The mystery dog illness that was discovered earlier this month is "still rapidly spreading", warns the vet who first raised the alarm.
Brogan-Alexandra Proud, who runs Yorkshire Coast Pet Care, started seeing dogs falling ill with vomiting and diarrhoea on January 10.
The illness has moved inland to Sheffield and Leeds after dog owners were warned to not go to the beach.
Brogan-Alexandra says she still receives a constant flow of ill animals, but the numbers seemed to be easing off since she had warned walkers not to go on the beach, YokrshireLive reports.
She first warned dog walkers that she has been "inundated with dogs coming off the beaches with vomiting and diarrhoea" and urged people not to take their dogs for walks on the beaches while the cause of the illness was unknown.
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Brogan-Alexandra said: "It's still much the same. The situation has not changed. It's still rapidly spreading."
She said that she believed dog walkers were not going on the beaches as much and keeping their pets on leads to avoid contact with others.
As a result, there were "not quite as many" ill dogs coming as there had been.
She said: "There's not 20 a day like there was but there's still a few coming in each day with the symptoms."
Brogan-Alexandra said she still believed the illness had originated from the beaches.
Brogan-Alexandra said that she shared the opinion of some who had theorised that the source of the illness was from toxins being released in the Yorkshire sea - something that may also explain the huge numbers of dead sea life being washed up on the coast.
She said: "These aren't normal things - there's definitely something doing on.
"We have had illnesses in the past but we rarely see dead seals washed up."
Some vets and Scarborough Borough Council have downplayed the concerns, saying that dogs regularly come down with illness during the winter months.
Brogan-Alexandra responded: "I've been doing this for 12 years and I know it gets worse this time of year but I have never seen numbers like this coming through. Local practices in the area have said the same thing.
"There was loads of people saying that their dogs had come off the beach and were ill just hours later on the post as well. This was definitely not normal."
Since the initial reports of the dog illness spreading in the likes of Whitby, Scarborough and Filey, dog owners in more inland areas such as Sheffield, Leeds and York have also reported a severe dog illness spreading.
Brogan-Alexandra said "it's impossible to say" if it was the same illness.
She added: "I know a lot of people I spoke to had been on holiday on the coast and were heading back home with their dogs. Whatever it is it's spreading like wildfire."