COVID-19 is an infectious respiratory illness caused by the coronavirus SARS-CoV-2. Symptoms can be mild and include fever, dry cough, and shortness of breath, but can also be severe, progressing to pneumonia and multi-organ failure through vascular damage. From the outset it was believed that this virus was zoonotic, bearing similarity to bat coronaviruses, and that it originated from an animal and seafood market, but the rapidly increasing rate of infection confirmed that humans can pass the virus to each other.
From the European Centre for Disease Prevention and Control:
On 31 December 2019, the Wuhan Municipal Health Commission in Wuhan City, Hubei province, China, reported a cluster of 27 pneumonia cases (including seven severe cases) of unknown aetiology, with a common reported link to Wuhan's Huanan Seafood Wholesale Market, a wholesale fish and live animal market.
The market was closed down on 1 January 2020. According to the Wuhan Municipal Health Commission, samples from the market tested positive for novel coronavirus. Cases showed symptoms such as fever, dry cough, dyspnoea; radiological findings showed bilateral lung infiltrates.
On 9 January 2020, the China CDC reported that a novel coronavirus (later named SARS-CoV-2, the virus causing COVID-19) had been detected as the causative agent for 15 of the 59 cases of pneumonia. On 10 January 2020, the first novel coronavirus genome sequence was made publicly available.
By 20 January 2020, there were reports of confirmed cases from three countries outside China: Thailand, Japan and South Korea. These cases had all been exported from China.
On 23 January 2020, Wuhan City was locked down – with all travel in and out of Wuhan prohibited – and movement inside the city was restricted.
The first European case was reported from France on 24 January 2020. This case had a travel history to China. In Germany, cases were reported on 28 January, related to a person visiting from China.
On 30 January 2020, the World Health Organization (WHO) declared this first outbreak of novel coronavirus a ‘public health emergency of international concern’. During the following weeks, several countries implemented entry screening measures for arriving passengers from China. Soon, several major airlines suspended their flights from and to China. Several countries repatriated citizens living in Wuhan.
A large number of cases have been diagnosed on board the Diamond Princess, a cruise ship docked in the port of Yokohama, Japan. The first cases were reported on 4 February 2020; the ship was put in quarantine. In total, 696 cases were identified among the ship’s passengers. Of these cases, seven died.
On 22 February, the Italian authorities reported clusters of cases in Lombardy and additional cases from two other regions, Piedmont and Veneto. Over the following days, cases were reported from several other regions. Transmission appears to have occurred locally, in contrast to first-generation transmission from people returning from affected areas. Transmission events were also reported from hospitals, with COVID-19 cases identified among healthcare workers and patients. During the following week, several European countries reported cases of COVID-19 in travellers from the affected areas in Italy, as well as cases without epidemiological links to Italy, China or other countries with ongoing transmission.
On 8 March 2020, Italy issued a decree to install strict public health measures including social distancing starting first in the most affected regions and on 11 March 2020, extending these measures at national level. Following Italy, Spain, France and many other European countries installed similar public health measures.
On 11 March 2020, the Director General of the World Health Organization declared COVID-19 a global pandemic. (https://www.ecdc.europa.eu/en/novel-coronavirus/event-background-2019)
Since it was first identified in Wuhan, Hubei province, China in late December 2019, thousands of cases of the Coronavirus disease 2019 (COVID-19), have been reported in China, as well as in other countries around the world. The virus spread rapidly to other countries, both in and outside of Asia, and lead the World Health Organization (WHO) to declare this a pandemic in early March 2020. As of 27 March 2020, more than 560,000 people had contracted the virus, and over 24,000 people had died from it worldwide. Apart from China, Italy and Spain, have been two of the hardest hit countries with the number of cases and deaths increasing rapidly on a daily basis. Across the world, thousands more cases were recorded as testing for the virus became more widespread.
Many prevention and management efforts around the world have been put in place to reduce the number of infections, including rigorous hygiene instructions, mandated social distancing, stay-at-home orders and self-quarantining.