PITTSBURGH — In 2003, when SARS was spreading, Edward Zhang was not yet a teenager and living with his parents in Wuhan, China, largely dependent on the morning paper and the nightly news to know what was happening in the next city over.

The world has changed a lot since then. Now, as the coronavirus renders his home city a ghost town, overwhelming hospitals and forcing his friends and family to don masks in their own homes, Mr. Zhang is updated constantly despite living over 7,000 miles away, in Pittsburgh.

“I might be finding things out faster than my parents,” he said, describing a steady stream of videos, photographs and reports from his friends in Wuhan, even information about specific apartments in specific buildings where the coronavirus has apparently struck.

It’s a small world after all, a frightening thought if the virus becomes a global pandemic, but a mixed blessing for the scores of Wuhan natives living in Pittsburgh, which has been a “sister city” of Wuhan for nearly 40 years.