More than a dozen countries, including the U.S., are isolating patients and screening travelers from China. No deaths from the respiratory disease have been recorded outside mainland China, where the toll rose to 170.

Fears that a sick passenger had the coronavirus led the Italian authorities to block more than 1,000 people from disembarking a cruise ship in a port town, until the passenger and her husband could be tested. And from Asia to Canada, the panic has unleashed anti-Chinese sentiment.

In the U.S.: The first person-to-person transmission, the husband of a woman who recently returned from Wuhan, was documented in Illinois.

World Health Organization: Officials declared the outbreak a global health emergency. The declaration has no force of law or practical effect, but it adds urgency to any W.H.O. appeal for money to fight it.