Pertussis (Whooping Cough)
Pertussis (Whooping Cough)
Do Many People Contract Pertussis?
What Happens to People Who Have Pertussis?
Pertussis (per-TUH-sis) is a bacterial infection of the respiratory tract* that causes severe coughing.
- *respiratory tract
- includes the nose, mouth, throat, and lungs. It is the pathway through which air and gases are transported down into the lungs and back out of the body.
KEYWORDS
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DTaP
Immunization
Respiratory system
Whooping cough
What Is Pertussis?
Pertussis is a respiratory disease found only in humans that is caused by the bacterium Bordetella pertussis. The first account of the infection was recorded in the sixteenth century, but it was not until the early twentieth century that B. pertussis was identified as the cause.
The infection causes a violent series of coughing fits ending in a high-pitched intake of breath that sounds like a “whoop,” giving the disease its other name: whooping cough. These coughing fits can be so severe that patients may vomit, lose consciousness, or turn blue from lack of oxygen.
Do Many People Contract Pertussis?
Pertussis occurs throughout the world in all age groups. In the early twentieth century, it was a common childhood disease and a leading cause of infant death. Since the widespread use of a vaccine* starting in the mid-1940s, however, infection rates in children in the United States have declined. Teens and adults account for the majority of infections in the twenty-first century, which may indicate that childhood immunization with the vaccine does not offer lifelong immunity*.
- *vaccine
- (vak-SEEN) is a preparation of killed or weakened germs, or a part of a germ or product it produces, given to prevent or lessen the severity of the disease that can result if a person is exposed to the germ itself. Use of vaccines for this purpose is called immunization.
- *immunity
- (ih-MYOON-uh-tee) is the condition of being protected against an infectious disease. Immunity often develops after a germ is introduced to the body. One type of immunity occurs when the body makes special protein molecules called antibodies to fight the disease-causing germ. The next time that germ enters the body, the antibodies quickly attack it, usually preventing the germ from causing disease.
Before the introduction of the vaccine, more than 200,000 cases of pertussis were diagnosed each year in the United States. Since the 1980s, the U.S. Centers for Disease Control and Prevention (CDC) has reported yearly U.S. averages ranging from about 3,000 to 8,000 cases. In many developing countries in Asia, Africa, and Latin America, however, pertussis is still a major cause of childhood deaths; the CDC attributes 300,000 deaths worldwide every year to the disease.
Is Pertussis Contagious?
Pertussis is an extremely contagious infection. The bacteria can spread through the air in drops of fluid released from the mouth and nose of a coughing or sneezing person who is infected. Inhaling those airborne drops can lead to disease, as can direct contact with the drops, such as touching them and transferring bacteria from a hand to the mouth or nose. Up to 90 percent of susceptible (non-immune) people living in the same house with someone who has whooping cough will become infected as well.
Pertussis is different from most other contagious respiratory illnesses because children generally do not infect adults. Instead, adults usually have a mild case of the disease first and unknowingly pass the bacteria to their children, who develop a more serious form of the illness.
What Happens to People Who Have Pertussis?
Signs and Symptoms
Following exposure to the bacteria, an incubation* period begins and generally lasts 7 to 10 days but occasionally stretches to as long as a month. During this time, the bacteria settle in the lungs where they produce toxins* that cause inflammation and make it difficult to clear out the mucus* that forms in the respiratory tract.
- *incubation
- (ing-kyoo-BAY-shun) is the period of time between infection by a germ and when symptoms first appear. Depending on the germ, this period can be from hours to months.
- *toxins
- are poisons that harm the body.
- *mucus
- (MYOO-kus) is a thick, slippery substance that lines the insides of many body parts.
After the incubation period, there are three distinct stages of pertussis infection: the catarrhal (kah-TAR-hul), paroxysmal (PAIR-ok-siz-mul), and convalescent (kon-vuh-LEH-sent) stages. In the catarrhal stage, the first symptoms of the disease appear and often are mistaken for those of a common cold or the flu. They include runny nose, sneezing, mild fever, and a cough that gradually worsens. This stage typically lasts 1 to 2 weeks.
In the paroxysmal stage, the characteristic symptoms of whooping cough take center stage. The occasional cough develops into sudden violent attacks, or paroxysms, of rapid coughing ending with the whooping noise. The coughing is due to the buildup of mucus in the respiratory tract and occurs frequently at night. Babies under 6 months of age may not have the strength to make the whooping sound that older children, teens, and adults typically do, but they do have bursts of coughing. It is difficult to breathe during these fits, and many patients turn blue from lack of oxygen. The severe coughing also can lead to vomiting and extreme tiredness. Between these bouts, patients look normal. The paroxysmal stage generally lasts from 1 to 6 weeks but can linger for up to 10 weeks.
In the final, convalescent stage, coughing slowly subsides over 2 or 3 weeks.
Diagnosis
In some cases, the doctor can make the diagnosis of whooping cough based solely on hearing the cough, but a definitive diagnosis requires an examination of fluid from the nose or throat. Samples of this fluid are checked for bacteria. Blood tests can look for the increased number of lymphocytes* commonly seen with this disease and for antibodies* to the bacterium.
- *lymphocytes
- (LIM-fo-sites) are white blood cells, which play a part in the body’s immune system, particularly the production of antibodies and other substances to fight infection.
- *antibodies
- (AN-tih-bah-deez) are protein molecules produced by the body’s immune system to help fight specific infections caused by microorganisms, such as bacteria and viruses.
Treatment
Doctors commonly prescribe a 2-week course of antibiotics to keep the disease from spreading to others. Antibiotics also can be prescribed for other people living in the same household with the patient to prevent them from contracting the infection. However, antibiotics can do little to improve the illness if they are not prescribed until after the characteristic whooping cough symptoms appear. Cough medicines do not ease the cough significantly, but using a cool-mist vaporizer and avoiding irritants such as smoke or fumes can help.
Children 18 months old and younger who contract whooping cough need to be watched carefully because they may choke or stop breathing during a coughing spasm. Infants less than 6 months old usually are hospitalized and given oxygen and intravenous* fluids, and their mouth and nose may need to be suctioned to keep their breathing passages clear of mucus.
- *intravenous
- (in-tra-VEE-nus), or IV, means within or through a vein. For example, medications, fluid, or other substances can be given through a needle or soft tube inserted through the skin’s surface directly into a vein.
Whooping cough usually lasts between 6 weeks and 2 months, but it can take even longer for a patient to recover completely. The coughing spasms may continue on and off for several months.
Complications
Complications of whooping cough include bacterial infections such as ear infections or pneumonia*; dehydration* due to poor fluid intake and vomiting after coughing; broken blood vessels in the eyes, nose, and brain from forceful coughing; problems associated with lack of oxygen such as seizures* or, rarely, brain damage; and, particularly among young infants, death.
- *pneumonia
- (nu-MO-nyah) is inflammation of the lungs.
- *dehydration
- (dee-hi-DRAY-shun) is a condition in which the body is depleted of water, usually caused by excessive and unre-placed loss of body fluids, such as through sweating, vomiting, or diarrhea.
- *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.
Can Pertussis Be Prevented?
Vaccination (vak-sih-NAY-shun) is the best way to prevent pertussis in children. The vaccine for pertussis is given in a combined vaccine including those for diphtheria* and tetanus*. The DTaP vaccine (made with acellular pertussis, which contains only parts of the pertussis bacterium and does not cause as many side effects as the vaccine made with the whole bacterium) is given in multiple doses, starting at 2 months of age.
- *diphtheria
- (dif-THEER-e-uh) is an infection of the lining of the upper respiratory tract (the nose and throat). It is a disease that can cause breathing difficulty and other complications, including death.
- *tetanus
- (TET-nus) is a serious bacterial infection that affects the body’s central nervous system.
Adults can lower their chances of becoming infected or spreading the disease by practicing good hygiene, such as regularly washing their hands; not sharing food, silverware, or drinking glasses; and covering their mouth when they sneeze or cough.
See also
Croup
Diphtheria
Pneumonia
Tetanus (Lockjaw)
Vaccination (Immunization)
Resources
Organization
U.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, Atlanta, GA 30333. The CDC is the U.S. government authority for information about infectious and other diseases. It offers information on pertussis and vaccinations at its website.
Telephone 800-311-3435 http://www.cdc.gov
Website
KidsHealth.org. KidsHealth is a website created by the medical experts of the Nemours Foundation and is devoted to issues of children’s health. It contains articles on a variety of health topics, including pertussis.
Pertussis
Pertussis
Pertussis, commonly known as whooping cough, is a highly contagious disease caused by the bacteria Bordatella pertussis. It is characterized by classic paroxysms (spasms) of uncontrollable coughing, followed by a sharp intake of air which creates the characteristic "whoop" from which the name of the illness derives.
B. pertussis is uniquely a human pathogen (a disease causing agent, such as a bacteria, virus, fungus, etc.) meaning that it neither causes disease in other animals, nor survives in humans without resulting in disease. It exists worldwide as a disease-causing agent, and causes epidemics cyclically in all locations.
B. pertussis causes its most severe symptoms by attacking specifically those cells in the respiratory tract which have cilia. Cilia are small, hair-like projections that beat constantly, and serve to constantly sweep the respiratory tract clean of such debris as mucus, bacteria, viruses , and dead cells. When B. pertussis interferes with this janitorial function, mucus and cellular debris accumulate and cause constant irritation to the respiratory tract, triggering the cough reflex and increasing further mucus production.
Although the disease can occur at any age, children under the age of two, particularly infants, are greatest risk. Once an individual has been exposed to B. pertussis, subsequent exposures result in a mild illness similar to the common cold and are thus usually not identifiable as resulting from B. pertussis.
Whooping cough has four somewhat overlapping stages: incubation, catarrhal stage, paroxysmal stage, and convalescent stage.
An individual usually acquires B. pertussis by inhaling droplets infected with the bacteria, coughed into the air by an individual already suffering from whooping cough symptoms. Incubation occurs during a week to two week period following exposure to B. pertussis. During the incubation period, the bacteria penetrate the lining tissues of the entire respiratory tract.
The catarrhal stage is often mistaken for an exceedingly heavy cold. The patient has teary eyes, sneezing, fatigue, poor appetite, and a very runny nose. This stage lasts about eight days to two weeks.
The paroxysmal stage, lasting two to four weeks, is heralded by the development of the characteristic whooping cough. Spasms of uncontrollable coughing, the "whooping" sound of the sharp inspiration of air, and vomiting are hallmarks of this stage. The whoop is believed to occur due to inflammation and mucous which narrow the breathing tubes, causing the patient to struggle to get air in, and resulting in intense exhaustion. The paroxysms can be caused by over activity, feeding, crying, or even overhearing someone else cough.
The mucus that is produced during the paroxysmal stage is thicker and more difficult to clear than the waterier mucus of the catarrhal stage, and the patient becomes increasingly exhausted while attempting to cough clear the respiratory tract. Severely ill children may have great difficulty maintaining the normal level of oxygen in their systems, and may appear somewhat blue after a paroxysm of coughing due to the low oxygen content of their blood. Such children may also suffer from encephalopathy, a swelling and degeneration of the brain which is believed to be caused both by lack of oxygen to the brain during paroxysms, and also by bleeding into the brain caused by increased pressure during coughing. Seizures may result from decreased oxygen to the brain. Some children have such greatly increased abdominal pressure during coughing, that hernias result (hernias are the abnormal protrusion of a loop of intestine through a weaker area of muscle). Another complicating factor during this phase is the development of pneumonia from infection with another bacterial agent, which takes hold due to the patient's weakened condition.
If the patient survives the paroxysmal stage, recovery occurs gradually during the convalescent stage, and takes about three to four weeks. Spasms of coughing may continue to occur over a period of months, especially when a patient contracts a cold or any other respiratory infection.
By itself, pertussis is rarely fatal. Children who die of pertussis infection usually have other conditions (e.g., pneumonia, metabolic abnormalities, other infections, etc.) that complicate their illness.
The presence of a pertussis-like cough along with an increase of certain specific white blood cells (lymphocytes) is suggestive of B. pertussis infection, although it could occur with other pertussis-like viruses. The most accurate method of diagnosis is to culture (grow on a laboratory plate) the organisms obtained from swabbing mucus out of the nasopharynx (the breathing tube continuous with the nose). B. pertussis can then be identified during microscopic examination of the culture.
In addition to the treatment of symptoms, Treatment with the antibiotic erythromycin is helpful against B. pertussis infection only at very early stages of whooping cough: during incubation and early in the catarrhal stage. After the cilia, and the cells bearing those cilia, are damaged, the process cannot be reversed. Such a patient will experience the full progression of whooping cough symptoms, which will only abate when the old, damaged lining cells of the respiratory tract are replaced over time with new, healthy, cilia-bearing cells. However, treatment with erythromycin is still recommended to decrease the likelihood of B. pertussis spreading. In fact, it is not uncommon that all members of the household in which a patient with whooping cough lives are treated with erythromycin to prevent spread of B. pertussis throughout the community.
The mainstay of prevention lies in the mass immunization program that begins, in the United States, when an infant is two months old. The pertussis vaccine , most often given as one immunization together with diphtheria and tetanus , has greatly reduced the incidence of whooping cough. Unfortunately, there has been some concern about serious neurologic side effects from the vaccine itself. This concern led huge numbers of parents in England, Japan, and Sweden to avoid immunizing their children, which in turn led to epidemics of disease in those countries. Multiple carefully constructed research studies, however, have provided evidence that pertussis vaccine was not the cause of neurologic damage.
See also Bacteria and bacterial infection; History of public health; Infection and resistance; Public health, current issues; Vaccination
Pertussis
PERTUSSIS
Pertussis (whooping cough) is a highly communicable infectious disease caused by the bacterium Bordetella pertussis. Pertussis is characterized by spasms (paroxysms) of severe coughing. The cough spasms are often followed by vomiting and by a characteristic inspiratory "whoop." The incubation period is about 7 to 20 days. Pertussis starts with symptoms similar to those of a minor upper respiratory infection and is followed by several weeks of episodes of paroxysmal coughing. Pertussis can occur among persons of any age, regardless of vaccination status, and may be relatively common among adolescents and adults in the United States, although infants less than one year old have the highest rates of reported disease. Infants with pertussis commonly require hospitalization and may die.
Between 1940 and 1945 in the United States, an average of 175,000 cases and 2,700 deaths occurred from pertussis each year. A vaccination program has been in place in the United States since 1948; in the 1990s, an average of 6,000 pertussis cases and 12 deaths are reported each year.
The U.S. vaccination schedule is five doses of diphtheria and tetanus toxoids and acellular pertussis vaccine (DtaP) for children under 7 years of age: three doses at ages 2, 4, and 6 months, a fourth dose at 15 to 18 months of age, and the fifth dose at 4 to 6 years. No pertussis vaccine is currently licensed for use in persons 7 years old or older.
Early diagnosis and antimicrobial treatment of case-patients may lessen the severity of symptoms and limit the period of communicability; treatment of close contacts can provide protection from developing pertussis.
Kristine M. Bisgard
(see also: Communicable Disease Control )
Bibliography
American Public Health Association (2000). "Pertussis." In Control of Communicable Diseases Manual, 17th edition, ed. A. S. Benenson. Washington, DC: Author.
Edwards, K. M.; Decker, M. D.; and Mortimer, E. A., Jr. (1999). "Pertussis Vaccine." In Vaccines, 3rd edition, eds. S. A. Plotkin and W. A. Orenstein. Philadelphia, PA: W. B. Saunders.
Guris, D.; Strebel, P. M.; Bardenheier, B. et al. (1999). "Changing Epidemiology of Pertussis in the United States: Increasing Reported Incidence among Adolescents and Adults, 1990–1996." Clinical Infectious Disease 28:1230–1237.
pertussis
per·tus·sis / pərˈtəsis/ • n. medical term for whooping cough.