Coronaviruses can cause a variety of diseases in mammals and birds. Diseases can vary from enteritis in cows and upper respiratory tract and kidney disease in chickens to lethal respiratory infections in humans. CoVs that primarily infect human lung cells typically do so via a receptor for an enzyme termed angiotensin-converting enzyme 2 (ACE2).
The first step leading to viral infection involves the virus spike (S) protein, which recognizes and binds to the ACE2 receptor. The virus then is incorporated into the lung cells and the viral RNA is released into the cytoplasm. These viral RNA molecules are then called upon to make thousands of copies of the viral RNA and instruct the cells to synthesize hundreds of thousands of nucleocapsid, membrane, envelope, and S proteins. These all combine into new virus particles which bud out of the cell surface membrane. Newly formed viral particles are then released to propagate and sustain the infection and eventually die.
In humans, there are several known CoVs that cause respiratory infections. These CoVs range from the common cold to more severe diseases, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and Coronavirus disease 2019 (COVID-19).
Note: Typically, coronavirus particles are rapidly inactivated by exposure to 70% ethanol or 90% isopropanol, hydrogen peroxide solutions, hypochlorite bleach, soaps, and detergents, as well as by UV light and the high temperatures of cooking.
