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    Health Officials Urge Caution as Hot Weather Spurs Blue-green Algae Growth in Wisconsin

    Record setting temperatures are contributing to blue-green algae blooms in some popular state waters leading human and animal health experts to urge caution during water-based recreation, dog training or pet exercise.

    Learn more about blue-green algae by visiting the DNR website dnr.wi.gov and searching “blue-green algae.” Pictures of blue green algae blooms are available on the Department of Health website.

    “Reports of health concerns due to exposure to toxins produced by some blue-green algae are growing after our recent hot weather,” said DNR aquatic research scientist, Gina LaLiberte. “People should be on the lookout for water with a green ‘pea soup’ appearance or which contains green, blue, white, red, or brown scums that may be foamy or in mats or blobs.

    “If you have any doubts about the appearance of water, you should stay out and consider taking steps to ensure that children and pets do not swim in or drink water containing blue-green algal blooms.”

    Most Wisconsin surface waters have good water quality and are safe for water sports and exercise but health officials advise people to avoid swimming, wading, water skiing, or coming into contact with the water in areas of lakes, ponds, and rivers where a scum or mat of algae is present. Washing off after swimming in any lake, pond or river also can be helpful.

    The most commonly reported symptoms of exposure to blue-green algae blooms in humans include rashes, gastrointestinal ailments, and respiratory irritation, according to Mark Werner, a toxicologist with the Department of Health Services. People experiencing symptoms that may be due to blue-green algal exposure should contact their health care provider or the Poison Control Center at 1-800-222-1222.

    People are also encouraged to report potential algae-related illnesses to the Wisconsin Department of Health Services by filling out an electronic form or calling (608) 266-1120.

    Protect your Pets

    Animal health experts recommend keeping pets from swimming in or drinking water from lakes with algae choked water and using clean water to remove algae from their fur if they do enter algae choked waters.

    “Animals have a higher risk from dying after exposure to blue-green algae toxins because they may ingest large amounts of toxins from drinking lake, pond, or river water or licking algae from their fur,” advises DNR veterinarian Dr. Lindsey Long. “Symptoms in dogs can include abnormal sluggishness, loss of appetite, vomiting, diarrhea or even seizures. If your animal shows any of these symptoms contact your veterinarian immediately.”

    Blue-green algae, technically known as cyanobacteria, are microscopic organisms that are naturally present in Wisconsin lakes, streams and ponds at low levels. When conditions are favorable, usually in summer, the number of algae can increase dramatically, forming pea-soup blooms and scums on the water surface. Their populations peak from July to September.

    Cyanobacteria blooms can develop in surface waters with high concentrations of nutrients, particularly phosphorus. Blooms tend to grow when there is a lot of sunlight, water temperatures are high, and there is little wind. Wind can push blooms to the windward side of lakes.

    All blue-green algae contain compounds that can cause rashes or gastrointestinal illness with ingestion. Additionally, some algal species produce toxins that, when ingested, can harm the neurological systems or liver of people, pets, livestock and wildlife. Not all cyanobacteria produce toxins, but the presence of blue-green algae blooms in lakes, ponds, or rivers is an indication that the public can use to determine a potential hazard.

    Logo courtesy of the Wisconsin Department of Natural Resources

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