LONDON — A British volunteer nurse who survived Ebola said he is returning to West Africa where he caught the disease "because there is still a lot of work to do out there." William Pooley was the first known U.K. citizen to be infected in the current outbreak but made a full recovery after he was flown to London in a military plane in August and treated in isolation with the experimental drug ZMapp.

The 29-year-old said Wednesday that he is preparing to fly back to Sierra Leone to help fight the outbreak that has claimed almost 4,500 lives. "I know my mum and dad are worried but they know it’s something I have to do," he said while at a training session for U.K. health workers who have volunteered to help on the ground to combat the spread of the disease.