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Definition: diphtheria from Merriam-Webster's Collegiate(R) Dictionary

(ca. 1851) : an acute febrile contagious disease typically marked by the formation of a false membrane esp. in the throat and caused by a gram-positive bacterium (Corynebacterium diphtheriae) that produces a toxin causing inflammation of the heart and nervous system

diph•the•ri•al \-ē-əl\ adj

diph•the•rit•ic \॑dif-thə-॑ri-tik, ÷॑dip-\ adj

Summary Article: Diphtheria
From Encyclopedia of Global Health

Diphtheria is a very contagious and potentially life-threatening bacterial disease that primarily affects the nasal passages, throat, and lungs. In some instances, the infection can spread or attack the skin, heart, and nervous system. Immunization efforts have been able to keep this bacterial infection out of most of the developed world and much of the developing world. However, there has been a global resurgence of diphtheria due to poorly managed vaccination programs, a lack of funding, and other preventative measures. Regionally, former Soviet Republics have seen a disproportionate increase of diphtheria infection. This is proposed to be from inadequate and nonexistent vaccine programs throughout the 1990s.

Diphtheria is caused by Corynebacterium diphtheriae bacteria and can be easily spread through mucous secretions by coughing or sneezing of infected persons. Cramped living conditions, poorly planned congested urban neighborhoods, lack of proper sanitation, lack of vaccination plans, and poor knowledge of the disease aid in its spread throughout the world. According to the Centers for Disease and Control (CDC), currently about 10,000 new cases are reported each year with a previous spike of some 60,000 cases reported annually during the mid-1990s. In a CDC report, it was noted that the overall case-fatality rate for diphtheria is five to the 10 percent, with higher death rates (up to 20 percent) among persons younger than 5 and older than 40 years of age.


There are toxigenic and nontoxigenic strains of Corynebacterium diphtheriae that can cause disease. Strains that produce toxins cause an inflammation of the heart (myocarditis) and nerve inflammation and disease (neuritis and neuropathy). These toxins can also cause low platelet counts (thrombocytopenia) and protein in the urine (proteinuria). Where myocarditis experiences an early onset, it is often fatal. Neuritis often affects motor nerves and can resolve with possible paralysis of the soft palate, eye muscles, limbs, and diaphragm. Secondary pneumonia and respiratory failure are known to occur from paralysis of the diaphragm. Other complications are otitis media and respiratory insufficiency from airway obstruction. This is most common in infected infants. When the infection manifests in nonimmunized persons, the bacteria releases the toxin and subsequent damage occurs in the body. Toxigenic strains are more often associated with severe or fatal illness. This is mainly in the form of respiratory or other mucosal surface infections.


Diphtheria is best diagnosed clinically by identifying a gray membrane covering the throat and possibly inflamed tonsils and with an accompanying sore throat, fever and malaise. Any mucosal membrane can be infected (i.e., various nasopharyngeal, coetaneous, genital, and ocular). The diagnosis can also be confirmed with a throat culture if the laboratory capabilities exist. Corynebacterium diphtheriae is an aerobic gram-positive bacillus.

For those who are not vaccinated and contract the disease, active immunization and strong antibiotics are the best course of treatment. For those who are infected and are exposed to diphtheria, they must receive a booster of diphtheria toxoid plus active immunization and strong antibiotics. The most common vaccination program is the diphtheria toxoid mixed with tetanus and or pertussis vaccines. Vaccination provides the best preventative treatment.


The fall of the Soviet Union in 1991 engendered the Newly Independent States (NIS) and Baltic States with a fragmented health infrastructure and delays in implementing control measures. During the early 1990s, diphtheria was at epidemic levels in these states. This rapid increase in new cases of diphtheria was the first comprehensive epidemic in industrialized countries in over three decades.

Much research in the literature conclude that the main contributing factors to this epidemic include a large population of susceptible adults and children, decreased childhood immunization programs, loss of a vaccination and preventative programs, poor socioeconomic conditions, deteriorated health infrastructure, and high population movement and migration. A large-scale and well-coordinated international effort met these challenges in the mid-1990s with aggressive control strategies and high-yield outcomes.

The legacy of this epidemic includes a reexamination of the global diphtheria control strategy, new laboratory techniques for diphtheria diagnosis and analysis, and a model for future public health emergencies in the successful collaboration of multiple international partners. Diphtheria remains a global health threat and the most recent epidemic in post–Soviet nations is a stark reminder of diphtheria’s potency.

  • Adolescent Health; Adult Immunization; Center for Disease and Control and Prevention (CDC); Childhood Immunization; Epidemic; Immunization/Vaccination; National Immunization Program (NIP).

  • W. Atkinson, Epidemiology and Prevention of Vaccine-Preventable Diseases. eds. 9th ed. (Public Health Foundation, 2006).
  • S. Dittmann; M. Wharton; C. Vitek, Successful Control of Epidemic Diphtheria in the States of the Former Union of Soviet Socialist Republics: Lessons Learned, The Journal of Infectious Diseases (v.181/Suppl 1, 2000).
  • Stanly A Plotkin, Vaccines, 4th ed. (Saunders, 2003).
  • World Health Organization (WHO), Immunizations, Vaccines and Biologicals, (cited July 2006).
  • John Michael Quinn V, MPH
    University of Illinois at Chicago
    Copyright © 2008 by SAGE Publications, Inc.

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