Toxic algae is suspected of killing a dog in Raleigh. How to keep your pets safe

·8 min read

A recent report of a dog dying after drinking water from the lake near Blue Jay Point County Park in northern Wake County is circulating on social media, renewing warnings about blue-green algae — a toxic, and sometimes lethal, algae that thrives in warm, slow-moving bodies of water.

Amy Walter reported the incident to the N.C. Department of Environmental Quality on Monday evening, according to the department’s Fish Kill & Algal Bloom Dashboard.

In the report, Walter wrote that her dog drank from the lake near the park and died three days later. The report is currently listed as “in progress” on the dashboard, meaning that N.C. DEQ has received the report but has not yet confirmed whether blue-green algae is present at the location.

Blue-green algae poisoning was in the national spotlight in 2019 after four dogs in the Southeast, including three from Wilmington, died within a matter of days after drinking from or playing in lakes.

The algae is naturally occurring, but as global temperatures warm up, it could form more often.

“It’s a growing problem not just here in North Carolina, but worldwide,” said Dave Dorman, a professor of toxicology at N.C. State’s College of Veterinary Medicine. “It’s thought that it’s due in part to global warming, that the longer summer seasons and increased use of fertilizers creates the growth conditions for the blue-green algae.”

The News & Observer talked with Dorman to learn more about blue-green algae and the risk it poses to your pets.

Here’s what we learned.

What is blue-green algae?

Though referred to as blue-green algae, it isn’t actually algae — it’s a naturally occurring bacteria called cyanobacteria.

Cyanobacteria are photosynthetic bacteria that get their energy from light.

Dorman said cyanobacteria can be found in almost any body of water, including salt and fresh bodies. According to the N.C. Division of Water Resources, cyanobacteria are present in most bodies of freshwater in North Carolina.

Under certain conditions, such as under bright sunlight and warm temperatures, cyanobacteria can rapidly reproduce to form a cyanobacterial bloom.

Blooms typically form during the warm summer season, or when water temperatures are warmer than usual. Drought has also been linked to an increase in harmful algal blooms, according to the Environmental Protection Agency.

Once cyanobacteria bloom, they may be able to produce toxins, called cyanotoxins, which can cause illness in humans and animals that come into contact with water affected by a bloom. The toxins can be lethal to animals, mostly dogs and livestock.

According to N.C. DEQ, there are no effective means of treating a cyanobacterial bloom once it appears. Treatment with algacides is not recommended, as they can cause the cyanobacteria to rupture and release toxins contained within the cells.

This is an example of a pond covered in the toxic blue-green algae in Charlotte, N.C. The algae is fed by sunlight and nutrients and can make people and animals sick.
This is an example of a pond covered in the toxic blue-green algae in Charlotte, N.C. The algae is fed by sunlight and nutrients and can make people and animals sick.

What does blue-green algae look like?

Blue-green algae may or may not be visible on the surface of water as microscopic analysis is necessary to confirm the presence of cyanobacteria, but some signs that could indicate the presence of the bacteria in bodies of water are:

Discoloration of the water. As its name suggests, “blue-green algae” can make water appear blue or green, but it can also make water take on other colors, including red and brown.

Surface scums. Dorman said cyanobacteria can have a “paint-like” appearance on the surface of the water — as if someone had dumped paint in the water and it’s now lingering on the surface.

Floating or submerged clumps, flecks or mats of algae.

Decaying cyanobacteria can produce milky blue and white surface scum.

Dorman noted that it can be easy to mistake pine pollen on the surface of water for cyanobacteria or algal blooms. Remember: Blue-green algae surface scums will generally have a paint-like appearance.

If you think a body of water in North Carolina contains blue-green algae, or you’re unsure, you can make a report with N.C. DEQ.

Can blue-green algae harm pets?

Blue-green algae can cause illness to humans or animals that come into contact with water affected by a cyanobacteria bloom. It can be lethal for livestock and dogs.

Dorman said illness is generally caused by the animals drinking water with the toxins, or getting the toxins in their skin by making contact with or submerging in the water — such as by swimming.

Dorman said there are generally two types of illness related to blue-green algae that occur in animals:

Liver damage to the animal. This type of illness generally produces symptoms within two to three days of ingesting or making contact with the water.

Neurological damage to the animal. This type of illness is much more rapid, with the animal showing symptoms within minutes or hours of ingesting or making contact with the water.

Illness with symptoms including itching, redness and blistering of the skin may also be possible within hours of contact, according to Veterinary Centers of America (VCA). These signs are not fatal, but may take several days to weeks to resolve, which can be uncomfortable for your animal.

The type of illness that an animal contracts generally depends on the class of toxins each algal bloom contains, Dorman said. Some algal blooms aren’t toxic, but there’s no way to tell just by looking at them, he said.

What are the symptoms for a dog with blue-green algae poisoning?

If your dog has liver damage from blue-green algae, symptoms might include:





Pale gums

Jaundice of the gums and skin

Signs of neurological damage to your dog caused by blue-green algae include:

Weakness or inability to walk


Muscle tremors and rigidity


Increased salivation

Difficulty breathing


What should I do if I think my dog has blue-green algae poisoning?

If your dog gets sick after ingesting or swimming in water, Dorman said it is an emergency situation and you should immediately seek medical care for your pet by contacting your local veterinarian.

The ASPCA also offers a national hotline for any animal poison-related emergencies. If you think your pet may have ingested a potentially poisonous substance, you can call 888-426-4435. A consultation fee may apply.

The national Pet Poison Helpline is also available. The helpline staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals and exotic species. The helpline charges $65 per incident, which includes all follow-up consultations. You can call the helpline at 855-764-7661.

Dorman said some animals can recover from illnesses caused by blue-green algae, but there is not a specific antidote to treat the poisoning. Instead, veterinarians can offer treatment for specific signs or symptoms that the animal is showing, offering symptomatic and supportive care.

VCA says if the possible illness is caught before clinical signs occur, therapy can be directed at ridding the body of the toxin, such as by pumping the animal’s stomach.

Because the toxins can enter the animals body so quickly, though, it is often too late to treat the animal once symptoms emerge.

“Despite aggressive treatment, the prognosis with blue-green algae toxicity is very poor,” VCA says. “Some animals actually pass away before reaching a veterinarian.”

How can I prevent my pet from getting blue-green algae poisoning?

The best way to prevent your pet from developing blue-green algae poisoning is by keeping them away from waters that may have blue-green algae.

Dorman recommended regularly checking DEQ’s dashboard for any reports of fish kills or algal blooms at locations you frequent with your dogs, such as ponds, lakes and parks.

Always pay attention to the appearance of bodies of water. If they show any signs of blue-green algae, do not let your pet go near the water.

If you see a fish kill, also known as a fish die-off, in the water near somewhere you’ve taken your dog to walk, avoid the water. Fish kills are a sign of algal bloom activity.

The N.C. Department of Health and Human Services offers the following tips to safeguard humans and pets from cyanobacteria:

Keep children and pets away from waters that appear discolored or scummy.

Do not handle or touch large accumulations of algae, also called “scums” or “mats”.

Do not water ski or jet ski over algal mats.

Do not use scummy water for cleaning or irrigation.

If you accidentally come into contact with an algal bloom, wash thoroughly.

If your child appears ill after being in waters containing a bloom, seek medical care immediately.

If your pet appears to stumble, stagger, or collapse after being in a pond, lake or river, seek veterinary care immediately.

If you are unsure whether or not a bloom is present, it is best to stay out of the water.

How to report algal blooms

If you suspect a blue-green algae bloom in your community, you can report it to N.C. DEQ using the department’s reporting app or by contacting your DEQ regional office.

Find the reporting app at:

Find your regional office at

You can also call the N.C. Division of Water Resources (DWR) emergency hotline at 1-800-858-0368.

When public health concerns arise from algae blooms, local health departments and NCDHHS determine an appropriate response with technical support from DWR.

Common actions include swimming closures, contact advisories and the issuance of public notifications.

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