Waterborne Diseases

Waterborne diseases is the grouping term for those human diseases that are caused by organisms that can be transmitted by contaminated food and water (waterborne transmission). Such diseases include amebiasis, cholera, cryptosporidiosis, enteroviroses, giardiasis, hepatitis A and E, leptospirosislisteriosis, salmonellosis, and typhoid fever. Another potential source of waterborne infection is contaminated recreational water (e.g., important for schistosomiasis transmission). In some special cases, other transmission ways can occur (e.g., by skin in leptospirosis, Chagas disease). Waterborne diseases represent an important environmental threat that is currently a relevant aspect for the global public health, which should be considered in the new perspectives of a more ecologically green world in which such risks should be significantly reduced or even eliminated. The safety of food, drink, and drinking water depends mainly on the standards of hygiene applied locally in their growth, preparation, and handling. There is a high risk of contracting such organisms or microbial agents in countries with low standards of hygiene and sanitation as well as poor infrastructure for controlling the safety of food, drink, and drinking water.

Guinea worm disease is a parasitic infection that can be spread through contaminated drinking water. This pond in Ogi, Nigeria, which served as a source of water for this woman in 2004, had been treated to prevent breeding by water fleas, which harbor Guinea worm larvae.

Water quality is regulated by a complex system of federal and state legal provisions and agencies, which has been poorly studied. Some authors have surveyed state and territorial [Page 490]agencies responsible for water quality about their laws, regulations, policies, and practices related to water quality and surveillance of cryptosporidiosis related to drinking water. The development and current status of federal drinking water regulations and identification of conflicts or gaps in legal authority between federal agencies and state and territorial agencies have been assessed in some studies. However, it is important to consider the court-imposed limitations on federal authority with regard to regulation of water quality. Recommendations are made for government actions that would increase the efficiency of efforts to ensure water quality, protect watersheds, strengthen waterborne disease surveillance, and protect the health of vulnerable populations.

The etiological organisms related to waterborne diseases can be bacteria (including enteric and aquatic bacteria), fungi, viruses (enteric), and parasites (enteric protozoa).

Of these, bacteria are considered among the most important. Fortunately, waterborne outbreaks of bacterial origin (particularly typhoid fever) in developing countries have declined dramatically in the last decades. Therefore, some early bacterial agents such as Shigella sonnei remain prevalent, and new pathogens of fecal origin such as zoonotic Campylobacter jejuni and Escherichia coli O157:H7 may contaminate pristine waters through wildlife or domestic animal feces. The common feature of these bacteria is the low inoculum (a few hundred cells) that may trigger disease. The emergence in early 1992 of serotype O139 of Vibrio cholerae with epidemic potential in southeast Asia suggests that serotypes other than V. cholerae O1 also could initiate an epidemic. Cholera significantly affected some countries in the Americas in the same decade (e.g., Peru, Ecuador, and Colombia).

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