April 2021

Prepare for Blue-green Algae Season

By Dr. Scott Fritz

Blue-green algae is a common concern for producers and pet owners alike. A case in North Carolina in August 2019 went viral on social media and increased awareness on this potentially disastrous occurrence. Blue-green algae are difficult to identify by sight alone, owners that are concerned about a public water body can alert the proper authorities (Harmful Algal Blooms (HAB) Hotline) (785-296-1664) or submit water from private ponds for testing at KSVDL.

Kansas is home to annual harmful algal blooms in many large recreational waters as well as pasture ponds, golf course ponds, and ponds within city limits. Milford reservoir in Clay and Geary counties has annual blooms each summer at the north end of the reservoir. KDHE monitors the algae levels in all recreational waters and issues warnings in cases where HABs are present. https://www.kdheks.gov/algae-illness/ When these warnings start to occur in locations near you, many of the farm ponds and other smaller water bodies can contain harmful levels of algal toxins. HABs generally occur in later summer when water temps are above 70 ℉ in non-moving water bodies. KSVDL finds algae in water samples from late May through September.

Blue-green algae are also known as cyanobacteria and produce toxins known as cyanotoxins. Cyanotoxins are very potent toxins and affect the liver and nervous system of animals and humans alike. The most common cyanotoxin traditionally encountered in Kansas is microcystin. Microcystin is toxic to the liver and will cause clinical signs including vomiting, diarrhea, jaundice, coagulation problems, hypovolemic shock, and death. Animals will exhibit signs within several hours to a day or more after ingesting this toxin. Dogs can be exposed by licking algal material off their coats after exiting the water, eating the algal scum that washes on shore, or drinking water that contains microcystin.

Another toxin occasionally seen in Kansas is anatoxin-a. This toxin is produced by a different species of algae and is toxic to the nervous system. Anatoxin-a is extremely potent with animals showing clinical signs within minutes of exposure. These signs include: tremors, agitation, seizures, coma, and death within minutes to hours. Anatoxin-a exposure is a very dire situation and many times animals will expire prior to veterinary intervention.

The best treatment is preventing exposure. Owners should be encouraged to look for warning signs at public water bodies and to keep dogs out of ponds that look questionable. KSVDL accepts submission of water samples and testing is relatively inexpensive. Two tests are available for diagnosis: Microscopic identification of algae or toxin quantification. Appropriate samples are a water sample of at least 100 mL collected an inch below the water surface. Samples should be refrigerated before and during shipping. Do not freeze the sample as this may lyse the cyanobacteria. When collecting water, gloves should be worn, as some cyanobacteria can cause severe skin irritation.

Scott Fritz, DVM, is a second year Toxicology resident in the Kansas State Veterinary Diagnostic Laboratory

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