Dog owners have been warned about a potentially deadly disease spread by ticks, which has infected four dogs in Essex.
Babesiosis is caused by microscopic parasites that infect red blood cells and are spread by certain ticks.
It causes the immune system to destroy its own blood cells.
The tick carrying the disease has only ever been found abroad, however four new cases in Harlow, Essex confirm that it has arrived in the UK.
According to the BBC, all four of the dogs infected with the disease survived, however two ended up "seriously ill" and needing blood transfusions.
The dogs were all walked on the same patch of land.
Symptoms of babesiosis, which pet owners need to look out for, include lethargy, weakness, pale gums, red or brown urine and a fever.
A spokesperson for the APHA said: "These particular dogs have not travelled outside England raising the possibility they have become infected within the country.
"We are providing support to veterinary practices to identify the possible source of infection."
A PHE spokesperson said: "The tick concerned, Dermacentor reticulatus is not a common tick in England, and PHE are currently monitoring the distribution of this tick across England."
Sean Wensley, president of the British Veterinary Association (BVA), said prevention is key.
"It is concerning that babesiosis has been diagnosed in the UK in dogs that have not travelled overseas, and dog owners in the local area will understandably be feeling anxious about the reported cases," he said.
"Prevention is always better than cure, and we would recommend that owners regularly discuss parasite control, including tick prevention treatments, with their vet.
"Owners should also check pets for ticks after walks and if one is found on the body it should be removed completely using a commercially available tick-remover or fine-pointed tweezers, even if they are dead.
"If owners have any concerns about their dog or suspect any signs such as weakness, pale gums or 'coffee-coloured' urine then they should contact their vet immediately."