The deadly Ebola virus, which emerged mysteriously from African forests, probably attacks people who butcher and eat infected animals, researchers said on Thursday. The virus, which most recently killed 29 people in the Congo Republic, seems to break out when people slaughter chimpanzees, gorillas and small antelopes called duikers, the scientists said. “Humans and duikers scavenging for meat probably became infected by contact with dead apes,” they wrote in their report, published in Friday’s issue of the journal Science.