A health alert remains in effect for Willow Creek Reservoir in Pierce County as blue-green algae continues to release toxins into the water.

The Nebraska Department of Health and Human Services and other agencies issued an alert for the reservoir last week. Swimming is prohibited.

An earlier alert for Red Willow Reservoir near McCook has been lifted.

The state plans to monitor 47 lakes through September.

People can still camp, fish and boat on lakes under the alert, but should not have full-body contact.

The algae, which scientists say are plantlike bacteria, are common in freshwater. Some types can produce dangerous toxins.

Drinking toxin-tainted water can cause vomiting, diarrhea, respiratory failure and, rarely, death.