RESEARCH STARTER

Diphtheria

Diphtheria is an acute and contagious disease primarily affecting children, caused by the bacterium *Corynebacterium diphtheriae*, which produces a harmful toxin. The disease typically presents with symptoms including a sore throat, malaise, mild fever, and the formation of a thick pseudomembrane in the throat, which can lead to respiratory difficulties. In severe cases, the toxin can enter the bloodstream, causing damage to vital organs such as the heart and nervous system. Diphtheria is spread through respiratory droplets or contaminated surfaces and can also manifest as a skin infection characterized by slow-healing ulcers.

Prompt treatment is crucial and generally involves antibiotics like penicillin or erythromycin, along with antitoxin administration to neutralize the effects of the toxin. Vaccination with diphtheria toxoid has been effective in preventing the disease, with immunization programs recommended for children and periodic boosters for adults. Although diphtheria was once a significant health threat in many parts of the world, its incidence has dramatically decreased in developed countries due to successful vaccination efforts. However, it remains a public health concern in some developing regions, where outbreaks can still occur.

Full Article

  • ANATOMY OR SYSTEM AFFECTED: Heart, nervous system, throat
  • CAUSES: Toxin production by bacteria
  • SYMPTOMS: Sore throat, malaise, mild fever, pseudomembrane formation in throat; when systemic, damage to heart, nervous system, or other organs
  • DURATION: Acute
  • TREATMENTS: Antibiotics (penicillin, erythromycin), antitoxin

DEFINITION: An acute, contagious disease found primarily in children, associated with toxin production by the bacterium Corynebacterium diphtheriae

Causes and Symptoms

The etiological agent of diphtheria, Corynebacterium diphtheriae, is found in some individuals as an inhabitant of the nasopharynx (nose and throat). Its symptoms are associated with the production of a toxin. Only those strains of the organism carrying a bacteriophage in a lysogenic state produce the toxin. Spread of diphtheria is generally person-to-person through respiratory secretions or through contaminated environmental surfaces.

Following an incubation period of several days to a week, symptoms often have a sudden onset and typically include a sore throat, malaise, and a mild fever. The disease is further characterized by an exudative, pseudomembrane formation on the mucous surface of the throat, which results from replication of the organism in the pharynx or surrounding areas. The pseudomembrane can become quite thick and may cause respiratory stress through obstruction of the breathing passages. Toxin is secreted into the bloodstream, where its presence can result in damage to the heart, nervous system, or other organs. Diagnosis is based upon a combination of symptoms, as well as isolation of the organism in a throat culture.

A less common form of diphtheria may be observed on skin surfaces. It contains bacteria that can be spread through contaminated environmental surfaces. Infection generally occurs through small cuts in the skin. Cutaneous diphtheria is characterized by an ulcer that heals slowly. If the organism is a strain that produces toxin, then systemic damage may result.

Treatment and Therapy

Most diphtheria infections respond to antibiotics, either a single dose of penicillin or a seven-day or ten-day course of erythromycin. Since symptoms are associated with toxin production, the administration of antitoxin is critical to early treatment. Once toxin has been incorporated into the target, cell death is irreversible. Antibiotic treatment, however, does result in the elimination of the organism and the termination of further toxin production.

Vaccination with diphtheria toxoid, an inactivated form of the toxin, has proven effective in immunization against the disease. Prophylaxis is generally started early in childhood as part of the trivalent DPT (diphtheria, pertussis, tetanus) series. Boosters are recommended at ten-year intervals.

Perspective and Prospects

Introduction of the diphtheria vaccine in the first decades of the twentieth century served to significantly reduce the incidence of the disease in the West. The use of antibiotic therapy further reduced the fatality rate associated with this disease, which ranged from 30 to 50 percent at its peak. Diphtheria is almost unknown in the United States in the twenty-first century, with cases rarely reported by state health departments, according to the Centers for Disease Control. The disease still exists in the developing world, with 25,000 cases reported worldwide in 2023, according to the World Health Organization.


Bibliography

Amevoin, Y., and F. Ale. “The Surge of Diphtheria in 2023: Global Overview, MSF Responses & Challenges.” Epicentre Scientific Day 2024, 23 May 2024, scienceportal.msf.org/assets/abstract-surge-diphtheria-2023-global-overview-msf-responses-challenges?. Accessed 14 Aug. 2025.

“Diphtheria.” Epidemiology and Prevention of Vaccine-Preventable Diseases. Edited by William Atkinson, Charles Wolfe, and Jennifer Hamborsky. 12th ed., Centers for Disease Control and Prevention, 2011.

“Diphtheria Outbreak Toolbox.” World Health Organization, Aug. 2024, www.who.int/emergencies/outbreak-toolkit/disease-outbreak-toolboxes/diphtheria-outbreak-toolbox. Accessed 14 Aug. 2025

"Diphtheria Surveillance and Trends." Centers for Disease Control and Prevention, 12 May 2025, www.cdc.gov/diphtheria/php/surveillance/. Accessed 14 Aug. 2025.

Grob, Gerald N. The Deadly Truth: A History of Disease in America. Harvard UP, 2002.

Parker, James N., and Philip M. Parker, editors. The Official Patient’s Sourcebook on Diphtheria. Icon Health, 2002.

Shuja, Muhammad H., et al. "Diphtheria: A Novel Cause of Concern for Pakistan." Journal of Global Health, vol. 13, 2023, p. 03038, doi.org/10.7189/jogh.13.03038. Accessed 14 Aug. 2025.

Full Article

  • ANATOMY OR SYSTEM AFFECTED: Heart, nervous system, throat
  • CAUSES: Toxin production by bacteria
  • SYMPTOMS: Sore throat, malaise, mild fever, pseudomembrane formation in throat; when systemic, damage to heart, nervous system, or other organs
  • DURATION: Acute
  • TREATMENTS: Antibiotics (penicillin, erythromycin), antitoxin

DEFINITION: An acute, contagious disease found primarily in children, associated with toxin production by the bacterium Corynebacterium diphtheriae

Causes and Symptoms

The etiological agent of diphtheria, Corynebacterium diphtheriae, is found in some individuals as an inhabitant of the nasopharynx (nose and throat). Its symptoms are associated with the production of a toxin. Only those strains of the organism carrying a bacteriophage in a lysogenic state produce the toxin. Spread of diphtheria is generally person-to-person through respiratory secretions or through contaminated environmental surfaces.

Following an incubation period of several days to a week, symptoms often have a sudden onset and typically include a sore throat, malaise, and a mild fever. The disease is further characterized by an exudative, pseudomembrane formation on the mucous surface of the throat, which results from replication of the organism in the pharynx or surrounding areas. The pseudomembrane can become quite thick and may cause respiratory stress through obstruction of the breathing passages. Toxin is secreted into the bloodstream, where its presence can result in damage to the heart, nervous system, or other organs. Diagnosis is based upon a combination of symptoms, as well as isolation of the organism in a throat culture.

A less common form of diphtheria may be observed on skin surfaces. It contains bacteria that can be spread through contaminated environmental surfaces. Infection generally occurs through small cuts in the skin. Cutaneous diphtheria is characterized by an ulcer that heals slowly. If the organism is a strain that produces toxin, then systemic damage may result.

Treatment and Therapy

Most diphtheria infections respond to antibiotics, either a single dose of penicillin or a seven-day or ten-day course of erythromycin. Since symptoms are associated with toxin production, the administration of antitoxin is critical to early treatment. Once toxin has been incorporated into the target, cell death is irreversible. Antibiotic treatment, however, does result in the elimination of the organism and the termination of further toxin production.

Vaccination with diphtheria toxoid, an inactivated form of the toxin, has proven effective in immunization against the disease. Prophylaxis is generally started early in childhood as part of the trivalent DPT (diphtheria, pertussis, tetanus) series. Boosters are recommended at ten-year intervals.

Perspective and Prospects

Introduction of the diphtheria vaccine in the first decades of the twentieth century served to significantly reduce the incidence of the disease in the West. The use of antibiotic therapy further reduced the fatality rate associated with this disease, which ranged from 30 to 50 percent at its peak. Diphtheria is almost unknown in the United States in the twenty-first century, with cases rarely reported by state health departments, according to the Centers for Disease Control. The disease still exists in the developing world, with 25,000 cases reported worldwide in 2023, according to the World Health Organization.


Bibliography

Amevoin, Y., and F. Ale. “The Surge of Diphtheria in 2023: Global Overview, MSF Responses & Challenges.” Epicentre Scientific Day 2024, 23 May 2024, scienceportal.msf.org/assets/abstract-surge-diphtheria-2023-global-overview-msf-responses-challenges?. Accessed 14 Aug. 2025.

“Diphtheria.” Epidemiology and Prevention of Vaccine-Preventable Diseases. Edited by William Atkinson, Charles Wolfe, and Jennifer Hamborsky. 12th ed., Centers for Disease Control and Prevention, 2011.

“Diphtheria Outbreak Toolbox.” World Health Organization, Aug. 2024, www.who.int/emergencies/outbreak-toolkit/disease-outbreak-toolboxes/diphtheria-outbreak-toolbox. Accessed 14 Aug. 2025

"Diphtheria Surveillance and Trends." Centers for Disease Control and Prevention, 12 May 2025, www.cdc.gov/diphtheria/php/surveillance/. Accessed 14 Aug. 2025.

Grob, Gerald N. The Deadly Truth: A History of Disease in America. Harvard UP, 2002.

Parker, James N., and Philip M. Parker, editors. The Official Patient’s Sourcebook on Diphtheria. Icon Health, 2002.

Shuja, Muhammad H., et al. "Diphtheria: A Novel Cause of Concern for Pakistan." Journal of Global Health, vol. 13, 2023, p. 03038, doi.org/10.7189/jogh.13.03038. Accessed 14 Aug. 2025.

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