During the last half-century there has been a decline in the death-rate from all causes, including the infectious diseases as a group; but it can hardly be said that whooping-cough has had a due share in this decline. Notably in Ireland, where the decline of infectious disease has been most marked, it has been, as it were, pushed to the front of its class by the shrinkage of the other items. In Scotland it is now decidedly at the head of the list, and in England it has shared the first place with measles since the great diminution of scarlatina deaths.
Annual average Death-rates per 100,000 living.
| Whooping-cough | Measles | Scarlatina | |||||
| England | 1871-80 | 51·2 | 37·7 | 71·6 | |||
| 1881-90 | 45·1 | 44·1 | 33·8 | ||||
| Scotland | 1871-80 | 63·1 | 37·0 | 79·5 | |||
| 1881-90 | 60·7 | 38·3 | 28·8 | ||||
| Ireland | 1871-80 | 34·8 | 21·0 | 43·5 | |||
| 1881-90 | 28·5 | 19·2 | 20·8 |
There is a small decrease in the death-rate of whooping-cough within the last decennial period, whereas in that of measles there is a slight increase (except in Ireland). The comparative steadiness of whooping-cough among the causes of death is doubtless owing to the fact that the bulk of its fatalities are among infants, and that there appears to be an irreducible minimum of the deaths from all causes at that age-period.
Whooping-Cough as a Sequel of other Maladies.
Although it is convenient to group whooping-cough among the infectious diseases, and although it is a clear case of a malady that comes in epidemics, yet its pathology is peculiar. It seems to be more a sequel of other diseases than an independent or primary affection. The whoop of the breath, from which it is named, is really proper to any convulsive cough of some infants or children. Adults, having undergone the change in the form and relative size of the larynx at puberty, have the convulsive cough usually without the whoop if they have it at all. After the successive influenzas of recent years (1889-92), many adults suffered from convulsive paroxysmal cough which was whooping-cough in all respects but the whoop, the choking fits, the blackness of the face, and the vomiting being, of course, all kept in subjection by the greater control of adults over their reflex actions.
It has been often remarked that the ordinary whooping-cough of children has followed epidemics of influenza, or widely prevalent catarrhs. Thus, Hillary records in July, 1753, an epidemic of whooping-cough, or “the fertussis,” all over the island of Barbados following the epidemic catarrh which was at a height in January of the same year. Whooping-cough had not been known in the island for many years past, “neither could I find by the strictest inquiry that I could make that any child or elder person did bring it hither[1243].” Willan, in his corresponding records of the succession of diseases at the Carey Street Dispensary, London, from 1796 to 1800, has the following:
“There was also among infants and children during the month of January [1796], an epidemic catarrh attended with a watery discharge from the eyes and nostrils, a frequent though slight cough, a shortness of breath, or rather panting, a flushing of the cheeks, great languor with disposition to sleep, and a quick small irregular pulse.... It was succeeded in February by the hooping cough.”
Measles, which is usually a catarrhal malady, has undoubtedly been followed by whooping-cough in many individual cases and in epidemics as a whole; and it may be that there is a closer association of whooping-cough with measles than with any other infectious disease. In the table on p. 647, the deaths by whooping cough in London from 1731 to 1830 have been reduced to ratios per cent. of the deaths from all causes, in a parallel column with the ratios of measles; it will be seen that the increase of both is equally remarkable towards the end of the table. But the Glasgow ratios abstracted by Watt show no such decided increase of whooping-cough from 1783 to 1812, side by side with the astonishing increase of measles; while his annual bills for the same period show that there were many deaths from whooping-cough in Glasgow for years before measles began to replace smallpox or to divide the mortality with it. The first high monthly mortalities from whooping-cough in Watt’s bills were from November, 1785, to the end of 1786; but there had been so little measles for twenty-four months before that epidemic began, that only one death from it is recorded all the time. Again, the great measles epidemic of 1808 in Glasgow was indeed followed by many deaths from whooping-cough in 1809; but, while the height of the measles epidemic was in May and June, 1808, it was not until April, 1809, that whooping-cough began to cause many deaths.
Glasgow: Deaths by measles and whooping-cough.