As fatalities doubled to at least six with hundreds more people infected, airports around the world, including in Australia and the U.S., were checking passengers on flights from Wuhan, where the virus began in a seafood and poultry market. North Korea temporarily closed borders to tours from China. Here’s what else we know.

The World Health Organization called a meeting to decide whether to declare the outbreak an international health emergency as evidence mounted that the virus spreads from person to person. In one case, a patient appeared to have infected 14 medical workers.

Fears: Many in China recalled the government’s slow response to the 2003 outbreak of the SARS virus, which killed more than 800 people and infected more than 8,000.