Diphtheria

Definition

Diphtheria is a potentially fatal, contagious disease that usually involves the nose, throat, and air passages but may also infect the skin. Its most striking feature is the formation of a grayish membrane covering the tonsils and upper part of the throat.

Description

Like many other upper respiratory diseases, diphtheria is most likely to break out during the winter months. At one time it was a major childhood killer, but in the early 2000s it is rare in developed countries because of widespread immunization.

Persons who have not been immunized may get diphtheria at any age. The disease is spread most often by droplets from the coughing or sneezing of an infected person or carrier. The incubation period is two to seven days, with an average of three days. It is vital to seek medical help at once when diphtheria is suspected, because treatment requires emergency measures for adults as well as children.

Demographics

Diphtheria is a reportable disease in many countries in the world. Since 1988, all confirmed cases in the United States involved visitors or immigrants. In countries that do not have routine immunization against this infection, the mortality rate varies from 1.5 to 25 percent.

Causes and symptoms

The symptoms of diphtheria are caused by toxins produced by the diphtheria bacillus, Corynebacterium diphtheriae (from the Greek for "rubber membrane"). In fact, toxin production is related to infections of the bacillus itself with a particular bacteria virus called a phage (from bacteriophage, a virus that infects bacteria). The intoxication destroys healthy tissue in the upper area of the throat around the tonsils or in open wounds in the skin. Fluid from the dying cells then coagulates to form the telltale gray or grayish green membrane. Inside the membrane, the bacteria produce an exotoxin, which is a poisonous secretion that causes the life-threatening symptoms of diphtheria. The exotoxin is carried throughout the body in the bloodstream, destroying healthy tissue in other parts of the body.

The most serious complications caused by the exotoxin are inflammations of the heart muscle (myocarditis) and damage to the nervous system. The risk of serious complications is increased as the time between onset of symptoms and the administration of antitoxin increases, and as the size of the membrane formed increases. The myocarditis may cause disturbances in the heart rhythm and may culminate in heart failure. The symptoms of nervous system involvement can include seeing double (diplopia), painful or difficult swallowing, and slurred speech or loss of voice, which are all indications of the exotoxin's effect on nerve functions. The exotoxin may also cause severe swelling in the neck ("bull neck").

The signs and symptoms of diphtheria vary according to the location of the infection.

Nasal

Nasal diphtheria produces few symptoms other than a watery or bloody discharge. On examination, there may be a small visible membrane in the nasal passages. Nasal infection rarely causes complications by itself, but it is a public health problem because it spreads the disease more rapidly than other forms of diphtheria.

Pharyngeal

Pharyngeal diphtheria gets its name from the pharynx, which is the part of the upper throat that connects the mouth and nasal passages with the voice box. This is the most common form of diphtheria, causing the characteristic throat membrane. The membrane often bleeds if it is scraped or cut. It is important not to try to remove the membrane because the trauma may increase the body's absorption of the exotoxin. Other signs and symptoms of pharyngeal diphtheria are mild sore throat , fever of 101–102°F (38.3–38.9°C), a rapid pulse, and general body weakness.

Laryngeal

Laryngeal diphtheria, which involves the voice box or larynx, is the form most likely to produce serious complications. The fever is usually higher in this form of diphtheria (103–104°F or 39.4–40°C) and the person is very weak. People may have a severe cough , have difficulty breathing, or lose their voice completely. The development of a bull neck indicates a high level of exotoxin in the bloodstream. Obstruction of the airway may result in respiratory compromise and death.

Skin

This form of diphtheria, which is sometimes called cutaneous diphtheria, accounts for about 33 percent of all diphtheria cases. It is found chiefly among people with poor hygiene. Any break in the skin can become infected with diphtheria. The infected tissue develops an ulcerated area, and a diphtheria membrane may form over the wound but is not always present. The wound or ulcer is slow to heal and may be numb or insensitive when touched.

When to call the doctor

A doctor should be called whenever a case of diphtheria is suspected.

Diagnosis

Because diphtheria must be treated as quickly as possible, doctors usually make the diagnosis on the basis of the visible symptoms without waiting for test results.

In making the diagnosis, the doctor examines the affected person's eyes, ears, nose, and throat in order to rule out other diseases that may cause fever and sore throat, such as infectious mononucleosis , a sinus infection, or strep throat . The most important single symptom that suggests diphtheria is the membrane. When a person develops skin infections during an outbreak of diphtheria, the doctor will consider the possibility of cutaneous diphtheria and take a smear to confirm the diagnosis.

Laboratory tests

The diagnosis of diphtheria can be confirmed by the results of a culture obtained from the infected area. Material from the swab is put on a microscope slide and stained using a procedure called Gram's stain. The diphtheria bacillus is Gram-positive which means it holds the dye after the slide is rinsed with alcohol. Under the microscope, diphtheria bacilli look like beaded rod-shaped cells, grouped in patterns that resemble Chinese characters. Another laboratory test involves growing the diphtheria bacillus on a special material called Loeffler's medium.

Treatment

Diphtheria is a serious disease requiring hospital treatment in an intensive care unit if the person has developed respiratory symptoms. Treatment includes a combination of medications and supportive care.

Antitoxin

The most important step is prompt administration of diphtheria antitoxin, without waiting for laboratory results. The antitoxin is made from horse serum and works by neutralizing any circulating exotoxin. The doctor must first test people for sensitivity to animal serum. People who are sensitive (about 10%) must be desensitized with diluted antitoxin, since as of 2004 the antitoxin is the only specific substance that counteracts diphtheria exotoxin. No human antitoxin is available for the treatment of diphtheria.

The dose ranges from 20,000 to 100,000 units, depending on the severity and length of time of symptoms occurring before treatment. Diphtheria antitoxin is usually given intravenously.

Antibiotics

Antibiotics are given to wipe out the bacteria, to prevent the spread of the disease, and to protect people from developing pneumonia . They are not a substitute for treatment with antitoxin. Both adults and children may be given penicillin, ampicillin, or erythromycin. Erythromycin appears to be more effective than penicillin in treating people who are carriers because of better penetration into the infected area.

Cutaneous diphtheria is usually treated by cleansing the wound thoroughly with soap and water and giving an individual antibiotics for ten days.

Supportive care

Persons with diphtheria require bed rest with intensive nursing care, including extra fluids, oxygenation, and monitoring for possible heart problems, airway blockage, or involvement of the nervous system. People with laryngeal diphtheria are kept in a croup tent or high-humidity environment; they may also need throat suctioning or emergency surgery if their airway is blocked.

People recovering from diphtheria should rest at home for a minimum of two to three weeks, especially if they have heart complications. In addition, persons should be immunized against diphtheria after recovery, because having the disease does not always induce antitoxin formation and protect them from reinfection.

Prevention of complications

People with diphtheria who develop myocarditis may be treated with oxygen and with medications to prevent irregular heart rhythms. An artificial pacemaker may be needed. Persons with difficulty swallowing can be fed through a tube inserted into the stomach through the nose. Persons who cannot breathe are usually put on mechanical respirators.

Prognosis

The prognosis depends on the size and location of the membrane and on early treatment with antitoxin; the longer the delay, the higher the death rate. The most vulnerable persons are children under the age of 15 years and those who develop pneumonia or myocarditis. Nasal and cutaneous diphtheria are rarely fatal.

Prevention

Prevention of diphtheria has four aspects: immunization, isolation of infected persons, identification and treatment of contacts, and reporting cases to health authorities.

Immunization

Universal immunization is the most effective means of preventing diphtheria. The standard course of immunization for healthy children is three doses of DPT (diphtheria-tetanus-pertussis) preparation given between two months and six months of age, with booster doses given at 18 months and at entry into school. Adults should be immunized at ten-year intervals with Td (tetanus-diphtheria) toxoid. (A toxoid is a bacterial toxin that is treated to make it harmless but still can induce immunity to the disease.)

Isolation of affected persons

Individuals with diphtheria must be isolated for one to seven days or until two successive cultures show that the individuals are no longer contagious. Children placed in isolation are usually assigned a primary nurse for emotional support.

Identification and treatment of contacts

Because diphtheria is highly contagious and has a short incubation period, family members and other contacts of persons with diphtheria must be watched for symptoms and tested to see if they are carriers. They are usually given antibiotics for seven days and a booster shot of diphtheria/tetanus toxoid.

Reporting cases to public health authorities

Reporting is necessary for tracking potential epidemics, to help doctors identify the specific strain of diphtheria, and to see if resistance to penicillin or erythromycin has developed.

Parental concerns

Parents in the United States should ensure that their children have full immunizations against diphtheria. Completion of the three-shot series initiates lifelong immunity from diphtheria.

KEY TERMS

Antitoxin —An antibody against an exotoxin, usually derived from horse serum.

Bacillus —A rod-shaped bacterium, such as the diphtheria bacterium.

Carrier —A person who possesses a gene for an abnormal trait without showing signs of the disorder. The person may pass the abnormal gene on to offspring. Also refers to a person who has a particular disease agent present within his/her body, and can pass this agent on to others, but who displays no symptoms of infection.

Cutaneous —Pertaining to the skin

Diphtheria-tetanus-pertussis (DTP) vaccine —The standard vaccine used to immunize children against diphtheria, tetanus, and whooping cough. A so-called "acellular pertussis" vaccine (aP) is usually used since its release in the mid-1990s.

Exotoxin —A poisonous secretion produced by bacilli that is carried in the bloodstream to other parts of the body.

Gram stain —A staining procedure used to visualize and classify bacteria. The Gram stain procedure allows the identification of purple (gram positive) organisms and red (gram negative) organisms. This identification aids in determining treatment.

Loeffler's medium —A special substance used to grow diphtheria bacilli to confirm the diagnosis.

Myocarditis —Inflammation of the heart muscle (myocardium).

Toxoid —A preparation made from inactivated exotoxin, used in immunization.

Resources

BOOKS

Diphtheria: A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References. San Diego, CA: ICON Health Publications, 2004.

Holmes, Randall K. "Diphtheria, Corynebacterial Infections and Anthrax." In Harrison's Principles of Internal Medicine, 15th ed. Edited by Eugene Braunwald et al. New York: McGraw-Hill, 2001, pp. 909–14.

Long, Sarah S. "Diphtheria (Corynebacterium diphtheriae)." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 886–9.

Miller, Debbie S. Great Serum Race: Blazing the Iditarod Trail. New York: Walker & Company, 2002.

Salisbury, Gay. The Cruelest Miles: The Heroic Story of Dogs and Men in a Race against an Epidemic. New York: Norton, 2003.

PERIODICALS

Bertuccini, L., et al. "Internalization of non-toxigenic Corynebacterium diphtheriae by cultured human respiratory epithelial cells." Microbial Pathogenesis 37, no. 3 (2004): 111–8.

Clarke, P., et al. "DTP immunization of steroid treated preterm infants." Archives of Disease in Childhood: Fetal and Neonatal Edition 89, no. 5 (2004): F468–9.

Colgrove, J. "The power of persuasion: Diphtheria immunization, advertising, and the rise of health education." Public Health Rep 119, no. 5 (2004): 506–9.

Netterlid, E, et al. "Persistent itching nodules after the fourth dose of diphtheria-tetanus toxoid vaccines without evidence of delayed hypersensitivity to aluminium." Vaccine 22, no. 27–28 (2004): 3698–706.

ORGANIZATIONS

American Public Health Association. 800 I Street, NW, Washington, DC 20001–3710. Web site: <www.apha.org/>.

Centers for Disease Control and Prevention. 1600 Clifton Road, Atlanta, GA 30333. Web site: <www.cdc.gov>.

Pan American Health Organization. 525 23rd St., NW, Washington, DC 20037. Web site: <www.paho.org>.

World Health Organization, Communicable Diseases. 20 Avenue Appia, 1211 Geneva 27, Switzerland. Web site: <www.who.int/gtb/>.

WEB SITES

"Diphtheria." MedlinePlus. Available online at <www.nlm.nih.gov/medlineplus/ency/article/001608.htm> (accessed January 5, 2005).

"Diphtheria." World Health Organization. Available online at <www.who.int/topics/diphtheria/en/> (accessed January 5, 2005).

"Diphtheria, Tetanus, and Pertussis." Centers for Disease Control and Prevention. Available online at <www.cdc.gov/travel/diseases/dtp.htm> (accessed January 5, 2005).

L. Fleming Fallon, Jr., MD, DrPH

Diphtheria

Definition

Diphtheria is a potentially fatal, contagious disease that usually involves the nose, throat, and air passages, but may also infect the skin. Its most striking feature is the formation of a grayish membrane covering the tonsils and upper part of the throat.

Description

Like many other upper respiratory diseases, diphtheria is most likely to break out during the winter months. At one time it was a major childhood killer, but it is now rare in developed countries because of widespread immunization. Since 1988, all confirmed cases in the United States have involved visitors or immigrants. In countries that do not have routine immunization against this infection, the mortality rate varies from 1.5-25%.

Persons who have not been immunized may get diphtheria at any age. The disease is spread most often by droplets from the coughing or sneezing of an infected person or carrier. The incubation period is two to seven days, with an average of three days. It is vital to seek medical help at once when diphtheria is suspected, because treatment requires emergency measures for adults as well as children.

Causes and symptoms

The symptoms of diphtheria are caused by toxins produced by the diphtheria bacillus, Corynebacterium diphtheriae (from the Greek for "rubber membrane"). In fact, toxin production is related to infections of the bacillus itself with a particular bacteria virus called a phage (from bacteriophage; a virus that infects bacteria). The intoxication destroys healthy tissue in the upper area of the throat around the tonsils, or in open wounds in the skin. Fluid from the dying cells then coagulates to form the telltale gray or grayish green membrane. Inside the membrane, the bacteria produce an exotoxin, which is a poisonous secretion that causes the life-threatening symptoms of diphtheria. The exotoxin is carried throughout the body in the bloodstream, destroying healthy tissue in other parts of the body.

The most serious complications caused by the exotoxin are inflammations of the heart muscle (myocarditis ) and damage to the nervous system. The risk of serious complications is increased as the time between onset of symptoms and the administration of antitoxin increases, and as the size of the membrane formed increases. The myocarditis may cause disturbances in the heart rhythm and may culminate in heart failure. The symptoms of nervous system involvement can include seeing double (diplopia), painful or difficult swallowing, and slurred speech or loss of voice, which are all indications of the exotoxin's effect on nerve functions. The exotoxin may also cause severe swelling in the neck ("bull neck").

The signs and symptoms of diphtheria vary according to the location of the infection:

Nasal

Nasal diphtheria produces few symptoms other than a watery or bloody discharge. On examination, there may be a small visible membrane in the nasal passages. Nasal infection rarely causes complications by itself, but it is a public health problem because it spreads the disease more rapidly than other forms of diphtheria.

Pharyngeal

Pharyngeal diphtheria gets its name from the pharynx, which is the part of the upper throat that connects the mouth and nasal passages with the voice box. This is the most common form of diphtheria, causing the characteristic throat membrane. The membrane often bleeds if it is scraped or cut. It is important not to try to remove the membrane because the trauma may increase the body's absorption of the exotoxin. Other signs and symptoms of pharyngeal diphtheria include mild sore throat, fever of 101-102°F (38.3-38.9°C), a rapid pulse, and general body weakness.

Laryngeal

Laryngeal diphtheria, which involves the voice box or larynx, is the form most likely to produce serious complications. The fever is usually higher in this form of diphtheria (103-104°F or 39.4-40°C) and the patient is very weak. Patients may have a severe cough, have difficulty breathing, or lose their voice completely. The development of a "bull neck" indicates a high level of exotoxin in the bloodstream. Obstruction of the airway may result in respiratory compromise and death.

Skin

This form of diphtheria, which is sometimes called cutaneous diphtheria, accounts for about 33% of diphtheria cases. It is found chiefly among people with poor hygiene. Any break in the skin can become infected with diphtheria. The infected tissue develops an ulcerated area and a diphtheria membrane may form over the wound but is not always present. The wound or ulcer is slow to heal and may be numb or insensitive when touched.

Diagnosis

Because diphtheria must be treated as quickly as possible, doctors usually make the diagnosis on the basis of the visible symptoms without waiting for test results.

In making the diagnosis, the doctor examines the patient's eyes, ears, nose, and throat in order to rule out other diseases that may cause fever and sore throat, such as infectious mononucleosis, a sinus infection, or strep throat. The most important single symptom that suggests diphtheria is the membrane. When a patient develops skin infections during an outbreak of diphtheria, the doctor will consider the possibility of cutaneous diphtheria and take a smear to confirm the diagnosis.

Laboratory tests

The diagnosis of diphtheria can be confirmed by the results of a culture obtained from the infected area. Material from the swab is put on a microscope slide and stained using a procedure called Gram's stain. The diphtheria bacillus is called Gram-positive because it holds the dye after the slide is rinsed with alcohol. Under the microscope, diphtheria bacilli look like beaded rod-shaped cells, grouped in patterns that resemble Chinese characters. Another laboratory test involves growing the diphtheria bacillus on a special material called Loeffler's medium.

Treatment

Diphtheria is a serious disease requiring hospital treatment in an intensive care unit if the patient has developed respiratory symptoms. Treatment includes a combination of medications and supportive care:

Antitoxin

The most important step is prompt administration of diphtheria antitoxin, without waiting for laboratory results. The antitoxin is made from horse serum and works by neutralizing any circulating exotoxin. The doctor must first test the patient for sensitivity to animal serum. Patients who are sensitive (about 10%) must be desensitized with diluted antitoxin, since the antitoxin is the only specific substance that will counteract diphtheria exotoxin. No human antitoxin is available for the treatment of diphtheria.

The dose ranges from 20,000-100,000 units, depending on the severity and length of time of symptoms occurring before treatment. Diphtheria antitoxin is usually given intravenously.

Antibiotics

Antibiotics are given to wipe out the bacteria, to prevent the spread of the disease, and to protect the patient from developing pneumonia. They are not a substitute for treatment with antitoxin. Both adults and children may be given penicillin, ampicillin, or erythromycin. Erythromycin appears to be more effective than penicillin in treating people who are carriers because of better penetration into the infected area.

Cutaneous diphtheria is usually treated by cleansing the wound thoroughly with soap and water, and giving the patient antibiotics for 10 days.

Supportive care

Diphtheria patients need bed rest with intensive nursing care, including extra fluids, oxygenation, and monitoring for possible heart problems, airway blockage, or involvement of the nervous system. Patients with laryngeal diphtheria are kept in a croup tent or high-humidity environment; they may also need throat suctioning or emergency surgery if their airway is blocked.

Patients recovering from diphtheria should rest at home for a minimum of two to three weeks, especially if they have heart complications. In addition, patients should be immunized against diphtheria after recovery, because having the disease does not always induce antitoxin formation and protect them from reinfection.

Prevention of complications

Diphtheria patients who develop myocarditis may be treated with oxygen and with medications to prevent irregular heart rhythms. An artificial pacemaker may be needed. Patients with difficulty swallowing can be fed through a tube inserted into the stomach through the nose. Patients who cannot breathe are usually put on mechanical respirators.

Prognosis

The prognosis depends on the size and location of the membrane and on early treatment with antitoxin; the longer the delay, the higher the death rate. The most vulnerable patients are children under age 15 and those who develop pneumonia or myocarditis. Nasal and cutaneous diphtheria are rarely fatal.

Prevention

Prevention of diphtheria has four aspects:

Immunization

Universal immunization is the most effective means of preventing diphtheria. The standard course of immunization for healthy children is three doses of DPT (diphtheria-tetanus-pertussis) preparation given between two months and six months of age, with booster doses given at 18 months and at entry into school. Adults should be immunized at 10 year intervals with Td (tetanus-diphtheria) toxoid. A toxoid is a bacterial toxin that is treated to make it harmless but still can induce immunity to the disease.

Isolation of patients

Diphtheria patients must be isolated for one to seven days or until two successive cultures show that they are no longer contagious. Children placed in isolation are usually assigned a primary nurse for emotional support.

Identification and treatment of contacts

Because diphtheria is highly contagious and has a short incubation period, family members and other contacts of diphtheria patients must be watched for symptoms and tested to see if they are carriers. They are usually given antibiotics for seven days and a booster shot of diphtheria/tetanus toxoid.

Reporting cases to public health authorities

Reporting is necessary to track potential epidemics, to help doctors identify the specific strain of diphtheria, and to see if resistance to penicillin or erythromycin has developed.

Resources

BOOKS

Chambers, Henry F. "Infectious Diseases: Bacterial & Chlamydial." In Current Medical Diagnosis and Treatment, 1998, edited by Stephen McPhee, et al., 37th ed. Stamford: Appleton & Lange, 1997.

KEY TERMS

Antitoxin— An antibody against an exotoxin, usually derived from horse serum.

Bacillus— A rod-shaped bacterium, such as the diphtheria bacterium.

Carrier— A person who may harbor an organism without symptoms and may transmit it to others.

Cutaneous— Located in the skin.

Diphtheria-tetanus-pertussis (DTP)— The standard preparation used to immunize children against diphtheria, tetanus, and whooping cough. A so-called "acellular pertussis" vaccine (aP) is usually used since its release in the mid-1990s.

Exotoxin— A poisonous secretion produced by bacilli which is carried in the bloodstream to other parts of the body.

Gram's stain— A dye staining technique used in laboratory tests to determine the presence and type of bacteria.

Loeffler's medium— A special substance used to grow diphtheria bacilli to confirm the diagnosis.

Myocarditis— Inflammation of the heart tissue.

Toxoid— A preparation made from inactivated exotoxin, used in immunization.

Diphtheria, a bacterial disease of children, spread most frequently by person‐to‐person contact, is characterized by the formation of a pseudomembrane in the throat that can lead to death by suffocation.The diphtheria bacillus also secretes an exotoxin that can cause other symptoms such as inflammation of the heart.

Diphtheria has probably existed since classical antiquity, but it was not identified as a specific disease until 1819. During the 1880s, scientists in Germany and France isolated the pathogen, the bacillus that caused the disease; developed means of laboratory diagnosis; and discovered the exotoxin. This disease is especially significant in modern medical history because diphtheria antitoxin, produced in a Berlin laboratory in 1890 and available on a commercial scale shortly thereafter, was the first effective therapeutic developed through bacteriological research.

The earliest notable diphtheria epidemic in America was probably the New England “throat distemper” of 1735–1740. Samuel Bard of New York reported another outbreak in 1771. In the 1850s diphtheria established itself as an endemic disease, and it emerged as the leading killer of children in the 1880s. Fear of the disease then justified measures ranging from placarding houses to forced isolation of patients in special institutions.

In 1892, the bacteriologist Hermann Biggs (1859–1923) established the New York City Health Department's laboratory of pathology and bacteriology, the first such facility in the world. Here, under the direction of William H. Park, diphtheria diagnosis and antitoxin production and distribution soon became the principal activities, and this innovation was quickly adopted elsewhere. The development of the diphtheria antitoxin also spurred the growth of the American pharmaceutical industry.

Although contemporaries had reason to question the efficacy of antitoxin in its early years, product standardization and further scientific developments soon led to dramatic declines, first in case mortality and later in the incidence of diphtheria itself. For most of the twentieth century, diphtheria in the United States was successfully controlled by childhood immunization and the availability of effective antibiotics.
See also Medicine; Public Health.

Bibliography

Ernest Caulfield , A True History of the Terrible Epidemic Vulgarly Called the Throat Distemper: Which Occurred in His Majesty's New England Colonies between the Years 1735 and 1740, 1939.
Terra Ziporyn , Disease in the Popular American Press: The Case of Diphtheria, Typhoid Fever, and Syphilis, 1988.
Evelynn Hammonds , Childhood's Deadly Scourge: The Campaign to Control Diphtheria in New York City, 1880–1930, 1999.

Edward T. Morman

DIPHTHERIA

Diphtheria is a communicable disease caused by infection with Corynebacterium diphtheriae, typically presenting as respiratory tract infection in temperate climates and as cutaneous infection in the tropics. Clinical manifestations include pseudomembrane formation in the respiratory tract and soft tissue swelling of the neck ("bull neck"). Serious complications, primarily damage to the heart muscle and certain nerves that activate muscles, are due to diphtheria toxin, a potent toxin. Nontoxigenic strains can produce respiratory tract illness with pseudomembrane. Clusters of cases of invasive disease due to nontoxigenic strains, predominantly among persons with antecedent injection use, have been reported recently from several countries.

Vaccines composed of inactivated diphtheria toxin—diphtheria toxic—were developed in the early twentieth century and have been widely used in most developed countries since the middle of the twentieth century. Prior to introduction of vaccination, diphtheria was a major cause of childhood mortality in the United States, but by the 1990s respiratory diphtheria has been virtually eliminated in the United States and in other countries with high levels of childhood vaccination for diphtheria. Nonetheless, the infection remains endemic in much of the developing world. In the 1990s, a massive resurgence of diphtheria occurred in the countries of the former Soviet Union. Factors contributing to the epidemic included low vaccination coverage among children, lack of routine adult booster vaccination, population movements, and multiple introductions from areas where diphtheria remained endemic.

In the World Health Organization's Expanded Programme on Immunization, diphtheria toxic is administered with tetanus toxic and pertussis vaccine (DTP) at 6, 10, and 14 weeks of age. Recommendations for subsequent doses vary among countries. In the United States, diphtheria toxic is routinely administered with tetanus toxic and acellular pertussis vaccine at 2, 4, and 6 months of age, with booster doses at 15 to 18 months and 4 to 6 years of age.

Diptheria antitoxin is the mainstay of treatment of diphtheria. Outcome improves with early diagnosis and treatment. Antimicrobial therapy with penicillin or erythromycin hastens elimination of the organism. Antimicrobial prophylaxis is recommended for those in close contact with diphtheria cases.

Melinda Wharton

Charles Vitek

(see also: Communicable Disease Control; Diphtheria Vaccine; Immunizations )

diphtheria , acute contagious disease caused by Corynebacterium diphtheriae (Klebs-Loffler bacillus) bacteria that have been infected by a bacteriophage. It begins as a soreness of the throat with fever. The bacteria lodge in the mucous membranes of the throat, producing virulent toxins that destroy the tissue. The resultant formation of a tough gray membrane is one of the most dangerous aspects of diphtheria, since it can spread to the larynx and cause suffocation. Deaths from diphtheria often result from inflammation of the heart. Diphtheria usually occurs in children of preschool age. Treatment with antitoxin is begun as early as possible. Penicillin or erythromycin is also given, particularly to guard against complicating factors such as pneumonia or streptococcal infection. Diphtheria was once a common and dreaded disease with a high mortality rate; it is now rare in countries where infants are vaccinated (see vaccination ). Underimmunization, however, can lead to epidemics such as the one in Russia during 1994-95.

diphtheria (dif-theer-iă) n. an acute highly contagious infection, caused by the bacterium Corynebacterium diphtheriae, that generally affects the throat but occasionally affects other mucous membranes and the skin. Early symptoms are a sore throat, weakness, and mild fever; later, a soft grey membrane forms across the throat, constricting the air passages and causing difficulty in breathing and swallowing. Bacteria multiply at the site of infection and release a toxin into the bloodstream, which damages heart and nerves. An effective immunization programme has now made diphtheria rare in most Western countries (see also Schick test).

Diphtheria

What Is Diphtheria?

How Common Is Diphtheria?

Is Diphtheria Contagious?

What Are the Signs and Symptoms of Diphtheria?

How Is Diphtheria Diagnosed and Treated?

Can Diphtheria Be Prevented?

Resources

Diphtheria (dif-THEER-e-uh) is an infection of the lining of the upper respiratory tract (the nose and throat). It is a serious disease that can cause breathing difficulty and other complications, including death. Routine vaccination against diphtheria has made it rare in the United States.

KEYWORDS

for searching the Internet and other reference sources

Antitoxin

Corynebacterium diphtheriae

Epidemic

Respiratory infection

Vaccination

What Is Diphtheria?

Diphtheria is an infection caused by a bacterium called Corynebacterium diphtheriae (kor-ih-nee-bak-TEER-e-um dif-THEER-e-eye) that infects the upper respiratory tract. As the bacteria infect the nose, throat, or larynx (LAIR-inks, the voicebox), a distinctive thick membrane forms over the site of infection. The membrane can become large enough to interfere with a person’s breathing and swallowing. Some strains of Corynebacterium diphtheriae also produce an exotoxin* that can cause arthritis and damage to the nerves and heart. Sepsis, a potentially serious spreading of infection (usually bacterial) through the bloodstream and body, can result from diphtheria, causing shock*, heart failure, and even death.

*exotoxin

(ek-so-TOK-sin) is a substance produced by bacteria that has harmful effects on the infected person.

*shock

is a serious condition in which blood pressure is very low and not enough blood flows to the body’s organs and tissues. Untreated, shock may result in death.

How Common Is Diphtheria?

Diphtheria infection occurs throughout the world and is common in developing regions of Africa, Asia, and South America where children often do not receive the diphtheria vaccine. Cases usually occur in winter and the cooler months of autumn and spring.

Diphtheria infection is extremely rare in the United States because of the widespread use of routine diphtheria vaccination during childhood. From 1980 through 2000, 51 cases of diphtheria were reported in the United States. However, a diphtheria epidemic* has affected the countries that make up the former Soviet Union; since 1990 more than 150,000 cases have been reported.

*epidemic

(eh-pih-DEH-mik) is an outbreak of disease, especially infectious disease, in which the number of cases suddenly becomes far greater than usual. Usually epidemics are outbreaks of diseases in specific regions, whereas worldwide epidemics are called pandemics.

A Canine Hero

In the winter of 1925, a diphtheria epidemic swept through Nome, Alaska. Antitoxin was located almost 1,000 miles away in the city of Anchorage. The only way to transport the medicine was by dog sled. A relay of sled-dog teams, with the last leg led by a dog named Balto, successfully carried the medicine through frigid Alaskan temperatures in time to save many lives. In honor of that achievement, a statue of Balto was erected in Central Park in New York City.

Is Diphtheria Contagious?

Diphtheria is highly contagious. An untreated person who has diphtheria can spread the infection for up to a month. Within 48 hours of receiving antibiotics, however, people infected with diphtheria are usually no longer contagious.

The bacteria that cause diphtheria are spread through the air in drops of moisture from the respiratory tract, often from coughing or sneezing. Sharing drinking glasses or eating utensils or handling soiled tissues or handkerchiefs that have been used by a person with the disease can also transmit the bacteria. A person can get diphtheria from someone who has symptoms of the disease or from someone who is just a carrier* of the bacteria.

*carrier

is a person who has in his body a bacterium or virus that he can transmit to other people without getting sick himself.

What Are the Signs and Symptoms of Diphtheria?

Within 5 days after becoming infected, a person typically begins to have symptoms of diphtheria. Early symptoms often include a severe sore throat, runny nose, mild fever, and swollen glands in the neck. People infected with diphtheria in the nose, throat, or larynx usually develop a thick membrane at the site of the infection. Membranes in the nose are often white, whereas those at the back of the throat are gray-green.

As diphtheria progresses, respiratory symptoms can become more severe and include difficulty breathing or swallowing and a bark-like cough. Sometimes inflammation and swelling in the throat and the diphtheria membrane itself can cause blockage of the upper airways, making emergency treatment necessary.

How Is Diphtheria Diagnosed and Treated?

Diphtheria is diagnosed when the membrane that signals the disease is seen in the nose or throat during an examination of someone with symptoms of the disease. The diagnosis is confirmed by taking a swab of the coating from underneath the membrane and performing a laboratory test that identifies diphtheria bacteria.

Hospitalized people who are known to have diphtheria are kept isolated to prevent the disease from spreading to others. Patients are treated in the hospital with antibiotics and diphtheria antitoxin*. The antitoxin, which is produced in horses, is given intravenously (directly into a vein).

*antitoxin

(an-tih-TOK-sin) counteracts the effects of a toxin, or poison, in the body. Antitoxins are produced to act against specific toxin, like those made by the bacteria that cause botulism or diphtheria.

In severe cases of diphtheria, patients may need a ventilator (VEN-tuh-lay-ter) to help with breathing or medication to treat complications of the disease, such as septic shock*, heart inflammation, or heart failure. After they leave the hospital, bed rest at home for several weeks is generally recommended. Members of the same household are usually given a diphtheria booster vaccine to protect against possible infection. Recovery from diphtheria often takes 4 to 6 weeks or more.

*septic shock

is shock due to overwhelming infection, and is characterized by decreased blood pressure, internal bleeding, heart failure, and, in some cases, death.

Complications of diphtheria include abnormal heart rhythms, arthritis, and neuritis*. Diphtheria is most dangerous for children under 5 and adults over 40. Death occurs in up to 10 percent of people with diphtheria who receive medical treatment; death rates are higher in some parts of the world where treatment is not readily available.

*neuritis

(nuh-RYE-tis) is an inflammation of the nerves that disrupts their function.

Can Diphtheria Be Prevented?

In the United States, immunization programs have been very effective in preventing diphtheria. The diphtheria vaccine is given in combination with vaccines for tetanus* and pertussis* (this is called the DTaP vaccine) as part of a child’s routine immunizations. Four doses of the vaccine are given before 2 years of age. A first booster dose is given at 4 to 6 years of age when a child enters school. Additional booster doses are recommended every 10 years, in combination with a tetanus booster.

*tetanus

(TET-nus) is a serious bacterial infection that affects the body’s central nervous system.

*pertussis

(per-TUH-sis) is a bacterial infection of the respiratory tract that causes severe coughing.

Sometimes people have mild reactions to the vaccine, including a low-grade fever, tenderness at the injection site, and irritability. Very rarely, stronger reactions such as seizures* or allergic reactions can occur.

*seizures

(SEE-zhurs) are sudden bursts of disorganized electrical activity that interrupt the normal functioning of the brain, often leading to uncontrolled movements in the body and sometimes a temporary change in consciousness.

See also

Arthritis, Infectious

Public Health

Sepsis

Vaccination (Immunization)

Resources

Organizations

Immunization Action Coalition, 573 Selby Avenue, Suite 234, St. Paul, MN 55104. The Immunization Action Coalition provides information about infectious diseases and immunization.

Telephone 651-647-9009 http://www.immunize.org

U.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton Road Atlanta, GA 30333. The CDC provides information about infectious and other diseases, including diphtheria, at its website.

Telephone 800-311-3435 http://www.cdc.gov

diph·the·ri·a / difˈ[unvoicedth]irēə; dip-/ • n. a highly contagious disease caused by the bacterium Corynebacterium diphtheriae and characterized by the formation of a breath-obstructing membrane in the throat and by a potentially fatal toxin in the blood. DERIVATIVES: diph·the·ri·al adj. diph·the·rit·ic / ˌdif[unvoicedth]əˈritik; ˌdip-/ adj.

diphtheria Acute infectious disease characterized by the formation of a membrane in the throat which can cause asphyxiation; there is also release of a toxin which can damage the nerves and heart. Caused by a bacterium, Corynebacterium diphtheriae, which often enters through the upper respiratory tract, it is treated with antitoxin and antibiotics

diphtheria infectious disease affecting chiefly the throat. XIX. — modL. — F. diphthérie (now diphtérie), substituted for earlier diphthérite, f. Gr. diphthérā, diphtherís skin, hide, piece of leather; so named on account of the tough membrane which forms on parts affected by the disease.

diphtheria •barrier, carrier, farrier, harrier, tarrier •Calabria, Cantabria •Andrea • Kshatriya • Bactria •Amu Darya, aria, Zaria •Alexandria •Ferrier, terrier •destrier •aquaria, area, armamentaria, Bavaria, Bulgaria, caldaria, cineraria, columbaria, filaria, frigidaria, Gran Canaria, herbaria, honoraria, malaria, pulmonaria, rosaria, sacraria, Samaria, solaria, tepidaria, terraria •atria, gematria •Assyria, Illyria, Styria, Syria •Laurier, warrior •hypochondria, mitochondria •Austria •auditoria, ciboria, conservatoria, crematoria, emporia, euphoria, Gloria, moratoria, phantasmagoria, Pretoria, sanatoria, scriptoria, sudatoria, victoria, Vitoria, vomitoria •Maurya •courier, Fourier •currier, furrier, spurrier, worrier •Cumbria, Northumbria, Umbria •Algeria, anterior, bacteria, Bashkiria, cafeteria, criteria, cryptomeria, diphtheria, exterior, hysteria, Iberia, inferior, interior, Liberia, listeria, Nigeria, posterior, Siberia, superior, ulterior, wisteria •Etruria, Liguria, Manchuria, Surya