State warns about bacteria in Silver Lake

State health officials warned swimmers at Silver Lake State Park in Hollis might contain dangerous levels of harmful bacteria.

The state Department of Health and Human Services issued a public health advisory Thursday afternoon after preliminary tests showed that the water might contain Shigella bacteria. Further tests are being conducted now, according to the department.

The department received reports of five people getting sick after swimming in the lake. Four of them proved to have illnesses caused by Shigella bacteria, including fever, diarrhea, and stomach cramps starting a day or two after being exposed to the bacteria, according to a DHHS statement.

The public health advisory was a “proactive” step, according to the department.

DHHS and the state Department of Environmental Services have also tested the lake for E. coli, which is an indicator of sewage contamination, and the levels were below state standards for public beaches, according to DHHS.

Shigella is usually spread from person to person or through contaminated food, according to Dr. Jose Montero, DHHS director of public health. He advised that, although it hasn’t been confirmed that Silver Lake is the source of the mini-outbreak, swimmers there should take precautions, including washing hands before eating.

Anyone who experiences Shigella symptoms, which usually clear up in five to seven days, should seek medical attention to be tested, according to DHHS.

More information about Shigella or “recreational water illness” can be found at, the Centers for Disease Control and Prevention at, or by calling the state Communicable Disease Control and Surveillance Section at 271-4496.