Monkeypox infection being treated in Newcastle.
A healthcare worker has become the third person to be diagnosed with monkeypox in England.
The individual was involved in the care of a patient at Blackpool Victoria Hospital earlier this month, before they were known to be carrying the infection, Public Health England (PHE) said.
The patient - who was only the second case of the rare infection recorded in the UK - is believed to have contracted the virus after travelling to Nigeria.
The first case was diagnosed just days earlier, after a resident of Nigeria staying at a naval base in Cornwall presented with symptoms.
PHE previously said there was "no UK link'' between the first two patients.
Monkeypox does not spread easily between people and most who contract the infection recover within a few weeks, although severe illness can occur in some people.
However, Dr Nick Phin, deputy director of the National Infection Service at PHE, said the third case is "not wholly unexpected''.
The third individual is being treated at the Royal Victoria Infirmary in Newcastle.
Dr Phin said: "This healthcare worker cared for the patient before a diagnosis of monkeypox was made.
"We have been actively monitoring contacts for 21 days after exposure to detect anyone presenting with an illness so that they can be assessed quickly. It is therefore not wholly unexpected that a case has been identified.
"This person has been isolated and we are taking a highly precautionary approach to ensure that all contacts are traced.''
There was a large outbreak of monkeypox in Nigeria in September 2017 and sporadic cases have been reported since