Diphtheria and its etiological agents

Abstract

Diphtheria, the 'strangling angel of children', plagued mankind for thousands of years. With the discovery of its etiological agent, Corynebacterium diphtheriae, it became a paradigm of an infectious disease. According to Koch's postulates C. diphtheriae was isolated by Klebs and Loeffler from infected patients, grown in pure culture and used to re-infect guinea pigs as test animals. Loeffler also recognized that the bacterium predominantly colonizes the nasopharyngeal cavity and, based on this observation, postulated that the secretion of a toxin might cause the often fatal damage of distant organs, a hypothesis, which was further supported by Roux and Yersin. While toxin production is the most dangerous aspect of diphtheria infection, the diphtheria toxin has also been the basis for effective diphtheria treatment and control. Already in 1890, von Behring suggested antitoxin application as a means of diphtheria treatment; in 1913 he developed a first vaccine against diphtheria toxin and in 1920 first mass vaccinations started. Mass immunization is still the most efficient means to prevent and control diphtheria, while antibiotics are effective to eradicate the bacteria from infected patients.