Coronaviruses are a family of viruses, which cause respiratory illness in humans. It gets its name from the crown-like halo (or corona) surrounding the virus and can be seen under an electron microscope. Scientists have long identified coronaviruses circulating among animals, such as camels, cats, and bats. Still, only a few have jumped to people – a spread that is defined by epidemiologists as “zoonotic.”
Deeper dive
Before 2020, six coronaviruses were known to be circulating among people, four of which cause about 25 percent of colds. Two others were known to cause extreme illness – Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). SARS and MERS spread between humans via respiratory droplets with close contacts, the way influenza and other respiratory pathogens have spread, but they don’t spread easily and could be controlled. Around 8,000 people worldwide were infected with SARS and approximately 800 died and MERS infected 2,500 and killed about 860.
There has been no known community spread of SARS since 2003 and very little community spread of MERS. In January 2020, China announced the emergence SARS-CoV-2019, the virus that causes COVID-19. The genetic sequence of the coronavirus causing COVID-19 shares some of the same genes as SARS. That is how SARS-CoV-2019 [or SARs-CoV-2 for short] got its name. The “2019” designation was given because the virus is known to have begun circulating at some point late in 2019.