Earth as a coronavirus, conceptual illustration. Different strains of coronavirus are responsible for diseases such as the common cold, gastroenteritis and SARS (severe acute respiratory syndrome). A new coronavirus (2019-CoV) emerged in Wuhan, China, in December 2019. The virus causes a mild respiratory illness (Covid-19) that can develop into pneumonia and be fatal in some cases. The coronaviruses take their name from their crown (corona) of surface proteins, which are used to attach and penetrate their host cells. As of 10 March 2020, over 113,000 have been infected worldwide with over 4,000 deaths. Travel restrictions and quarantines have been put in place to slow the spread of the Covid-19 virus.