A dog walking event in Warwickshire has been cancelled after a number of dogs died from a mystery illness.
The Great British Greyhound walk was due to take place in Stratford-upon-Avon on Sunday.
The organisers said the dogs had become ill after walking in an area along the River Avon and Seven Meadows Road.
Vets in the town said they had not identified a cause but advised all owners to avoid communal dog walking areas for about a week.
Organiser Norman Gee, from the Perry Barr Retired Greyhound Trust, said three dogs had died in the past week.
"I've been told it was due to pesticide spreading on crops in the area and even Japanese hogweed but not even the vets seem to know exactly why," he said.
"We normally have 60 dogs on this walk and the danger to all those is obviously too great to risk so we decided to cancel."
Sickness and diarrhoea
Julian Marcus, who is a director of the Ark Veterinary Practice in Stratford, said they had treated a number of dogs for sickness and diarrhoea but there was no clear cause.
He confirmed some dogs had died from the condition but said he did not know exactly how many.
"Our advice is for dog walkers to stay away from communal areas in the town and to be very wary of stagnant water or puddles that have been there for a few days," he said.
"As with any disease, if you're cautious and avoid communal areas to avoid it spreading you should be alright."
Stratford-upon-Avon District Council said its environmental health team had investigated the issue and referred it to animal health teams at trading standards to look into.