TRAIL — State public health officials Friday reissued a voluntary advisory warning people and pets against contact with Lost Creek Lake water after tests showed an outbreak of blue-green algae above levels considered unhealthy.

TRAIL — State public health officials Friday reissued a voluntary advisory warning people and pets against contact with Lost Creek Lake water after tests showed an outbreak of blue-green algae above levels considered unhealthy.

Friday's advisory marks the second time the lake has fallen under the public-health warning this year and the fourth straight September in which Jackson County's largest reservoir was hit with an algae bloom.

Water sampled Monday showed levels of aphanizomenon at more than 25 times the level deemed to be safe for exposure, said Jennifer Ketterman, who heads the state's Harmful Algae Bloom Surveillance Program.

The samples also showed levels of anabaena flos-aquae of more than five times the healthy threshold, Ketterman said.

Aphanizomenon and anabaena flos-aquae are both technically bacterium and along with mycrosystis form a threesome of so-called blue-green algae that plague Oregon lakes in summers and fall. They can produce toxins that can be harmful to people or pets.

The lake, which feeds the Rogue River, had a similar advisory beginning in June that lasted three weeks.

Corps officials started posting warning signs at lake boat ramps and swimming areas to inform lake-users of the strictly voluntary advisory.

Dangerous toxin levels have never been found at Lost Creek Lake or any other Oregon lake or reservoir. But illnesses and deaths have been documented worldwide, and public health officials nevertheless report its presence and issue advisories as precaution.

There has never been a confirmed human illness in Oregon caused by the algae or its related toxins, though two dogs have died, one in each of the past two years, from algae-related toxins consumed from a large, stagnant puddle along the Umpqua River near Elkton.

Ketterman said the water sampled at Lost Creek Lake was near the spillway.

"But we know from other blooms that they can move around in the water body," Ketterman said.

Under the state public health guidelines, visitors are advised to avoid swallowing lake water.

Anglers are encouraged to practice catch-and-release fishing. People who eat fish from algae-tainted waters should remove all fat, skin and organs before cooking because toxins can collect there. People should not eat crayfish or freshwater shellfish taken from infested lakes during an advisory.

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