Water Education - Water and Health

Where do waterborne diseases rank in causing human health problems?

Threats to water quality can be biological and chemical. About 300 million people in the Americas are at risk of contracting serious diseases such as cholera, typhoid fever, and viral hepatitis. Parasites such as Giardia and Cryptosporidium are also a serious threat, particularly in developing countries. Biological and chemical contaminants enter source waters mainly through the discharge of human, animal, and industrial wastes.

In Latin America and the Caribbean less than 12% of collected wastewater is treated. This means that enormous amounts of raw sewage, along with industrial effluents and run-off water contaminate the ground and surface water sources needed for public water supplies. It is estimated that a reduction in the incidence of certain bacteriological diseases of up to 80% could be achieved through effective water source protection from raw sewage. Even where most people have access to treated water, there is an ever-present risk of an outbreak of waterborne diseases or other human illnesses from direct ingestion of, or exposure to, contaminated water or the consumption of any foods so contaminated by water. In Canada, mostly in small towns and villages, many "boil water" advisories are regularly issued over concerns about the microbiological safety of the water.

The threat from waterborne disease was highlighted in the spring of 2000 when the spread of E. Coli bacteria in the drinking water supply of a small town resulted in several deaths and a large number of ill people. The disparity in the water supply is also an issue. Poor people are less likely to be connected to regular sources of water supply and often are forced to purchase highly-priced poor quality water from vendors. The high cost of water and lack of quality are generally responsible for the low level of personal hygiene and the associated spread of communicable diseases, and the high prevalence of water-related diseases. Inequities are also visible between water supply coverage in urban and rural populations.

A recent global assessment carried out by WHO-PAHO-UNICEF indicates that in most developing countries the best-served rural dweller is much worse off than the worst-served urban dweller. Insufficient and ineffective management of surface and coastal waters also has important detrimental impacts on the potential for rivers and beaches to be used for bathing, swimming, and other recreational activities. Not only does this cause 3 problems to public health, but it can also be responsible for the loss of revenue from tourism." II. Summary of Water-Related Diseases Worldwide: · Bacterial Diseases: According to WHO and the US Centers for Disease Control and Prevention (CDC), over 2 billion people, mostly living in developing countries, are at elevated risk of water-related bacterial diseases.

While there are many illnesses that may be identified in this category, the major water-related diseases include acute dehydrating diarrhea (cholera), abdominal illness (typhoid fever), acute diarrhea (dysentery), and chronic diarrhea (Brainerd diarrhea). The following is a more precise description of these culprits...

  • Cryptosporidiosis: In the past two decades, in many regions of the world, including the United States, a common water-related diarrhea disease that is increasingly been recognized as a major public health problem is cryptosporidiosis, caused by a microscopic parasite (Cryptosporidium). It is generally found in drinking water, swimming pools, and recreational streams that have been accidentally contaminated by human fecal wastes.