Italian general practitioners remember seeing strange pneumonia cases as early as November, which could mean the virus was circulating in parts of Italy before doctors became aware of China's COVID-19 outbreak, a U.S. radio outlet reported, citing a paper on Italy's coronavirus crisis.

The report published Thursday by U.S. media outlet National Public Radio (NPR) cited Giuseppe Remuzzi, co-author of a recent paper in The Lancet about Italy's epidemic.

According to the report, some question why Italy was caught off guard when the virus outbreak was revealed on Feb. 21. Remuzzi said he is hearing information about it from general practitioners.

"They remember having seen very strange pneumonia, very severe, particularly in old people in December and even November," the report quoted Remuzzi as saying. "This means that the virus was circulating, at least in (the northern region of) Lombardy and before we were aware of this outbreak occurring in China."

Remuzzi believed other countries can learn important lessons from Italy. The takeaways include how to swiftly convert a general hospital into a coronavirus care unit with specially trained doctors and nurses, said the NPR report.

Italy reported 6,557 new cases of coronavirus on Saturday, raising the total to 53,578 since the pandemic first broke out in its north on Feb. 21, according to the latest data provided by the Civil Protection Department managing the COVID-19 emergency.