The healthcare worker, who is based at the University Hospital of North Staffordshire, is said to be responding well to treatment.

A spokeswoman from the Health Protection Agency said the risk of other health workers and patients contracting the illness was "small".

People who have been inpatients on a number of wards in the last three months are being contacted.

A spokesman from the agency said the disease did not spread easily and was treatable with antibiotics.

"In line with national guidelines, we are contacting family and friends, staff colleagues and GPs of patients who have had prolonged close contact with the healthcare worker," he said.

"These close contacts will be assessed and offered information and screening as necessary."

The agency advises anyone concerned to contact NHS Direct.