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C;ryptosporidium (part 1 of 2) Page 1 of 13 �• �-i� .� s,�N wuNC�eco PubGc Utilities Commisaion Cryptosporidium (part i of 2) This paper summarizes relevant information and current research issues on Cryptosporidium relevant to its public health significance in water supplied. From this assessment, suggestions are made for actions to be taken by the San Francisco Public Utilities Commission Background To safeguard public health, regulations have been promulgated regarding drinking water authorized by the 1986 Amendments to the Safe Drinking Water Act. A pertinent piece of legislation is the Surface Water Treatment Rule, which was enacted by both the United States Environmental Protection Agency and the State Department of Health Services (DHS) in June 1989 and 1991, respectively. San Francisco is under a compliance order to meet this regulation by 1999. The purpose of the Safe Drinking Water Treatment Rule is to minimize microbial risk due to parasites (i.e., Giardia), bacteria (i.e., Legionella) and viruses from surface water suppiies. While this rule does not place limits on Cryptosporidium due to lack of information, it has, however, become of great interest due to recent outbreaks in England and in North America. Cryptosporidium will be regulated under the Enhanced Surface Water Treatment Rule (interim rule to be promulgated in 1998 with a long-term version to be promulgated in 2002); watershed monitoring will be an essential element as well as removal or inactivation requirements. History Cryptosporidium was first described in 1907 by Ernest Edward Tizzer. His work was not regarded as important at the time, and half a century passed before Cryptosporidium became of minor interest in association with the incidence of cryptosporidiosis in turkeys. Interest in Cryptosporidium heightened in 1971 when Cryptosporidium was found to be associated with diarrhea in cows. In 1976, the first cases of human cryptosporidiosis were reported. After that, relatively few cases were reported until 1982, when cryptosporidiosis was associated with protracted diarrhea in patients with acquired immune deficiency syndrome (AIDS).�-is This finding stimulated intense medical and veterinary interest in the epidemiology, diagnosis, treatment, and � prevention of cryptosporidiosis. The first reported human outbreak of cryptosporidiosis due to water supply occurred in Texas in 1984 concurrently with an outbreak of Norwalk virus. This was followed by the second largest North American outbreak in Carrolton, Georgia, in 1987, where over 13,000 people were affected. Two outbreaks of Cryptosporidium occurred in the United Kingdom in 1988; the larger in December 1988 affected approximately 5,000 people. Since this time, several smaller outbreaks have occurred in the United http://sfwater.org/printContent.cfin/C ID/446/ 10/19/2004