Coloured scanning electron micrograph (SEM) of SARS-CoV-2 coronavirus particles (red) budding from an infected cultured cell. SARS-CoV-2 (previously 2019-nCoV) was first identified in Wuhan, China, in December 2019, and has been declared a pandemic. It is an enveloped RNA (ribonucleic acid) virus. It causes Covid-19, a respiratory infection that can lead to fatal pneumonia. Social restrictions and infection control measures have been put in place to slow the spread of the virus. Virus provided by The Peter Doherty Institute for Infection and Immunity, Australia. Magnification: x18,500 when printed at 10 centimetres wide.