Covid-19 coronavirus particles, illustration. The SARS-CoV-2 coronavirus was first identified in Wuhan, China, in December 2019. It is an enveloped RNA (ribonucleic acid) virus. Within the membrane are spike proteins (large protrusions) as well as membrane proteins and envelope proteins. SARS-CoV-2 causes the respiratory infection Covid-19, which can lead to fatal pneumonia. As of March 2020, the virus has spread to many countries worldwide and has been declared a pandemic. Hundreds of thousands have been infected with tens of thousands of deaths.