UK nurse's colleague on dangers of working with Ebola

Dr Umar Ahmad is a 29-year-old NHS medic who worked at a hospital in east London before deciding to come to Freetown to help in the Ebola outbreak.

He worked with nurse Pauline Cafferky treating patients with Ebola for a couple of weeks - when she first arrived in Sierra Leone at the end of November.

Since she was infected with Ebola, he told the BBC's Tulip Mazumdar that he has become even more careful, but is determined to continue with his work.