1993 Cryptosporidium Outbreak

Contamination of Milwaukee city water supply with cryptosporidium Early in 1993, there was an outbreak of flu-like symptoms in many people in the Milwaukee area. After some investigation, city inspectors realized the city water supply had been contaminated by cryptosporidium, which various testing and filtering systems had failed to detect and screen out. It is estimated that over 400,000 people were sickened, and approximately 100 people died (according to some reports, concentrated among people with AIDS).