Nebraska has issued a health alert for toxic algae for Swan Creek Lake in Saline County, while another alert remains in effect for Kirkman's Cove in Richardson County.

Officials say samples taken earlier this week show high levels of a toxin released by blue-green algae. The levels exceed the state's threshold.

Officials say the alerts for the two lakes in southeast Nebraska will continue for at least two more weeks.

People can still camp, boat and fish, but shouldn't swim in the lakes or drink the water. Ingesting toxic-tainted water can cause health problems, including vomiting, diarrhea and rarely, death.

Nebraska has been testing 49 public lakes since May.