Department of Health Extends Swimming Advisory for Lake Anna

Virginia Department of Health (VDH) has extended a swimming advisory for Lake Anna as a harmful algae bloom continues. The VDH cautioned this algae bloom is not connected to the Shiga toxin-producing Escherichia coli (STEC) outbreak that occurred after Memorial Day.

According to the VDH, some harmful algae, called cyanobacteria, can cause skin rashes and gastrointestinal illnesses. Algae blooms can occur when warm water and nutrients combine to make conditions favorable for algae growth. Most algae species are harmless; however, some species may produce irritating compounds or toxins. Avoid discolored water or scums that are green or bluish-green because they are more likely to contain toxins.

The VDH’s Harmful Algal Bloom map shows which areas to avoid, and VDH provides a status report containing the updated advisory areas.

The sections of the lake currently under a swimming advisory due to unsafe levels of cyanobacteria are:

North Anna Branch (advisory extended)

• Upper North Anna Branch – From the upper inundated waters of the North Anna arm, to include the “Sandbar” of the lake and downstream to the Route 522 Bridge.
• Upper and Middle North Anna Branch – From the Route 522 Bridge, to include Route 719 (Holladay Bridge), to Lumsden Flats at Rose Valley Drive

Pamunkey Branch (advisory added)

• Upper-Upper Pamunkey Branch- From the upper inundated waters of Pamunkey Branch to Runnymede Park
• Upper Pamunkey Branch – From Runnymede Park to the confluence with Terry’s Run
• Middle Pamunkey Branch – From confluence with Terry’s Run to Route 612 (Stubbs Bridge)

The VDH will lift the advisory when algae concentrations return to acceptable levels. Follow-up monitoring above Route 208 on the lake is planned (weather permitting) for the week of August 15.

The warning comes after children were sickened and hospitalized at the popular vacation destination on Memorial Day, prompting The Virginia Department of Health (VDH) to investigate. On July 2, VDH reported the case closed and noted that recent water samples from Lake Anna showed no presence of Shiga toxin-producing Escherichia coli (STEC) O157, leading to the conclusion of their STEC outbreak investigation linked to Memorial Day weekend.

VDH noted it had been over 20 days since the last reported illness from the lake, and laboratory tests did not find STEC O157 bacteria in the samples. However, a swimming advisory remains in effect for the upper section of the North Anna Branch of Lake Anna due to unrelated harmful algal blooms (HABs).

VDH advises the public to follow safe water practices, such as avoiding swallowing untreated water, washing hands frequently, and avoiding swimming after heavy rain. Enhanced public health surveillance would continue through mid-July. VDH and the Virginia Harmful Algal Bloom Task Force will keep monitoring water quality.