The following is a release from the Snohomish County Health District:

Swimming or playing in water that is contaminated or high in bacteria or natural toxins can affect your health. Swimming pools, spas, lakes, rivers, or oceans are all potential sources of water-related illness. Recreational water illnesses typically affect a person’s stomach and intestines, causing diarrhea and vomiting. Water quality can also affect your skin or respiratory system.

The recent outbreak of illness at Horseshoe Lake in Kitsap County was caused by norovirus found in the water at the swimming beach. The lake is closed until testing from the Centers for Disease Control and Prevention confirm that the virus is no longer present.

While Snohomish Health District has investigated a handful of illness reports related to local lakes, no common cause or illness has been identified. “We’ve seen nothing to indicate an outbreak of water-related illness here,” said Health Officer Dr. Gary Goldbaum.

The Health District is working with the Snohomish County Parks Department and city beach programs to ensure that required public health warnings (PDF) are present at beaches, including this language:

“The swimming waters at this beach are not treated to control spread of disease. Swimming beach water, if swallowed, can sometimes cause illness because of bacteria, viruses or parasites in the water. All beach users should follow bathing beach recommendations to prevent contamination of the water and should avoid swallowing of any beach water.”

Recreational water illnesses such as norovirus, cryptosporidium, giardia, shigella, and E. coli have the potential to infect a person who accidentally swallows or has contact with contaminated water. In most instances, the symptoms of diarrhea and vomiting will improve one to two days after you get sick. Some people get dehydrated or have other side effects, and need to see a doctor.

“Lake water is not the same as drinking water,” Dr. Goldbaum reminds children and parents.

If you think you got sick from a public water or food source – such as a swimming beach, campground, or restaurant – contact the Snohomish Health District at (425) 339-5278.

We will ask you questions about what you ate and where you’ve been over the past several days to try to narrow down the many possible causes of illness.

For more tips on keeping safe while swimming, see the Hot Topic page of our website.