DOG walkers are being warned to keep a close eye on their pets when walking at Canvey Heights Country Park after a number of dogs became ill after visiting the beauty spot.

It is thought that as many as four dogs have had to be treated at vet surgeries, with some being so bad they’ve had to be put on drips.

Walkers have taken to the popular Canvey Then and Now Facebook page to warn others and speculate the potential dangers their dog might face. Some think it is to do with poisonous algae or possibly caterpillars.

Elaine Kelly, the owner of In the Dog House, on Adelsburg Road, said she now avoids walking dogs in the park.

She said: “It seems to be an annual thing in the area when the dogs go in the puddles.

“It’s often in the summer time and there’s a big caterpillar infestation up there. This would now make it the third year in a row, though some say it’s down to the saliva left by snails. Dogs seem to get an upset stomach which carries on for longer than usual.

If they get ill it’s usually for about three days, but this goes on for longer.

“Some people have even said they have seen blood when they’ve been sick. People just have to be wary and observant.”

Canvey’s two vet surgeries, Riverside Veterinary Group and Medivet, both said they weren’t aware of dogs coming to their clinics ill because of the park, adding it would be hard to specify what could be a potential cause of the illness.

The Echo reported in August 2012 a Staffie called Derek became ill after drinking poisonous bacteria cyanobacteria – known as blue-green algae – from the parks lake. He spent 36 hours on a drip as he recovered.

Caterpillars in the park have even led to humans suffering in past from allergic reactions.

Tory councillor Ray Howard said he would be taking up the matter with Environmental Health: He said: “I don’t like to see any dogs getting hurt, and so if this is the case, I will be asking Environmental Health to look into this immediately.

“County Park is a nice open place where people enjoy going and taking their dogs for walks. I’m very sorry to hear that dogs are feeling unwell after visiting.”

Castle Point Borough Council were contacted, but unavailable for comment.