Starkly illustrating the global east-to-west spread of the new coronavirus, Italy began an extraordinary, sweeping lockdown Tuesday while in China, the diminishing threat prompted the president to visit the epicenter and declare: “We will certainly defeat this epidemic.”

Chinese President Xi Jinping’s trip to the central city of Wuhan — his first since the start of the outbreak — was the latest sign that China is edging back toward normal after weeks of extreme quarantine measures. China reported just 19 new infections Tuesday, down from thousands each day last month.