Pet owners have warned of a mystery illness after 150 dogs were struck down with symptoms following visits to coastal areas.
Hundreds of dogs started falling ill across Yorkshire last week with cases expected to escalate over the next seven days.
The bug is thought to have originated by the North Yorkshire coast which many owners visited before noticing their pups were under the weather, Yorkshire Live reports.
Vet practices in the region shared warnings on Facebook, urging owners to avoid beaches in Scarborough and Saltburn.
But it would appear the bug is now moving inland as Brits in towns and cities, including Hebden Bridge, York, and Sheffield, reported similar symptoms.
One person posted on a group in Hebden Bridge saying: "The dog sickness bug is spreading here like wildfire. My dog came down it on Thursday and I had only taken her to school and back!
"The vet said every other dog he has seen has this bug."
She said that her dog was "fine" now but that her mother's dog had now come down with the same illness.
She said: "Just be careful as they don't know what the cause is or how it's spreading."
Another person from Sheffield posted saying that there was a "nasty bug doing the rounds that will knock your dog off its feet".
They added that the virus is "spreading like wildfire and is in most areas" and had caused her dog to vomit and have diarrhoea, which were similar symptoms to the virus reported from the coast.
Emily Storey, from York, warned others about the illness - which she said was "taking longer than normal to recover from" - after her six-month old cockapoo Loki became ill last week.
She said that she had taken him on walks around Copmanthorpe and discovered that other dogs in the area had fallen ill with a similar illness.
She said that he was also vomiting and had diarrhoea and that he was not eating properly. She also said that when she took him to the vets she was told that it "seems to be worse than usual".
In Leeds, a woman was walking her dog at Hunslet canal before it also caught the mystery illness. She said she thinks the virus came from the coast but is now being spread from dog to dog in the city.
But one of the vets at the Minster Veterinary Practice played down the idea that a new illness was affecting canines though, saying that she didn't think there was a new illness in York.
She said: "We often unfortunately get waves of unwell pets with vomiting and diarrhoea around this time of year, just as in the summer we often get cases of kennel cough. I did mention to a client at Willow Grove that I had seen a few cases of vomiting and diarrhoea, but this can be a normal occurrence this time of year.
"Any cases that have had to be hospitalised due to vomiting and diarrhoea have responded to supportive care. My main advice to any pet owners would be that if your pet is unwell then seek veterinary attention, if we have a mild stomach upset then a bland diet is little and often is a good idea.
"Please be reassured that if we felt that there was something pet owners should avoid or minimise to stop their pet becoming generally unwell then we would advise of this."