Yes. Escherichia coli (abbreviated as E. coli) are a large and diverse group of bacteria. Although most strains of E. coli are harmless, others can produce toxins that make you sick. These harmful strains are called Shiga Toxin-Producing E. coli (STEC). The most common type of STEC is E. coli O157:H7. Often when you hear news reports about outbreaks of E. coli infections, they are talking about E. coli O157:H7.

No. The Harmful Algal Bloom (HAB) is not the same as the STEC outbreak investigation. They are two separate, unrelated health concerns that happen to be occurring at the same time. 

HABs are not uncommon in Lake Anna but can be dangerous to the health of humans and animals in the area. The Virginia Department of Health has issued a swim advisory for some parts of Lake Anna as a result of this HAB. 

Separately, there was an outbreak of Shiga toxin-producing Escherichia coli (STEC) in people who were in the Lake Anna area around Memorial Day weekend. At this point, VDH does not expect to find new cases associated with the Memorial Day weekend exposure to Lake Anna. 

It is likely that these STEC illnesses are a result of people being exposed to bacteria in the water over Memorial Day weekend. We have not yet been able to confirm the presence of STEC O157 bacteria in the water samples; laboratory testing is still in progress. It is unlikely that VDH will be able to specifically identify the source of bacteria in the water. 

 Potential sources of STEC infections include environmental pollution from any of the following: 

• Heavy rains 
• Livestock 
• Failing septic systems 
• Boating discharge 
• Swimmers  

Consider the following steps to prevent getting sick from natural bodies of water, like lakes, rivers, or oceans.  

 Before visiting natural bodies of water: 

•  Check online before visiting. Check to see if the area is currently monitored, is under advisory, or has been closed for health or safety reasons. See the following for possible advisories: 
  • www.SwimHealthyVA.com for Harmful Algal Bloom (HAB) and coastal beach maps  
  • The Swim Guide for Citizen Monitoring Group results  
  • LACA’s Water Quality (WQ) and Cyanobacteria Data website 
• Avoid swimming for three days after a heavy rain. Germs can come from overflowing sewage, polluted storm water and runoff from land.  

 While visiting natural bodies of water: 

• Avoid swimming  
  • if you are sick with vomiting or diarrhea or if you have skin with cuts or open wounds 
  • near storm drains (pipes that drain polluted water from streets) 
  • in water if there is a green film on the water. Keep pets out as well. This film may mean that an algal bloom and some algae produce toxins are present. These blooms and toxins can make people sick.  
  • near the vicinity of livestock 

• Never swallow untreated water. Natural bodies of water contain germs and contaminants, which can cause illness.  
• Keep sand away from your mouth and children’s mouths. Sand contains germs that can cause illness if swallowed. 
• Do not poop in the water. 
  • Take kids on bathroom breaks and check diapers in bathrooms or diaper-changing areas.  
• Wash your hands after using the bathroom and before preparing and eating food. This is particularly important if you have been playing in or touching sand. 
• For people with boats: Use the proper methods to dispose human waste. Discharge boat sewage at marinas with a pump-out unit or dump station. 
  • See Pump-out locations around Virginia.  

After visiting natural bodies of water: 

• Shower or bathe after swimming to wash off possible germs and contaminants.  

 For recommendations on healthy practices during water activities, see www.swimhealthyva.com and CDC’s How to Safely Visit Oceans, Lakes, and Rivers website. 

People with stomach cramps, diarrhea, or other gastrointestinal symptoms should talk with their healthcare provider. 

People with diarrhea should drink plenty of fluids to prevent dehydration. Dehydration is not having enough water in the body. Talk to your healthcare provider before taking anti-diarrheal medication, such as Imodium®. People with STEC infections should not use anti-diarrheal medication. Using anti-diarrheal medication with STEC infection can increase the chance of hemolytic uremic syndrome (HUS). 

 It is best to stay home when you have diarrhea. The health department will give advice on each situation in which the person with STEC infection is a food handler, healthcare worker, childcare worker, or childcare attendee. Some people might not be allowed to go back to childcare or work until two stool specimens test negative for the bacteria. 

 If you are sick with gastrointestinal illness, be sure to follow safety practices so that you do not pass this on to other members of your household: 

• Always carefully wash hands before and after preparing foods. 
• Always carefully wash hands with soap and warm water after using the toilet or changing diapers. 

For this outbreak, DEQ collected water samples on June 11, June 17, and June 25 for 3 different tests: fecal coliforms, E. coli, and enterococci. Fecal coliforms are a broad category. E. coli and enterococci are more specific. These routine fecal bacteria tests help tell us if there is human or animal feces (poop) in the water. These tests are not able to identify all strains of E. coli or STEC that cause disease, like STEC O157.  

On June 25, DEQ also collected water samples for a different test that can look for strains of STEC that cause disease, like STEC O157. The test results are pending.  

In general, routine fecal indicator bacteria testing is thought to be a good at predicting if someone who is exposed to the water will become sick, but it has limitations. VDH initially understood the routine E. coli testing could detect E. coli strains that cause disease, like STEC O157. We later learned that it could not. The routine water testing conducted by DEQ and analyzed by DCLS, does not have the capability to test for STEC O157. Collecting water samples and testing for disease-causing E. coli, like STEC O157 requires a different type of water sample collection and lab test. 

Fecal indicator bacteria tests used in this investigation looked for fecal coliforms, E. coli, and Enterococci. They are reliable and widely used for analyses recommended by the Environmental Protection Agency (EPA). They are designed to look for fecal contamination.  

In general, the fecal indicator bacteria testing is thought to be a good predictor of if someone is exposed to the water will become sick, but it has limitations. They are not designed to detect all types of bacteria that can cause illness, including STEC O157.  

There are many different strains of E.coli. To target a specific strain, such as STEC O157, special collection procedures and laboratory testing are needed.  

DEQ will continue its routine monthly monitoring of Lake Anna that occurs during April to October each year. As part of this monitoring, water quality testing includes looking for fecal bacteria, E. coli. This DEQ's water quality monitoring data are available to the public through the Water Quality Data Portal: Water Quality Data Home. 

Lake Anna Civic Association (LACA) also conducts routine water quality monitoring on Lake Anna. More information on the water quality program conducted by LACA and their test results can be found at LACA’s Water Quality (WQ) and Cyanobacteria Data website. 

Yes. Water quality monitoring data are available at DEQ’s Water Quality Data Home. 

 DEQ's annual water quality monitoring plan, including an interactive map with station locations, is available to the public. 

VDH is taking the steps listed below to protect the public:

• Conducting a thorough outbreak investigation to determine who is affected, what is the cause, and how to prevent more illnesses.
• Sharing information with the public. To date, VDH has issued news releases on
  • June 6
  • June 14
  • June 21, 2024
• Asking the public, healthcare providers, and public health partners in other states to rapidly report suspected STEC cases.
• Working closely with our state laboratory, the Division of Consolidated Laboratory Services, to test samples from people who are ill and analyze environmental samples.
• Collaborating with the Virginia Department of Environmental Quality (DEQ) on the environmental health investigation. This involves reviewing results from routine water testing that DEQ had conducted before the outbreak began and collecting new water samples to see if there are any irregularities.
• Collaborating with Virginia Department of Agriculture and Consumer Services to better understand livestock access to Lake Anna.

No, VDH did not issue a public health advisory for Lake Anna. Most of the people with STEC infection reported swimming or other water activities in Lake Anna. These exposures occurred over the Memorial Day weekend (May 24-27). VDH did not identify STEC infections in people who visited the lake after that weekend. This tells us that the exposure period of greatest risk (Memorial Day weekend) had passed. Because there is always some risk of getting sick after visiting natural bodies of water, VDH emphasized steps people could take to lower their risk of getting sick.  

There are 2 main reasons why VDH is calling this outbreak over: 

• There have been no new cases among people who visited Lake Anna over the Memorial Day weekend. A total of 25 confirmed and probable cases have been reported, including 12 cases caused by STEC O157.  
• It has been more than 20 days (two 10-day incubation periods) since the last person who visited Lake Anna over the holiday became ill. 

VDH does not plan to provide any more regular updates to this website. VDH plans to provide a website update on July 5 when STEC water results are available for water samples collected on June 25. 

More information is also available: 

• For information about the types of illnesses, see VDH’s Shiga-Toxin Producing E. coli (STEC) Fact Sheet and Hemolytic Uremic Syndrome Fact Sheet 
• For recommendations on healthy practices during water activities, see www.SwimHealthyVA.com and CDC’s How to Safely Visit Oceans, Lakes, and Rivers website