocean systems intersect.
The workshop and this report on the Ocean's Role in Human Health
were designed to initiate this type of interaction and provide
guidelines for future programs.
In 1998, awareness of the dangers associated with marine driven
weather events was heightened by the occurrence of an unusually
strong El Niño which brought record rainfall and flooding to
coastal communities. Because the majority of the world's population
lives in coastal zones, the hazards associated with these events
have an inordinate impact on public health. Coastal communities are
especially vulnerable to storm surges, coastal flooding, and the
outbreak of diseases that invade marine habitats. These natural
disasters in turn stress the public health infrastructure that
ensures safe drinking water, sewage treatment and disposal, and
emergency medical care.
Another growing concern in the international community is the
potential for global climate change due to alterations in
atmospheric conditions from human activities such as the burning of
fossil fuels and deforestation. Because the ocean acts as an
immense reservoir for water, heat, and carbon (mineral and
biogenic),
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Page 9
INTRODUCTION
When fishermen report strange episodes of memory loss associated
with a bloom of the dinoflagellate Pfiesteria or there is an
announcement of a new cancer-fighting drug isolated from a marine
organism, the public becomes aware of the potential of the ocean
both to threaten and benefit human health. Attention is then
directed to the scientific experts to interpret these events and to
make the appropriate policy recommendations. However, this requires
an active research community that recognizes the links between
human health and ocean processes and nurtures cooperative studies
in fields as diverse as physical oceanography, public health,
epidemiology, marine biology, and medicine. There is clearly a need
for scientific exchange among these fields to ensure an integrated
approach to issues where human health and ocean systems intersect.
The workshop and this report on the Ocean's Role in Human Health
were designed to initiate this type of interaction and provide
guidelines for future programs.
In 1998, awareness of the dangers associated with marine driven
weather events was heightened by the occurrence of an unusually
strong El Niño which brought record rainfall and flooding to
coastal communities. Because the majority of the world's population
lives in coastal zones, the hazards associated with these events
have an inordinate impact on public health. Coastal communities are
especially vulnerable to storm surges, coastal flooding, and the
outbreak of diseases that invade marine habitats. These natural
disasters in turn stress the public health infrastructure that
ensures safe drinking water, sewage treatment and disposal, and
emergency medical care.
Another growing concern in the international community is the
potential for global climate change due to alterations in
atmospheric conditions from human activities such as the burning of
fossil fuels and deforestation. Because the ocean acts as an
immense reservoir for water, heat, and carbon (mineral and
biogenic),
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Page 10
an understanding of ocean processes is essential for predicting
climate change. Also, because the oceanic and atmospheric systems
interact dynamically, there is concern that a change in atmospheric
conditions due to global warming could modify the thermal-driven
circulation of the world's ocean. This dynamic circulation is
essential for replenishing seawater with nutrients and oxygen and
represents one of the driving forces behind changing atmospheric
conditions and weather. As demonstrated during the 1997–1998
El Niño, a change in the temperature of a body of water in
the equatorial Pacific can have dramatic impacts on the climates of
countries as far away as Africa and Asia.
However, why should the medical community be concerned with
changes in climate and weather? Experts in infectious diseases warn
that in concert with changes in temperature and rainfall, there
will be a change in the distribution of both waterborne and
vector-borne diseases (Colwell, 1996; Haines and Parry, 1993;
Rogers and Packer, 1993). Disease organisms are sensitive to
changes in their environments and can quickly spread into new areas
when conditions become favorable for their survival or decrease or
disappear when conditions become unfavorable. Add to this the
increasing mobility of human society and the probability of
dispersal of disease agents worldwide increases with increasing
travel and commerce.
In the past, outbreaks of cholera have been traced to shipping
activities (Colwell, 1996). Current research indicates that the
bacterium responsible for causing cholera, Vibrio cholerae,
can spread through attachment to marine organisms in ship ballast
water. In addition, recent studies have linked some disease
outbreaks to changes in marine conditions such as prolonged periods
of elevated sea surface temperature (Colwell, 1996). Vibrio
cholerae inhabits the guts of planktonic crustaceans,
specifically copepods. In this milieu, the bacteria can become
concentrated into a dose sufficient to cause cholera if only a few
copepods contaminate ingested shellfish or drinking water.
Therefore, conditions that favor the growth and reproduction of
planktonic organisms may also favor the propagation of resident
cholera pathogens.
The primary source of marine-borne illness in humans is
ingestion of seafood contaminated with hepatitis and caliciviruses,
and pathogenic bacteria including both indigenous marine vibrios
and a variety of non-marine species from human and animal fecal
contamination (IOM, 1991). Traditional methods for assessing
bacterial and viral contamination are not always adequate for
assessing the public health risk. The increasing demand for seafood
in both industrialized and developing countries, compounded by the
variety of waterborne pathogens, adds to the potential for
outbreaks of disease, a threat that may be offset by vigilant
public health surveillance.
Other public health threats associated with marine conditions
include harmful algal blooms (HABs) which have increased in
frequency and geographic range in the past two decades. HABs result
in human health hazards caused by dead and dying fish, adulteration
of food supplies by at least five different types of
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toxic agents, and inhalation of these toxins when they become
aerosols through wave action. Many of these toxins affect the
nervous system and cause paralytic, diarrheic, neurotoxic, and
amnesic shellfish poisoning, and ciguatera fish poisoning, with
symptoms ranging from mild nausea to paralysis and death. As
discussed in Marine Biotoxins and Harmful Algae: A National
Plan 1992 (Anderson et al., 1993) and The Ecology and
Oceanography of Harmful Algal Blooms: A National Research
Agenda (ECOHAB, 1995), management of this problem will require
research in biological oceanography to study how ocean processes
affect the blooms and the distribution of different algal species,
in biochemistry and molecular biology to identify algal toxins and
the metabolic pathways affected by algal toxins for improved
diagnosis and treatment, and in epidemiology and public health to
document the association between outbreaks of illness and incidence
of algal blooms, and to provide appropriate health warnings.
Scientists have investigated the algal toxins in order to
understand the pathology of the illness listed above and to use
these toxins as molecular probes of neural function. Many marine
organisms have contributed to biomedicine through the unique
molecules they produce. Other examples include bioluminescent and
fluorescent indicator proteins, restriction enzymes used in
molecular cloning, and novel antibiotics, anti-inflammatory agents,
and anti-neoplastic drugs. Why do organisms produce these novel
compounds that are incidentally valuable to humans? Similar to
their terrestrial counterparts, marine organisms have evolved
molecular strategies for evading disease and predation. Many of
these strategies include the production of inhibitory chemicals
that have biological activity in humans and may provide new
therapies for a variety of diseases.
Finally, there has been a long tradition in the biological
sciences of exploiting the properties of marine organisms as models
for biomedical research. Through study of their unique adaptations
to the marine environment, these organisms have contributed to our
understanding of human biology from the most reductionist cellular
process to the unraveling of the neural processes underlying
behavior. Some of these discoveries have started new areas of
investigation in cancer research, immunology, inflammatory joint
diseases, kidney physiology, and neurochemistry to name a few
prominent examples.
Clearly, we have benefitted greatly from our past studies of the
ocean and marine life. However, challenges remain to develop more
accurate forecasting of climate and weather, to assess the threat
of the emergence and spread of infectious diseases, to anticipate
changes in the growth and distribution of harmful algal species,
and to explore marine biodiversity in order to uncover new
pharmacologic agents and animal models for biomedical research.
Organization of the Report
This report evolved from the workshop on The Ocean's Role in
Human Health, hosted by the National Research Council's Ocean
Studies Board. In the
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first part of the workshop, experts in physical oceanography,
public health, infectious diseases and harmful algal blooms
discussed areas in which the ocean presents risks to human health.
In the second part, experts in marine pharamacology and marine
biomedical models presented examples of how marine organisms have
provided a source of new compounds for treating human disease and
have led to discoveries of biological processes that underlie many
human diseases. A complete description of the workshop appears in
Appendix C, the general topics and speakers are listed below:
Part I.
Hazards to Human Health From the Ocean
•
Marine Natural Disasters
Speakers:
Claude de Ville de Goyet (Pan American
Health Organization)
Peter Rhines (University of Washington)
Lynn K. Shay (University of Miami,
RSMAS)
William Wiseman (Louisiana State
University)
•
Infectious Diseases
Speakers:
Frances Carr (USAID)
D. Jay Grimes (The University of Southern
Mississippi)
Joan Rose (University of South Florida)
Milan Trpis (The Johns Hopkins
University)
•
Harmful Algal Blooms
Speakers:
Lorraine C. Backer (Centers for Disease
Control and Prevention)
Daniel G. Baden (University of Miami, NIEHS
Marine and Freshwater Biomedical Science Center)
Sherwood Hall (Food and Drug
Administration)
Patricia A. Tester (National Marine
Fisheries Service NOAA)
Part II.
Value of Marine Biodiversity to Biomedicine
•
Marine Natural Products
Speakers:
William Fenical (Scripps Institution of
Oceanography)
Shirley A. Pomponi (Harbor Branch
Oceanographic Institution, Inc.)
Baldomera Olivera (University of Utah)
•
Marine Organisms as Models for Biomedical
Research
Speakers:
Robert Baker (New York University Medical
School)
David Epel (Stanford University)
Joan D. Ferraris (National Institutes of
Health)
John J. Marchalonis (University of
Arizona)
Following the workshop, the Committee on the Ocean's Role in
Human Health met and discussed the major findings presented and
outlined conclusions based
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on these findings. The committee structured the report using the
same organization as the workshop. Hence the five sessions of the
workshop correspond to Chapters 1, 2, 3, 4, and 5 of this report.
Because each chapter addresses a discrete topic, conclusions are
presented at the end of each chapter. Finally, this report is meant
to serve as an overview, not a comprehensive discussion of all the
possible connections between human health and the oceans. For this
reason, health hazards such as shark bites and jellyfish stings and
the secondary effects of pollution and changes in ocean-based food
resources were not included in the scope of the study.
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Representative terms from entire chapter:
harmful algal
