The Multnomah County Health Department is working closely with Blue Lake Regional Park officials to investigate reports of diarrheal illness from people who visited the lake the weekend of July 12 and 13.
As a precaution, park officials closed the lake to swimming the morning of Monday, July 14, after two families reported several people in both parties having a combination of diarrhea, vomiting, rash and cramps. The Multnomah County Health Department Communicable Disease program is investigating the reports today to determine what kind of diarrheal illness this is and whether it can be traced to swimming in the lake.
“Our initial impression is that the illness is due to norovirus or a similar stomach virus,” said Deputy Health Officer Dr. Jennifer Vines. Park officials collected water samples for E coli testing yesterday as a precaution. Routine water samples from earlier this month showed low levels of E coli. The water samples are not tested for norovirus.
Outbreaks of both norovirus and E coli have been associated with Blue Lake in the past.
Norovirus is a very common cause of vomiting and diarrhea. There is no treatment and most people recover in 24 to 48 hours. The very young and elderly can suffer dehydration as a complication. “Anyone with these symptoms should be sure to drink plenty of fluids and contact their health care provider with any concerns,” added Dr. Vines.
Viruses and bacteria that cause diarrhea can be transmitted in shallow lakes when someone who is ill sheds stool in the water. Other swimmers can inadvertently swallow contaminated water and become ill. Park officials take precautions to promote water flow and minimize risk to bathers.
The Health Department will continue to work closely with park officials to determine when it is safe to re-open the lake and will provide an update later today.