CAIRO: The World Health Organization says a diphtheria outbreak in war-torn Yemen has spread rapidly nationwide and infected more than 1,300 people. WHO said in a statement that children and young adults account for almost 80 percent of cases and more than 70 people have died. Diphtheria, first reported in Yemen in October last year, is a contagious and potentially fatal disease that primarily infects the throat and airways. WHO said Friday a vaccination campaign targeting 2.7 Yemeni children has been completed in 11 governorates.