Expert issues urgent warning to dog owners over fatal bacteria in UK - and there's no cure

Daily Mail​

16-07-2025

An expert has warned dog owners they should be cautious when taking their pets for walks and swims.
Following the recent warm weather, and heavy rains forecast to follow this week, blue-green algae, which can bloom as a result of mixed weather, has sprung up in lakes and ponds in popular walking spots.
Dog walkers should remain alert and keep an eye out for the algae, as it can be dangerous for animals.
Among the areas affected by the blue-green algae are bodies of water in parts of Cumbria and Lancashire, Llandrindod Lake in Wales, and Loch Watten in Scotland.
Simon Crawshaw, dog nutrition expert at dog food supplier Hilltop Pet Food, told the Mirror: 'At this time of year, it's really common for certain bodies of water to become less safe, especially after a warm spell followed by rain.
'Most owners just want to do the right thing for their dogs.'
He added that people should make sure they know what the algae looks like, and what signs they should look out for, to ensure they can enjoy Summer walks, while still staying safe.
'You don't need to stop enjoying the outdoors,' Simon said.
'It's just about staying informed and making small decisions that keep your dog safe. A bit of extra caution goes a long way.'
Blue-green algae, or cyanobacteria, is a group of bacteria that can contain dangerous toxins harmful and potentially fatal to pets, livestock and birds even if ingested even in small quantities.
The algae can appear as a film, or greenish scum, on the surface of water, or it may make water appear cloudy.
When ingested by dogs, even if they only consume a small amount, it can make the animals extremely ill - or even be fatal.
Canines can come into contact with the toxins in the algae by either drinking affected water, or licking it off their fur after swimming in it.
Speaking previously about the algae, the British Veterinary Association (BVA) urged pet owners to watch out for the algae near freshwater bodies, warning that there is no known antidote.
British Veterinary Association President Malcolm Morley said: 'Toxic blue-green algae is very difficult to identify and, if ingested, can make dogs seriously unwell – and can even be fatal.
'We're urging pet owners to keep their dogs on leads near water bodies where blue-green algae has been confirmed or, if unsure if a water body is safe, to keep them away from it completely.
'There is no known antidote for the toxins and prompt treatment is critical to help give a chance of recovery.
'Symptoms can appear within a few minutes or hours of exposure, and commonly include vomiting, diarrhoea, drooling, disorientation, trouble breathing, seizures, and blood in faeces.
'If you have any concerns or are worried your pet may have had contact with blue-green algae, speak to your vet as soon as you can.'
People can try to find out if there is algae in their walking spot by checking for warnings, which are sometimes posted by councils and environmental agencies near affected areas.
If an animal comes into contact into blue-green algae, they should be rinsed off immediately, and treatment instantly sought.
It can also affect humans, who should also rinse off themselves off instantly if they come into contact with the growth - before seeking medical attention.
WHAT IS THE DEADLY ALGAE?
Blue-green algae is a type of bacteria (called cyanobacteria) that shares some of the same characteristics as plants.
Blue-green algae exists all over the world and is found naturally in many inland waters, estuaries and the sea.
Blue-green algae generally grows in lakes, ponds, and slow-moving streams when the water is warm and enriched with nutrients like phosphorus or nitrogen.
The algae is very small and can't be seen with the naked eye unless it is concentrated into clumps.
It tends to look like green flakes, greenish bundles or brown dots in the water.
When environmental conditions are just right, blue-green algae can grow very quickly.
It is buoyant and floats to the surface, where it forms scum layers or floating mats.
An extensive growth is sometimes referred to as a bloom.
What are the health risks?
Blue-green algae is capable of producing several different toxins. People may be exposed to these toxins through contact with the skin (e.g. when swimming), through inhalation (e.g. when motor boating or water skiing), or by swallowing contaminated water.
These toxins can cause skin rashes, nausea, vomiting, stomach pains, fever and headaches.
Occasionally, the toxins can cause more serious illness such as liver and brain damage.
Children are at greater risk than adults of developing problems because of their lower body weight.
How can the health risks be minimised?
Not all blue-green algae blooms and scums are toxic but it is not possible to tell from appearance and so it's best to assume they are harmful and take the following precautions:
Do not swim in the water
Do not swallow the water
Avoid contact with the algae
Do not eat fish caught from the water
Observe and abide by any warning notices positioned around the water
Anyone who has come into contact with water containing blue-green algae should shower with fresh water immediately.
Anyone who has come into contact with affected water and has become ill should seek medical attention.