More than 2 million people die each year from diseases such as cholera, typhoid, and dysentery that are spread by contaminated water or by a lack of water for hygiene. These illnesses have largely been eradicated in developed nations, although outbreaks can still occur. In 1993 an infestation of cryptosporidium, a protozoan that causes gastrointestinal illness, killed 110 people and sickened an estimated 400,000 in Milwaukee, Wisconsin. The city's water treatment system was in compliance with federal and state regulations at the time, but after the outbreak federal regulators increased testing requirements for turbidity (cloudiness) in drinking water, an indicator of possible contamination.
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