World battles to stop the spread of the deadly coronavirus

1. What is COVID-19? What is SARS-CoV-2?

The 2019 novel coronavirus is  now named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) while the disease associated with it is referred to as COVID-19. Coronaviruses are a group of viruses that cause diseases in mammals and birds. In humans, coronaviruses cause respiratory tract infections that are typically mild, such as the common cold, though rarer forms such as SARS, MERS, and COVID-19 can be lethal. Symptoms vary in other species: in chickens, they cause an upper respiratory tract disease, while in cows and pigs they cause diarrhea. There are yet to be vaccines or antiviral drugs to prevent or treat human coronavirus infections.

Coronaviruses comprise the subfamily Orthocoronavirinae, in the family Coronaviridae, order Nidovirales, and realm Riboviria. They are enveloped viruses with a positive-sense single-stranded RNA genome and a nucleocapsid of helical symmetry. The genome size of coronaviruses ranges from approximately 27 to 34 kilobases, the largest among known RNA viruses. The name coronavirus is derived from the Latin corona, meaning "crown" or "halo", which refers to the characteristic appearance reminiscent of a crown or a solar corona around the virions (virus particles) when viewed under two-dimensional transmission electron microscopy, due to the surface covering in club-shaped protein spikes. SARS-CoV-2, was identified in China at the end of 2019 and is a new strain of coronavirus that has not been previously identified in humans.

2. Where do Coronaviruses come from?

Coronaviruses are viruses that circulate among animals but some of them are also known to affect humans. After they have infected animals, they can eventually be transmitted to humans.  A wide range of animals is known to be the source of coronaviruses. For instance, the Middle East respiratory syndrome coronavirus (MERS-CoV) originated from camels and the Severe Acute Respiratory Syndrome (SARS) originated from civet cats. More information on coronaviruses can be found on the ECDC factsheet: