Two near-death cases show toxic blue-green algae can be as much, or more, of a health threat to pets than to their owners, according to a Stuart veterinarian.

"Dogs don't know the dangers of what they're getting into like people do, or should," said Cristina Maldonado, a veterinarian at Monterey Animal Clinic in Stuart. "Dogs get their noses down into everything and will eat just about anything."

Maldonado is treating Costa, a 4-year-old, 65-pound golden retriever she suspects suffered from liver failure from drinking water tainted with blue-green algae near her home on the north shore of the St. Lucie River in the Rio community.

Costa's owners declined to talk to TCPalm and asked not to be identified.

Becky Harris of Stuart, suspects the liver failure that nearly killed her 2-year-old, 5-pound miniature Pomeranian, Pandora, resulted from the dog biting into a dead fish on a St. Lucie River beach with blue-green algae.

Harris said she ruled out some other possible causes:

There's no rat poison in the house.

The yard has no sago palms, which have seeds dogs like to eat but contain high amounts of the toxin cycasin.

Family members don't chew sugarless gum, which sometimes contains a sweetener that can cause similar symptoms in dogs.

Tests found no signs Pandora ingested rodent urine or feces.

DEP toxin tests

A blue-green bloom reported Aug. 27 at the Evans Crary Bridge near Harris' home contained microcystin at a level of 6.7 parts per billion, according to the Florida Department of Environmental Protection. That's below the 10 parts per billion threshold the World Health Organization considers safe for recreational contact.

A sample taken July 30 near Costa's home had less than 1 part per billion of microcystin, which is the level considered safe enough to drink.

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Still, Maldonado, who's active in efforts to clean up Treasure Coast waterways, said toxins in blue-green algae are to blame for both dogs' illnesses.

"Both dogs showed classic signs of cyanobacteria toxicity," Maldonado said, using the scientific term for blue-green algae. "But we can't be 100 percent sure. There's no test available to prove it until the dog is dead."

Quick action

Costa and Pandora are alive thanks to quick action by their owners, said Maldonado, who is not Pandora's vet but talked with Harris about the dog's illness.

"That's the message I really want to get across," she said. "These cases get bad quick. If you have any suspicion that your dog is vomiting or having diarrhea because of contact with blue-green algae, get it to a veterinarian — quick."

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It's been widely reported that microcystin, a toxin often found in blue-green algae, can cause symptoms in people, including nausea and vomiting if ingested, rashes and hay fever symptoms if touched or inhaled. People who drink water with the toxin can suffer long-term liver disease.

Between July 23 and Aug. 15, Martin Health System emergency rooms treated 125 people for symptoms doctors said could be algae-related.

Healthy dogs

"Costa's been healthy all her life," Maldonado said, "but she snuck away from her owners Saturday and went down to the river."

Within an hour, Costa was vomiting, Maldonado said, and was "almost dead" when she got to an emergency veterinary clinic soon afterward.

Pandora also was a healthy dog before she bit into that catfish. Within a few hours, she was throwing up and so lethargic "her head kept falling into her water bowl," Harris said.

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Both dogs were diagnosed with acute liver failure and both received, among other treatments and medications, plasma transfusions so their blood would clot and they wouldn't bleed to death.

"Thousands of dollars later," Harris said, Pandora slowly started improving and came home Thursday.

"I just want people to know that if you live on the river or take your dog to the river, keep it on a leash," Harris said.