Blue green algae

1st July 2016

Blue-green algae in the UK can become a problem when there is an overgrowth that turns fresh and brackish water bluish green in colour. The algae, also known as cyanobacteria, can produce poisons that are harmful to most animals.

The algae growth often occurs in hot weather, especially in mid to late summer. Higher water temperatures and fertiliser run off into lakes and ponds are known to be triggers to a sudden bloom. We find in Bollington that the problem is most likely in July, August and September.

What is the toxin and how does it work?

Not all blue-green algae produce harmful poisons. It’s impossible however to know just by looking at the water whether a toxin has been produced, so at Bollington Veterinary Centre we’d recommend all pet owners consider ponds and lakes a potentially problem.

Microcystins and anatoxins are the most common toxins produced by the algae. Microcystins are harmful to the animal’s liver and anatoxins to the nervous system.

Dogs are particularly at risk. The toxin can enter the body by drinking or licking after swimming.

What are the signs?

Specific signs depend on the particular toxin produced.

Animals that drink water contaminated with microcystins often develop vomiting, diarrhoea, weakness, lethargy, and pale mucous membranes within a few hours of exposure. Death can occurs within the first 24 hours.

Animals that drink water contaminated with anatoxins show weakness, lethargy, muscle tremors, rigidity, and seizures within 30 to 60 minutes of exposure. Excessive salivation may occur in some animals. Death from respiratory paralysis quickly follows the onset of signs.

Look out for these signs

  • Vomiting
  • Diarrhoea
  • Blood in faeces or black, tarry faeces
  • Pale mucous membranes
  • Jaundice
  • Seizures
  • Disorientation
  • Coma
  • Shock
  • Excessive salivation
  • Muscle tremors & rigidity
  • Paralysis
  • Blue discolouration of the skin or mucous membranes
  • Difficulty breathing

Is there any treatment available?

Unfortunately, there is no antidote for either of the toxins. Treatment is limited and often unsuccessful due to the devastating effect on the liver or nervous system. Any treatment has to be offered quickly, so whatever you do, don’t delay.


Don’t delay

Call us on 01625 573375 if you suspect your dog has been exposed.

We may need to use intravenous fluids, electrolytes, and medications to control seizure.

Prevention of exposure is critical - animals should be kept away from ponds and lakes with visible blue-green algae blooms.

Look out for warning signs – local authorities will often put up signs to warn dog owners of the potential risk during the summer months, so do heed these warnings.

The Environment Agency have produced a useful leaflet which discuss the problem in more depth. It’s worth a look.

Download the Environment Agencly Leaflet