Increases in population over the past century have placed tremendous pressures on water resources of both the developed and developing world. These pressures include direct contamination from domestic, industrial, and agricultural wastes and less direct effects caused by climate change and other ecological disturbances. The result is a contaminated and often increasingly scarce global resource, which in turn is contributing to a rise in waterborne disease outbreaks worldwide. Population projections for the next century suggest that these pressures can only increase. Without appropriate intervention, waterborne disease outbreaks/epidemics/pandemics are also expected to increase dramatically.
Waterborne disease cannot be eradicated, as was smallpox, because of the variety of disease agents transmitted by water. Trade and travel are too extensive; border closures have not proved effective. On the contrary, they are more often destructive to both the economy and the culture of a region. Risks of disease must, therefore, be controlled at the community level by basic sanitation and availability of uncontaminated water. A systems approach is needed for water management, including watershed protection, drinking water treatment and distribution, and wastewater collection and treatment.
Control of waterborne disease is dependent on education at every level—from household to government. Solutions to the problem of waterborne disease vary, depending on regional economy and climate. For developing countries, a low technology approach—i.e., education and minimal treatment—may dramatically reduce incidence of waterborne disease, which, as an immediate consequence, will significantly effect the economy of that region. Industrial productivity, including tourism, depends on a disease-free environment. To induce governments to invest in water quality improvements, emphasis needs to be placed on economic benefits.
Developed countries face the very real demands of existing infrastructures, emergence of pathogens resistant to water treatment and disinfection, and increasing numbers of immuno-compromised individuals. In addition, poorly defined risks from toxicity of disinfection byproducts need to be considered. Clearly, education is critical, from the level of the average citizen to water utility personnel, professional organizations, and universities conducting research. One area of notable concern involves use of indicator organisms. Dependence on traditional indicators, such as coliforms, can be misleading, particularly when viral and/or protozoal contamination is suspected. There is a critical need for the immediate future to identify more appropriate indicators for both temperate and tropical regions and/or to validate/modify the use of current indicators. In the long run, however, direct detection and enumeration of pathogens must be accomplished.
In summary, the quality of global water supplies cannot continue to deteriorate without serious consequences to global distribution, incidence, and severity of waterborne disease. Accurate risk analysis and global public education at all levels are critical. Although application of advanced technologies can improve water quality, massive investment is required. Low technology options, coupled with appropriate education, can provide dramatic improvements in human health in even the least developed countries. Ideally, a multidisciplinary approach would be undertaken internationally, with both developed and developing nations working in unison to address water quality issues. Sanitary engineers, microbiologists, epidemiologists, and public health officials working as a team to address the health risks posed by microbial pathogens should be the highest priority, nationally and internationally.