State completes investigation into bacterial outbreak in Lake Anna

The agency said more than 20 days have passed since the last person to visit Lake Anna was infected. The agency took samples from the lake after 25 people became ill following the holiday weekend in late May. Neither those tests nor the most recent samples taken on June 25 were able to identify the bacteria in the water, the health agency said in a statement Tuesday.

The health department was unable to locate the source of the bacteria.

The state agency announced on June 6 that it was investigating a cluster of gastrointestinal illnesses among people who had been in the Lake Anna area over the holiday weekend. Three of the four cases were children infected with E. coli.

It turned out that those affected were suffering from what is known as Shiga toxin-producing Escherichia coli (STEC). Severe cases of STEC can develop into hemolytic uremic syndrome and can be particularly serious, the state said.

The health department noted that the June 25 tests were a “snapshot at a specific location” conducted four weeks after the outbreak, so “the results may not reflect the water environment during the holiday weekend.”

In light of the July 4 holiday, the health department announced it will conduct enhanced public health surveillance through July 17. This will include monitoring visits to emergency rooms and urgent care clinics and investigating any reports of bacterial cases if they occur.

The Department of Environmental Quality will also continue to regularly test the lake for bacteria. This testing is carried out annually between April and October.

Although the bacteria problem appears to have disappeared, the North Anna Branch of the lake is still closed to swimming due to harmful algal blooms. This harmful algae has plagued parts of the lake for the past six summers and is not related to the bacteria outbreak.

The 13,000-acre man-made lake, which cools the Dominion Energy North Anna nuclear power plant, is a popular spot in the summer, but algal blooms have placed it on the state’s impaired waterways list in 2022.