The first reports of infection by the novel coronavirus began to emerge in December 2019. The virus had not previously been identified. The numbers were small initially: more than 50 people in the city of Wuhan, in central China, complained of high fever and had respiratory infections and pulmonary lesions. Some of them worked at a fish market in the city, at which live animals were also sold. It is believed that the virus may have passed from animals to humans in the market.

This was a period of heavy migration in China, and the confirmed cases multiplied within just a few weeks, spreading to neighbouring countries: first Japan, then Taiwan, South Korea, Vietnam, and Singapore. At the end of January, the outbreak reached Europe – first France, and soon afterwards, Germany. On 11 March, the World Health Organisation (WHO) declared the virus to be a pandemic – a term that is used to describe an epidemic that has spread to several countries or continents and affected a large number of people.

In the second half of February, the authorities became very concerned about Italy. In just 5 days, the number of people infected in Europe had shot up from fewer than ten to several hundred confirmed cases. When the virus reached Brazil at the end of February, Antarctica would become the only continent with no cases of infection. This marked the beginning of a new phase in which covid-19 is spreading more rapidly in the rest of the world than it did in China.

Corinaviruses are a family of viruses that cause respiratory problems. They are first transmitted to humans through contact with animals, and then passed from human to human. When they are seen under a microscope, coronaviruses are surrounded by what looks like a crown of spines, hence the name (corona = crown in Latin). This novel coronavirus was identified in China and is officially designated SARS-CoV-2. It is related to other coronaviruses that cause infection in human beings, such as the Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV).