A big black dog running through the water

Blue-green algae poisoning in dogs

Blue-green algae typically grows in lakes, ponds and slow moving streams, as well as marine water bodies throughout the UK. When favourable environmental conditions are present (sunny weather, high water temperature and abundant nutrients), blue-green algae quickly multiply forming massive growths, also known as a ‘bloom’. Blooms occur most commonly in late Spring, Summer and early Autumn.

This article was written by a FirstVet vet

Did you know that FirstVet offers video calls with experienced, UK registered vets? You can get a consultation within 30 minutes by downloading the FirstVet app for free from the Apple App Store or Google Play.

✓ Included free as part of many pet insurance policies
✓ Help, treatment and if you need it, a referral to your local vet
✓ Open 24 hours a day, 365 days a year

Symptoms of blue-green algae poisoning

  • Vomiting or vomiting blood
  • Diarrhoea
  • Abdominal discomfort
  • Drooling
  • Blood in stools
  • Disorientation
  • Weakness / wobbliness / muscle twitches or rigidity / paralysis
  • Breathing difficulties
  • Shock
  • Seizures or coma

Cause of blue-green algae poisoning

There are many species of blue-green algae; only some produce toxic compounds. The toxins produced are not only poisonous to dogs but also dangerous to cats, cows, horses and humans. These toxins result in rapidly developing signs of ill health, and exposure frequently causes fatalities. It is thought that concentrated scum at the edges of water bodies present a highly toxic dose in a very small volume.

The mechanism of toxicity depends on the species of algae: some produce liver-specific toxins and others produce toxins that affect the nervous system. Signs often start within 1 hour to 24 hours of exposure.

How can you help your dog?

  • Prevent your dog going near ponds or lakes known to contain blue-green algae.
  • Walk your dog on a lead near affected water sources. Do not let them drink or swim in affected water.
  • Check for posters or notices around ponds and lakes. Keep a watchful eye on local and social media for any notifications.
  • If your dog has been swimming in a pond or lake, always wash them thoroughly with mild detergent and lukewarm water. Do not let them lick their coat.

Treatment of blue-green algae poisoning

Take your pet to your nearest vet clinic straight away. The vet will examine your dog and decide what treatment is necessary. To start, vomiting may be induced to decontaminate the stomach. Activated charcoal may then be given to absorb toxins. They may require oxygen and intravenous fluids to help flush the toxins out of their body. Blood tests are often required to monitor liver and kidney function. If your dog is seizuring, or has already developed liver failure, intensive symptomatic and supportive care will be administered. Unfortunately, in animals showing symptoms of toxicity, the prognosis is poor.

When to see your physical veterinarian

  • If you have any concerns about blue-green algae exposure or toxicity.

Still worried?

Book a video appointment to have a chat with one of our vets.

More articles about Dog