The virus has spread to some two dozen countries and territories and sickened more than 20,000 in Asia. At least 427 people have died, including a man in the Philippines over the weekend.

Other developments: Hong Kong has closed many, though not all, crossings with the mainland. Macau, the gambling hub that’s also a semiautonomous region of China, said it would shut its casinos for two weeks, and Japan quarantined a passenger ship with 3,700 people aboard. Hyundai said that it was suspending operations at factories because of supply-chain disruption. Travelers have been struggling to get refunds on canceled flights.

Political dangers: China’s state-run news media reported that President Xi Jinping on Monday called the outbreak “a major test of China’s system and capacity for governance.” China is turning to familiar authoritarian techniques to contain the outbreak, including asking neighbors to inform on one another. And it is making herculean efforts to keep the country fed amid food hoarding.

Analysis: Our New New World columnist, Li Yuan, writes that the crisis has eroded trust in the government, perhaps permanently.