In 2005, the Guardian featured 10 newborn babies in countries across Africa. We have followed their progress at five-year intervals. In one case, this sadly hasn’t been possible. Sijjin Kuang, in what was then southern Sudan, died days after he was born. And although Prosper Mumba from Zambia is doing well, his family declined to participate this year. So here we revisit eight of the children. Now aged 10, they tell us their stories and reveal the challenges they face