Pertussis (Whooping Cough)
Pertussis (per-TUH-sis) is a bacterial infection of the respiratory tract * that causes severe coughing.
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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 * .
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.
* 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.
* 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.
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 acoughing 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.
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.
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.
* 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.
* 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.
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.
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 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.
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.
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.
* 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,
* 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.
* 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 unreplaced 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.
* 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.
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.
. 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.