From Monsoons to Microbes Understanding the Ocean's Role in Human Health (1999) / Chapter Skim
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2 Oceans and Infectious Diseases
2 Oceans and Infectious Diseases
Pages 43-58
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From page 43... ...
There is also evidence that ships are responsible for the dissemination of exotic species, including human pathogens, through the discharge of bilge water into coastal waters (NRC, 1996~. Recreation is another source of exposure through ingestion of seawater or contact of skin and/or mucous membranes with seawater.
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From page 44... ...
The apparent emergence of these pathogens could be the result of anthropogenic influences or may reflect more sensitive modern detection technologies. Whatever the cause, it is clear that infectious diseases, including waterborne diseases conveyed by the ocean, still plague humankind.
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From page 45... ...
has reviewed the literature on estuarine bacteria capable of causing human disease. TABLE 2-1 Selected List of Major Agents of Waterborne Disease Conveyed by the Coastal Ocean and Their Usual Routes of Transmission to Humans Agent Disease Usual Transmission Route Viruses Hepatitis A virus Hepatitis E virus Caliciviruses Rotaviruses Astroviruses Enteroviruses Autochthonous Bacteriaa Mycobacterium marinum Vibrio alginolyticus Vibrio cholerae Vibrio parahaemolyticus Allochthonous Bacteriaa Escherichia cold Leptospira interrogans Listeria monocytogenes Morganella morganii Salmonella species Shigella species Nematodes Anisakis simplex Anisakiasis Infectious hepatitis Hepatitis Gastroenteritis Infantile gastroenteritis Gastroenteritis Varied Granuloma Wound infections Cholera Gastroenteritis, wound inf.
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From page 46... ...
Detection and counting of specific bacteria, historically referred to as fecal indicator bacteria, have comprised the generally accepted method for estimating the public health safety of both drinking and recreational water and seafood (Dufour, 1984~. This technique relies on the culture of coliforms, a term used to include several genera and species, including Escherichia colt, Enterobacter aerogenes, Klebsiella pneumonias, and even some Salmonella serotypes, thought to derive from the colon of warm blooded animals.
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From page 47... ...
Today, it is accepted that the fecal coliforms provide public health practitioners with a useful indicator; however, it is also widely recognized that the fecal coliform test has some serious disadvantages: · Not only fecal, but also non-fecal bacteria such as K pneumonias, make up the fecal coliform group, reducing the accuracy of the test; · Fecal coliforms have little, if any, quantifiable association with specific pathogens that are important in human disease, including viral diseases (Table 2-1~; · Fecal coliforms survive for a long time in aquatic habitats, notably in estuaries and in shellfish, either in the detectable (culturable)
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From page 48... ...
Some investigators have suggested that enterococci may be the preferred indicator, but these microorganisms have some of the same limitations as the fecal coliforms (Koh et al., 1994~. Because of these limitations and reliance on the existing database for fecal coliforms, the enterococci have not been universally accepted by state, county, and local regulatory agencies as a substitute indicator group, even though some states have adopted the new E
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From page 49... ...
While point sources therefore continue to cause degradation of coastal areas, it is now generally believed that nonpoint sources are equally if not more important. Nationwide, it has been estimated that indirect loadings account for more than half of the suspended solids, nutrients, fecal coliforms, and metals entering coastal waters annually (NOAA, 1998a)
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From page 50... ...
It is worth noting that the vibrios are capable of degrading a wide variety of organic compounds, including aliphatic and aromatic hydrocarbons, and this generalization includes the pathogenic vibrios. However, proper experiments have not been done to establish linkages between toxic chemicals, declining fisheries, human disease, and densities of pathogenic vibrios.
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From page 51... ...
Global Climate Change and Infectious Disease One of the first documented associations of a human pathogen with an estuarine animal subject to climate-induced fluctuations was the Vibrio parahaemolyticus-zooplankton relationship described by Kaneko and Colwell (1973) in the Chesapeake Bay.
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From page 52... ...
disease caused by V cholerae versus seasonal sea surface temperature data obtained by remote sensing, revealed a correlation between the cholera case data and increasing water temperature.
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From page 53... ...
cholerae, nutrients, and chlorophyll, and with epidemiology for cholera incidence. Storms fueled by the 1997-1998 E1 Nino increased urban runoff, saturated septic tank leach fields thereby causing overflows, and caused a weakened sewage main to break and spill 120 million gallons of raw sewage into Santa Monica Bay.
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From page 54... ...
However, in the high rainfall area of Sri Lanka, lack of rainfall from the failure of the monsoons led to reduced flow of rivers and the formation of standing pools of water that provided favorable breeding conditions (Bouma and van der Kaay,1996~. Drought associated with the failure of the south-west monsoons are twice as frequent in the year following an E1 Nino (Dilley and Heyman, 1995)
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From page 55... ...
There are several other viral diseases that may be affected by changing weather and climate patterns including yellow fever, hantavirus, and viral encephalitis as well as other parasitic diseases such as schistosomiasis and sleeping sickness since the vectors are sensitive to changes in temperature and rainfall (Rogers and Packer, 1993; Stone, 1995~. Evaluating the Impacts of ENSO on Vector-borne Disease Future research should aim to improve the quality of the indicators and data on disease exposure and health outcome.
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From page 56... ...
One program that is currently being conducted to address these issues is the ENSO Experiment (Box 2-1~. CONCLUSIONS Given current world population dynamics, including growing populations near coastal waters and increased recreational use of ocean and coastal waters, particularly in developing countries, there are several pressing scientific needs for better understanding the ocean and infectious diseases.
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From page 57... ...
Specific suggestions include: . Evaluate cost/benefits of the use of coliforms as indicators of fecal pollution in estuaries and seawater, as introduction of newer molecular genetic and immunological methods for direct detection and evaluation of pathogens proves applicable.
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From page 58... ...
, so that disease transmission to humans can be prevented. · Seek advice and participation from key organizations in developing epidemiological methods for application to global climate change issues (EIS Program/CDC; American Teachers of Preventative Medicine; American College of Epidemiology; Society for Epidemiology Research; International Society for Environmental Epidemiology; American Public Health Association; American Society for Microbiology)
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