In Part 2 of this 4-part series on blue-green algae, Lieutenant Colonel and veterinarian Dr. Eileen Jenkins describes the key symptoms we should be on the look out for and what to do when we suspect our dog may have been exposed. 

How does blue-green algae affect search dogs?

black lab leaning over boat licking waterSearch dogs most likely are exposed during a training exercise or call out when they wade or swim in warm surface waters – ponds, lakes or streams. Exposure is most common in summer months when the water temperature rises above 20° Celcius (68° Fahrenheit), and in still or slow-moving waters (read Part 1 for more details).  Dogs are exposed by swallowing contaminated water or from licking their paws or fur after swimming or wading in contaminated water.

The most common blue-green algae toxins cause rapid and usually fatal liver failure.  Another group of toxins, anatoxins, cause neurologic symptoms and death.

Although there are more than 2000 species of cyanobacteria, less than 100 create toxins that are a health risk to mammals. Unfortunately, it is difficult to predict which algal blooms are dangerous to your dog, so it is best to avoid water with visible blooms if at all possible.

What symptoms should a handler be looking out for?

Signs of exposure depend on the type of toxin ingested and include:

  • Vomiting or diarrhea (sometimes bloody or tarry)
  • Pale or yellow mucous membranes
  • Lethargy or disorientation
  • Muscle tremors or rigidity
  • Seizures
  • SLUD: salivation, lacrimation, urination, defecation
  • Difficulty breathing
  • Shock, coma or death

What should a handler do if they suspect their dog has been exposed?

If you suspect your dog has been exposed…

…take him to the nearest veterinarian IMMEDIATELY. Blue-green algae toxicity can cause liver failure within minutes of exposure, so RAPID treatment is essential to survival. Even if you aren’t sure, get your search dog checked by a veterinarian if they show any illness after working in water.

If your dog is sick but still alert…

…you can induce vomiting and/or administer activated charcoal, if you are trained to do so, while someone else drives you to veterinary care. If your dog is having seizures, or is not alert or cannot swallow, do NOT induce vomiting or administer charcoal.

There are no specific antidotes to blue-green algae toxicity; treatment is aggressive supportive care and monitoring.

Are there any preventive measures a handler can take to protect their search dog?

If your dog is regularly working in warm, surface waters you can discuss the use of hepatoprotectants (like silymarin) and antioxidants (like vitamin E) with your veterinarian. Although not yet studied in dogs, these compounds may help reduce toxicity associated with chronic exposure to microcystins.


(In case you missed it, read Part 1 to learn how to recognize blue-green algae and get some useful tools that will help you identify compromised bodies of water before you respond to a call out)

Dr. Eileen Jenkins headshotEileen Jenkins, DVM, MS, DACVIM (SAIM) is a veterinarian, board-certified in small animal internal medicine by the American College of Veterinary Internal Medicine.  She is a Lieutenant Colonel in the U.S. Army Veterinary Corps.  She received a Bachelor of Science in Biology from the University of Lynchburg, a Doctorate in Veterinary Medicine from North Carolina State University, and a Master of Biomedical Sciences from Auburn University.  Dr. Jenkins’ primary research interests are working canine performance, olfaction and decontamination.