On December 31, China alerted the World Health Organization (WHO) to several cases of pneumonia in Wuhan, a port city of 11 million people in the central Hubei province. The virus is unknown.
Several of those infected worked at the city’s Huanan Seafood Wholesale Market, which was shut down on January 1.
As health experts worked to identify the virus amid growing alarm, the number of infections exceeded 40.
On January 5, Chinese officials ruled out the possibility that this was a recurrence of the severe acute respiratory syndrome (SARS) virus – an illness that originated in China and killed more than 770 people worldwide in 2002-2003.
On January 7, they announced that they had identified a new virus, according to the WHO. The novel virus is from the coronavirus family, which includes SARS and the common cold, and is named 2019-nCoV. Coronaviruses are common and spread through coughing, sneezing, or touching an infected person.
On January 11, China announced its first death, a 61-year-old man who had purchased goods from the seafood market. Treatment did not improve his symptoms after he was admitted to hospital and he died on the evening of January 9 when his heart failed.
On January 13, WHO reported a case in Thailand, the first outside of China, a woman who had arrived from Wuhan.
On January 16, Japan’s health ministry reported a confirmed case, a man who had also visited the city.
On January 17, as a second death was reported in Wuhan, health authorities in the United States announced that three airports would start screening passengers arriving from the city.