NAIROBI — African countries must carry out more coronavirus testing and make people use masks, a regional disease control body said as cases topped half a million in the continent. New cases in Africa were up 24 percent over the past week, with data from governments and the World Health Organization showing it had 512,499 confirmed COVID-19 cases, with 11,930 deaths. “The pandemic is gaining full momentum,” John Nkengasong, head of the Africa Centers for Disease Control and Prevention (CDC), told a virtual news briefing from Addis Ababa. Nkengasong said African countries, many of which do not have reliable data, must adopt an aggressive approach to encourage the wearing of face masks and ramp up testing and tracing. “This will save lives and save (the) economy.” Egypt, Nigeria, South Africa, Ghana, and Algeria account for 71 percent of infections on the continent, Nkengasong said. — Agencies