Posted on: September 23, 2024 Posted by: Petsynse Comments: 0

Black Lab jumping into a lake.
Image credit: My July, Shutterstock

Nothing is better than a refreshing water dip on a hot summer’s day, right? As true as it is, water can also be dangerous for our pups. Knowing what’s in the water is more important than ever, and harmful algae blooms pose a life-threatening risk to our dogs. Algae blooms, particularly blue-green algae, are tiny organisms with a toxic punch. I discover what harmful algae blooms are, how deadly they can be, how to spot them, and tips on how to protect you and your pup.

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What Are Algae Blooms?

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Algae is crucial for a healthy aquatic ecosystem. An algal bloom is the overgrowth of microscopic algae in water. When they bloom, the algae are the most toxic, and some types can harm pets, humans, livestock, and the environment. Algae come in many colors, including blue-green, green, brown, yellow, red, and pink.

Algae blooms can occur in freshwater, seawater, or brackish water (a mixture of fresh and saltwater) as long as they are exposed to the sun and carbon dioxide and have a rich supply of nutrients, especially phosphorus and nitrogen. Although algae blooms can grow anywhere, they are most common in standing bodies of water. They usually bloom when the water heats up mid-to-late summer through fall.

Richard Stumpf, an oceanographer from the National Oceanic and Atmospheric Administration (NOAA,) states that these toxic blooms are becoming more frequent year after year, thanks to warmer temperatures and increased fertilizer pollution, among other factors.

What Algae Is Poisonous To Dogs?

Not all types of algae are poisonous, but the toxic ones are often called harmful algal blooms (HABs). Three HABs are the most responsible for making dogs and humans sick.

  1. Cyanobacteria. This is what is known as blue-green algae, which is technically not an algae but a bacteria. It is the most common cause of HABs in freshwater, such as lakes or rivers. Blue-green algae have been reported in every state in America, and there are multiple species of cyanobacteria.
  2. Dinoflagellates & Diatoms. These are the most common causes of HABs in salt water, such as oceans or bays. They can be any color, but they are usually red or orange, which is why they are also known as “red tides.” These commonly affect coastal Texas and the Gulf Coast of Florida.

Watch this informative video about how to protect your dog from toxic algae.

What Does Blue-Green Algae Look Like?

Blue-green algae is the most common HAB affecting dogs, mainly because it occurs in freshwater, a popular swimming spot for dogs and humans. Plus, the blue-green algae is more difficult to see, and pup parents are often only aware of it once it’s too late. Avoiding all types of algae is safer because it is difficult to tell which types are poisonous without precise monitoring and analysis. Plus, the results of these tests are only correct at that moment. In the right conditions, HABs can spread quickly. Just because a popular swimming spot is deemed safe one day doesn’t mean it is safe on another.

Cyanobacteria are invisible to the naked eye until they clump together. According to the U.S. Environmental Protection Agency (EPA), depending on the species of cyanobacteria, it can look like any of the following:

  • A greenish, thick, paintlike substance that accumulates along shores. The layer of froth that dries on the shores of lakes sometimes contains high concentrations of toxins for several months
  • Slimy blooms that float on the surface of the water
  • Colonies of large dark green dots on the surface
  • Long, slender, thread-like surface scum
  • Dark green, blue, or black woolly-looking mats on the bottom of streams and ponds
  • Dark green, blue, red, brown, or yellow film on the bottom surfaces, including on rocks and plants
  • Dark green or brown gelatinous or ear-shaped colonies in the margins of the water

Why Is Blue-Green Algae Toxic To Dogs?

Dogs are at risk of blue-green algae toxins if they swim or ingest the contaminated water. The toxins produced by blue-green algae can cause liver failure, shut down the nervous system, and cause severe and painful rashes. Unfortunately, ingesting the toxins is often fatal for dogs. There is no antidote for blue-green algae toxicity. All your vet can do is induce vomiting or flush the toxins and hope that this rids their body of them. Even if a dog survives, it often causes long-term health problems.

I recommend investing in Dr. Cuddles ReadyRESCUE activated charcoal for pet owners, especially those who live near bodies of water that regularly have HAB notices. It is a potentially life-saving product that could help reduce the effects of blue algae toxins and other harmful substances.

Symptoms Of Blue-Green Algae Poisoning

Dogs can exhibit symptoms within 15 minutes of consuming the contaminated water, and it can be fatal in as little as 30 minutes. Time is of the essence when it comes to HAB toxicity. Here are the most common symptoms to look out for:

If your dog shows any of the following signs after coming into contact with water, whether drinking from or swimming in it, contact your vet immediately. These are common symptoms of other health concerns, so it’s important to tell the vet you suspect your dog has come into contact with blue-green algae.

If your dog comes into contact with the contaminated water, it’s crucial to immediately rinse the water from their fur and paws with fresh, clean water. Dogs can ingest the toxins from cleaning their fur or chewing their paws hours after entering the contaminated water. Getting to a vet or a pet hospital as soon as possible is vital. Alternatively, you could contact either of the U.S.’s two animal poison control centers:

Both services are available for emergency support 24/7, but there is a fee for each.

Please read our article on how to transport your dog safely in an emergency.

Blue-Green Algae Treatment

Although there is no antidote to HABs, there are a few things a vet might do to reduce the effect of algal bloom toxicity when you arrive, such as administering:

  • IV fluids
  • Oxygen
  • Activated charcoal
  • Anti-seizure medication
  • Anti-nausea medication
  • Anticholinergic medicines such as atropine
  • Electrolytes and glucose
  • Blood products

If your vet determines there is a chance of survival, they will monitor their blood and other vitals and adjust medications as necessary. If your pup does survive, they might need antibiotics and life-long medication. However, if your dog is in a critical condition, your vet might suggest euthanasia is the best option.

How Can Pet Insurance Help?

It’s important to consider pet health insurance for your pup. Some companies also offer accident-only pet insurance, which can be cheaper than emergency and illness coverage. Accident-only insurance covers foreign body ingestion, poisoning, and other related emergencies. We mention this because a poisoning accident is likely where a toxic algae ingestion would fall. Our pet insurance experts have reviewed the best accident-only pet insurance, which could help cover many of the costs of such emergencies.

5 Tips To Avoid Blue-Green Algae

No dogs swimming in water sign in front of lake.
Image credit: glenrichardphoto, Shutterstock

You and your dog can take a few precautions to help protect yourselves from blue-green algae and other HABs. Let’s look at the best ways to protect your dog from algal toxicity.

1. Do Not Visit Places With Known Algal Blooms

Although this might sound obvious, you might be surprised (or not) to learn that some pet parents let their pups swim and play in water known to have HABs. If you know that a local area is or has previously been affected by HABs, I recommend you keep your dog away and visit somewhere else. According to NOAA, dogs are attracted to algal scum odor, so don’t let them explore shorelines without supervision. Not only can the toxins accumulate into foam or scum that could blow away from the water into nearby fields and wooded areas, you never know when your dog might escape their leash.

2. Keep Your Dog Leashed Around All Bodies Of Water

Even if you’ve been visiting a place for years without any issues, keeping your dog away from all bodies of water is wise. As tempting as it is to let your dog go for a dip in lakes or streams, don’t risk it if you see discolored or algae-affected water. Please keep your dog leashed so you can be sure they will not enter the water until you’ve inspected it. It might be unsafe even if you see people or other dogs playing in the water.

3. Look For Blue-Green Algae Signs

Be alert for blue-green algae signs posted around the area. If you see a sign, I recommend leaving and heading somewhere else. But remember that just because you don’t see a warning doesn’t mean no algal blooms are present.

4. Check Government Websites

HABs are becoming increasingly more common, and local agencies are working hard to keep us and our pets safe. The EPA has jurisdiction over HABs in freshwater environments, whereas NOAA focuses on marine HABs. EPA and NOAA share authority over the Great Lakes throughout the country. Here are some resources and HAB forecasts that could help you identify local blue-green algae or other HABs near you:

  • EPA’s CyAN App – This app provides almost real-time data on cyanobacterial algal blooms for a large population of lakes across the country
  • How’s My Waterway – The EPA provides the same data from the CyAN app through this application, and users can search specific waters of interest
  • NOAA Ecological Forecasting – NOAA provides forecasts, reports, news, and historical data for oceanographic and Great Lake HABs
  • Water Quality Portal – This is the nation’s largest source for water quality monitoring data, with data from the United States Geological Survey (USGS), EPA, and over 900 other agencies

5. Remove Stagnant Water From Your Yard

Do not allow your dog to drink from any water that may contain blue-green algae. HABs can establish themselves anywhere as long as the conditions are right, including stagnant water in your yard. If you have a pond, ensure it is covered. If there are pockets of stagnant water around the yard, for example, in plant containers or bird baths, clean them regularly or remove them completely.

Frequently Asked Questions

Some of our readers still have questions about algae blooms and how to keep their dogs safe from blue-green algae. If you don’t see your question below, please ask us in the comments, and we’ll find the answer for you.

How Much Blue-Green Algae Is Toxic To Dogs?

A tiny amount of blue-green algae toxins can be enough to harm your dog or, worse, have fatal consequences. This is why you should keep your dog away from bodies of water that contain or may contain HABs. Do not allow your dog to swim, paddle, drink, or come into contact with discolored water from lakes, streams, or the coast. It only takes a little bit of toxic scum, foam, or froth to harm your pup, so keep them on a leash when exploring around the water’s edge.

Where Are Algae Blooms Near Me?

Check agency and government websites and apps, such as the options I recommended above. However, it’s important to know that these might not always be up-to-date. Because it’s difficult to determine if water contains HABs, most veterinarians recommend avoiding all bodies of water to be safe.

Is Blue-Green Algae Toxic To Humans?

Yes, blue-green algae and other HABs are toxic to humans. Exposure to high levels of toxic blue-green algae can cause diarrhea, nausea, vomiting, breathing difficulties, and skin, eye, or throat irritations. It’s very rare for blue-green algae to be fatal for humans.

Other Ways To Keep Your Dog Safe

Being a dog owner is so much fun, but it also comes with lots of responsibility. Part of that responsibility is being safe and prepared for the worst. Learn what to do if you find a tick on your dog. I also recommend carrying a pet first aid kit for vacations and adventures with your pup. And if you have to avoid your local park because of HABs, check out our list of the best summer activities for dogs to try instead.

Do you have regular HABs near you? Or perhaps you and your dog have had the unfortunate experience with blue-green algae. Whatever your stories on this topic, we love to hear from our readers in the comments below.

Why Trust Canine Journal?

Emma is a dog mom to two rescue dogs, Bonkers and Chips. Living on the coast of England means that Emma regularly checks local agency websites for water pollution and safety advice, and she has seen many local dogs find themselves in trouble. Respecting the water is incredibly important for you and your dog’s safety. She works with a dedicated team at Canine Journal to bring their readers the best and most useful canine content.