Whooping-cough, or pertussis, is a respiratory-tract infection caused by Bordetella pertussis and spread by droplets. It may occur at all ages, but around 90 per cent of cases are children aged under ﬁve. Most common during the winter months, it tends to occur in epidemics (see EPIDEMIC), with periods of increased prevalence occurring every three to four years. It is a notiﬁable disease (see NOTIFIABLE DISEASES). The routine vaccination of infants with TRIPLE VACCINE (see also VACCINE; IMMUNISATION), which includes the vaccine against whooping-cough, has drastically reduced the incidence of this potentially dangerous infection. In the 1990s over 90 per cent of children in England had been vaccinated against whooping-cough by their second birthday. In an epidemic of whooping-cough, which extended from the last quarter of 1977 to mid-1979, 102,500 cases of whooping-cough were notiﬁed in the United Kingdom, with 36 deaths. This was the biggest outbreak since 1957 and its size was partly attributed to the fall in vaccination acceptance rates because of media reports suggesting that pertussis vaccination was potentially dangerous and ineﬀective. In 2002, 105 cases were notiﬁed in England.
Symptoms The ﬁrst, or catarrhal, stage is characterised by mild, but non-speciﬁc, symptoms of sneezing, conjunctivitis (see under EYE, DISORDERS OF), sore throat, mild fever and cough. Lasting 10–14 days, this stage is the most infectious; unfortunately it is almost impossible to make a deﬁnite clinical diagnosis, although analysis of a nasal swab may conﬁrm a suspected case. This is followed by the second, or paroxysmal, stage with irregular bouts of coughing, often prolonged, and typically more severe at night. Each paroxysm consists of a succession of short sharp coughs, increasing in speed and duration, and ending in a deep, crowing inspiration, often with a characteristic ‘whoop’. Vomiting is common after the last paroxysm of a series. Lasting 2–4 weeks, this stage is the most dangerous, with the greatest risk of complications. These may include PNEUMONIA and partial collapse of the lungs, and ﬁts may be induced by cerebral ANOXIA. Less severe complications caused by the stress of coughing include minor bleeding around the eyes, ulceration under the tongue, HERNIA and PROLAPSE of the rectum. Mortality is greatest in the ﬁrst year of life, particularly among neonates – infants up to four weeks old. Nearly all patients with whooping-cough recover after a few weeks, with a lasting IMMUNITY. Very severe cases may leave structural changes in the lungs, such as EMPHYSEMA, with a permanent shortness of breath or liability to ASTHMA.
Treatment Antibiotics, such as ERYTHROMYCIN or TETRACYCLINES, may be helpful if given during the catarrhal stage – largely in preventing spread to brothers and sisters – but are of no use during the paroxysmal stage. Cough suppressants are not always helpful unless given in high (and therefore potentially narcotic) doses, and skilled nursing may be required to maintain nutrition, particularly if the disease is prolonged, with frequent vomiting.