Leona Lewis has said the "horrors" she witnessed on a recent trip to South Africa to help HIV victims will never leave her.The X Factor winner headed to Johannesburg to raise awareness of the plight of children who've lost their parents to Aids and are also battling with the disease.During the three-day trip, she visited a number of different projects including a day care centre for children affected by HIV and Aids.She also met six-year-old Nyah Ngugu, and young girl who is HIV positive at the Leith'emba Care Centre.The 22-year-old said: "Some of the horrors I have seen will never leave me.She added: "To look at Nyah you would never guess she is HIV positive. Because of the antiretroviral drugs she is able to live a normal life."© Independent Television News Limited 2008. All rights reserved.