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Cyanobacteria in Wyoming waters threaten both people and pets

A harmful cyanobacterial bloom, or HCB, by the Bishops Point Campground at Pathfinder Reservoir in 2018. "The blooms can be blue, bright green, brown, or red," notes the Wyoming Department of Health page about HCBs. "Sometimes the blooms can look like paint floating on the water’s surface."
Wyoming Department of Health
A harmful cyanobacterial bloom, or HCB, by the Bishops Point Campground at Pathfinder Reservoir in 2018. "The blooms can be blue, bright green, brown, or red," notes the Wyoming Department of Health page about HCBs. "Sometimes the blooms can look like paint floating on the water’s surface."

Cyanobacterial blooms in Wyoming rivers and reservoirs can be harmful or even deadly for people, pets and livestock. So state agencies, including the Departments of Health and Environmental Quality, and the Wyoming Livestock Board, are warning residents to keep their distance.

Sometimes called blue-green algae — despite not technically being algae — these cyanobacterial blooms can produce neuro and liver toxins that are harmful and sometimes even deadly to humans, dogs and other animals.

The Department of Health warns against drinking, swimming in or even just touching water that looks like it might contain cyanobacteria — for example, if the water appears scummy or discolored.

Suspected blooms can be reported to the state. While the Wyoming Department of Health follows up on potential HCB-related illnesses, Wyoming DEQ investigates reported blooms to determine if they are harmful.

DEQ then issues advisories for specific bodies of water across the state. Both agencies recommend that outdoor recreators check for these advisories online before heading outside.

"HCBs [Harmful Cyanobacterial Blooms] typically develop in mid to late summer and can occur in flowing and non-flowing waters such as streams, rivers, lakes, and reservoirs," notes an advisory published by Wyoming DEQ. "HCBs may be green, tan, brown, or blue-green in color. HCBs may float in or on the water and look like spilled paint, grass clippings, clumps, or scums. HCBs may also be attached to aquatic plants, rocks, or other material and look like films, mats, or gelatinous balls."

If you do come into contact, rinse off immediately with fresh water. Seek medical attention if you or a pet starts experiencing any symptoms, like vomiting, fatigue, difficulty breathing or skin, throat or other irritations.

"Young children, pregnant women, people with weak immune systems, and animals are especially at risk," notes Wyoming DEQ.

Despite the health risks posed by cyanobacteria today, humans could not have evolved without it.

About 2.4 billion years ago, these blooms filled earth's atmosphere with the oxygen we now breathe, establishing the environment in which humans, dogs and all other large oxygen-breathing multicellular organisms evolved.

Jeff is a part-time reporter for Wyoming Public Media, as well as the owner and editor of the Laramie Reporter, a free online news source providing in-depth and investigative coverage of local events and trends.

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