What is the COVID-19 coronavirus?
COVID-19 is short for coronavirus disease 2019, a new infectious disease caused by a novel coronavirus that has not been previously found in humans . In COVID-19, ‘CO’ stands for ‘corona,’ ‘VI’ for ‘virus,’ and ‘D’ for disease .
The disease-causing virus is the Severe Acute Respiratory Syndrome Corona Virus 2, abbreviated as SARS-CoV-2. Coronaviruses are named for their characteristic virus particles that are covered by protruding spikes reminiscent of a crown (from Latin “corona”).
This outbreak emerged in the Chinese city of Wuhan and since the first COVID-19 cases were reported in December 2019 has rapidly spread into other countries . The source of infection has been associated with a Wholesale Market where live animals were sold and the disease, in similarity to other coronaviruses, was likely acquired through zoonotic transmission from animals to humans . The specific animal reservoir of SARS-CoV-2 has not yet been identified, though its genome is related to coronaviruses found in bats .
On March 11 2020, the World Health Organization (WHO) declared this by then global outbreak as a pandemic (from Greek pan "all" and demos "people"), which is defined as a disease that spreads over a wide geographic area, often worldwide, and affects a high proportion of the population . Besides SARS-CoV-2, two other pathogenic coronaviruses, SARS-CoV  and MERS-CoV, the agent of Middle East Respiratory Syndrome, have caused large-scale human outbreaks in the recent past, the latter is still ongoing .