Algae Deadly To Dogs, Toxic To People May Be Back In Illinois Lakes

ILLINOIS — As the beginning of summer nears and Illinoisans venture into the great outdoors, the state health department is warning nature lovers that at least one aspect of the outdoors is not so great in the summer: cyanobacteria blooms.

The blue-green algae are microscopic organisms that naturally occur in lakes, streams and ponds, and they can produce chemicals that are toxic to both people and pets, according to the Illinois Department of Public Health.

Local officials are advised to post signage warning of waters that are confirmed to be affected, although not all algae blooms are reported to the state, according to the health department. As a result, people should avoid water that:

• Looks like spilled green or blue-green paint.
• Has surface scums, mats or films.
• Has a blue or green crust at the shoreline.
• Is discolored or has green streaks.
• Has greenish globs suspended in the water below the surface.

The most common routes of exposure to cyanobacteria are skin contact, ingestion of contaminated water, or inhalation of droplets in the air, the health department said. Young children, the elderly and immunocompromised people are most at risk of developing adverse health effects, such as rashes, hives, diarrhea, vomiting, coughing or wheezing.

Anyone concerned about symptoms from exposure to algal toxins should contact their health care provider or call the Illinois Poison Center at 800-222-1222.

Residents should also keep pets out of water that may contain cyanobacteria, and not allow them to drink from it or lick their fur after swimming in water with a cyanobacteria bloom. People and animals that have contact with cyanobacteria should rinse with clean water as soon as possible.

In 2019, the state health department urged pet owners to keep their dogs away from the shiny algae, as ingestion was causing serious illness and even death in the animals.

“If pets experience symptoms that may be the result of exposure, contact a veterinarian immediately,” the health department said in a news release last week.

Activities near, but not in or on, a lake or river — such as camping, picnicking, biking and hiking — are not affected by cyanobacteria blooms.

To report a bloom to the Illinois Environmental Protection Agency, click here; to report an illness from exposure, click here. For more information, visit the agency’s website.