Each article in the Encyclopedia of Diseases and Disorders falls into one of three categories: infections; noninfectious diseases and disorders; and mental disorders. Articles in these three categories are color coded:
Infections include systemic, local, contagious, and noncontagious infections by bacteria, viruses, protists, parasites, and other pathogens.
The category of infections includes disorders such as acne, a localized bacterial infection, which is not contagious, as well as infectious diseases such as the common cold, which is highly contagious.
The category of noninfectious diseases and disorders includes any medical disorder not defined as an infection.\
The category of mental disorders includes conditions that manifest behavioral, psychological, or biological dysfunction in the person.