Health Alert-Toxic blue-green algae

Health Alert – Toxic blue-green algae

July 25, 2011

The Kansas Department of Health and Environment Requests Veterinarians Report Any Suspect Illness in Animals due to Blue-green Algae to KDHE at 1-877-427-7317.

Cyanobacteria (also known as blue-green algae) are prominent in Kansas waters and, under certain conditions, harmful algal blooms (HABs) will produce toxins that pose a health risk to people and animals. These blooms are an emerging public health issue in Kansas. In 2010 public health advisories or warnings were issued to public waters in seven counties due to HABs. The Kansas Department of Health and Environment (KDHE) has received reports of at least two cases of human illness due to contact with HABs thus far during 2011.

Cyanobacteria and their toxins in freshwaters have been implicated in human and animal illness in at least 36 states in the United States. The greatest risk of adverse human health effects after exposure to cyanotoxins is through ingestion or inhalation of water and cyanobacterial cells during recreational activities such as swimming and skiing. Adverse health effects can vary and are dependent upon the type of toxin and route of exposure. Contact with high concentrations of cyanobacteria, independent of the level of toxins, may also cause adverse health effects. The most common complaints after recreational exposure include vomiting diarrhea, skin rashes, eye irritation and respiratory symptoms. These toxins have also been responsible for several deaths in dogs.

Cyanobacterial toxins can be classified into two categories; hepatoxoins and neurotoxins. The most common in Kansas is Mycrocystis species which produce hepatotoxins. Exposure occurs through ingestion or inhalation of water droplets; some animals may become ill after swimming in contaminated waters and grooming their coat after it dries. The first signs of poisoning in animals usually occur within 30 minutes of exposure and include vomiting and diarrhea. This is followed by progressively worsening signs of liver failure such as anorexia, lethargy and depression. Jaundice, abdominal swelling, and tenderness in the abdominal area may also be observed. Blood values of liver enzymes are typically very high. If an animal survives the initial phase of liver failure, neurological dysfunction secondary to liver failure is possible. If a neurotoxin is involved, neurological signs typically occur minutes to hours following exposure and may include tremors, salivation, seizures, weakness and respiratory paralysis. Acute deaths are possible if the toxin dose is high.

There is no specific antidote available; treatment is aimed at early decontamination, control of symptoms, and supportive care. Inducing emesis can be beneficial prior to onset of clinical signs. Activated charcoal can be given, but efficacy is limited. Contaminated skin should be bathed, but protective clothing and gloves should be used by handlers to prevent skin contact. Hepatoprotectant drugs such as silymarin and s-adenosyl-methionine may be beneficial. Depending on the type and severity of neurological signs, they may be controlled with diazepam, phenobarbital or methocarbamol. Supportive treatment includes intravenous fluids and blood products, maintenance of normal body temperature, and a low quantity, high quality protein diet. The prognosis is poor in animals that develop severe liver failure.

Diagnosis in animals is usually based on clinical signs and the presence of cyanobacteria in water that the animal was in contact with. Identification of cyanobacteria in water, stomach contents, and hair coat samples is available at most regional veterinary diagnostic laboratories, including the Kansas State Veterinary Diagnostic Laboratory (KSVDL) in Manhattan, KS. The laboratory can be contacted at 785-532-5678 to coordinate sample and specimen submission.

Animals often serve as sentinels for human illness therefore the Kansas Department of Health and Environment requests veterinarians report any suspect case of blue-green algae poisoning to the Epidemiology Hotline at 1-877-427-7317 (available 24 hours a day, 7 days a week). KDHE will investigate all suspect cases of blue-green algae poisoning in animals that involve public-use waters.

For more information, including current public health advisories and warnings, or to report a suspect case of blue-green algae poisoning, please go to the KDHE website at: http://www.kdheks.gov/algae-illness/index.htm.

By Dr. Ingrid Garrison, State Public Health Veterinarian (igarrison@kdheks.gov) and Dr. Deon van der Merwe, Head of Toxicology, Kansas State University Veterinary Diagnostic Laboratory (dmerwe@vet.ksu.edu). 

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