What is corona?

Since December 2019, the term coronavirus has been known to almost everyone in the world. What exactly is a coronavirus? And where does it come from?

Coronaviruses (CoV) are part of a large family of viruses that have been known since the 1940s. Coronaviruses are spherical and are on average 125 nanometres (one millionth of a millimeter) in diameter. They have bat-shaped spines on the outside of the mantle, which gives them the name "corona" - Latin for "crown". Like all viruses, they need a host to survive and multiply. Viruses from the Coronaviridae family are normally found in animals, such as livestock, camelids, felines, and bats, and in humans.

The latest coronavirus, SARS-CoV-2, has spread around the world starting in December 2019 in the Wuhan region of China. The virus originated through zoonosis: that means the virus already existed in one or more animal species and has spread to humans. Other types of coronaviruses have also become world famous – or rather, infamous: Severe Acute Respiratory Syndrome (SARS-CoV) in 2003 and Middle East Respiratory Syndrome (MERS-CoV) in 2014. SARS-CoV-2 most likely originated from bats and was transmitted to humans through direct contact or through another animal, the pangolin.

Coronaviruses are mainly present in humans in the respiratory tract and the gastrointestinal tract. SARS-CoV-2 can cause the disease COVID-19. Most people that are infected develop no symptoms or only mild, common cold-like symptoms. However, in a few percent of patients, SARS-CoV-2 can also cause serious complaints such as breathing problems or pneumonia, or patients may even die.