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Cryptosporidium (p� 2 of 2) Page 8 of 11 � � f3-30 flows, treating high turbidity water, washwater handling, etc.) is planned to determine how plant operations can adapt to adverse conditions and protect against parasite breakthrough. Major upgrades are under design at our Sunol Valley Water Treatment Plant. ■ Watershed Sanitary Survev - A comprehensive watershed survey has been conducted which (1) identlfies the origin of the Cryptosporidium oocysts (i.e., sampling major tributaries into reservoirs, camping areas, septic tanks, stables, etc.), (2) evaluates the transport and fate of the oocysts, and (3) determines the degree to which the oocyst sources can be controlled. The recommendations for watershed management are under development. ■ Risk Communication - The SFPUC is devetoping an education pian for presenting information on risks and mitigative measures to sensitive populations. These four activities are planned for completion by the end of 1998. Possib/e Furure Studies In addition to the studies currently being conducted by the SFPUC, the following studies will also be valuable: ■ Exposure Assessment - If a current seroprevalency research project examining the contributions of water to the degree of exposure of a population proves successful, it would be advisable for San Francisco to conduct similar studies to ascertain the contribution of exposure un�itered water presents to the various affected populations. This may be the key piece of data needed to determine the refative significance of water in cryptosporidiosis cases. ■ Imaroved Samvle Method Deve%pment - In light of the importance of Cryprosporidium and the SFPUC's current unfiltered status, it may be prudent to join in efforts to further development of Cryptosporidium detedion methods. ■ Assess Willingness to Pay - Since some populations are more impacted than others, it may aid policymakers to quantify the amount various individuals are willing to pay for different treatment improvements (e.g., ozonation, �Itration, and point of use devices). Such determinations need to use the rigorous methods developed in survey research. ■ Molecular Epidemio%gical Srudies - Using recently developed methods, it should be possible to type and subtype Cryptosporidium parvum isolates. This will allow matching of the organism shed by the infected person and the source of the organism. To address the waterborne route, SFPUC needs to start collecting and storing water samples until a case of cryptosporidiosis is reported. Once the organism from the infected person is isolated and typed, an attempt could be made to match this to an organism found in the stored water samples. If a positive match is made, this would implicate the water route. If the organism matched that from a pet, a member of a family, etc., then these would be the suspected routes of infection. Such a study would provide definitive answers to whether there is a link between the drinking water and cryptosporidiosis. http://sfwater.org/printContent.cfrn/C_ID/445/ 10/19/2004