On April 7, Milwaukee Mayor John Norquist warned residents the city's water supply had become contaminated with an intestinal parasite.
Residents were told to boil water. The parasite, cryptosporidium, is a protozan that normally lives in the intestines of animals. It is not affected by normal chemical water treatment methods.
Rains washing animal waste into Lake Michigan, the city's reservoir, were blamed for the contamination.
More than 280,000 people were sickened during March and early April. As many as 50 people with impaired immune systems died.
