Whooping cough

• Pertussis, also known as whooping cough, is a highly contagious respiratory disease.
• It is caused by the bacterium Bordetella pertussis.
• Pertussis is known for uncontrollable, violent coughing which often makes it hard to breathe.
• After cough fits, someone with pertussis often needs to take deep breaths, which result in a “whooping” sound.
• Pertussis can affect people of all ages, but can be very serious, even deadly, for babies less than a year old.
• The best way to protect against pertussis is by getting vaccinated.

Girl with Whooping Cough poster

Causes

• Pertussis, a respiratory illness commonly known as whooping cough, is a very contagious disease caused by a type of bacteria called Bordetella pertussis. These bacteria attach to the cilia (tiny, hair-like extensions) that line part of the upper respiratory system. The bacteria release toxins (poisons), which damage the cilia and cause airways to swell.

Transmission

• Pertussis is a very contagious disease only found in humans. Pertussis spreads from person to person. People with pertussis usually spread the disease to another person by coughing or sneezing or when spending a lot of time near one another where you share breathing space. Many babies who get pertussis are infected by older siblings, parents, or caregivers who might not even know they have the disease.

• Infected people are most contagious up to about 2 weeks after the cough begins. Antibiotics may shorten the amount of time someone is contagious.

• While pertussis vaccines are the most effective tool to prevent this disease, no vaccine is 100% effective. When pertussis circulates in the community, there is a chance that a fully vaccinated person, of any age, can catch this disease. If you have gotten the pertussis vaccine but still get sick, the infection is usually not as bad.

Bordetella pertussis

Signs and Symptoms

• Pertussis (whooping cough) can cause serious illness in babies, children, teens, and adults. Symptoms of pertussis usually develop within 5 to 10 days after you are exposed. Sometimes pertussis symptoms do not develop for as long as 3 weeks.

Early Symptoms

• The disease usually starts with cold-like symptoms and maybe a mild cough or fever.
• In babies, the cough can be minimal or not even there. Babies may have a symptom known as “apnea.”
• Apnea is a pause in the child’s breathing pattern. Pertussis is most dangerous for babies.
• About half of babies younger than 1 year who get the disease need care in the hospital.

In those who have gotten the pertussis vaccine:

• In most cases, the cough won’t last as many days
• Coughing fits, whooping, and vomiting after coughing fits occur less often
• The percentage of children with apnea (long pause in breathing), cyanosis (blue/purplish skin coloration due to lack of oxygen) and vomiting is less
• Early symptoms can last for 1 to 2 weeks and usually include:

• Runny nose
• Low-grade fever (generally minimal throughout the course of the disease)
• Mild, occasional cough
• Apnea – a pause in breathing (in babies)
• Pertussis in its early stages appears to be nothing more than the common cold. Therefore, healthcare professionals often do not suspect or diagnose it until the more severe symptoms appear.

Later-stage Symptoms

• After 1 to 2 weeks and as the disease progresses, the traditional symptoms of pertussis may appear and include:

Pertussis

• Paroxysms (fits) of many, rapid coughs followed by a high-pitched “whoop” sound
• Vomiting (throwing up) during or after coughing fits
• Exhaustion (very tired) after coughing fits
• Pertussis in Babies
• It is important to know that many babies with pertussis don’t cough at all. Instead it causes them to stop breathing and turn blue.

• Pertussis can cause violent and rapid coughing, over and over, until the air is gone from your lungs. When there is no more air in the lungs, you are forced to inhale with a loud “whooping” sound. This extreme coughing can cause you to throw up and be very tired. Although you are often exhausted after a coughing fit, you usually appear fairly well in-between. Coughing fits generally become more common and bad as the illness continues, and can occur more often at night. The coughing fits can go on for up to 10 weeks or more. In China, pertussis is known as the “100 day cough.”

• The “whoop” is often not there if you have milder (less serious) disease. The infection is generally milder in teens and adults, especially those who have gotten the pertussis vaccine.

Recovery

• Recovery from pertussis can happen slowly. The cough becomes milder and less common. However, coughing fits can return with other respiratory infections for many months after the pertussis infection started.

Complications

Babies and Children

• Pertussis (whooping cough) can cause serious and sometimes deadly complications in babies and young children, especially those who have not received all recommended pertussis vaccines.

• About half of babies younger than 1 year old who get pertussis need care in the hospital. The younger the baby, the more likely they will need treatment in the hospital. Of those babies who are treated in the hospital with pertussis about:

• 1 out of 4 (23%) get pneumonia (lung infection)
• 1 out of 100 (1.1%) will have convulsions (violent, uncontrolled shaking)
• 3 out of 5 (61%) will have apnea (slowed or stopped breathing)
• 1 out of 300 (0.3%) will have encephalopathy (disease of the brain)
• 1 out of 100 (1%) will die

Teens and Adults

Pertussis world map

• Teens and adults can also get complications from pertussis. They are usually less serious in this older age group, especially in those who have been vaccinated with a pertussis vaccine. The cough itself often causes complications in teens and adults. For example, you may pass out or break (fracture) a rib during violent coughing fits.

• In one study, less than 1 out of 20 (5%) teens and adults with pertussis needed care in the hospital. Healthcare professionals diagnosed pneumonia (lung infection) in 1 out of 50 (2%) of those patients. The most common complications in another study were:

• Weight loss in 1 out of 3 (33%) adults
• Loss of bladder control in 1 out of 3 (28%) adults
• Passing out in 3 out of 50 (6%) adults
• Rib fractures from severe coughing in 1 out of 25 (4%) adults

• Disease Specifics
• On This Page
• Bordetella pertussis
• Pathogenesis
• Reference
• The bacterium Bordetella pertussis causes pertussis, an acute infectious disease. In the 20th century, pertussis was one of the most common childhood diseases and a major cause of U.S. childhood mortality. Before the availability of pertussis vaccine in the 1940s, public health experts reported more than 200,000 cases of pertussis annually. Since widespread use of the vaccine began, incidence has decreased more than 75% compared with the pre-vaccine era.

• However, since the 1980s there has been an increase in the number of reported cases of pertussis. In 2012, the last peak year, CDC reported 48,277 cases of pertussis. However, CDC believes that much of the disease goes unrecognized and unreported.

• Several factors have likely contributed to the increase in reported cases, including

• Increased awareness and improved recognition of pertussis among clinicians
• Greater access to and use of laboratory diagnostics, especially polymerase chain reaction (PCR) testing
• Increased surveillance and reporting of pertussis to public health departments
• Waning immunity from vaccines
• Additionally, B. pertussis are also always changing at a genetic level. CDC continues to evaluate what impact, if any, molecular changes in B. pertussis are having on public health.

• Bordetella pertussis
• B. pertussis is a fastidious, gram-negative bacterium requiring special media for isolation. B. pertussis produces multiple antigenic and biologically active products including:

• Gram stain of Bordetella pertussis
• Gram stain of Bordetella pertussis

• Pertussis toxin
• Filamentous hemagglutinin (FHA)
• Agglutinogens
• Adenylate cyclase
• Pertactin
• Tracheal cytotoxin
• These products are responsible for the clinical features of pertussis. An immune response to one or more of them produces immunity following infection. Some observational studies suggest that pertussis infection can provide immunity for 4 to 20 years, but that it is not life-long.

Bordetella pertussis

• Pathogenesis
• Pertussis is primarily a toxin-mediated disease. The bacteria

• Attach to the cilia of the respiratory epithelial cells
• Produce toxins that paralyze the cilia
• Cause inflammation of the respiratory tract, which interferes with the clearing of pulmonary secretions
• Until recently, scientists thought that B. pertussis did not invade the tissues. However, recent studies suggest that the bacteria are present in alveolar macrophages.

Diagnosis Confirmation

• Clinicians commonly use several types of laboratory tests to diagnose Bordetella pertussis. Scientists consider culture the gold standard because it is the only 100% specific method for identification. Other tests that can be performed include polymerase chain reaction (PCR) and serology.

Culture

• Since culture has excellent specificity, it is particularly useful for confirming pertussis diagnosis when you suspect an outbreak. Many other respiratory pathogens have similar clinical symptoms to pertussis and co-infections do occur. Furthermore, obtaining isolates from culture allows for strain identification and antimicrobial resistance testing. Identifying which strains of B. pertussis are causing disease is of public health importance. It is best for you to obtain a culture from nasopharyngeal (NP) specimens collected during the first 2 weeks of cough. This is when viable bacteria are still present in the nasopharynx. After the first 2 weeks, sensitivity decreases and the risk of false-negatives increases.

PCR

• Key Resource
• Best Practices for Health Care Professionals on the use of Polymerase Chain Reaction (PCR) for Diagnosing Pertussis
• Best Practices for Healthcare Professionals on the Use of Polymerase Chain Reaction (PCR) for Diagnosing Pertussis

• PCR is a rapid test and has excellent sensitivity. However, PCR tests vary in specificity. Therefore, you should obtain culture confirmation of pertussis for at least one suspicious case any time there is suspicion of a pertussis outbreak. You should interpret results along with the clinical symptoms and epidemiological information. You should test with PCR from NP specimens taken at 0 to 3 weeks following cough onset. PCR may also provide accurate results for up to 4 weeks. After the fourth week of cough, the amount of bacterial DNA in the nasopharynx rapidly diminishes, which increases the risk of obtaining falsely-negative results. PCR assay protocols that include multiple target sequences allow for speciation among Bordetella species. The high sensitivity of PCR increases the risk of false-positivity, but following some simple best practices can reduce the risk of obtaining inaccurate results.

Bordetella pertussis

Treatment

• Healthcare providers generally treat pertussis with antibiotics and early treatment is very important. Treatment may make your infection less serious if you start it early, before coughing fits begin. Treatment can also help prevent spreading the disease to close contacts (people who have spent a lot of time around the infected person). Treatment after three weeks of illness is unlikely to help. The bacteria are gone from your body by then, even though you usually will still have symptoms. This is because the bacteria have already done damage to your body.

• There are several antibiotics (medications that can help treat diseases caused by bacteria) available to treat pertussis. If a healthcare professional diagnoses you or your child with pertussis, they will explain how to treat the infection. Learn more about pertussis treatment recommended by CDC.

• Pertussis can sometimes be very serious, requiring treatment in the hospital. Babies are at greatest risk for serious complications from pertussis. View photos of a baby getting treatment for pertussis in the hospital.

Manage pertussis and reduce the risk of spreading it to others by:

• Following the schedule for giving antibiotics exactly as your child’s doctor prescribed.
• Keeping your home free from irritants – as much as possible – that can trigger coughing, such as smoke, dust, and chemical fumes.
• Using a clean, cool mist vaporizer to help loosen mucus and soothe the cough.
• Practicing good handwashing.
• Encouraging your child to drink plenty of fluids, including water, juices, and soups, and eating fruits to prevent dehydration (lack of fluids). Report any signs of dehydration to your doctor immediately. These include dry, sticky mouth, sleepiness or tiredness, or thirst. They also include decreased urination or fewer wet diapers, few or no tears when crying, muscle weakness, headache, dizziness or lightheadedness.
• Encouraging your child to eat small meals every few hours to help prevent vomiting (throwing up) from occurring.

Vaccines

• The best way to prevent pertussis (whooping cough) among babies, children, teens, pregnant women, and adults is to get vaccinated. Also, keep babies and other people at high risk for pertussis complications away from infected people.

• Two vaccines in the United States help prevent whooping cough: DTaP and Tdap. These vaccines also provide protection against tetanus and diphtheria. Learn who needs a pertussis vaccine and when.

Infection

• Graphic depicting young children, preteens, pregnant women, and adults, all of which need whooping cough vaccines.
• Some observational studies suggest that pertussis infection can provide immunity for 4 to 20 years.

Immunization schedule

Treatment

Tips

• Treat appropriately for pertussis.
• Because pertussis may progress rapidly in young infants, treat suspected and confirmed cases promptly.
• However, treatment is ineffective if started late in the course of illness.
• Quickly report cases of pertussis to the local public health department to assist with preventing additional cases.

Timing

• Early treatment of pertussis is very important. The earlier a person, especially an infant, starts treatment the better.
• If a patient starts treatment for pertussis early in the course of illness, during the first 1 to 2 weeks before coughing paroxysms occur, symptoms may be lessened.
• Clinicians should strongly consider treating prior to test results if clinical history is strongly suggestive or patient is at risk for severe or complicated disease (e.g., infants). If a clinician diagnoses the patient late, antibiotics will not alter the course of the illness.
• Even without antibiotics, those patients should no longer be spreading pertussis.
• Persons with pertussis are infectious from the beginning of the catarrhal stage (runny nose, sneezing, low-grade fever, symptoms of the common cold).
• They remain infectious through the third week after the onset of paroxysms (multiple, rapid coughs) or until 5 days after the start of effective antimicrobial treatment.

Postexposure Antimicrobial Prophylaxis (PEP)

• CDC supports targeting postexposure antibiotic use to persons at high risk of developing severe pertussis and to persons who will have close contact with those at high risk of developing severe pertussis. Learn more about use of PEP.
• A reasonable guideline is to treat persons older than 1 year of age within 3 weeks of cough onset and infants younger than 1 year of age and pregnant women (especially near term) within 6 weeks of cough onset.
• Administer a course of antibiotics to close contacts within 3 weeks of exposure, especially in high-risk settings. Use the same doses as in the treatment schedule.
• Pediatric clinicians play a critical role in treating infant pertussis.
• Early empiric treatment is important for infants

Antimicrobial Choice

• The recommended antimicrobial agents for treatment or chemoprophylaxis of pertussis are

• Azithromycin
• Clarithromycin
• Erythromycin
• Clinicians can also use Trimethoprim-sulfamethoxasole.

Clinicians should choose the antimicrobial after consideration of the

• Potential for adverse events and drug interactions
• Tolerability
• Ease of adherence to the regimen prescribed
• Cost

Infants

• Macrolides erythromycin, clarithromycin, and azithromycin are preferred for the treatment of pertussis in persons 1 month of age and older. For infants younger than 1 month of age, macrolides should be used with caution as an association between orally administered erythromycin and azithromycin with infantile hypertrophic pyloric stenosis (IHPS) has been reported. However, azithromycin remains the drug of choice for treatment or prophylaxis of pertussis in very young infants because the risk of developing severe pertussis and life-threatening complications outweigh the potential risk of IHPS. Clinicians should monitor infants younger than 1 month of age who receive a macrolide for the development of IHPS and for other serious adverse events. For persons 2 months of age and older, an alternative to macrolides is trimethoprim-sulfamethoxazole.

Hygiene

Like many respiratory illnesses, pertussis spreads by coughing and sneezing while in close contact with others, who then breathe in the bacteria. CDC recommends practicing good hygiene to prevent the spread of respiratory illnesses. To practice good hygiene you should:

• Cover your mouth and nose with a tissue when you cough or sneeze.
• Put your used tissue in the waste basket.
• Cough or sneeze into your upper sleeve or elbow, not your hands, if you don’t have a tissue.
• Wash your hands often with soap and water for at least 20 seconds.
• Use an alcohol-based hand rub if soap and water are not available.

External links

• Pertussis at Todar's Online Textbook of Bacteriology

Whooping cough Resources
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