Cholera is one of the most severe and contagious diseases transmitted by water. It is marked by severe diarrhea, resulting in fluid loss and dehydration, sometimes followed by shock and death. If not treated, mortality occurs in over 60% of cases. The Latin American cholera epidemic claimed 4,002 lives in 1991, and resulted in 391,742 reported cases that year, mostly in Peru and Ecuador. Cholera is caused by the bacillus Vibrio cholerae, a member of the family Vibrionaceae, which are described as Gram negative, non-sporulating rods that are slightly curved, motile, and have a fermentative metabolism.

The natural habitat of V. cholerae is human feces, but some studies have indicated that natural waters may also be a habitat of the organism. Fecal contamination of water is the most common means by which V. cholerae is spread, however, food, insects, soiled clothing, or person-to-person contact may also transmit sufficient numbers of the pathogen...