People should stay out of the Jordan River and keep their dogs from swimming in or drinking the water, the Utah Department of Environmental Quality is warning, because of an outbreak of the algae-related toxin cyanobacteria.

The DEQ announced Tuesday that low levels of anatoxin-a, a toxin produced by growth of blue-green algae, have been detected at three recreation areas along the Jordan River and its tributaries:

• Jordan Narrows, north of Lehi’s Thanksgiving Point.

• Blackridge Reservoir in Herriman.

• And the east canal of Wheeler Farm in Murray, which lies along Little Cottonwood Creek, which feeds into the Jordan.

The Salt Lake County Health Department is warning residents not to swim in the river. Signs are being posted at Blackridge Reservoir and Wheeler Farm because they are popular recreation spots, the DEQ said.

No bodies of water in Salt Lake County are expected to be closed, but the DEQ is advising caution because algae and toxins can spread quickly.

In Utah Lake, algae levels remain dangerously high at Lincoln Marina, Lincoln Beach and Lindon Marina, and signs are posted.

Symptoms of exposure can include headaches, fever, gastrointestinal distress, abdominal pain, nausea, vomiting, and allergy-like reactions on the skin. DEQ recommends that anyone who has concerns about exposure should contact Utah Poison Control at 800-222-1222, or a health care provider.