Record-high levels of toxic algae were detected this week at Isabella Lake, leading county health officials to issue an urgent warning Friday against touching water at the popular access points of Paradise Cove and Kissack Cove, and to be extra cautious at French Gulch and other parts of the lake. Kern County Public Health Director Matt Constantine said state testing found concentrations of blue-green algae 20 times the level considered dangerous at Paradise and Kissack. Never have such high levels been seen in the Central Valley, he added. The naturally occurring cyanobacteria are apparently thriving as a result of climate changes, stagnation and nutrients found in the lake, Constantine said. He was unable to elaborate. The algae look greenish or bluish, and can also appear as a foam. The bacteria can cause rashes, neurological problems and even death. They can be especially dangerous for pets and livestock. No instances of harm have been confirmed in Kern County. "If you see the green algae there, let's avoid it," said Kern County's 1st District supervisor, Mick Gleason, who joined Constantine at a Friday morning news conference. Gleason said the county will retest and expand testing of the lake water. Cyanobacteria are believed to be present in other parts of Isabella Lake and may also exist in the Kern River, though concentrations are thought to be lower there because of the river's fast flow. No recent tests have been done in the river. Public health officials have posted signs around the lake's popular access points and are handing out flyers warning of the safety risks. Constantine said no measures to address the algae bloom directly are currently contemplated. "Unfortunately, in Kern County, this is something we're going to have to live with," he said.