STPAN 2 Saint Pancras. HEALTH DEPARTMENT. REPORT UPON The Cause of the Increase of Mortality from Diphtheria in London. BY JOHN F. J. SYKES, D.Sc., M.D., Medical Officer of Health, St. Pancras, N.W. Saint Pancras. HEALTH DEPARTMENT. Vestry Hall, Pancras Road, N.W. May, 1894. To the Members of the Health Committee. Gentlemen, In accordance with the instructions of your Committee I beg to present herewith a report upon the probable causes of the increase of diphtheria. Comparing scarlet fever, diphtheria, and enteric fever in the three previous decennia, the following are the results as recorded in Tables 18 & 19 of the Registrar General's last Annual Report. Annual Mortality per million living. Decennial Periods. England and Wales. London. Scarlet Fever. Diphtheria. Enteric Fever. Scarlet Fever. Diphtheria. Enteric Fever. 1861-70 971 187 (886)* 1133 179 (904)* 1871-80 719 121 326 600 122 244 1881-90 338 163 198 335 259 189 * Includes also Typhus and Simple Continued Fever. It will be observed that the scarlet fever mortality per million for London fell from 1133 in the first to 600 in the second decennium, and in the 47th report (1834) of the Registrar General, it is suggested that the greater fall in 4 London than in England and Wales may have been due to the provision of greater isolation and hospital accommodation. This would appear to be corroborated by the fact that in the next decennium more isolation hospitals having been provided in the larger towns, the fall in the mortality in England and Wales was greater even than in London, and the two ratios per million were almost equal in 1831-90. The mortality from enteric fever fell in London from 244 per million in the decennium 1871-80 to 189 per million in the last decennium, and in and in England from 326 to 198 per million, due to improved sanitation. Comparing London with England, exactly the same order of fall in mortality is observed as in the case of scarlet fever. In the decennium 1861-70, enteric fever was embraced under the head of Fevers, which included also typhus and simple fever; at this period the combined mortality from the three diseases in London was higher than in all England and Wales, the former being 904, and the latter 886. The effect of sanitation first became apparent in London when the mortality from enteric fever, taken alone, in the next decade fell below that in England and Wales; in the last decade, when sanitary measures outside London had also improved, the ratios for England and for London fell so as to approach each other. Turning to diphtheria on the other hand, in both England and London the mortality was less in the second decennium than in the first, but in the last decennium it was greater than in the second, and in London had increased to a higher ratio even than in the first. Comparing London to England, in the first decennium the ratio of mortality was about 5 per cent lower than in England, in the second was about equal, and in the third it was about 60 per cent. higher. Dr. Longstaff, in his paper on "the Geographical Distribution of Diphtheria in England and Wales," in the extra supplement to the Report of the Medical Officer of the Local Government Board for 1887, found the death-rates from diphtheria per million of population, according to density to be as follows:— Districts according to density of population. 1855-60. 1861-70. 1871-80. Dense Districts 123 163 114 Medium „ 182 164 125 Sparse „ 248 223 132 The noticeable feature in these figures is that a progressive diminution in the mortality from diphtheria appears to have been taking place in rural districts, being most marked in the mostly sparsely inhabited. Dr. Thorne Thorne, Medical Officer of the Local Government Board, in his work upon diphtheria published in 1891, showed in tabular form (Table No. IX.) that since 1871, whereas the annual death-rates from all causes, from the seven principal zymotic diseases, and'from enteric fever, have been steadily falling in England and Wales, in the large towns, and in London, the annual death-rates from diphtheria have been rising slightly in England and Wales, more markedly in the large towns, and most markedly iu London. 5 Annual Mortality from Diphtheria per 1000 living. Year. England and Wales. 28 large Towns. London. 1871 0.11 – 0.10 1872 0.09 – 0.08 1873 0.11 – 0.09 1874 0.15 – 0.12 1875 0.14 – 0.17 1876 0.13 – 0.11 1877 0.11 – 0.08 1878 0.14 – 0.15 1879 0.12 – 0.15 1880 0.11 – 0.14 1881 0.12 – 0.17 1882 0.15 0.16 0.22 1883 0.16 0.16 0.24 1884 0.18 0.17 0.24 1885 0.16 0.17 0.22 1886 0.15 0.16 0.20 1887 0.16 0.18 0.23 1888 0.17 0.21 0.30 1889 0.18 0.26 0.39 1890 0.18 0.24 0.33 In searching into the cause of this apparently persistent and progressive increase of the mortality from diphtheria in London, the first point that strikes one is that, unlike that of scarlet fever, the mortality of diphtheria is not subject to great epidemic fluctuations, but, like that of typhoid fever, it is comparative stead}', as the following diagram shows. Diagram I. LONDON. Curves of Annual Death Rates per Million Living. From the Registar General's Annual Summary of London and Great Towns. 6 This diagram also shows that whereas the mortality rate of diphtheria is steadily rising, that of typhoid is equally steadily falling pari passu with improving sanitation, and that that of scarlet fever is also falling pari passu with increased hospital isolation, no hospital accommodation having been provided for diphtheria until the end of 1889. It is important to note these points because diphtheria resembles scarlet fever in its power of spreading directly from person to person, and also resembles typhoid fever, in that either diphtheria, or some form of throat diseaes closely allied with it, may arise from certain insanitary conditions. Comparing the two last diseases, whereas typhoid only occasionally spreads directly from one person to another, diphtheria always spreads with great facility frrm person to person ; and whereas typhoid varies in direct proportion to insanitary conditions, the relationship of diphtheria to insanitary conditions is overwhelmed by the influence of personal infection. So that, whereas the improvement of sanitation markedly decreases the mortality of the former, it appears to have no effect upon the latter, and whereas the increase of general density of population in all districts, of special density in towns, and of aggregation in schools, only remotely and indirectly affect typhoid, they closely and directly affect diphtheria. Dr. Thorne Thorne has called marked attention to the special incidence of diphtheria in children attending schools, and concludes " that apart from age susceptibility, 'school-influence' so called, tends to foster, diffuse, and enhance the potency of diphtheria, and this, in part at least, by t he aggregation of children suffering from that 'sore-throat' which commonly is prevalent antecedent to, and concurrently with, true diphtheria." The period of life at which there is most susceptibility to acquire diphtheria is from 3 to 12 years of age, and school attendance increases the risks of personal infection by the aggregation and prolonged association of children together. The progress of educational legislation traces the progressive increase of elementary education, and of school attendance. In 1870, the Elementary Education Act was passed for the establishment of School Boards and Elementary Schools. The Act of 1872 empowered the London School Board to borrow money and to erect further offices. By the Elementary Education Act of 1873, any out-relief given to the parent or guardian of a child aged from 5 to 13 years, was made conditional on the child receiving elementary education. In the Act of 1876, a child was defined as a person between the age of 5 and 14 years. A certificate of proficiency or of due attendance at school was required for the employment of a child over 10 years of age, and further provision was made as to the employment and education of children in factories, 250 attendances being necessary; and for the payment of school fees for poor parents, 350 attendances being nccessary. An Order of the Court was made obtainable for enforcing the attendance of a child at school. Day Industrial Schools were established. An increase of the Parliamentary grant was made. School Attendance Committees were given power to make bye-laws like School Boards, and to appoint local committees. The Act of 1880 compelled bye-laws to be made by every School Attendance Committee, under Sec. 74 of the Act of 1870, respecting the attendance of children at school, and prevented children from 10 to 13 years of age being employed previous to reaching the standard fixed by bye-law. 7 By the Education Code Act, 1890, a special grant of £10 annually was made to schools where the population was less than five hundred, and "elementary education" was not to be the condition of a Parliamentary grant to Evening Schools. By the Elementary Education Act, 1891, schools in which the fee for each child from 3 to 15 years of age did not exceed ten shillings a-year, were allowed a fee grant of that amount and rendered free. But, the average number of children on the roll of the London School Board annually gives a more definite idea of the increase of elementary education in London, and for the purposes of comparison I have framed the following table:— London. Year. Census Population Number of Deaths from Diphtheria. RegistrarGeneral'e Annual Summary, 1892. Average number on roll of Board and Non-Board Schools. Number of Cases of Diphtheria admitted to Hospitals of Metropolitan Asylums Board. Number of Cases of Diphtheria notified. 1861 V 2,804,000 674 1862 730 1863 799 1864 611 1865 431 1866 462 1867 447 1868 495 1869 340 1870 334 1871 3,254,260 344 222,518 1872 267 240,927 1873 320 319,149 1874 419 370,794 1875 581 387,023 1876 387 405.467 1877 316 426,953 1878 566 444,322 1879 575 468,564 1880 544 483,493 1881 3,815,544 657 498,504 1882 857 519,130 1883 952 557,562 1884 951 570,280 1885 904 592,421 1886 851 591,565 1887 953 617,343 1888 1,311 628,801 (2 months) 89 1889 1,617 644,068 722 (2 months) 981 1890 1,382 653,932 942 5,870 1891 4,211,743 1,435 661,497 1,312 5,907 1892 1,885 678,309 2,009 7,781 1893 —– 700,107 2,848 13,026 8 On examining the table it is to be observed that whereas during the decennium 1861-70 the number of deaths from diphtheria decreased annually, during that of 1871-80 they increased annually, and in similar proportions. Although when the increase of population is taken into account the increase is not quite so great. Comparing the number of scholars on the roll of the London School Board, the influence of elementary education appears to have had some effect in producing this result. But, on tcanning the decennium 1881-90, it is to be observed that there are two suddenly pronounced and permanent increases in the number of deaths, the first extending from near the beginning of the decennium to 1887, and the second from that year to the end and continuing into the next decennium. These increases are seen more clearly on referring back to Diagram I. of curves of mortality produced above and previously commented upon. On further examining this table it is apparent that these distinct and permanent increases in the number of deaths from diphtheria are out of all proportion to the increase of population and of scholars, and the lust is more or less coincident with the commencement of notification of diphtheria, and of the admission of the disease to the hospitals of the Metropolitan Asvlums Board. The mortality from diphtheria in the hospitals of the Metropolitan Asylums Board was falling during this period, as shown by the following table: Year. Admissions. Deaths. Mortality per cent. 1888 (2 months) 89 46 59.35 1889 722 275 40.74 1890 942 316 33.55 1891 1312 397 30.63 1892 2009 583 29.35 The hospital cases were therefore not the cause of the increase in the number of deaths from diphtheria in London. These peculiar increases led me to examine more closely the statistical figures in relation to diphtheria, and to compare those relating to other diseases attacking the palate, uvula, tonsils, pharynx, larynx, and trachea. It was not possible to go further back than the beginning of the last decennium as previous to 1881 the Registrar-General gave no details of deaths occurring from these diseases in London. For the sake of brevity I have termed them throat-diseases, and in the following table the deaths from these diseases are set out:— LONDON.—Deaths from Throat Diseases. (Extracted from tables of causes of deaths at different periods of life, male and female, in Registrar-General's Annual Reports.) Year. Total Throat Diseases. Diphtheria. Total Throat Diseases other than Diphtheria. Thrush. Croup. Laryngitis Other diseases of Larynx and Trachea. Sore Throat, Quinsy.* Estimated population. 1881 1887 657 1230 164 663 260 52 91 3,824,964 1882 2318 853 1465 110 868 312 55 120 3,862,876 1883 2382 952 1430 134 824 283 46 143 3,901,164 1884 2295 951 1344 121 730 307 49 137 3,939,832 1885 2100 904 1196 104 690 264 26 112 3,978,883 1886 1873 851 1022 118 530 248 28 98 4,018,321 1887 2081 953 1128 80 626 259 46 117 4,058,150 1888 2279 1311 968 62 501 251 41 113 4,098,374 1889 2510 1616 894 84 458 218 41 93 4,138,996 1890 2373 1382 991 92 505 234 36 124 4,180,021 1891 2183 1433 750 70 339 210 33 98 4,221,452 * This includes Tonsilitis, Pharyngitis, and Œsophagitis. 9 From this table it appears that there has been a very marked fall in the number of deaths from thrush and croup, a distinct but less marked fall in those from laryngitis and other diseases of larynx and trachea, and an irregular and slight decrease under the head of sore throat, only observable on comparing the quinquennium 1881-5 with that of 1886-90. All these diseases, taken together, show progressive and very distinct fall in the number of deaths attributed to them. Diphtheria on the other hand shows a progressive and distinct rise, in fact, when compared side by side, the numbers of the two classes proceed in inverse ratio, and when the two classes are totalled together any increase disappears. Thinking that the influence of age incidence might have affected the result, I extracted the deaths from the several diseases and classified them in two categories, under 15 years, and 15 years and over, the incidence of diphtheria being greatest under 15 years. The result is shewn in the following table:— LONDON.—Deaths from Throat Diseases — Under 15 Years, and 15 Years and Over. (Extracted from tables of Causes of Deaths at different periods of life, Male and Female, in Registrar's General Annual Reports). Year Total throat diseases. Diphtheria. Total throat diseases other than diphtheria. Thrush. Croup. Laryngitis. Other diseases of larynx & trachea. Sore throat, quinsy. 1881 1741 + 146 607 + 50 1134 + 96 164 + – 663 + – 209 + 51 31 + 21 67 + 24 1882 2174 + 144 808 + 45 1366 + 99 110 + – 867+ 1 2 54 + 58 45 + 10 90 + 30 1883 2210 + 172 892 + 60 1318 + 112 132 + 2 824 + – 229 + 54 29 + 17 104 + 39 1884 2124 + 171 883 + 68 1241 + 103 119+2 730 + – 263 + 44 30 + 19 99 + 38 1885 1972 + 128 854 + 50 1118 + 78 104 + – 690 + – 218 + 46 21 + 5 85 + 27 1886 1732 + 141 798 + 53 934 + 88 118 + – 530 + – 202 + 46 15 + 13 69 + 29 1887 1926 + 155 901 + 52 1025 + 103 80 + – 625 + 1 219 + 40 28 + 18 73 + 44 1888 2141 + 138 1242 + 69 899 + 69 62 + – 501 + – 215 + 36 33 + 8 88 + 25 1889 2370 + 140 1546+ 70 824 + 70 84+ – 458 + – 188 + 30 24 + 17 70 + 23 1890 2186 + 187 [320 + 62 866+ 125 92 + – 505 + – 180 + 54 l8 + 18 71 + 53 1891 2010 + 173 1369 + 64 641 + 109 70 + – 339 + – 153 + 57 20 + 13 55 + 39 This table shows how little the numbers of deaths at 15 years of age and upwards affect the results. The numbers are few, but comparing the quinquennium 1881-85 with that of 1886-90, although there is an increase of 33 deaths from diphtheria, and a decrease of the same number from other throat diseases, equal only to 3'3 a year, the total numbers remain the same in the two quinquennia, showing a stationary number of deaths from all throat diseases at and over 15 years of age, and taking increase of population into account, an actual decrease of mortality. If we turn to the numbers under this age, we find the figures of the previous table, which are large, are corroborated by the enormous increase in the number of deaths attributed to diphtheria, and the decrease in the number from other throat diseases, and comparing the total number of deaths from both classes under fifteen years of age in the first quinquennium with the second there appears only an increase of 134, equal to 13.4 per annum, or taking population into account, also a decrease in the mortality. 10 The deaths, therefore, of 15 years and over, having so little effect, the total numbers have been taken in calculating the table of death-rates per million. LONDON.—Death Rates per million living per annum. Year. Diphtheria. Diseases of Throat other than Diphtheria. Total Diseases of Throat. Quinquennial Mean. 1881 172 321 493 562 1882 222 379 600 1883 244 366 610 1884 241 341 582 1885 227 300 527 1886 212 254 466 542 1887 235 278 513 1888 319 236 555 1889 391 216 607 1890 331 237 568 1891 340 177 518 — In this table the progressive increase of mortality attributed to diphtheria and the equally progressive decrease of mortality due to other throat diseases in London are distinctly shown, the inverse ratio in the progression being so well marked and corresponding so closely that the total of the two classes of diseases shows no progressive variation, until the means of the two quinquennia are compared, and then it appears that the mortality from all throat diseases taken together is decreasing, a result for which the increase in diphtheria mortality had scarcely prepared us. This diagram of curves of annual death rates from diphtheria and from other throat diseases in London graphically represents the change that has taken place. Diagram II. LONDON.—Curves of Annual Death Rates per million living. 11 The conclusions that I have therefore come to are:— (1) That a slight diminution is taking place in the death rate from throat diseases taken as a whole; and (2) That the great rise in the mortality from diphtheria corresponds with a great fall in that from other throat diseases. As to the former, it may be due to diminished prevalence, or to greater vigilance, or to better treatment. Parents, guardians, teachers, nurses, medical men and the public generally are more alive to the danger of throat diseases than formerly. As to the latter, many causes are possibly at work, and a few words may be devoted to each. 1.—The effect of the Infectious Disease Notification Act.—This Act came into force in the Metropolis at the end of October. 1889, and has tended to more care and attention being bestowed, not only upon diphtheria, but upon all infectious diseases. On referring to Diagram II. it will be noticed that the great rises in the diphtheria mortality curve of the last decennium took place from 1881 to 1883, and from 1887 to 1889, antecedent to the introduction of compulsory notification, and that the persistent and gradually progressive fall in the mortality curve of other throat diseases commenced in 1883, seven years previous to the introduction of compulsory notification into the Metropolis. Furthermore, during the past decennium there has not been any rises in the mortality from other notifiable diseases comparable to that of diphtheria. It will be observed also that my conclusions are not based upon notifications but upon deaths, that the fatal—not the benign—forms of disease are in question. 2.—The effect of the Reception of Cases into the Hospitals of the Metropolitan Asylums Board—It will be unnecessary to discuss here the effect of the Board's hospitals upon diphtheria raised in the interesting Paper of Mr. R. D. R. Sweeting upon Post-Scarlatinal Diphtheria in the Transactions of the Epidemiological Society, 1892-3, nor the etiology of the various forms of diphtheritic throat affections treated so fully and with such exactitude by Dr. Klein in the supplementary Reports of the Local Government Board, seeing that it has already been shown by figures from the Asylums Board's own reports that the mortality of diphtheria cases admitted diminished in each succeeding year. It may be that the admission of cases to hospital may have had some slight indirect effect in directing more care and attention to sore throats, but the upward tendency of diphtheria commenced prior to this date, and therefore this effect would be only part of the generally increasing attention already being paid to the disease. 3.—The effect of Sanitary Legislation generally.—This must also be taken into account, for the Public Health Act, 1875, came into force during the very decennium when compulsory education came into force, and the effect of the Act was to stimulate the recognition and prevention of infectious diseases in England, especially in large towns. Compare the dates in the earlier tables of this Report. This stimulus, doubtless, extended to the Metropolis, and, in conjunction with additional sanitary legislation, directed closer attention to infectious diseases in London also. 12 4.—The effect of Elementary Schools.—Dr. Thorne Thorne has so fully and so carefully entered into this subject that his conclusion that increased school attendance has had a material influence in increasing the spread of Diphtheria is irresistable. 5.—Alteration in Classification.—Any changes made in classification by the Registrar-General are usually commenced at the beginning of a decennium and therefore would not affect the detailed London figures of throat diseases in this Report. The Superintendent of Statistics, Dr. Tatham, has kindly informed me that "membranous croup" was not classed with Diphtheria until the commencement of the present year (1894), although "diphtheritic croup" has been classed with Diphtheria for a long period, so that classification can have had little or no effect upon the returns of mortality. 6.—Variation in Nomenclature.—Improved medical diagnosis due to improved medical education and increased knowledge of diseases of the throat, enables these diseases to be more readily differentiated than formerly. Now, most forms of infectious sore throat are regarded as diphtheria, and the fatality of such diseases is recognised, whereas formerly the term was restricted to typical cases. The danger of the earlier practice has been pointed out in the many instances brought to light in which apparently simple sore throats in schools have culminated in serious and fatal epidemics. 7.—Change of Type.—In the last place, the question may be seriously asked whether the variation in nomenclature may not be due to a change of type in disease of the throat? Dr. Thorne Thorne says "that there is reason to believe that attacks of so-called sore-throat exhibit under certain favouring conditions a progressive development of the property of infectiveness, culminating in a definite specific type which is indistinguishable from true diphtheria." A change of type is probably taking place as the result of increased density of population, especially in towns, more particularly of the aggregation in schools, and of the effects of personal infection consequent on these. There is also a strong probability, and it only remains to be definitely proved, that a sore throat caused by insanitary or other conditions, may possess or acquire infective properties, and in passing from person to person may also acquire such virulence as to cause death from infectious sore-throat of a type which the clinician would certify as diphtheria, whatever the pathologist might declare it to be as the result of bacteriological examination. I have the honour to be Gentlemen, Your obedient Servant, JOHN F. J. SYKES, D. Sc., M.D., Medical Officer of Health, St. Pancras, N. TV.