Contagious Diseases and Immunology

A contagious disease is one that is easily transmitted (that is, communicated) from one person to another by the transmission of a pathogen. The ease with which contagious diseases are spread varies. COVID-19, for example, is exceedingly contagious and spreads by transmission of the SARS-CoV-2 coronavirus from one person to another. A non-contagious disease, on the other hand, either cannot be passed from one person to another or has a low risk of being transmitted to another person. A contagious disease is one that can be transmitted from one person to another. A contagion is the agent that causes communicable diseases, such as a virus or bacteria. The disease is also referred to as a contagion. An infectious disease is a disease caused by a virus or its toxic product that is transmitted to a susceptible host by an infected human, an infected animal, or a contaminated inanimate object. For thousands of years, infections have fought against the host's immunological responses. To regulate viral and bacterial infection, the immune system has developed a variety of strategies, ranging from direct pathogen killing to the production of cytokines that impede reproduction. Pathogens have developed a range of immune evasion methods to prevent immune detection of infected cells by inhibiting cytokine activity.

• Contagion
• Effect on public health response
• COVID-19