During the hot summer months, many dogs like nothing more than diving into the nearest lake for a cooling swim. Normally this is a perfectly safe past-time but there is one thing that owners need to be aware of – blue-green algae. If ingested, blue-green algae can be highly toxic or even deadly for dogs so it is vital that dog owners know about the risks; what to do – and how to tell if your dog has been affected. 

What are blue-green algae

The term ‘blue-green algae’ is a bit of a misnomer – it is not always blue-green, and it’s not actually algae. It is really a group of bacteria that when they clump together in water, give the appearance of algae. The appearance can vary from a green ‘scum’ on the surface that resembles pea soup, green, red or brown patches or even just foam around the edges of ponds and lakes. Not all blue-green algae is toxic but it is impossible to tell simply by appearance. Just like true algae, blue-green algae will bloom most after a period of hot and dry weather. It is found most commonly in lakes and ponds with little to no water flow. 

What are the symptoms of blue-green algae toxicity?

Due to the toxins affecting the liver or nervous systems of the dogs, the symptoms of blue green algae can include:

None of these are specific to blue-green algae poisoning and may be seen with a number of other conditions. But if these signs are seen in a dog that has recently been near a body of water that could be contaminated, it would be very suspicious for it. Because of the speed of onset of toxicity, it is vital that you think your dog could be affected by blue-green algae, you seek veterinary help as soon as possible. 

How is it toxic to dogs?

Dogs will be exposed to blue-green algae when they drink from or go swimming in water contaminated with it. Even if they don’t ingest any water at the time of swimming, they could lick it off their coats afterwards. The toxins that the algae produce are incredibly damaging to the liver and neurological system and in many cases, sadly, they are fatal. This is likely due to the speed at which the toxins will affect the animal. Symptoms can be seen as little as 15 minutes after exposure and even if promptly recognised and treated, the damage is often irreversible. 

What is the treatment for blue-green algae toxicity?

Sadly, there is no specific antidote for the toxins within blue-green algae. Treatment will centre on symptomatic and supportive care which may need to be very intense in an attempt to save the dog’s life. 

Initially, a vet will take a blood sample to assess the damage to any internal organs, initiate intravenous fluid therapy and provide oxygen if appropriate. Unlike with other potential poisonings, it is usually inappropriate to attempt to decontaminate the stomach by making the dog vomit. This is because the effects have usually taken hold by the time they reach a veterinary clinic. And they are unlikely to be in a stable-enough condition for it to be carried out safely. 

Medications such as liver supplements, anti-nausea medications, anti-seizure medications and muscle relaxants may also be given. 

Survival after confirmed exposure is rare and if a dog does survive to discharge, they are often left with long-term health issues affecting their liver and nervous system. 

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How to prevent blue-green algae toxicity

The simplest way to prevent a case of blue-green algae poisoning is to not allow your dog to drink from, paddle or swim in any still bodies of water that could contain the bacteria, especially during the summer months. If you think your dog could have been exposed, rinse off their coat with fresh water and take them immediately to seek veterinary attention. 

It is also important to report any cases of suspected algal bloom or any clinical cases of toxicity in order to try to help others avoid it and so the authorities can provide alerts. 

The Environment Agency can also be contacted 24 hours a day on 0800 80 70 60.

Further reading:

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