June 2024
Blue-Green Algae (Cyanobacteria) Concerns in Small Animals
By: Drs. Savannah Charnas and Katherine Klenda
Summer is just around the corner but it’s not all fun in the sun. Warm water temperatures along with stagnant water and low rainfall lead to an increased risk for the development of cyanobacterial blooms (excessive bacterial growth). As the name implies, blooms are characterized by the blue-green color of the surface water. However, the presence of cyanobacteria is not always easy to discern with the naked eye, and microscopy is used for confirmation. The health risks from blue-green algae (BGA) are a result of the cyanotoxins that can be produced. There are two main classes of cyanotoxins: hepatotoxins (microcystin and Nodularins) and neurotoxins (Guanitoxin (previously anatoxin-a(s)).
The toxic dose of cyanotoxins is unknown. Most studies have been in lab animals, making it difficult to extrapolate to companion animal and livestock species. The typical route of exposure is oral ingestion either from directly drinking contaminated water or through self-grooming after swimming in the affected water. Clinical signs vary depending on the type of toxin ingested. Hepatotoxin ingestion is characterized by acute onset of clinical signs associated with liver insult (usually within a few hours) including icterus, diarrhea, vomiting, and lethargy. Neurotoxin ingestion is characterized by acute onset of clinical signs including muscle tremors, rigidity, seizures/convulsions, respiratory failure, and may result in death in less than 30 minutes.
Diagnosis is typically based on an animal’s history of exposure to contaminated water. With high-level exposures, the prognosis is grave as there is no antidote for cyanotoxins. Treatment is mostly supportive care, but even with treatment, toxicosis is often fatal.
Prevention is always best, but not always easy. Do not let dogs or other animals drink from or swim in bodies of water that are suspected or confirmed for a BGA bloom. In the event they are exposed to a suspected body of water be sure to rinse animals as soon as possible with clean water.
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| Figure 1: Cyanobacterial Bloom |
KSVDL offers two tests for blue-green algae. Suspect water samples can be analyzed via microscopy to detect any BGA (cyanobacteria) species (KSVDL Test Code TOX-1003) as well as by ELISA to detect the presence of Anatoxin and Microcystin/Nodularins (KSVDL Test Code TOX-1077 & TOX-1072.)
The Kansas Department of Health and Environment tracks the presence of BGA blooms in Kansas. To view current information, please follow the link below.
https://www.kdhe.ks.gov/777/Harmful-Algal-Blooms
For more information, please reach out to our client care department at 866-512-5650 or clientcare@vet.k-state.edu.
Savannah Charnas, DVM, MPH is a Toxicology Resident in the KSU College of Veterinary Medicine.
Katherine Klenda, DVM, is the KSVDL Client Care and Accessioning Section Head and the Companion Animal Outreach Veterinarian.
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