Concerns about potential blue-green algae poisoning have been increasing as the extreme heat and drought continue to stretch water resources. Until just a few days ago I had not heard of any cases in Missouri.
A dense, potentially fatal bloom of this algae can occur when surface water gets very warm, has lots of sun exposure, contains a good level of nutrients, and when wind concentrates the algae against the shore where livestock drink.
The toxins produced by the algae are released into the water around the algae bloom. These toxins affect the nervous system and liver of animals (and people) who consume them in the water. Toxic effects may occur within 1 hour after drinking the water and death can occur in less than 24 hours.
Clinical signs can include muscle tremors, abdominal pain, excess salivation and difficulty breathing. Treatment requires the assistance of the local veterinarian.
Affected animals should be removed from the water source, put in a shaded area out of direct sunlight (liver damage can create prolonged photosensitivity), and offered good quality feed and unlimited fresh water.
Prevention of the poisoning requires monitoring surface water sources for evidence of advancing algae growth and being prepared to control animal access. Use of copper sulfate or other algicides to treat the water can decrease the level of algae present, but does not remove any toxins already present.
See a video to help identify dangerous blue-green algae (Wisconsin Department of Health)
Some representative photos of blue-green algae:
Blue-green algae can harm gun dogs: