Two Dutch doctors who have returned to the Netherlands after being exposed to the ebola virus while working in Sierra Leone are being looked after in a special quarantine unit at Leiden University’s teaching hospital.

Neither doctor is showing any symptoms of the disease but they have opted not to return to their homes until they are absolutely certain they have not picked it up.

The doctors, who worked for a Dutch charity, are soon to move to another secret location to wait out the maximum incubation period, Dutch media said on Monday.