This article is based on the experiences of Wall Street Journal reporters Stephanie Yang, Shan Li and James T. Areddy, as recounted by Ms. Yang.

Arriving at a hotel on Jan. 26 in a city about 200 miles from Wuhan, our plan was set. My colleague Shan Li and I would leave in the early-morning darkness the following day, traveling by car into the city to report from the center of a deadly viral epidemic.

Almost...