PET owners and farmers are being warned to keep their animals away from lakes and rivers as blooms of a deadly algae spread across South Lakeland.

A potentially toxic blue-green algae called cyanobacteria has been found in waters in Windermere, Ambleside and near Kendal, which vets warn could kill an animal in just 10 minutes.

Steve Dodwell, a vet at Oakhill Veterinary Group, Windermere, warned dog owners and farmers not to take any risks.

“It can be extremely dangerous,” he said. “Animals can die very quickly - in as little as 10 minutes. I would advise people to take sensible precautions and stay away.”

He explained that the toxins could cause gastroenteric, liver, brain and skin diseases and that some of the symptoms included salivation, lethargy, weakness, loss of balance, collapse, vomiting, problems maintaining normal temperature and too rapid or too slow a heart beat.

Mr Dodwell advised pet owners who saw any symptoms to wash the animal quickly and if possible put a collar on to prevent licking.

He also advised that the dog be kept out of direct sunlight and taken immediately to see a vet.

“It doesn’t seem to be very common in livestock, the problems appear to be mainly in dogs. But it’s not something to take very lightly,” said Mr Dodwell.

The Environment Agency, which regularly inspects lakes and rivers and carries out water sampling, confirmed that sites in South Lakeland had tested positive for blooms of blue-green algae.

South Lakeland District Council said the blooms have been found at several points on Windermere including Ferry Nab, Brockhole, Rayrigg Meadow and Miller Ground as well as Pull Wyke Bay at Ambleside and Killington Lake.

Warning signs have been put up in the affected areas where people may intend to use the water.

SLDC’s environmental health team leader, Tracy Howard, warned that the algae could also make people feel ill or cause skin rashes if they swallowed affected water or simply swam in it.

“We just want people to be aware of the effects and are asking people to be extra careful and vigilant when using the lakes and rivers for recreational purposes during the summer months,” she said.

“The public should observe any notices near affected areas and avoid contact or drinking the water.”

She advised that all blue-green algae blooms - which vary in colours from discoloured green, blue-green, greenish brown or reddish brown - should be assumed to be toxic.

Further information about blue-green algae can be found at www.environment-agency.gov.uk.