Coronaviruses and acute respiratory syndromes (covid-19, mers, and sars)

[Vania]

Coronaviruses are a large family of viruses that cause respiratory illness ranging in severity from the common cold to fatal pneumonia.
There are many different coronaviruses. Most of them cause illness in animals. However, 7 types of coronaviruses are known to cause illness in humans.
Four of these 7 human coronavirus infections involve mild upper respiratory tract illness that causes symptoms of the common cold.
However, 3 of the 7 human coronavirus infections can be much more severe and have recently caused major outbreaks of deadly pneumonia:

SARS-CoV-2 is a novel coronavirus that was first identified in Wuhan, China in late 2019 as the cause of coronavirus disease 2019 (COVID-19) and spread worldwide.
MERS-CoV was identified in 2012 as the cause of Middle East respiratory syndrome (MERS).
SARS-CoV was identified in 2003 as the cause of an outbreak of severe acute respiratory syndrome (SARS) that began in China near the end of 2002.

These coronaviruses that cause severe respiratory infections are transmitted from animals to humans (zoonotic pathogens).