Waterborne cryptosporidiosis

Waterborne disease outbreaks due to parasites and other etiologic agents have increased in the U.S. for the past 20 years despite regulations and measures taken to ensure safe drinking and recreational waterfor all. More waterborne disease outbreaks were reported during 1971 to 1985 than during any 15-year period since 1920. During this interval, 502 outbreaks involving 111,228 cases of illness were reported to the Centers for Disease Control (CDC) and the U.S. Environmental Protection Agency (USEPA). ¹⁷⁸ Of these, 92 (18.3%) involving 24,365 individuals were directly attributable to the protozoan parasite, Giardia lamblia, making it the predominant cause of identifiable waterborne disease. For all the outbreaks during the 1971 to 1985 period, the responsible agent was identified only 50% of the time.