Real-time tentative assessment of the epidemiological characteristics of novel coronavirus infections in Wuhan, China, as at 22 January 2020

Wu, Peng; Hao, Xinxin; Lau, Eric H Y; Wong, Jessica Y; Leung, Kathy S M; Wu, Joseph T; Cowling, Benjamin J; Leung, Gabriel M

On 31 December 2019, the Wuhan Municipal Health Commission announced a cluster of cases of viral pneumonia of unexplained aetiology. The Southern China Seafood Wholesale Market in Wuhan was suspected to be related to the first 27 pneumonia cases without identified pathogenic agents that were reported in late December 2019 [12] . Most of the early cases were reportedly either shop owners, largely in the West District of the Southern China Seafood Wholesale Market, or people who visited the market before symptom onset. This market is a large open complex of 50,000 square metres including sections selling seafood, fresh meat, produce, other perishable goods, and a very wide variety of live wild animals for consumption. While wet markets selling such perishable food products are common in China, they usually do not sell such a wide variety of wild animals. Environmental disinfection of the Southern China Seafood Wholesale Market was initiated on 30 December 2019 and the market was closed on 1 January 2020 [13] . Contact tracing was initiated, and by 5 January, more than 160 close contacts of these cases were under medical surveillance, and none of them had an infection [14] .