Human to Human Transmission of Wuhan Novel Coronavirus Infection outside China: Situation of the First Case and What’s the Source of Infection?

An important thing for successful prevention of any new disease is knowledge of its natural history and epidemiology. For the newest emerging infectious disease that World Health Organization (WHO) declares as global emergency, Wuhan novel coronavirus infection, it is a febrile illness with pulmonary problem.[1] The human to human transmission has just been confirmed since late December 2020. The disease widely spread from human to human in China and the disease is already imported to several countries around the world.[2] At present, apart from imported cases, either Chinese tourist or returning traveler, there are some cases of newly diagnosed cases of infection outside China who have no history of traveling to China. The human‑to‑human transmission of Wuhan novel coronavirus infection outside China among the local people who have no history of travel to China is interesting.