Maps show where coronavirus started and why officials are so worried

Since it was first detected in the closing weeks of 2019, the coronavirus that originated in Wuhan, China, has infected more than 2,500 people and killed several dozen. The virus is transmitted through coughing or sneezing.

This is the market where officials say the coronavirus first jumped from animal to person. Known for selling exotic wildlife, the market is in the heart of Wuhan, a city of nearly 11 million people in the Hubei province.

The market — which was closed Jan. 1 — is about a half-mile from a large train station that connects the city to the rest of China.

On the Yangtze River, Wuhan is a key transport hub for goods moving from China’s interior to the coast, as well as for north-south commercial traffic.

The city reflects China’s role at the center of pan-Asian supply chains for electronics, pharmaceuticals and automobiles.

Within this map’s range live more than 9 million people, according to estimates by a NASA data center. That’s more than the population of New York City.

As confirmed cases mounted, Wuhan and the surrounding cities of Huanggang and Ezhou announced plans to restrict travel into and out of the area.

Within this map’s range are 13 million people. That’s about the same population as Pennsylvania.

By Friday, at least a dozen more cities in the Hubei province were on lockdown.

Within this map’s range are more than 140 million people. Higher density areas are shown with lighter colors.

Wuhan is just one city in a string of densely populated areas within China along the Yangtze River. So far, more than 2,500 cases of coronavirus have been confirmed in China, overwhelming hospitals, most of them in this area.

A few cases have been confirmed in the major population centers of Beijing, Shanghai and Hong Kong.

Chinese officials have canceled many public celebrations of the Lunar New Year, which began Saturday, in an effort to slow the spread of the virus.

About two dozen cases have been confirmed outside of mainland China, including five in the United States so far.