The first known cases involved mainly the workers of the market in Wuhan, China, where fish and other live animals were sold. In the first weeks of January 2020, scientists identified in these subjects strange pneumonia caused by a new type of coronavirus, called SARS-CoV-2, which means severe acute respiratory syndrome of type 2 coronavirus. It was found to be similar for at least 70 % of its gene sequence to that of SARS-CoV, which triggered the SARS epidemic that began in 2002 and ended in 2004.
At the end of January 2020, the characteristics of the virus had not yet been well determined, despite the fact that it was able to be transmitted from person to person, and there were still uncertainties about the exact modes of transmission and pathogenicity. The associated disease was recognized as COVID-19.
The first report attributable to the new virus occurred on 31 December 2019, although the first patients with symptomatic disease appeared already on 8 December. On January 1, 2020, the authorities ordered the closure of the Wuhan market and the isolation of those with signs and symptoms of the infection.
The first confirmed death dates back to January 9, 2020. As of January 23, 2020, Wuhan was placed in quarantine, with the suspension of all public transport in and out of the city, measures that the following day were extended to the neighboring cities of Huanggang, Ezhou… In January 13 there are about 40 cases in Wuhan, where in the space of a month the cases reach about 75000.