A newly identified coronavirus, provisionally termed 2019-nCoV (an acronym for 2019 novel coronavirus) and subsequently named COVID-19 (an acronym for coronavirus disease 2019), emerged in central China in December 2019. The infectious virus initially affected individuals in the city of Wuhan, predominantly those working at or frequenting certain animal markets. At first, the virus was thought to spread from animals (possibly bats or pangolins) to people. However, affected individuals who did not have exposure to any animal markets have been subsequently identified, suggesting that person-to-person transmission is occurring. Because of the many unknowns concerning this novel coronavirus and the rapidity with which it is spreading, health professionals and epidemiologists are extremely concerned that the outbreak in China may quickly grow into a pandemic (worldwide epidemic). On January 30, 2020, the World Health Organization declared COVID-19 to be a global health emergency. See also: Animal virus; Disease ecology; Epidemic; Epidemiology; Infectious disease; Virus; Virus classification
Coronaviruses comprise a major group of common animal viruses that typically infect mammals and birds. The name coronavirus (Latin corona, meaning crown or a halo appearance) comes from the shape of the virus when the virus is observed using an electron microscope. Fewer than ten coronaviruses have been determined to cause disease in humans. In the twenty-first century, though, a few emergent coronaviruses have resulted in serious and contagious diseases—especially pneumonia or other respiratory illnesses—in humans. Two of the most significant coronavirus diseases are severe acute respiratory syndrome (SARS), which was initially reported in Asia in 2003 and affected more than 8000 people (with 744 deaths), and Middle East respiratory syndrome (MERS), which was first reported in Saudi Arabia in 2012 and affected about 2500 individuals (including more than 840 deaths). As of late February 2020, COVID-19 has been confirmed in more than 80,000 individuals in China, including more than 2700 deaths. Furthermore, due to the ease and rapidity of air travel, more than 2400 cases have been identified in two dozen countries outside of China, including the United States, Australia, Canada, Japan, France, and Germany. Isolated outbreaks in South Korea, Iran, and northern Italy have also occurred. Multiple airlines have thus temporarily suspended all flights to China due to the coronavirus outbreak, and those airlines that are still flying to China are adopting a series of measures to prevent the spread of the deadly disease. See also: Pneumonia; Respiratory system disorders
Individuals infected by COVID-19 have displayed a wide spectrum of symptoms, ranging from mild cold- or flu-like illness to severe respiratory distress and even death. Typical symptoms include cough, fever, shortness of breath, and breathing difficulties. Although further determinations are necessary, symptoms have appeared in as few as 2 days or as long as 14 days after exposure to the coronavirus. This range is similar to that observed for the incubation period of MERS viruses. However, COVID-19 is not the same as the coronavirus that causes either MERS or SARS. Despite this, preliminary genetic analyses suggest that the new virus emerged from a virus related to SARS. See also: Genetics
There is currently neither a vaccine nor any specific antiviral therapy to prevent or treat COVID-19 infection. The only proven methodology to prevent infection is to avoid being exposed to the virus; thus, uninfected individuals (except for properly protected health-care professionals) need to avoid contact with afflicted persons. In general, those infected with COVID-19 should receive supportive treatment based on their clinical presentation—that is, to help relieve symptoms in relatively mild cases or to ensure respiratory function in the most severe cases. See also: Critical care medicine
