2 Dogs Reportedly Died From Blue-Green Algae Last Week

Last week, one TikTok user, Anaïs Felt, posted a heartbreaking video to raise awareness about a deadly summertime threat to dogs. In it, she shared that she took her dog, Cora, swimming at Lake Tahoe’s El Dorado Beach, and “within an hour she was very sick, and within three hours she had passed away.”

The veterinarians at an emergency hospital told her that Cora had ingested blue-green algae, a toxin-producing cyanobacteria. The animal hospital alerted the USDA Forest Service and National Forest Supervisors. Lahontan Regional Water Quality Control Board performed a site check on Monday that did not identify visual signs of blue-green algae, and they are waiting for results from tests which will likely come back within the week. In the meantime, the City of South Lake Tahoe has added caution signs to the beaches, warning visitors that the water may contain the toxic substance. 

This is the time of year when blue-green algae typically makes an appearance. “They thrive in warm, nutrient-rich waters, especially during the summer months,” veterinarian Dr. Alex Crow tells us. Blue-green algae has recently been found in water sources across the country, from New York to Southern California. A dog in Texas recently died after swimming in Lake Travis; tests are being conducted to confirm whether the death was caused by blue-green algae.

Blue-green algae can show in the water as discoloration and scum when it blooms, but it’s not always visible to the naked eye. When Felt took Cora for a swim, the water was extremely clear, and many dogs and people were wading. She posted her video to warn people against taking their dogs swimming in Lake Tahoe — because once dogs have ingested blue-green algae, there’s no cure. “The doctors were amazing. They did everything they could to save her,” Felt said. “Our lives will never be the same. She was the heart and soul of our family and we miss her so much.”

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The dangers of blue-green algae 

Blue-green algae is a microscopic organism that can be found in a variety of water sources, including freshwater lakes, ponds, and streams, Dr. Crow explains. Any dog who comes into contact with water that contains blue-green algae is at risk of getting sick. “For dogs, exposure often occurs when they drink contaminated water, lick their fur after swimming, or even inhale water droplets from an algal bloom,” Dr. Crow says.

All animals, including cats and humans, can be harmed by blue-green algae — but dogs are at especially high risk, since cats are less likely to swim and pickier about what water they drink. In humans, blue-green algae causes symptoms including numbness, dizziness, vomiting, and abdominal pain but is not fatal.

Once ingested, blue-green algae is extremely dangerous. Many species of the cyanobacteria produce toxins that affect the liver, nervous system, and skin — this can happen within minutes to hours. “Liver toxins can cause symptoms such as vomiting, diarrhea, blood in the stool or vomit, weakness, and jaundice,” Dr. Crow says. “Neurotoxins can lead to more immediate and severe symptoms like drooling, muscle tremors, difficulty breathing, seizures, and even sudden death.”

If your pet shows symptoms or you think they may have ingested water containing blue-green algae, it’s important to get them to a veterinarian as soon as possible. “Detecting blue-green algae exposure can be challenging because the symptoms are often non-specific and can resemble other conditions,” Dr. Crow says. Diagnostic tests, clinical signs, and exposure history can help vets make their diagnosis. Though there’s no cure for blue-green algae poisoning, vets can help manage a pet’s symptoms.

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How to keep pets safe from blue-green algae 

When blue-green algae multiplies, it can appear to the naked eye as “algal blooms that appear as greenish, blue, or brown scum on the water’s surface,” Dr. Crow says. Pet parents should avoid areas where they see signs of blue-green algae. 

In general, stagnant water should be avoided as much as possible, Dr. Crow adds. “During warm months, avoid letting your dog swim or drink from stagnant bodies of water, especially if you notice greenish scum on the surface.”

Take note of any local advisories and research a body of water before you bring your dog. “Many communities monitor water bodies for harmful algal blooms and issue warnings when levels are unsafe,” Dr. Crow says.

Keep an eye on your dog any time they’re outdoors to be sure they aren’t ingesting water from an unknown source. If you take your dog swimming, Dr. Crow recommends rinsing them off with clean water as soon as possible after they get out.