David Nott told the Western Mail the boy's arm had already been partially amputated after he was attacked by a hippopotamus. In October, when Nott saw him, the stump had become infected and he needed a drastic operation that included removing the shoulder and the scapula, a bone in the back.

Nott, a consultant at a London hospital who was spending a month with Doctors Without Borders, is an experienced surgeon whose patients have included former Prime Minister Tony Blair. He had no experience with this operation but called on his friend, Meirion Thomas, who was on vacation, for help.

"The boy had an 80 percent chance of dying and the potential for things to go wrong was enormous," Nott said. "We only had one pint of blood, one scalpel, one pair of forceps and I wasn't sure if the anesthetic was strong enough. I just knew that Meirion had done this operation before and just knew that he would be there to help me -- and he was."