Coronavirus Disease-2019 (COVID- 19) Epidemiology

At the end of December 2019, patients were diagnosed with a pneumonialike infection in the Wuhan wholesale market of seafood, Hubei Province, China. Laboratory diagnosis revealed a novel coronavirus named severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), that causes coronavirus disease-19 (COVID- 19). Initially, t he novel virus was reported in bats. Due to the highly contagious nature of pathogens and the susceptibility of every human the virus spread rapidly across China then Globally. Respiratory droplets of infected patients played a significant role in the transmission of COVID-19 from human to human. Wuhan being a transport hub, and the crowd of people during New Chinese Year played a considerable role in the virus spread across the country. In link with earlier coronaviruses, the SARS-CoV-2 was noticed with a more contagious nature, and it quickly spread throughout the world. It was declared a pandemic by the World Health Organization (WHO) on March 12, 2020. In March 2021, the spread of infection decreased in China but increased globally, mainly in Europe. In April 2020, the disease burden increased in the USA. Till April 17 2020, China reported 84,149 cases with 4642 deaths, while worldwide cases reached 2,074,5279 with 139378 deaths. Europe reported confirmed cases 1,050,871 with 93,480 deaths, 743,607 patients in USA regions, Western Pacific regions with 127,595 patients, Eastern Mediterranean Regions reached 115,824 cases, and South-East Asia Regions reported 23,560 cases while African regions had 12,360 cases. The below figure illustrates the analysis of the epidemiological studies of COVID-19 (Fig. 1).

Keywords: Bats, COVID-19, Host Susceptibilities, Morbidity, Mortality, Pandemic, SARS-CoV-2, Virology.