Deschutes County health officials issued an advisory Tuesday about reported cases of "swimmer's itch" at Cascade lakes and said warning notices would be posted at the lakes where incidents have been reported.
However, the county advisory did not specify which lakes, and said the reports had not yet been confirmed.
"The problem is for us is that it's really hard for us to tell which lakes have it and which lakes don't," said Thomas Kuhn, a program manager with Deschutes County Public Health.
"A lake could have it one week, and then not have it the next week," he said. "So it's something that you just have to keep an eye on and look for patterns."
Forest Service officials confirmed that they will be putting up signs at South Twin Lake, warning visitors of the potential of catching swimmer's itch while in contact with those waters.
Here's the county's advisory, in its entirety:
Deschutes County Health Services has received several reports of rash and bite-like symptoms from persons recently bathing at area lakes. Although none of these reports have been confirmed, it is likely that they may be suffering from “Swimmer’s Itch.”
Swimmer’s Itch is caused by an allergic reaction to parasites found in some birds and mammals. Humans can be exposed to the parasites when working, wading or swimming in lakes and streams. The parasites are released into fresh and salt water from infected snails.
Rather than finding a host bird or animal, the parasite burrows into the skin of a swimmer, causing an allergic reaction and rash. It cannot be spread from person to person and symptoms may last up to a week.
Deschutes County Health Services is working with the U.S. Forest Service to post notices at associated lakes.
What are the symptoms?
• The skin might tingle, burn or itch.
• Small red spots on the skin which begin to itch within 12-hours of exposure.
• Itching may last up to a week or more.
• Symptoms are caused by an allergic reaction, so the more often you swim or wade in contaminated water, the more severe the symptoms get.
How is it treated?
If you find yourself itching after swimming:
• Get out and towel-off briskly; this helps to remove the tiny larvae that cause the itch.
• Shower as soon as possible after a swim.
• Treatment is supportive only, with-over-the-counter anti-itching ointments or lotions.
• Apply a cool compress to the affected areas.
• Try not to scratch the irritated area of skin because this may cause the rash to become infected.
• If itching becomes prolonged, see your doctor for additional treatment.
How is it prevented?
• Avoid still pools of non-chlorinated water, especially on warm days.