Public health officials hope water samples taken Thursday from Willow Lake will lead to the end of an advisory against water contact prompted by the appearance of a potentially toxic blue-green algae bloom in April.

Public health officials hope water samples taken Thursday from Willow Lake will lead to the end of an advisory against water contact prompted by the appearance of a potentially toxic blue-green algae bloom in April.

But even if those samples show algae levels are dying off, the advisory that has kept campers and anglers away from the High Cascades reservoir likely will not be lifted until after Memorial Day.

The algae die-off could release toxins considered dangerous to people and pets, so health officials typically wait two weeks after receiving an all-clear test before lifting the voluntary advisory. In this case, that would be June 3.

"The advisory's still in effect," said Jennifer Ketterman, the program coordinator for the state Department of Human Services' Harmful Algae Bloom Program. "Hopefully, we'll have some good news here soon."

A lifting of the advisory can't come soon enough for Dick Goodboe, whose business called Rogue Recreation operates the Willow Lake Campground and other facilities under a contract with the county.

"They've stayed away in droves," Goodboe said. "No day-users. No campers.

"It's a big overkill," he said. "But we'll make due with what we got."

Despite cold-weather conditions not normally associated with algae blooms, Willow Lake in mid-April sported levels of blue-green algae that were 52 times higher than World Health Organization thresholds considered safe for contact by people and pets.

Under the advisory issued April 21, people and animals should avoid swallowing or inhaling water droplets and skin contact with the water. Health officials also warned people not to eat crayfish or freshwater shellfish taken from Willow Lake while the advisory is in effect.

However, boating and catch-and-release fishing were not part of the advisory, and people can safely eat fish caught during the advisory if they first remove all fat, skin and organs.

Public health officials advise campers and other lake visitors that toxins cannot be removed by boiling, filtering or treating the water with camping-style filters.

Blue-green algae has been the bane of inland Oregon waterways this decade. The toxin prompted 29 public health advisories last year alone.

Willow Lake remained Thursday as the only Oregon water body under a harmful algae advisory, Ketterman said.

No human illnesses have been directly linked to the algae in Oregon since DHS officials began issuing public health advisories in 2004, records show. However, a dog died from algae exposure last summer along the Umpqua River near Elkton.

The cause of the Willow Lake outbreak is unknown.

Reach reporter Mark Freeman at 541-776-4470, or e-mail at mfreeman@mailtribune.com.