What is whooping cough?

Whooping cough is a highly infectious disease mainly occurring in children. It was first recognised after a whooping cough epidemic in Paris in 1578. It was known then as the "dog bark" the "chin" cough or "kin" cough meaning "convulsive" cough.

Pertussis bacteria causes sudden attacks of an irritating cough which often ends in a high-pitched whooping sound as the child takes a breath. Although immunisation has reduced its severity, making it a less severe disease, it is still a common infection in our community.

Regular epidemics occur every three to five years. New Zealand appears to have a higher incidence of whooping cough than the USA or Britain. For some unknown reason it affects females more commonly than males and is particularly severe in children less than one year of age.

If your child gets whooping cough and they have not been vaccinated, they are more likely to develop pneumonia. A severe case of whooping cough or pneumonia could result in death. If your child has never had the disease and has not been vaccinated against it, they are likely to get whooping cough if they come into contact with the bacteria.

Because of the regular epidemics which have occurred, a fifth dose of pertussis vaccine has now been included in the New Zealand childhood immunisation programme. Whooping cough is also dangerous in elderly people but tends to be less severe in older children and adults.

What causes whooping cough?

Whooping cough is usually caused by a bacteria called Bordetella pertussis. Bacteria enter the air passages and damage the lining of the windpipe and the main air passages in the lungs The inflamed airways produce more mucus which starts the irritating cough. The bacteria is passed from person to person by the infected mucus during coughing.

What are the symptoms of whooping cough?

Symptoms of whooping cough develop about seven to 10 days after being exposed to the bacteria. Whooping cough usually runs a six week cycle in three stages, each lasting about two weeks - but it can last up to three months. (In some countries it is known as the 100-day cough.)

The first stage usually produces an irritating hacking cough at night, loss of appetite, sneezing and possibly a slight fever. It is not common however for whooping cough to cause a fever. It is highly contagious at this stage but difficult to diagnose, as whooping cough can be mistaken for bronchitis.

Nose and throat swabs which detect the pertussis bacteria will only show up in the early stages of the disease. If your doctor suspects that your child has whooping cough because of the classic cough symptoms, they will take a swab and send it to the laboratory to make sure of the diagnosis.

The second stage begins after seven to 14 days. It is known as the paroxysmal stage because of the coughing spells. These coughing spells may produce plenty of mucus and the cough may finish with a loud whoop. Choking on the mucus can cause vomiting.

Many young children diagnosed with whooping cough may not necessarily have the typical "whoop". The persistent coughing spells can cause a child to temporarily stop breathing, or turn blue. Complications such as pneumonia or middle ear infections are more likely to develop at this time.

The third stage (convalescent) is when the coughing and vomiting starts to subside. Sometimes, the coughing can start again months later if the child develops an upper respiratory tract infection.

How is whooping cough treated?

Some cases of whooping cough can be treated at home, depending on how severe the whooping cough is. Others will need to be treated in hospital. An antibiotic may be prescribed if a secondary infection has developed or to help make the disease less infectious to others.

A child may be infectious to others for up to a month after the start of the cough, but if an antibiotic has been prescribed the infectious period is reduced to less than a week. Comfort and plenty of cuddles for young children will aid in recovery.

Small healthy meals and fluids can be given to your child. Steam in the bedroom or sitting the child on your knee in a steamy bathroom may give some temporary relief. Cough medicine is of little value.

Caring for your child with whooping cough is hard work, especially as the cough is often worse at night. Ask family and friends to help so you can catch up with sleep.

Keep your child away from others to prevent infection spreading. If there is an outbreak of whooping cough and your child is unimmunised they will have to stay away from their early childhood centre until the outbreak is over.

Immunisation to prevent whooping cough

Prevention by immunisation is vital. There are very few medical reasons why a child should not have pertussis immunisation. It is now accepted that contraindications (reasons why a child should not have the immunisation) have been overstated in the past.

The childhood schedule for pertussis immunisations now consists of a course of five injections which are combined with others. It is given at six weeks, three months and five months and children should have booster doses at four and 11 years.

If you suspect your child has whooping cough or if you have concerns about your child's health, call your doctor or practice nurse.

To find out more about whooping cough immunisation, contact the Immunisation Advisory Centre (IMAC), details under 'Further information and support' below.

Written by Anna Mickell RCpN. Reviewed by everybody, February 2005.