The third zoonotic human coronavirus (CoV) of the century emerged in December 2019, with a cluster of patients with connections to Huanan South China Seafood Market in Wuhan, Hubei Province, China. Similar to severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) infections, patients exhibited symptoms of viral pneumonia including fever, difficulty breathing, and bilateral lung infiltration in the most severe cases [ 1 ]. News reports of patients with an unknown pneumonia were first identified on 31st December with the Wuhan Municipal Health Commission saying they were monitoring the situation closely ( Figure 1 ). On 1st January 2020, the seafood market was closed and decontaminated while countries with travel links to Wuhan went on high alert for potential travelers with unexplained respiratory disease. After extensive speculation about a causative agent, the Chinese Center for Disease Control and Prevention (CDC) confirmed a report by the Wall Street Journal and announced identification of a novel CoV on 9th January [ 2 ]. The novel CoV (2019-nCoV) was isolated from a single patient and subsequently verified in 16 additional patients [ 3 ]. While not yet confirmed to induce the viral pneumonia, 2019-nCoV was quickly predicted as the likely causative agent.

The first sequence of 2019-nCoV was posted online one day after its confirmation on behalf of Dr. Yong-Zhen Zhang and scientists at Fudan University, Shanghai [ 4 ]. Subsequently, five additional 2019-nCoV sequences were deposited on the GSAID database on 11th January from institutes across China (Chinese CDC, Wuhan Institute of Virology and Chinese Academy of Medical Sciences & Peking Union Medical College) and allowed researchers around the world to begin analyzing the new CoV [ 5 ]. By 17th January, there were 62 confirmed cases in China and importantly, three exported cases of infected travelers who were diagnosed in Thailand (2) and Japan (1) [ 6 ]. The sequences of these exported cases and several additional 2019-nCoV isolated in China have also been deposited on the GSAID database [ 5 ]. Diagnostic tests have subsequently been developed and some are being used on suspect cases identified in other locations including Vietnam, Singapore, and Hong Kong [ 7 ]. To date there have been twenty-six fatalities associated with 2019-nCoV infection, many of these cases had significant co-morbidities and were older in age (>50). A range of disease has been observed highlighted by fever, dry cough, shortness of breath, and leukopenia; patients have included mild cases needing supportive care to severe cases requiring extracorporeal membrane oxygenation; however, compared to SARS-CoV (10% mortality) and MERS-CoV (35% mortality), the 2019-nCoV appears to be less virulent at this point with the exception of the elderly and those with underlying health conditions. Initial monitoring of case close contacts had not revealed any further 2019-nCoV cases. However, modeling analysis based on official case numbers and international spread suggested that there may be cases going undetected [ 8 ]. On 19th January, these fears were seemingly confirmed as an additional 136 cases were added from further surveys raising the total in Wuhan to 198 infected patients [ 9 ]. Among the 198 total cases in Wuhan, 170 remained in hospitals, 126 mostly with mild symptoms, 35 in serious condition, and 9 in critical condition. The expanded numbers and extended range of onset dates (12 December 2019–18 January 2020) suggested likely human to human transmission or ongoing transmission from a market or other primary sources. On 20th January, the outbreak was further expanded to other parts of China (Beijing, Shanghai, & Shenzhen) as well as another exported cases to South Korea. As of January 24, the total case number has expanded to at least 870 total cases with 26 deaths across 25 provinces in China and 19 exported cases in 10 countries [ 10 ]. Public health authorities have quarantined travel from Wuhan to limit the spread of the virus and reports indicate other Chinese cities have also been isolated [ 11 ]. With the heavy travel season for lunar New Year underway in Asia, major concerns exist for the 2019-nCoV outbreak to continue and spread.