Africa should “prepare for the worst” as the coronavirus begins to spread locally, the World Health Organization’s director-general said Wednesday, while South Africa became the continent’s new focus of concern as cases nearly doubled to 116 from two days before. South Africa’s health minister, Zweli Mkhize, this week called that kind of rate “explosive” in the country with the most cases in sub-Saharan Africa. Fourteen of the latest cases were from local transmission — and six were in children under 10. Though the pandemic is in its early days on the continent, health experts have warned that even facilities in Africa’s richest nation could be overwhelmed by the virus’ spread. “I think Africa should wake up. My continent should wake up,” said WHO chief Tedros Adhanom Ghebreyesus, who comes from Ethiopia. Crowded conditions in poor areas could lead to even faster transmission, experts say. Countless South Africans continue to pack into commuter trains and minivan taxis. But the annual pilgrimage of the Zion Christian Church, which attracts about 3 million people, was cancelled.