A research scientist at the University of Bristol's veterinary school believes she has identified the UK's first case of a tick which is deadly to dogs.
Dr Susan Shaw said her laboratory diagnosed babesia after a dog was bitten by a tick which has only been found away from the mainland before.
"First we don't know how widespread this tick is in the UK," said Dr Shaw.
"Number two, we don't know how many dogs travelling under the pets' scheme are coming back with these ticks."
The veterinary school is the only one of its kind in the UK able to use DNA to spot such rare types of blood-born disease.