Good News! No New Cases! — Lake Committee
Lake Committee Report
With summer coming to an end, it’s a good time to provide an update on the status of this year’s lake program. The best news is that there have been no new cases of O157:H7 reported to the Health Department this year. The Health Department continued their “Swim at Your Own Risk” advisory for the Lake all summer, and the Association provided easy access to the test data to help people make informed decisions.
A conservative approach was taken to help ensure no other illnesses occurred, and affected beaches were closed anytime the O157:H7 strain was detected at or near a beach. Safety was the primary concern.
The increased lake monitoring and research that was instituted this year in response to last year’s E. coli O157:H7 outbreak was discussed at the town hall meeting on May 23 and described in a series of e-Bits articles earlier this summer.
A progress report on the project was prepared for the County Health Department and released on July 18. That report was also posted on the Association website for the community.
Much new information has been developed since the progress report was prepared. This year’s monitoring/research program will end in early October, and a comprehensive report and analysis of the findings will be prepared at that time.
A copy of the July 18 progress report was also sent to the State Water Resources Board. The report generated increased interest in the Lake Wildwood issues at the state level, and three staff members from the Water Board visited Lake Wildwood on Sept. 6 to learn more about the Association’s efforts to address the outbreak.
One of the Water Board staff that was here is the person currently working on the elevated E. coli problems in the American River. While we don’t have firm commitments yet, there was a strong indication that the State would assist Sierra Streams Institute and provide the expertise to conduct a sanitary survey. A sanitary survey is a defined process where one identifies potential sources of contamination and would be the first step in conducting a watershed source study.
On July 26 the County held a meeting for watershed stakeholders to hear and review a draft of the advisory report from John Griffith, the consultant hired by the County to provide technical guidance. The meeting was attended by representatives from the county Public Health and Environmental Health departments, the county Sanitation District, Lake Wildwood, Nevada Irrigation District and Nevada City (Wastewater Treatment Plant).
In addition, there was a representative attending remotely by conference call from each of the California State Health Department, the California State Water Board and the Centers for Disease Control. Dr. Griffith presented his review remotely using an online slide presentation.
From the Lake Wildwood perspective, the report was disappointing. It was a summary of information we already knew. In short, it primarily recommended that a source study be conducted that was estimated to cost on the order of $300,000 and then mitigate the sources. Alternatively, the Association could institute an STEC (shiga toxin E. coli) monitoring program.
It would be inappropriate to present definitive conclusions from the Association’s monitoring program this year before the testing and data analyses are completed. There are some general observations that have been alluded to that can be confirmed. The expanded monitoring program in conjunction with voluntary lakefront homeowners’ water testing established that there is not lake-wide microbial contamination present in Lake Wildwood. The indicator E. coli problem in the Lake is confined to the shallow water at the shoreline of the sandy beaches at the Parks, with the greatest levels of contamination occurring at two of the five Parks this year.
The experimental test that was employed to test directly for the O157:H7 strain has proved to be very promising. Validation testing is still in progress for many samples but the presence of the O157:H7 E. coli strain was confirmed in the stream flowing into the Lake at Meadow Park. Our test results for that creek were also confirmed by CDC.
The CDC lab performed “genetic fingerprinting” analysis on the O157:H7 strain detected in the Meadow Park creek and reported that it was not a genetic match to the strain that caused the illnesses last year. We cannot confirm at this time that the Meadow Park creek was the source of the outbreak. Since then, E. coli O157:H7 has also been detected in other locations outside of the Lake but confirmation testing is still pending so it is premature to list those locations until the tests are validated.
Given the experimental nature of the O157:H7 test we are using, we concentrated our efforts and available resources on evaluating the test for water and sand samples. Recently a sample of goose feces was tested just to see if there would be problems with that kind of sample. The goose poop was positive for E. coli O157:H7. That result is also still awaiting independent confirmation. If it confirms, we may have a simple tool available to better assess the role of the geese in transporting or amplifying the O157:H7 strain. There is little doubt at this point that geese are responsible for the high levels of generic E. coli measured at the Beach shorelines.
The formal testing program for this season will end in a couple weeks. It is anticipated the final report of the Association’s program this summer will be available later in the fall and will include a detailed discussion and potential recommendations.
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