Nelson Mandela is back in the hospital and listed in serious condition with a lung infection, reports the BBC. The 94-year-old had been battling the infection from home for days and was transferred to the hospital in Pretoria last night when his condition worsened. It's the third hospitalization for the former South African leader since December. "Doctors have assured us he is comfortable," said a government statement, and its lack of the usual "it's-only-routine" sentiment has set off more concern than usual, notes Reuters Africa. (More Nelson Mandela stories.)