Harmful Algal Bloom-Related Illness Information for Veterinarians

On this page:
Disease Reporting
Clinical Features
Treatment
Laboratory Tests
Fact Sheet for Veterinarians

Disease Reporting

To better understand the incidence and geographic distribution of harmful algal bloom (HAB)-related illnesses in Minnesota, the Minnesota Department of Health (MDH) requests veterinarians report suspected cases of HAB-related illness to the MDH Waterborne Diseases Unit. Illness in animals is often the first sign that a toxic bloom is present in a waterbody due to their smaller size and behavior. Identification and reporting of animal cases can help identify a harmful algal bloom and prevent future animal and human illnesses.

How to report HAB-related illnesses

• Veterinary HAB Small Animal Report Form (PDF)
  For small animal cases, please fill out this form.
• Veterinary HAB Large Animal Reporting Form (PDF)
  For large animal cases, please fill out this form.
• Phone
  Illnesses may be reported by phone to 651-201-5414 or 877-676-5414.

Clinical Features

Clinical features depend on the type of toxin and route of exposure.

Toxin	Exposure Route	Onset to Symptoms	Likely Symptoms
Hepatotoxins Cylindrospermopsins Microcystins Nodularins	Ingestion	1 to 2 hours, or more	Acute depression Weakness & incoordination Loss of appetite Excessive drooling Vomiting & diarrhea Abdominal tenderness Jaundice Dark urine
Neurotoxins Anatoxin-a Anatoxin-a(s) Saxitoxins	Ingestion	Minutes to hours	Excessive drooling Apprehension & anxiousness Vomiting Muscle twitching Seizures Respiratory failure
Dermatotoxins Lyngbyatoxin-a Aplysiatoxin	Skin contact	Minutes to hours	Rash Hives Allergic reaction

Treatment

• There are no specific antidotes to these toxins.
• Treatment is symptomatic and supportive.
• Inducing vomiting within the first 2 hours of ingestion can help minimize absorption of ingested toxins.
• An activated charcoal slurry may be useful to bind toxins in the gut and reduce absorption. (1)
• Liver function should be monitored, and animals should be aggressively treated with fluids and corticosteroids to support liver function and prevent shock.
• Neurologic symptoms may require seizure control and ventilator support.
• Case reports have suggested that cholestyramine may be effective at treating microcystin poisoning, but this treatment is considered experimental. (2)
• Milk thistle (Silybum mariamum) has also been used intravenously for general liver protection; this is also experimental. (3)
  

1. The Merck Veterinary Manual. “Overview of Algal Poisoning.” Last modified December 2013. Attention: Non-MDH link.
   
2. Rankin KA, Alroy KA, Kudela RM, Oates SC, Murray MJ, Miller MA. Treatment of cyanobacterial (microcystin) toxicosis using oral cholestyramine: case report of a dog from Montana. Toxins (Basel). 2013;5(6):1051-1063.
   
3. Hackett ES, Twedt DC, Gustafson DL. Milk thistle and its derivative compounds: a review of opportunities for treatment of liver disease. J Vet Intern Med. 2013;27(1):10-16.

Laboratory Tests

If you suspect your client is experiencing a HAB-related illness or died from a HAB-related illness, please contact the Minnesota Department of Health at 651-201-5414 or 877-676-5414 for possible testing options.

Fact Sheet for Veterinarians

• Harmful Algal Bloom Facts for Veterinarians
  Information provided includes general HAB facts, symptoms, differential diagnoses, possible laboratory findings, and treatment options.

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Contact us:

If you have questions or comments about this page, use our IDEPC Comment Form or call 651-201-5414 for the MDH Infectious Disease Epidemiology, Prevention and Control Division.