The Dow sank nearly 1,200 points, or 4.4 percent. It was the worst one-day drop for the market since 2011, and stocks are now headed for their worst week since October 2008, during the global financial crisis. 6:26 p.m.
Health officials confronted tough questions and doubts Thursday about testing to intercept the fast-spreading virus, with scrutiny focused on a four-day delay in screening an infected California woman despite her doctors’ early calls to do so. 5:49 p.m.