11.2.5.4. Other Diseases
The distribution of water-borne infectious diseases is influenced mainly by
the hygienic circumstance of water (Epstein, 1992; Echeverria et al., 1995;
Colwell, 1996; Esrey, 1996). Water-borne diseases—including cholera and
the suite of diarrheal diseases caused by organisms such as giardia, salmonella,
and cryptosporidium—are common with contamination of drinking water quality
in many countries of south Asia (Echeverria et al., 1995; Colwell, 1996; Esrey,
1996). Higher SSTs and rich nutrient load in major river deltas would support
extended phytoplankton blooms in selected coastal areas of temperate and tropical
Asia. These phytoplankton blooms are habitats for the survival and spread of
infectious bacterial diseases. The cholera outbreak in Bangladesh during 1994
has been attributed to the presence of extended phytoplankton blooms (Colwell,
1996). The aforementioned water-borne diseases could become more common in many
countries of south Asia in a warmer climate.
For preventive actions, impact assessments are necessary on various aspects
such as the nutritional situation, drinking water supply, water salinity, and
ecosystem damage (Kaye and Novell, 1994; Graczyk and Fried, 1998). Water-borne
infectious diseases, natural disaster, environmental migration, nutritional
deficiency, and environmental pollution should be major risk factors for human
health (Thongkrajai et al., 1990; Pazzaglia et al., 1995, Colwell, 1996). The
risk factor of diseases also will depend on infrastructure, economic conditions,
the hygienic situation, and medical facilities. Risk could be reduced by awareness
in the communities that are more vulnerable to instability in the future environment.
In Asia, economic and population growth will expand rapidly during the 21st
century in many countries. The rapid increase in population will be accompanied
by migration from rural communities to overcrowded large cities (Stephens, 1995).
Disasters linked to climate extremes such as floods and droughts also would
impact local and regional populations and enforce migration. The huge energy
consumption by the expanding population in urban cities would result in degradation
of air and water quality, whereas rapid expansion of the economy will bring
about improvements in living standards, such as improved environmental sanitation,
hygienic practice, and medical treatment facilities. Therefore, better understanding
of the interaction among climate change and environmental and health status
in communities at regional and local scales is crucial to forge physiological
acclimatization and social adaptations in the future.
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