The town of Cumberland put up signs at Twin Brook Recreation Area on Monday warning park-goers of potentially toxic blue-green algae in the water in the park’s brooks. Cumberland resident Elayna Girardin alerted officials to the issue after she had to put both of her dogs down last week when they became sick a day after playing in the water at the park. Brianna Soukup/Staff Photographer

Two dogs were euthanized last week after swimming in a suspected toxic algae bloom at Twin Brook Recreation Area in Cumberland, and town officials now are warning residents to keep pets and people out of the water.

Town workers erected warning signs and sent an emergency notification to residents Monday after two residents reported that their dogs became ill after swimming in the water at the public green space, which is between Tuttle and Greely roads, a town spokeswoman said.

The two dogs that were euthanized showed signs that they had been poisoned after swimming in murky water on the Greely Road side of the public park a week ago Sunday.

The town is working with an environmental consultant and the state Department of Environmental Protection to conduct tests and analysis this week, said Whitney Miller, the town’s director of communications.

“We don’t have confirmation of it at this point, but out of an abundance of caution we’re encouraging people to use extreme caution,” she said. “With the high heat and sunny warm weather, it seems this is where this blue-green algae can thrive, so it can be damaging to animals and humans.”

The water samples are expected to be taken from three sources in Twin Brook: the east branch of the Piscataqua River, Windle Brook and a third unidentified body of water in the public park.

One resident, Elayna Girardin, had to put down her two dogs after a visit to the park and apparent contact with the toxic algae bloom. Girardin posted the warning on a community Facebook page for Cumberland and North Yarmouth, drawing scores of comments and responses.

Girardin, a biology teacher at Freeport High School, said she took her two dogs, Stella and Luna, to the Greely Road side of Twin Brook on Aug. 21 and let them swim around to cool off. The water was murky, but Girardin said she knew blue-green algae toxicity was not common in Maine.

Elayna Girardin posted a warning on a community Facebook page after she had to put both of her dogs down last week when they became sick after playing in the water at the park. Brianna Soukup/Staff Photographer

Luna, a 25-pound chihuahua mix, lost control of her bladder within hours and developed muscular stillness a day after exposure to the water. Stella, a roughly 45-pound boxer-pitbull mix, also showed signs of muscle pain, and yelped after jumping onto a bed. They stopped eating and drinking. By Wednesday, Luna’s condition had worsened. She experienced a series of seizures and the family euthanized her that night.

The veterinarian at Cumberland Animal Clinic, which is located only a few steps from Twin Brook, performed a necropsy and took tissue samples. Further testing revealed blue-green algae toxicity, Girardin said, but it was not yet clear what precise toxin was discovered.

Stella’s condition worsened until Saturday, when Girardin and her family euthanized the dog. It was the same day that the veterinarian’s office returned the results of the lab test on Luna. Girardin said she immediately posted online about what happened. The veterinarian’s office also contacted the state to report the findings.

“As awful has it been with these two dogs passing, it’s comforting to know at least their death will help other people this week not have to go through the same,” Girardin said in a phone interview.

For at least one other dog owner, the online warning worked.

Cumberland resident Tracy Silverman had walked her dog at Twin Brook on Saturday hours before Girardin’s post, but took the animal directly to a veterinarian after reading Girardin’s warning, a decision that appeared to save her pet’s life, she said.

Although a positive link to blue-green algae toxicity has not been confirmed, her dog’s liver function spiked into abnormal ranges a day after the exposure. The warning was enough for doctors to save the animal’s life, she said.

One of the meandering streams at Twin Brook Recreation Area on Monday. Water samples were taken from three sources in Twin Brook: the east branch of the Piscataqua River, Windle Brook and a third unidentified body of water. Brianna Soukup/Staff Photographer

“It surprised them the treatment worked, because (the algae poisoning) is so fatal, but we went right away because we saw Elayna’s post,” she said.

The state regularly tests some lakes for toxic algae and keeps an updated interactive map online of concerning results. But blue-green algae toxicity is not common in Maine, so the state does not test for it often, said Linda Bacon, a lake biologist and the section leader for lake assessment at the Maine DEP.

Blue-green algae is the most common type in the world and exist virtually everywhere, but it does not always produce the toxic byproducts that are deadly to animals and harmful to humans, Bacon said. Researchers are still trying to figure out why some toxins are produced, but there is no settled answer yet.

Dogs typically ingest the algae by drinking lake water or consuming bits of green algae that are left on their coats. Dogs also are attracted to the pungent stink of algae clumps that float to the surface and rot. Humans, who rarely drink large quantities of unfiltered lake water, are less likely to become ill, but can still be affected.

Some lake-borne algae in Maine are known to produce microcystin, a strain of toxin that breaks down the cell walls in liver tissue, which can lead to liver failure, but the level of the substance has not been high enough to cause serious alarm, Bacon said.

The other type of toxin the algae produce is anatoxin. It rapidly attacks the nervous system, causing organ failure and death. Symptoms in dogs include gastric distress, vomiting, incontinence, excessive drooling, malaise, stumbling and other muscular weakness, according to the U.S. Centers for Disease Control and Prevention.

There is no known treatment or cure for the poisoning. Because it’s impossible to tell from sight whether an algae bloom is toxic, pet owners and swimmers should avoid contact with water they suspect of containing algae or that does not appear clean and clear.

“You want to be able to see through the water,” Bacon said. “If it’s a freshwater beach, keep your dogs out of green water.”

Cumberland isn’t the only town that’s experienced harmful blooms. For the last four years, toxic blooms have emerged in the pond at Hinckley Park in South Portland, drawing warnings from town officials there.