According to the World Health Organization (WHO), coronaviruses are a family of viruses that cause illness ranging from the common cold to more severe diseases such as SARS and Middle East respiratory syndrome (MERS). These viruses were originally transmitted between animals and people. SARS, for instance, was believed to have been transmitted from civet cats to humans while MERS travelled from a type of camel to humans.
Several known coronaviruses are circulating in animals that have not yet infected humans. The name coronavirus comes from the Latin word corona, meaning crown or halo. Under an electron microscope, the image of the virus is reminiscent of a solar corona.
A novel coronavirus, identified by Chinese authorities on January 7 and named 2019-nCoV, is a new strain that had not been previously identified in humans. Little is known about it, although human-to-human transmission has been confirmed.