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Harmful Algal Bloom-Related Illness Information for Veterinarians
On this page:
Disease Reporting
Clinical Features
Treatment
Laboratory Tests
Fact Sheet for Veterinarians
Resources 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 Harmful Algal Bloom (HAB) Case Report Form (PDF)
For all animal cases, please fill out this form. Fax completed form to 1-800-233-1817. - 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)
- The Merck Veterinary Manual. “Pet Owner Version, Algal Poisoning.” Last modified Sept. 2024.
- 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.
- 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 (PDF)
Information provided includes general HAB facts, symptoms, differential diagnoses, possible laboratory findings, and treatment options.
Resources for Veterinarians
 | Suspect Illness is Due to Harmful Algae? Harmful Algal Bloom Magnet (PDF) Printable template for magnet or card |