The origin of most common waterborne pathogens in the United States can be traced to the fecal wastes of animals and humans (see Table Path-1) (USEPA 2001, 2013; Hilborn et al. 2013; Hlavsa et al. 2014). Other pathogenic microorganisms, such as Legionella, Naegleria fowleri, Vibrio spp., and Pfiesteria, occur naturally in waters and can multiply in response to environmental changes such as increased water temperature (Legionella) or excess nutrients (Pfiesteria) (ASM 1998). More than 100 different types of pathogens can be found in contaminated water (ASM 1998).
Waterborne pathogens spread to humans through ingestion of contaminated drinking water, exposure to contaminated water from recreational activities like swimming, or indirectly through contaminated food (Rose et al. 2001; Charron et al. 2004). Outbreaks of waterborne illness are most prevalent in economically disadvantaged communities where water supplies and sanitation are often inadequate. Human exposure can cause gastrointestinal, respiratory, eye, ear, nose, and throat irritation; skin diseases; impairment of cells of the digestive tract and organs; and life-threatening infections in people with depressed immune systems (see Table Path-1) (USEPA 2001).
Many waterborne pathogens are difficult to identify and isolate. As a result, scientists and public health officials typically monitor nonpathogenic fecal indicator bacteria (FIB) (e.g., fecal coliform, E. coli, and fecal streptococci and enterococci), which are currently a leading cause of stream/river water quality impairment and coastal shoreline impairment in the United States (USEPA 2015; Pandey et al. 2014). FIB are more easily detected and point to the possible presence of pathogens associated with fecal waste (USEPA 2001). FIB are not, however, considered to be effective as an indicator of enteric viruses and protozoa from fecal waste or naturally occurring waterborne pathogens (Fujioka et al. 2015). State and federal recreational water quality standards commonly include criteria for three FIB: E. coli, enterococci, and fecal coliform bacteria (USEPA 1986, 2001, 2012).


Sura Hasan Hasnawi
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