We all know the coronavirus that is causing the 2020 pandemic, but there are more coronavirus types out there. Coronaviruses are a large family of viruses that usually cause mild to moderate upper-respiratory tract illnesses, like the common cold, in people. Coronaviruses are named for the crown-like spikes on their surface.
There are hundreds of coronaviruses, most of which circulate among animals including pigs, camels, bats and cats. Sometimes those viruses jump to humans and can cause disease. Currently there are 7 known coronavirus types that can infect people.
The four common human coronaviruses are:
- 229E
- NL63
- OC43
- HKU1
People around the world commonly get infected with the above four human coronaviruses. They usually cause mild to moderate upper-respiratory tract illnesses, like the common cold. Most people get infected with one or more of these viruses at some point in their lives.
Three times in the 21st century coronavirus outbreaks have emerged from animal reservoirs to cause severe disease, serious outcomes and global transmission concerns. These are:
- MERS-CoV (it causes the Middle East Respiratory Syndrome, or MERS)
It emerged in 2012 and remains in circulation in camels. It was first reported in Saudi Arabia in 2012 and has since spread to more than 27 other countries, according to the World Health Organization. From its emergence through December 2019, WHO has confirmed 2,499 MERS cases and 861 deaths (or about 1 in 3). Among all reported cases in people, about 80% have occurred in Saudi Arabia.
- SARS-CoV (it causes the Severe Acute Respiratory Syndrome, or SARS)
It emerged in late 2002 and disappeared by 2004. SARS was first reported in Asia in February 2003, though cases subsequently were tracked to late 2002. SARS quickly spread to about two dozen countries before being contained after about four months. Since 2004, there have been no known SARS cases.
- SARS-CoV-2 (the novel coronavirus that causes coronavirus disease 2019, or COVID-19)
It emerged in December 2019 from China and a global effort is under way to contain its spread.
Source: www.cdc.gov, www.niaid.nih.gov