A new coronavirus appeared in Wuhan, China at the start of December, and has already infected hundreds of people in nearly a dozen countries. The World Health Organization said that it’s too early to declare a public health emergency globally, although the outbreak is a major emergency in China.
Coronaviruses are common in many types of animals, and can sometimes jump to humans. In this case, the virus probably came from a bat. Two other coronaviruses have infected humans, causing outbreaks of SARS and MERS in 2002 and 2012, respectively. This time, scientists were able to quickly sequence the virus and develop a diagnostic test.
The new coronavirus appears to cause symptoms like fever, cough, difficulty breathing, and other respiratory symptoms. It causes severe illness in around a quarter of cases, and can be deadly. Public health officials are working to understand how dangerous this virus is, how fast it’s spreading, and how to contain it. As that work continues, the virus is causing anxiety around the world.
Follow all the updates on this evolving story here.