I found this article to be pretty interesting, an overview from the start of the outbreak.
"temperatures were warmer than usual in early December in Wuhan, an inland port city with a population larger than New York. By mid-month, it had cooled to the 9 to 10 degrees Celsius typical of the mild early winters in the city that sits on a bend in the Yangtze, Asia’s longest river. Its metropolitan district spreads out on both banks of the waterway to cover an area five times the size of London.
the first cases started to trickle into Wuhan’s major hospitals in mid-December. The patients typically had dry, raking coughs, high fevers and laboured breathing – symptoms that could mean a bad bout of winter flu.
But something else showed up in X-ray images constructed into computed tomography scans of their lungs. Medically, they were described as “ground-glass opacities”, or areas filled with fluid or partially collapsed, a telling sign of pneumonia.
Lung infection was evident in one of the early patients moved to Tongji Hospital, one of Wuhan’s leading medical centres, for treatment. He was transferred on Christmas Day with “widespread patches of shadows” on his lungs, a Tongji doctor says. “Even after antibiotics, he showed no sign of improvement.”
That patient was among many with combinations of fever, coughs and lung shadows who started to “flood in” to Tongji in the last week of December, says the doctor, who asked to remain anonymous because of his hospital’s restrictions on speaking to the media.
Discussing the cases with colleagues, he says they wondered whether Sars was back.
Patients with Sars-like symptoms were also being admitted to Wuhan Union Hospital."
Coronavirus: How Disease X, the epidemic-in-waiting, erupted in China
