Whooping cough is a highly infectious bacterial childhood disease, which can be fatal in babies.
High temperature is a key symptom of whooping cough
What is whooping cough?
It is caused by the Bordetella pertussis bacterium which is spread from one individual to another by droplets of moisture expelled through sneezing or coughing
It affects the lining of the breathing airways which become inflamed and swollen and produce too much mucus.
Symptoms develop between five and 21 days after infection.
The "whoop" is its most well known characteristic.
It is caused by the child gasping for air at the end of a coughing bout.
Children - especially babies - may not have the whoop, but will experience coughing fits, and young children may have breathing problems. A runny nose and raised temperature are usually also seen.
Older children with whooping cough tend not to be too seriously affected.
But babies can develop pneumonia, an infection of the small airways in the lung or a collapsed lung, and the condition is fatal in one in 500 cases.
Do children get whooping cough anymore?
Yes. A study, published by the British Medical Journal, shows 40% of children who go to the doctor with a persistent cough have had the infection.
Official figures from the Health Protection Agency show that in 2004, there were 140 cases among children under the age of one year, rising to 185 in 2005.
And among those aged one to four, there were 97 cases in 2004, rising to 104 last year.
But aren't children vaccinated?
A vaccination against whooping cough was first introduced in the 1950s.
Before then, there were about 100,000 cases each year in the UK.
But there was a scare about the vaccine in the late 1970s, and the number of cases rose again.
Children are now vaccinated at two, three and four months of age and also receive a pre-school booster.
How is the condition treated?
Antibiotics are usually given to kill the bacteria. However, even then coughing will continue for six to eight weeks.
Other treatment is lots of rest, taking in plenty of fluids and should stay away from other children.
About two thirds of babies with whooping cough need to go into hospital. Some require intensive care.