Diphtheria is an acute, infectious, and highly contagious bacterial disease. Most often found in children, diphtheria causes intense inflammation of the nose, throat, and larynx and can bring about tissue damage, heart defects, and death - the last either by suffocation due to false membranes developing in the throat or from the effects of a toxin produced by the bacteria.
A diphtheria epidemic in New England during the early 1700s killed approximately 2.5% of the total population, including 30% of the region's children. Diphtheria continued to be a major killer of children thereafter, usually appearing in wavelike intervals of approximately 25 years. Diphtheria was difficult to identify accurately because it resembled the croup, distemper, and other diseases. Diphtheria was also difficult to control because some people were susceptible, some were immune, and some otherwise healthy individuals were unwitting carriers.