Pertussis, also known as whooping cough, is a highly contagious disease caused by the bacterium Bordetella pertussis; it derived its name from the characteristic severe hacking cough followed by intake of breath that sounds like “whoop”; a similar, milder disease is caused by B. parapertussis. Although many medical sources describe the whoop as “high-pitched”, this is generally the case with infected babies and children only, not adults.
Worldwide, there are 30–50 million pertussis cases and about 300,000 deaths per year. Despite generally high coverage with the DTP and DTaP vaccines, pertussis is one of the leading causes of vaccine-preventable deaths world-wide. Most deaths occur in young infants who are either unvaccinated or incompletely vaccinated; three doses of the vaccine are necessary for complete protection against pertussis. Ninety percent of all cases occur in the developing world. Children tend to catch it more than adults.
Causes and Symptoms of Whooping Cough
Whooping cough is caused by bacteria entering a person’s body. The bacteria are usually carried in droplets of water coughed into the air by an infected person. The incubation period for the disease is 7-14 days. The incubation period for a disease is the time between the start of the infection and the first appearance of symptoms. During this period, bacteria are multiplying in the respiratory tract.
The second stage of whooping cough lasts about 10-14 days. During this period, the disease is often mistaken for a bad cold. The patient has teary eyes, sneezing, fatigue, poor appetite and a runny nose. The third stage of the disease lasts two to four weeks. It’s during this stage that the characteristic whooping cough begins. The cough is thought to be caused by inflammation of the respiratory system. The breathing tubes become narrowed, making it difficult for the person to get enough air to breathe normally. The effort to get air causes the gasping sound that accompanies the cough.
The vast majority of people who have whooping cough recover without further damage. Less than 1 percent of whooping cough cases end in death. Children are most likely to develop complications that lead to death. Common complications include pneumonia and extreme weight loss.
Treatment of Whooping Cough
- Whooping cough is highly contagious. Your child can get whooping cough through the air (airborne molecules from the sick child’s coughing, laughing or sneezing) or through physical contact. Pertussis is most contagious for up to two weeks after the cough begins—however antibiotics can shorten that period to 5 days after the first dose. It is recommended that anyone who has not been vaccinated for B. pertussis and comes into close or regular contact with a person who has whooping cough receive antibiotics to prevent the disease from spreading.
- An x-ray or blood test may also be necessary. A physician may check a child’s mucus and test it for the pertussis bacteria, and send it out to a laboratory, to confirm diagnosis. If the test is positive, your child will be started on antibiotics until symptoms are gone. It can take anywhere from two weeks to two months for your child to return to normal after having pertussis depending on the severity of the condition.
- There are many antibiotic types. Three macrolides—erythromycin, azithromycin and clarithromycin—are used in the U.S. for treatment of pertussis; trimethoprim-sulfamethoxazole is generally used when a macrolide is ineffective or is contraindicated. Close contacts who receive appropriate antibiotics (chemoprophylaxis) during the 7-21 day incubation period may be protected from developing symptomatic disease. Close contacts are defined as anyone coming into contact with the respiratory secretions of an infected person in the 21 days before or after the infected person’s cough began.
- An antibiotic can help, but it’s not a cure. Treatment with an effective antibiotic (erythromycin or azithromycin) shortens the infectious period but does not generally alter the outcome of the disease. However, when treatment is initiated during the catarrhal stage, symptoms may be less severe.
- Antibiotic treatment has limited value, however. The cilia are damaged early in the disease and once they are damaged, no drug can repair them. The cilia eventually grow back and begin to function normally. Until that happens, however, the patient will simply have to endure the symptoms of the disease. There are ways, however, to make the patient more comfortable during the later stages of the disease. For example, liquids are recommended to keep the patient from becoming dehydrated. Rest is also suggested in order to reduce the amount and the intensity of the coughing.
- Whooping cough can be prevented efficiently by immunization. Immunization is the process of injecting a person with a vaccine that prevents an infectious disease from occurring. A vaccine is a substance that causes the body immune system to build up resistance to a particular disease. The immunization shot given for whooping cough (pertussis) also contains vaccines for two other diseases, diphtheria and tetanus (see tetanus entry).
- The vaccine is sometimes called the DPT vaccine for the three diseases it helps protects against. Medical experts recommend vaccinating all children for these diseases at the age of two months. The children are then protected for life. At one time, there was some concern about possible side effects from the DPT vaccine. Research has shown, however, that the vaccine is safe. In areas where it has not been used, there have been widespread epidemics of one or more of these diseases.
- Development of vaccines is ongoing, even to the present day. In mid-2005, the US Food and Drug Administration approved two new combination vaccines for tetanus, diphtheria and acellular pertussis (Tdap) for booster immunization beyond primary childhood immunization. These products are intended to replace the current tetanus-diphtheria (Td) booster given at age 11-12 years. Boostrix (Glaxo SmithKline) is approved for persons aged 10-18 years; Adacel (Sanofi Pasteur) is approved for patients aged 11-64 years. On June 30, 2005, the CDC’s Advisory Committee on Immunization Practices voted to recommend the use of Tdap instead of Td for immunization of adolescents.
- Pertussis vaccines are highly effective, strongly recommended and save many infant lives every year. Though the protection they offer lasts only a few years, they are given so that immunity lasts through childhood, the time of greatest exposure and greatest risk. The immunizations are given in combination with tetanus, diphtheria, polio and haemophilus influenzae type B immunizations at ages two, three and four months, and a later booster at three years and four months or soon after.
- Booster immunizations are called for in later ages. The short term effectiveness of the vaccines and the presence of B. pertussis infection in adults and adolescents who may transmit the bacteria to infants have caused many in the medical field to call for booster immunizations at later ages. Although Canada, France, the U.S. and Germany now have approved booster shots for adolescents, adults or both, other countries adhere to the tradition of discontinuing pertussis vaccination after the age of seven, from concerns that there are side effects associated with the first available “whole-cell” pertussis immunizations that tended to increase with age. The whole-cell vaccine is still used in poor countries, since it’s cheaper than the newer and safer acellular formulation.
- Because nowadays there are less immunizations, whooping cough is on the rise. The resurgence in pertussis is attributed partly to waning primary childhood immunizations, leaving adolescents and adults susceptible. Although the disease typically manifests itself as mild in this older population, adolescents and adults may spread it to more vulnerable populations, such as newborns. Pertussis may cause severe illness in young infants and result in significant complications, such as apnea, cyanosis, feeding difficulties, pneumonia and encephalopathy.
Now that you know most everything there is to know about whooping cough, your respiratory health should be safe once again. Just remember to make use of these tips and information before it’s too late; an ounce of prevention—and a booster shot—beats a pound of cure and expensive doctor bills.
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