Blue-green algae and its risks for dogs

If your dog likes to swim in lakes, streams or other areas of open water, or drink from such watercourses when out on walks, this article is a must-read for you. Blue-green algae within various bodies of water can be a potential toxin to dogs, and it is not always obvious when an algae bloom is underway, which can make a pool or stream that was previously fine, suddenly pose a danger to your dog. In this article, we will look at blue-green algae and its effects on dogs in more detail, plus give some advice on identifying it. Read on to learn more about blue-green algae and its risk to dogs.

What is blue-green algae and why is it a problem?

When the water levels in bodies of water are normal, algae is distributed evenly throughout the water, serving to diffuse it widely and lower its concentration. However, when the water tables are low, such as when the weather has been very hot and there has not been a lot of rain, poor air circulation and lower water levels increase algae production, causing it to form into large blooms, which are followed shortly afterwards by a large-scale die off of the algae itself.

The gas that dying colonies give off raises the algae to the surface of the water, where it collects, and ultimately, finds its way towards the banks of the watercourse, where it can easily be ingested by animals stopping to drink, such as dogs walking or swimming.

Dogs can develop poisoning from blue-green algae when they drink from such water, or lick themselves after swimming in it, and this in turn has a toxic effect on the stomach and internal organs, which may prove fatal.

The symptoms of blue-green algae toxicity in dogs

The type of symptoms that affected dogs can present with, and how severe they are, depends on whether the toxin is affecting the liver, or has begun to have a systemic effect on the entire nervous system.

Symptoms of liver toxicity include:

• Generalised weakness and lethargy.
• Diarrhoea, which may be bloody.
• Pale mucous membranes.
• Neurological changes and changes in temperament.

Symptoms of nervous system toxicity include:

• Laboured breathing.
• Lethargy and difficulty moving.
• Muscle tremors.
• Convulsions or fitting.

Left untreated, both types of toxicity can soon prove fatal.

Diagnosing blue-green algae poisoning

If your dog has been swimming in or drinking from an outdoor water source and exhibits any of the above symptoms, you should take them to the vet as a matter of urgency. You should explain to the vet where your dog has been, and if possible, take a water sample from where your dog was for testing.

Blood and urine panels can help your vet to make a definitive diagnosis, but the history of your dog’s activities and the water that they have been in are the most important tools in diagnosis.

Can blue-green algae poisoning be treated?

Successfully treating blue-green algae poisoning in the dog can be challenging, as water is quickly absorbed by the body, and its associated toxins along with it. The faster you can get help, the better your dog’s chances of survival, and if your dog can be taken to the vet shortly after ingestion, they may be able to be given an emetic to encourage them to vomit up the water, or a product like activated charcoal to absorb as much of it as possible in the stomach.

Treatment then depends on how the algae is affecting the dog, and relies upon supporting their liver and nervous system functions, while minimising pain and discomfort where possible. Blue-green algae toxicity can be difficult to treat, and often proves fatal. Even for dogs that ultimately recover, the after effects of poisoning may have repercussions for the rest of their lives.

Keeping your dog safe

Blue-green algae in water often makes the water appear very green in colour, and you may actually be able to see huge algae blooms within the water itself. However, it is not always possible to tell if water is undergoing a bloom and the associated die-off, and so just because water looks clear and clean, you should not assume that it is. Even water that your dog regularly swims in or drinks from can be affected by blooms, so you should not consider any particular body of water as safe, particularly in hot weather when water levels are low.

Certain large bodies of water, including the Witham Navigable Drains in Lincolnshire, and areas of the River Lea in London, are prone to algae blooms of this type annually, but even small bodies of water such as garden ponds can be affected too.

Never let your dog swim in or drink from unknown water sources, and if your dog has been swimming outside, wash them off when they get back home.