Health department closes investigation into E. coli cases in Lake Anna

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The Virginia Department of Health will continue its enhanced surveillance for reports of E. coli exposure through July 17, but has suspended its investigation into the outbreak that sickened more than two dozen people at Lake Anna over Memorial Day weekend.

The health department could not find a specific cause and concluded its investigation on June 28, reporting that no new cases had occurred and that no new cases were expected in connection with the Memorial Day weekend.

“It is likely that the STEC infections are a result of contact with lake water over Memorial Day weekend,” the department said of the Shiga toxin-producing E. coli strain.

About 25 people, mostly children, became ill. 23 of them had been at the lake between May 24 and 27 and the others had been in close contact with an infected person. The confirmed and suspected cases affected people between the ages of 1 and 45.

E. coli causes gastrointestinal illness, including stomach cramps, diarrhea, vomiting, fever, and chills. According to the Centers for Disease Control and Prevention, infections can be serious. Seven cases of hemolytic uremic syndrome have been 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) failed to identify STEC O157 bacteria in water samples from the lake. In addition, VDH was unable to identify the source of the bacteria in the water,” the health department said in a press release.

As part of the investigation, water tests were conducted at six Lake Anna locations on June 11, 17 and 25. The health department said the fecal bacteria tests “did not reveal levels that would normally raise health concerns.”

On June 25, various tests were conducted by the Virginia Division of Consolidated Laboratory Services, the Department of Health said on a website 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 indicate whether the genetic fragments came from live or dead bacteria. When DCLS conducted further testing, no live bacteria could be found,” the department said.

The health department had previously stated that pollution from heavy rains, livestock, broken sewage systems, boat runoff and swimmers were among the potential sources of E. coli.

Because large crowds are expected at Lake Anna for the Fourth of July holiday, the health department said its enhanced surveillance on July 17 will include monitoring emergency room and urgent care visits for gastrointestinal illnesses.

Regardless of the E. coli outbreak, a swimming warning remains in effect for the upper section of the North Anna Branch of Lake Anna in Louisa County due to harmful algal blooms.

“Some harmful algae, called cyanobacteria, can cause skin rashes and gastrointestinal disorders such as upset stomach, nausea, vomiting and diarrhea,” the agency said when it issued the warning in June.

Cover image by Matthew Carroll/stock.adobe.com

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