Whooping cough (pertussis)

What is whooping cough (pertussis)?

Whooping cough, also known as pertussis, is a very contagious childhood disease that causes inflammation in the respiratory tract. Whooping cough mostly affects children under two years of age, but can infect older children and young adults.

Despite vaccination efforts, millions of whooping cough cases are still reported globally each year. Whooping cough causes many deaths, especially among infants. In 2008, an estimated 195,000 children worldwide died of whooping cough. ^[1]

Whooping cough infection numbers have dropped greatly since the vaccine was introduced into the US in the late 1940s, but there has been something of a resurgence in the past few decades. The highest numbers of infections are found in children in countries where vaccination is not effective. However, even in developed countries where vaccination rates are high, several thousand cases appear every year.

Signs and symptoms

Early symptoms

At first, whooping cough displays similar symptoms to a cold. The symptoms begin a week or two after infection and can include:

• Sneezing;
• A runny nose;
• Reddish, watery eyes;
• Mild fever;
• A dry cough;
• Sore throat;
• A feeling of weakness and discomfort, and;
• In infants, a short pause in breathing.

If breathing problems appear, urgent medical attention may be required.

Coughing

The distinctive sounding 'whooping' cough usually develops after a week or two and can last for 4-8 weeks. The coughing comes in fits of repeated fast coughs. A fit can last a minute or two. The cough is often accompanied by thick mucus. The fits can be violent and leave the person gasping for air (this makes the 'whoop' sound at the end of a fit). The continuous coughing fits can be exhausting and can also cause vomiting.

Whooping cough can also have a non-specific cough. Alternatively, some people who contract whooping cough do not develop the cough at all, or have only mild coughing fits.

Recovery

The coughing fits gradually becomes less intense, but may take up to three months to disappear completely.

Causes

Whooping cough is caused by a type of bacteria called Bordetella pertussis. It infects the body's airways and causes inflammation of the airway linings. Thick mucus collects in the airways and makes breathing difficult.

When an infected person sneezes or coughs, the bacteria spread into the air via millions of tiny droplets, each containing many individual bacteria. If a droplet enters your nose or mouth, you may then become infected. The droplets can also collect on surfaces and objects; you can then catch the bacteria by touching an infected surface and then touching your nose or mouth area.

Methods for diagnosis

Your doctor will diagnose whooping cough by its signs, particularly the distinctive cough.

Your doctor may also wish to take a mucus sample from the throat to test for the presence of the pertussis bacteria, or a sample of blood to test for antibodies that the body produces against the bacteria.

Types of treatment

Supportive treatment

For light cases of whooping cough, home-care measures can include:

• Bed rest;
• Drinking plenty of fluids (to prevent dehydration);
• Clearing away of mucus, and;
• Medication to ease fever.

Medications

Antibiotics

If diagnosed early, whooping cough can be treated with antibiotics such as clarithromycin, azithromycin or erythromycin.

In the two or three weeks after infection, antibiotics often do not ease the symptoms of the disease, but can prevent the person from infecting others.

Contacts of individuals infected with whooping cough may be offered antibiotics to prevent the development of an established infection. This is particularly relevant for household contacts and is given before any symptoms develop.

Cough medication

Cough medications do not generally help in the treatment of whooping cough.

Potential complications

Whooping cough is a serious condition that can cause severe harm, including death, to infected people. It is especially dangerous to babies and young children. Complications of whooping cough can include:

• Pneumonia;
• Pauses in breathing (apnea), stopped breathing;
• Seizures;
• Brain damage, and;
• Kidney failure.

Prevention

Whooping cough is highly contagious to any person who comes into contact with an infected person.

The best way to prevent whooping cough is developing an immunity to the bacterial infection. A whooping cough vaccine is available and forms part of the routine immunization schedule in many countries, including the US, usually as part of childhood immunization.

Additional prevention strategies for babies too young to receive the vaccine are being considered. These include 'cocooning' - vaccinating parents and family members of newborns.

References

1. WHO | Estimates of disease burden and cost-effectiveness. Accessed 11 July 2014 from link here
2. Murtagh J. MD. (2011). John Murtagh’s General Practice (5th Revised edition edition.). North Ryde N.S.W.: McGraw-Hill Medical Publishing.
3. CDC - Pertussis: Complications. Accessed 3 March 2015 from link here
4. Murtagh J. MD. (2011). John Murtaghs General Practice (5th Revised edition edition.). North Ryde N.S.W.: McGraw-Hill Medical Publishing.
5. Black R.E. Cousens S. Johnson H.L. et al. (2010). Global regional and national causes of child mortality in 2008: a systematic analysis. The Lancet 375: 19691987.
6. CDC - Pertussis: Causes and Transmission. Accessed 11 July 2014 from link here
7. Chiappini E. Stival A. Galli L. et al. (2013). Pertussis re-emergence in the post-vaccination era. BMC Infectious Diseases 13: 151.
8. Choices N.H.S. (2013 December 19). Whooping cough - NHS Choices. Accessed 11 July 2014 from link here
9. Decker K.B. James T.D. Stibitz S. et al. (2012). The Bordetella pertussis model of exquisite gene control by the global transcription factor BvgA. Microbiology 158: 16651676.
10. Higgs R. Higgins S.C. Ross P.J. et al. (2012). Immunity to the respiratory pathogen Bordetella pertussis. Mucosal Immunology 5: 485500.
11. Murtagh J. MD. (2011). John Murtaghs General Practice (5th Revised edition edition.). North Ryde N.S.W.: McGraw-Hill Medical Publishing.
12. Pertussis (whooping cough) - Blue Book - Department of Health Victoria Australia. instructional. Accessed 11 July 2014 from link here
13. Treatment and prevention of Bordetella pertussis infection in adolescents and adults. Accessed 11 July 2014 from link here
14. WHO | Estimates of disease burden and cost-effectiveness. Accessed 11 July 2014 from link here
15. WHO | Pertussis. WHO. Accessed 11 July 2014 from link here
16. Whooping cough. Better Health Channel. Accessed 11 July 2014 from link here
17. Team Australian Prescriber Web. Pertussis Prophylaxis - Australian Prescriber. Accessed July 18 2014. link here

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