Autumn mites could be the cause of a mystery dog illness that has emerged in a Gainsborough beauty spot for the third year.
Vet Raoul Dowding says that all of the dogs he has seen with "seasonal canine illness" have had the mites on their feet.
It comes after Eric and Val Snaith had to take their six-year-old Cocker spaniel Beanie, and boxer Hooch, eight, for urgent treatment after a walk in Laughton Forest and Blyton Carr, near Gainsborough.
"We had just cut short a week's holiday in a cottage at Blyton Carr after both of our dogs became seriously ill," said Mr Snaith, a 55-year-old driving examiner from the Blackpool area.
"They had contracted what has been called 'seasonal canine illness'.
"They started vomiting within 48 hours of walking in the woods and spent two nights at the vet, on drips and medication.
"We took them home as soon as they were showing signs of recovery.
"The vet said it was most likely caused by harvest mites that were living in the woods.
"We now know that there was a big outbreak of this in the eastern region in 2010 which caused about 35 deaths – including one of the Queen's corgis on the Sandringham estate.
"I think that all dog owners should be made aware that this seasonal problem still exists as it is a life-threatening illness if not caught early and very expensive to treat."
Mr Snaith said his dogs were well on the way to a full recovery – but he had paid £465 to ensure they were brought back from the brink.
Mr Dowding, of Spital Terrace in Gainsborough, confirmed that both of Mr Snaith's dogs had very serious symptoms.
"I've lived in this area for the past 11 years and until three years ago we'd never heard of this illness," said Mr Dowding.
"It was a major problem three years ago because we just didn't know how to treat it and we lost one dog.
"We had a dozen cases last year and another ten in September this year.
"No one knows what causes it, but every animal which comes in to our surgery has harvest mites on its feet.
"It seems to be associated with bracken and pine, in the type of woodland areas like Laughton Forest.
"All the dogs we see have just been walked in areas like that and it's always in the autumn.
"We treat them very quickly with intravenous antibiotics and fluids. They are always very ill and always get better within three days.
"The vets who see this aren't worried because the dogs always respond to the correct treatment.
"I'm confident that when it starts to get both cold and wet we won't see any more cases."