Vet issues urgent warning over 1 'deadly substance' found in water as heatwave approaches

A vet has issued an urgent warning to dog owners as a deadly toxin could be found in ponds and lakes across the UK during the upcoming heatwave. Temperatures are expected to soar to 32C by Friday, with heat health alerts issued for the entire country. The Met Office says this will be the third heatwave of the summer and is likely to last longer and affect a wider area than previous hot spells.

Last weekend saw highs of 34.7C in London, while Faversham in Kent recorded the year's hottest temperature so far at 35.8C. Although this week's heat may not break records, it could linger into the weekend, putting vulnerable people and pets at risk. The Met Office is forecasting highs of 31C on Thursday and 32C on Friday in parts of southern England and Wales. In northern areas, temperatures are expected to reach up to 30C or even 31C by Saturday, while the east coast of Scotland could also see a record-breaking 31C, according to Met Office meteorologist Liam Eslick.

The UK Health Security Agency has issued yellow heat health alerts across England, warning that elderly people and those with health conditions are at increased risk from the extreme heat.

Now, veterinary nurse Jess Worthington from Vets Now is urging dog owners to be cautious as the hot weather brings a spike in cases of blue-green algae poisoning.

"Blue-green algae can be deadly," Jess said. "It thrives in warm, stagnant water and appears as a green, blue-green or brown scum on the surface. But sometimes, you can't see it at all, and even a small amount is enough to cause serious harm."

The toxic bacteria are commonly found in lakes, ponds, and garden water features during hot spells.

Dogs can be poisoned after drinking contaminated water or licking algae from their fur after a swim.

Symptoms usually appear within minutes to hours and include vomiting, diarrhoea, excessive drooling, confusion, difficulty breathing, seizures and collapse.

"The toxins attack the liver and nervous system, and there is no known antidote," Jess warned.

"Every second counts. If you suspect your dog has come into contact with blue-green algae, contact your vet immediately. We've seen many cases where early warning signs were missed."

Vets Now, which runs more than 60 emergency clinics and hospitals across the UK, sees a surge in algae poisoning cases during periods of heat and low rainfall, when water sources are more likely to stagnate.

To reduce the risk, dog owners are being told to avoid still, discoloured or scummy water, check for any local warning signs, and rinse pets off after swimming in natural water.

Carrying fresh drinking water and offering regular breaks during walks is also strongly advised.

Jess also warned of other hidden water dangers, including drowning and saltwater poisoning.

"Water can be great fun for dogs, but it's not risk-free," she said. "Not all dogs are strong swimmers. Even confident ones can panic in deep water or if caught in currents, which can lead to drowning."

Jess recommends keeping dogs under supervision at all times near water and using dog life jackets when boating.

She added that dogs who swallow too much seawater can suffer dehydration, kidney damage or even death.

"A few easy steps can make all the difference," Jess added. "Be cautious around water, know the warning signs of poisoning, and don't delay if something doesn't seem right with your dog."