The Virginia Department of Health will continue enhanced surveillance for reports of E. coli exposure through July 17 but has closed its investigation into the outbreak that sickened more than two dozen people at Lake Anna over Memorial Day weekend.
The health department did not find a specific cause and closed its investigation on June 28, saying that no new cases had surfaced and that it did not expect any new cases related to Memorial Day weekend.
“It is likely that the STEC infections are a result of exposure to lake water over Memorial Day weekend,” the department said of the Shiga toxin-producing E. coli strain.
Some 25 people, mostly children, got sick. Of those 23 had been to the lake between May 24 and 27 and the others had close contact with a person who had the infection. The confirmed and suspected cases involved people between the ages of 1 and 45.
E. coli causes gastrointestinal illness, including stomach cramps, diarrhea, vomiting, fever, and chills. Infections can be serious, according to the Centers for Disease Control and Prevention. Seven cases of hemolytic uremic syndrome were reported. The syndrome affects a person’s kidneys and blood-clotting ability.
“Laboratory testing by the Virginia Department of General Services Division of Consolidated Laboratory Services (DCLS) was not able to identify STEC O157 bacteria in water samples from the lake. Additionally, VDH was not able to identify the source of the bacteria in the water,” the health department said in a news release.
As part of the investigation, water testing was done on June 11, June 17, and June 25 at six locations on Lake Anna. The health department said that the testing for fecal bacteria “did not show levels that typically rise to public health concern.”
Different testing was done on June 25 by the Virginia Division of Consolidated Laboratory Services, the health department said on a webpage set up after the outbreak.
“STEC O157 was not found in any of the samples. Genetic material from non-O157 STEC bacteria was identified in the Sandbar and Cocktail Cove samples. This initial test cannot specify if the genetic fragments are from live or dead bacteria. When DCLS did more testing, live bacteria could not be found,” the department said.
The health department previously said that potential sources of E. coli involved environmental pollution from heavy rains, livestock, failing septic systems, boating discharge, and swimmers.
With lots of people expected on Lake Anna for the July 4 holiday, the health department said its enhanced surveillance though July 17 will involve monitoring emergency department and urgent care visits for gastrointestinal illnesses.
Unrelated to the E. coli outbreak, the upper section of the North Anna Branch of Lake Anna in Louisa County remains under a swimming advisory due to harmful algal blooms.
“Some harmful algae, called cyanobacteria, can cause skin rash and gastrointestinal illnesses, such as an upset stomach, nausea, vomiting and diarrhea,” the department said when it issued the advisory in June.
Feature image by Matthew Carroll/stock.adobe.com
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