Coronaviruses are a family of hundreds of viruses that can cause illness ranging from the common cold to more severe disease. Seen under an electron microscope, the coronavirus particles appear to have a crown or "corona" of club-shaped spikes on their surface - hence, the name.
A "novel" coronavirus (nCoV) is a new strain that has not been previously identified in humans.
On December 31, 2019, a cluster of pneumonias of unknown cause was reported in Wuhan, a city in the Hubei Province of China. These infections were found to be caused by a new coronavirus which was given the name "2019 novel coronavirus" or 2019-nCoV. It was later renamed "severe acute respiratory syndrome coronavirus 2", or SARS-CoV2, as the virus is a genetic cousin of the coronavirus that caused the SARS epidemic between 2002 and 2004 (SARS-CoV).
COVID-19 is the name given to the disease caused by SARS-CoV2. It is an acronym for COronaVIrus Disease of 2019 and was given this abbreviated name on February, 11, 2020 by the World Health Organization (WHO).
Seven strains of coronavirus are known to infect humans, four of which are responsible for the common cold. The 2019 novel coronavirus (aka 2019-nCoV or SARS-CoV2) is one of three strains, including MERS-CoV and SARS-CoV, known to cause severe, and sometimes fatal respiratory infections in humans and have been responsible for several major outbreaks in the last 20 years.
◎SARS-CoV: identified in 2002 as the cause of an outbreak of Severe Acute Respiratory Syndrome (SARS).
◎MERS-CoV: identified in 2012 as the cause of Middle East Respiratory Syndrome (MERS).
◎SARS-CoV2: the novel
coronavirus identified as the cause of Coronavirus Disease of 2019 (COVID-19) that was first reported in Wuhan, China in late 2019 and has since spread worldwide to over 210 countries.
◎The coronaviruses mentioned above are "zoonotic pathogens", meaning that they begin with infecting animals and are then transmitted from animals to people.