Coronaviruses are a family of RNA viruses that causes several diseases in mammals and birds. The term ‘coronavirus’ comes from the Latin word ‘corona’ meaning ‘crown’ or ‘wreath’. The virus is named this way because it has microscopic spikes on its surface. Generally they cause different respiratory tract infections which can be both mild and lethal. In mild cases, they cause common cold in humans and when it becomes serious they can cause diseases like SARS, MERS and Covid-19. Other than humans, coronaviruses can attack other mammals and can cause diarrhoea in cows and pigs as well as hepatitis in mice. The earliest infection of animals by coronavirus was recorded in 1920 while the existence of human coronaviruses was not discovered until the 1960s. Coronavirus infection begins when viruses attach to the host cell and penetrate its genetic materials into the host cell. Then the RNA of the virus takes control of the cell and make copies of itself using the cell mechanism. Thus, the virus grow in number and more cells of the host are being destroyed in the process. Most human coronaviruses originate form bat while mice also carry some coronaviruses which can infect other mammals. Bat do not usually infect human directly. Generally there are intermediate carriers like camels, cows, pigs and so on. Although coronaviruses have been in limelight before, most recently this is the centre of attention because of a pandemic caused by SARS-Cov-2, the most deadly coronavirus yet.
