FAIRVIEW, Ore. -- The swimming area at Blue Lake Park was closed Tuesday after several people who visited the beach got sick afterward and officials said Friday the beach would remain closed through the weekend.
"The Multnomah County Health Department is looking into reports by 13 people who said they experienced some kind of vomiting or diarrhea after being in the water at Blue Lake,” said county spokeswoman Julie Sullivan-Springhetti.
The health department collected water samples Monday to figure out what was making people sick. But until officials get the results back, the swim beach will remain closed.
On Friday, officials said they had narrowed the areas of concern to the swimming beach and lake water. Both will remain closed through the weekend.
The park's playgrounds, bathrooms, drinking water, concessions and splash pad were deemed safe for visitors.
“Our initial impression is that the illness is due to norovirus or a similar stomach virus,” said deputy health officer Dr. Jennifer Vines.
Twice-weekly water samples have shown extremely low levels of E. coli and on Tuesday, that possibility was ruled out by health officials. The water was not tested for norovirus.
Norovirus is the most common cause of vomiting and diarrhea, Sullivan-Springhetti said. There is no treatment, but most people recover within 48 hours.
“Anyone with these symptoms should be sure to drink plenty of fluids and contact their healthcare provider with any concerns,” Vines said.
"Viruses and bacteria that cause diarrhea can be transmitted in shallow lakes when someone who is ill sheds stool in the water," Sullivan-Springhetti said. "Other swimmers can inadvertently swallow contaminated water and become ill."
She warned that people should not swim in Blue Lake, or even come in contact with the water.
An advisory was issued for Blue Lake Park last year when blue-green algae scum was found in the water. Health officials said Tuesday no algae blooms were found on the lake.