NOTTS woodlands should be declared no-go areas for dogs, owners say, after more pets were struck down by a mystery illness.
The illness has struck down dogs being walked in and around Sherwood Forest or Clumber Park every autumn since 2009.
Several animals have died, although there have been no recorded fatalities so far this year.
Each autumn warning signs are put up in woodland car parks and on information boards about the condition, known as seasonal canine illness.
Now one woman says it is time for the authorities to stop people walking dogs in Notts woodland until the cause is found. Chloe Stark, 22, of Ratcliffe-on-Soar, spoke after her Jack Russell crosses Alfie and Lunar, and chihuahua Roma, all fell seriously ill after a walk in Sherwood Pines, near Clipstone, on September 30.
Within 48 hours of the trip all three were vomiting and only recovered after being admitted to the vets and given antibiotics.
Miss Stark, who lives on a narrow boat on the River Soar with boyfriend Mark Smith, said: "It's fair enough putting signs up but they are easily missed.
"It's happened four years running now and it's time to say to dog walkers 'don't come in at this time of year.
"It was absolutely horrific with my dogs."
Seasonal canine illness was first linked to areas of woodland in 2009, but an exact cause has never been found. Dog owners are advised to look out for vomiting, diarrhoea or lethargy which usually appears within 24 to 72 hours of dogs having walked in woodland in autumn. At least 11 Notts dogs have died since 2009, all after being walked in and around Sherwood Forest or Clumber Park.
Miss Stark's comments were backed by Angie Shaw, club secretary of the Nottingham Dog Training Club, based in St Ann's.
She said: "You are only putting your dog at risk by visiting these areas at that time of year until they find out what's causing it."
Louise Fleetwood, of the Forestry Commission, which runs Sherwood Pines, said out of thousands of visitors the commission was only aware of four cases this year. "We would never dissuade people from coming when it's only a minority of dogs that have been affected," she said.
A spokeswoman for the Animal Health Trust, which is investigating the illness, added: "We will not be advising owners to stay away from woodland at this point in the investigation because we still don't have a definitive cause."