The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; previously provisionally named 2019 novel coronavirus or 2019-nCoV) disease (COVID-19) in China at the end of 2019 has caused a large global outbreak and is a major public health issue. As of 11 February 2020, data from the World Health Organization (WHO) have shown that more than 43 000 confirmed cases have been identified in 28 countries/regions, with >99% of cases being detected in China. On 30 January 2020, the WHO declared COVID-19 as the sixth public health emergency of international concern. SARS-CoV-2 is closely related to two bat-derived severe acute respiratory syndrome-like coronaviruses, bat-SL-CoVZC45 and bat-SL-CoVZXC21. It is spread by human-to-human transmission via droplets or direct contact, and infection has been estimated to have mean incubation period of 6.4 days and a basic reproduction number of 2.24–۳٫۵۸٫ Among patients with pneumonia caused by SARS-CoV-2 (novel coronavirus pneumonia or Wuhan pneumonia), fever was the most common symptom, followed by cough. Bilateral lung involvement with ground-glass opacity was the most common finding from computed tomography images of the chest. The one case of SARS-CoV-2 pneumonia in the USA is responding well to remdesivir, which is now undergoing a clinical trial in China. Currently, controlling infection to prevent the spread of SARS-CoV-2 is the primary intervention being used. However, public health authorities should keep monitoring the situation closely, as the more we can learn about this novel virus and its associated outbreak, the better we can respond.

Introduction

Since the emergence of the 2019 novel coronavirus (2019- nCoV) infection in Wuhan, China, in December 2019 [1], it has rapidly spread across China and many other countries [2–۸]. So far, 2019-nCoV has affected more than 43 000 patients in 28 countries/regions and has became a major global health concern (https: //www.who.int/docs/default-source/coronaviruse/situation-reports/ 20200211-sitrep-22-ncov.pdf?sfvrsn=6f80d1b9_4). On 11 February 2020, the World Health Organization (WHO) announced a new name for the epidemic disease caused by 2019-nCoV: coronavirus disease (COVID-19). Regarding the virus itself, the International Committee on Taxonomy of Viruses has renamed the previously provisionally named 2019-nCoV as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) [3]. Although early studies reported a link between a single local fish and wild animal market and most cases of infection, indicating possible animal-to-human transmission, studies have increasingly demonstrated human-to-human transmission of SARS-CoV-2 through droplets or direct contact [2,8–۱۰]. Moreover, according to one study, presumed hospital-related transmission of SARS-CoV-2 was suspected in 41% of patients [8]. Based on the evidence of a rapidly increasing incidence of infections [11] and the possibility of transmission by asymptomatic carriers [12], SARS-CoV-2 can be transmitted effectively among humans and exhibits high potential for a pandemic [5,10,13].