Coronaviruses were discovered in the 1960s. They are a group of ＿＿（56）＿＿ that cause diseases in ＿＿（57）＿＿ and birds. In humans, coronaviruses cause ＿＿（58）＿＿ tract infections that are typically mild, such as the common cold. The name "coronavirus" is ＿＿（59）＿＿ from the Latin corona, meaning crown or halo. The name refers to the characteristic appearance of the infective form of the virus, which is ＿＿（60）＿＿ of a crown or a solar corona. At the end of 2019, a new type of coronavirus started ＿＿（61）＿＿ in China. This type of coronavirus is often called 2019-nCoV,＿＿（62）＿＿ coronavirus, or COVID-19. It is believed that the virus was ＿＿（63）＿＿ from animals to humans. Some of the first cases were ＿＿（64）＿＿ in people who had visited a market selling live seafood and animals. Unfortunately, when viruses are transmitted from animals to people, it can take scientists a lot of time before they can develop a vaccine or medicines to cure ＿＿（65）＿＿.