Blue-green algae lethal to dogs also can affect humans

Published: Aug. 16, 2019 at 3:43 PM CDT
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A strain of blue-green algae that's blooming in certain lakes in Texas not only can quickly kill dogs, but also can affect humans.

The algae blooms have been found in lakes in the Texas Hill Country and near Austin, but so far none has been found blooming in major lakes in Bell, Coryell or McLennan counties, Michael Champagne, lead ranger for the U.S. Army Corps of Engineers, said.

"It's in the water all the time but it becomes a problem when its enriched with nutrients from agricultural runoff and bright, hot sunlight," he said.

One professor at Texas A&M University, however, says concerns over algae blooms this year are likely overblown.

The ample rainfall the area experienced this spring and early summer likely added to the richness of runoff in area lakes, he said.

According to the National Institutes of Health, Cyanobacteria are "a group of photosynthetic bacteria, some of which are nitrogen-fixing, that live in a wide variety of moist soils and water.

"Also known as Cyanophyta, are a phylum of bacteria that obtain their energy through photosynthesis and the name cyanobacteria comes from the color of the bacteria, in Greek, Cyan, or in English, blue."

Cyanobacteria reproduce explosively under the right conditions, which result in algal blooms that can become harmful to other species, and pose a danger to humans and animals.

Dr. Britt Clay, DVM, of the Coryell Veterinary Clinic in Gatesville, said he's not seen a case of exposure yet, but he explained the neurotoxins contained in the algae, introduced to a dog that drinks affected water, can quickly kill the animal.

"Several cases of human poisoning have been documented, but a lack of knowledge prevents an accurate assessment of the risks," a NIH report states.

Recent studies suggest that significant exposure to high levels of cyanobacteria producing toxins can cause amyotrophic lateral sclerosis (ALS), noting that people living within half a mile of contaminated lakes have had a 2.3 times greater risk of developing ALS than the rest of the population.

In a paper prepared just Friday by Adam Russell, Communication Specialist for Texas A&M AgriLife, Dr. Todd Sink, Ph.D., AgriLife Extension aquaculture specialist, addressed recent stories involving companion animal deaths linked to toxins in surface water, hoping to set off fears and provide information to help the public protect themselves and their animals. "Sink said cyanobacteria, or blue-green algae as they are often incorrectly referred, are everywhere in the environment, and exist in virtually every single body of water in the world," wrote.

There are hundreds of different species in the U.S. alone. "Many people are very concerned regarding the safety of their dogs in the wake of these national news stories, which in my opinion is sensationalism to attract an audience," he said.

"So far seven to eight dogs out of the millions of dogs in the U.S. have died due to toxic cyanobacteria blooms this year. These are localized, isolated incidences," Sink pointed out.

"Sensationalizing these cyanobacteria-related deaths has only served to scare dog owners." Sink said he typically receives only six to eight cases of livestock or wildlife deaths due to cyanobacteria toxicity per year at the Aquatic Diagnostic lab. "There are 1.3 million ponds in the state of Texas, and the vast majority of livestock animals are solely reliant on these as a source of drinking water, yet I only receive six to eight cases a year," he said.

"As the nutrients begin to run out under bloom conditions and competition for sunlight increases, cyanobacteria increase their production of toxins to eliminate their competition," he said.

When the weather cools and sunlight is less intense, the blooms will subside and the bacteria will revert to an invisible form, no longer toxic.

"But, "it's always there and when the conditions are right, it will bloom again."

"So only under certain conditions in certain situations, do some cyanobacteria, or blue-green algae, produce toxins at concentrations that may become dangerous to companion animals, wildlife, livestock or humans."