Infectious diseases are those that are transmitted from one individual to another. These diseases, also known as contagious diseases, are caused by microorganisms, such as protozoa, fungi, viruses, and bacteria, that invades the body and causes a series of changes that leads to infection and damage to the body. Infectious diseases are one that can be transmitted by direct or indirect contact or through the air. While most infectious diseases last a short amount of time they can be quite serious, and sometimes fatal.
Public health has come a long way in being able to track the spread of infectious disease outbreaks and that many of the diseases that used to kill people are not prevented through vaccines. Public health plays a critical role in protecting people by watching out for any unusual diseases, and alerting the public and medical community on treatment and control methods to limit the spread.