- Email: [email protected]
THE PROBLEM OF DIPHTHERIA
170
PUBLIC HEALTH THE
PROBLEM
OF
DIPHTHERIA
Prevalence A YEAR ago we drew attention1 to the sharp rise in diphtheria which took place during the autumn of 1933. The number of notifications was about 20 per cent. in excess of those received during the corresponding period of 1932, and, for each week, between 10 and 20 per cent. above the average (as measured by the median value) of the corresponding weeks of the preceding nine years. We then suggested that the incidence and mortality might be serious during the winter 1933-34, and this has proved to be true. Throughout the late winter and spring of 1934 the notifications remained at a high level but, more important, the usual summer decline of incidence was arrested, so that the excess of cases beyond expectation became higher at the season when prevalence is normally low. When the subsequent course of events is examined (Chart 1), it will be seen that there was again a rapid rise in prevalence from the already high minimum in August, 1934, and in the last two weeks of the year the number of notifications received has, in fact, exceeded expectation by 60 per cent. The actual number of notifications in the 118 great towns of England and Wales during 1934 was 44,367, as compared with 32,585 in 1933. For the whole country they numbered 69,009 as against 47,435 in the previous year, an increase of 45 per cent. The incidence is likely to fall after the end of January, but at what rate cannot be easily predicted. In passing it may be noted that scarlet fever has behaved in a similar way, this concurrence of the two diseases having been constantly observed but never satisfactorily explained. Recent experience cannot be seen in true perspective without reference to the past behaviour of diphtheria. The Registrar-General gives us each year a statement of the proportion of cases notified in England and Wales to the total estimated population of the country, and these rates are presented in Chart 2 for the years 1911 to 1933. During this period there were two waves of high prevalence, culminating respectively 1 THE LANCET, 1933, ii., 1288.
in 1920 and 1930, but the latter declined a little more rapidly than the former. While the interval between them was ten years, a notification-rate almost as high as either of them (1-7 per 1000) has been reached
CHART 2. COMPARATIVE PREVALENCE Notification-rates of diphtheria per 1000 of population during the years 1911 to 1933. (From the Registrar-General’s Statistical Review.)
in 1934-i.e., within the short spell of four years. It is very unlikely that the rise will be continued for a further six years-if it were, public health departments would be faced with a grave problem-but it is at least probable that 1935 will not see any marked abatement. To illustrate what these notification-rates mean, we have charted them also for two areas where they have tended in recent years to be higher than in the whole country-viz., London and the Welsh county boroughs. The consistently high rates in London during the post-war years are attributed by the Registrar-General rather to better observance
of
the
statu-
tory duty of notification than to any pronounced excess of prevalence, and this contention is borne out by the crude fatality-rates based upon deaths and notifications in London which are consistently lower than elsewhere. So far as Wales is concerned, however, this does not appear to be the case, and the principality seems to than have been more usually affected since 1928.
Mortality While Chart 2 shows
no
CHA.RT 1. GENERAL PREVALANCE
pronounced tendency on the part of notification-
Notifications of diphtheria in the 118 great towns of England and Wales in each week from August 5th, 1933, to December 29th, 1934. (From the Registrar-General’s Weekly Returns.)
rates to fall during the last 23 years, a similar illustration (Chart 3) of the death-
PUBLIC HEALTH
rates from diphtheria in England and Wales, although it has peaks corresponding with those of Chart 2, shows the mortality during the last ten years to be much lower than the prevalence would have led It is difficult to say how much of this us to expect. in fall fatality is due to better notification apparent
illustrated 118
great
171
by the deaths-to-notifications rates in the towns during 1932, 1933, and 1934 :-
proportion is definitely, if not strikingly, increasing. It is possible therefore that diphtheria is taking The
a rather more serious form. Even if any increase of virulence were only slight, its association with a continued rise in prevalence would swell the death-rate from the disease. The actual number of deaths in England and Wales during 1934 is not yet available, but if they have increased in the same proportion as in the great towns they will exceed anything recorded during the last ten years, and this in spite of a steady fall in the number of children at the most susceptible ages.
The Seed and the Soil
CHART 3. DEATH-RATE IN THE YOUNGER POPULATION Deaths from diphtheria and croup in England and Wales per million under 15 years of age from 1911 to 1933.
and the use of bacteriological aids to diagnosis, how much to better treatment or how much to a real decline in virulence. The present epidemic may afford evidence which will help to a conclusion. At present we can only record the facts as they appear in statistical returns. A rough-and-ready measure of the fatality of the disease from year to year may be found in the number of deaths per 1000 notifications in England and Wales (Chart 4). Here the impression gained from examination of the notification- and death-rates is confirmed. The rate during the war years appears inflated owing to defective notification as a result of
CHART 4. CASE MORTALITY
Deaths from diphtheria in England and Wales per thousand notified cases from 1911 to 1931.
the absence of a large proportion of practitioners on service. If however the decline were entirely due to improved notification, it should be continuous or at least the rate should not increase, since any falling off in this respect is now unlikely to occur. A slight upward tendency since 1930 may therefore be genuine evidence of an increase of virulence which is reported from some parts of the country. The point is further
In certain parts of Great Britain and Ireland there has been, as remarked above, an increase in the severity as well as in the amount of diphtheria. Anderson, McLeod, and their colleagueswere the first to show (1931) that the exacerbation of diphtheria morbidity and fatality at Leeds was associated with. an increased prevalence of special types of diphtheria bacilli-and observation since confirmed in many other localities. It now becomes justifiable to explain variations in the clinical picture, complications, and epidemiological phenomena by observed changes in the types of infecting organisms ; one need no longer assume that these variations are caused wholly by unobserved changes in the susceptibility or environment of the human community. The demonstration that severe and epidemic diphtheria tends to be associated with one type of diphtheria bacillus, mild and endemic diphtheria with another kind, is a notable step forward in the epidemiology of the disease. This advance is quite independent of any claim that the epidemic " virulent variants (so-called gravis) and the endemic " milder (so-called mitis) types of diphtheria bacilli are constant in their cultured character or other attributes, when and wherever they are encountered. Why, at certain intervals and places, the more infective and invasive strains of diphtheria bacilli should appear, or originate from milder endemic strains, is not known. It is however worth recalling that 40 years ago Sir Arthur Newsholme correlated2 diphtheria epidemics in England, and many other countries, with deficient rainfall. Nevertheless, most authorities did not think that rainfall was a factor of consequence in determining fluctuations in diphtheria rates in comparison with variations in population density and environmental hygiene. No doubt these latter factors would have a greater effect than the weather on the periodicity of diphtheria, provided that they themselves varied. But during the last 20 years in England, environmental and hygienic conditions have, on the whole, improved or remained unchanged. Again Schick-test surveys made during the last decade have given no evidence of any significant decline in the mean susceptibility of the population to diphtheria. It is noteworthy that the very dry summer of 1921 was followed by many local outbreaks of diphtheria, and the present epidemics have materialised during the recent long 1 Anderson, J. S., Happold, F. C., McLeod, J. W., and Thomson, J. 2G.: Jour. Path. and Bact., 1931, xxxiv., 667. Epidemic Diphtheria, London, 1898.
PUBLIC HEALTH
172
deficient rainfall. There may well be in Newsholme’s theory ; dry weather may in some indirect way favour the dissemination of the more invasive strains of diphtheria bacilli. If this be so, the present predominance of the virulent " epidemic " types of C. diphtherice may be expected to subside gradually with the re-establishment of normal rainfall.
period of something
Cases and Carriers Far more diphtheria infections are caught from earriers than from cases of the disease, because the former so greatly outnumber the latter. Moreover although under identical conditions the case may be a more dangerous source of infection than the carrier, yet most cases are rendered harmless by being isolated in hospital, or at least immobilised in bed, while the vast majority of carriers remain undiscovered and wander freely among their fellows. Carriers are found to be infected with exactly the same types of bacilli that are found in the cases which are seen at the same time and place. Whether certain kinds of diphtheria bacilli are more prone to produce carriers rather than cases is not known with certainty ; but it is possible at one time to have a great prevalence of carriers accompanied by few diphtheria cases, and at another time to have a sharp outbreak of diphtheria with a relatively low carrierrate-although at both times the percentage of the population having positive Schick reactions is about the same. Certainly some of the " epidemic " strains of C. diphtherice which are now causing anxiety can produce just as high carrier-rates as are caused by any endemic strain which has been investigated. The carrier-rate depends on a host of known and unknown factors, but other things being equal the rate should be directly proportional to the percentage of the population which is Schick-immune. In practice it can be assumed that all carriers of virulent diphtheria bacilli have negative Schick reactions. On the other hand those in whom the Schick reaction remains positive are susceptible to diphtheria and cannot harbour virulent diphtheria bacilli for any length of time without exhibiting symptoms of the disease. The exceptions to this working rule are too few to invalidate the argument which follows. Further, a Schick-susceptible when attacked by virulent diphtheria bacilli often becomes Schick-immune so rapidly as to escape without noticeable symptoms. This phenomenon, known as latent immunisation, must occur more frequently than attacks of clinical diphtheria, because in urban areas there are only about one in six to one in ten persons who having acquired negative Schick tests have also had clinical diphtheria. There is yet another possibility. When attacked by a virulent diphtheria bacillus the Schick-susceptible may remain Schick-susceptible, but the virulent bacillus becomes "
"
avirulent., It is now easy to see that the greater the proportion of Schick-immunes in a community the greater will be the number of potential diphtheria carriers in that community. It is a peculiar fact that, while artificial active immunisation is an almost absolute protection against clinically recognisable diphtheria, it has no effect whatever in preventing subsequent carrier infection ; at the same time and place the virulent carrier-rate is just as high among the artificially immunised as among those with natural negative Schick tests. When a number of children in a school or community are made Schick-immune by inoculation with a diphtheria prophylactic, the density of virulent diphtheria carriers may be correspondingly increased.
Such an increase in the carrier-rate has been shown to have followed the artificial immunisation of at least one institution. The Individual and the Herd Should any increase in the density of diphtheria carriers follow on the protection of a part of the community, it will of necessity increase the risk of infection tb those who remain Schick-susceptible. This accounts for the well-established observation that an antidiphtheria campaign is in general followed by no significant fall in the diphtheria rates until over a certain percentage of the population has been immunised. American experience is definite on this point. Three years ago E. S. Godfrey showed3 that the incidence of diphtheria in all of ten American towns did not fall, even after 50 per cent. or more of the school-children had been immunised ; directly 30 per cent. of the pre-school children had been
protected, diphtheria practically disappeared.
Every
effort should therefore be made to inoculate children as young as possible, especially as the disease is so much more fatal at the pre-school age. For the same reason it is advisable to immunise all the susceptible children of the same household. If some are protected and others not, the former, should they subsequently become carriers, are liable to infect the latter under the intimate conditions of home life. The attitudes of the medical officer of health and general practitioner toward antidiphtheria inoculation should be somewhat different. The health authority wishes to reduce the number of diphtheria cases in his whole district. He must therefore prepare a scheme whereby he will ensure that enough children under 5 are protected to achieve this end. Otherwise if he conducts a half-hearted compaign, especially if it is limited to the school-children, he may fail to produce any favourable effect on the diphtheria rates, or conceivably increase them. The general practitioner need not be swayed by such considerations. Every individual has the right to have his children protected on request, even if the risk of infection to those whose parents are too ignorant, or too indifferent, to do likewise is increased thereby. Moreover, provided antidiphtheria inoculation is made available for everyone who demands it, the protection of sensible human stocks from the ravages of C. diphthei-ice at the expense of foolish human strains may commend itself on eugenic grounds.
Necessarily Immunisation pressing the artificial immunisation
Inoculation is not
The necessity of of young children becomes more urgent in view of the " fact that the illness, caused by some of the " epidemic strains of the diphtheria bacillus which are in evidence to-day, is relatively irresponsive to diphtheria antitoxin, unless it is given very early in large doses. If a child has been made Schick-immune it is practically safe from severe diphtheria, whatever the type of infecting bacillus. Admittedly mild cases of diphtheria do occasionally develop in subjects whose Schick test is negative. In such cases the causative organisms nearly always belong to the so-called gravis or intermediate varieties of C. diphtheria. Fatal or severe cases are practically unknown in those whose Schick reaction is known to have become It is, negative after antidiphtheria inoculation. however, quite improper to use the word " inoculated " as a synonym for " immunised " in antidiphtheria work. Some 5 to 10 per cent. of children, according to circumstances, are not made Schick3
Amer. Jour. Pub. Health, 1932, xxii., 237.
173
UNITED STATES OF AMERICA
immune by a single course of antidiphtheria inoculation. It is just those few children who, because of their inability to respond to the artificially introduced products of the diphtheria bacillus (toxoid, &c.), are the most likely to have a poor response to infection with the living diphtheria bacillus, and who are therefore most likely to contract a severe form of diphtheria. This is the great argument for using the Schick test after each course of inoculation, in order to find out if immunity has resulted, and, if it has not, to go on giving inoculations until Otherwise repeated the reaction becomes negative. of of severe cases diphtheria among children, reports who have been inoculated but never immunised, may cause antidiphtheria inoculation to fall into
disrepute. In a proportion
of successfully immunised children the Schick test may become positive again, but this is not of much consequence. Provided a child has once had a negative Schick reaction he has been sensitised against diphtheria toxin ; should he subsequently become infected with toxigenic diphtheria bacilli, even though his Schick reaction has relapsed to positive, he responds so rapidly and effectively that he generally escapes symptoms altogether, or only gets a trivial illness. This is not true of inoculated children in whom Schick immunity has never been successfully stimulated. For the sake of brevity and lucidity many of the questions touched on above have been dealt with dogmatically. For scientific exactitude some of the statements would require qualification. The evidence on which they are based is critically discussed in a recent report4 by S. F. Dudley, P. H. May, and J. A. O’Flynn to the Medical Research Council.
INFECTIOUS DISEASE IN ENGLAND AND WALES DURING THE WEEK JAN.
ENDED
5TH, 1935
Notifications.-The following cases of infectious disease were notified during the week : Small-pox, 0 ; scarlet fever, 2861 ; diphtheria, 1907 ; enteric fever, 17 ; acute pneumonia (primary or influenzal), 1029 ; puerperal fever, 43 ; puerperal pyrexia, 109 ; cerebro-spinal fever, 25 ; acute poliomyelitis, 8 ; acute polio-encephalitis, 2 ; encephalitis lethargica, 5 ; continued fever, 1 (Tottenham) ; dysentery, 12 ; ophthalmia neonatorum, 81. No case of cholera, plague, or typhus fever was notified during the week. The number of case" in the Infectious Hospitals of the London County Council on Jan. 14th-15th was as follows : Small-pox, 0 under treatment, 0 under observation ; scarlet fever, 1413 ; diphtheria, 2244 ; measles, 171 ; whooping-cough, 280 ; puerperal fever, 19 mothers (plus 7 babies) ; encephalitis lethargica, 268 ; poliomyelitis, 8 ; " other diseases," 290. At St. Margaret’s Hospital there were 18 babies (plus 11 mothers) with ophthalmia neonatorum.
Deaths.-In 121 great towns, including London, was no death from small-pox, 3 (0) from enteric fever, 3 (0) from measles, 5 (0) from scarlet fever, 8 (3) from whooping-cough, 65 (10) from diphtheria, 54 (13) from diarrhoea and enteritis under 2 years, and 54 (9) from influenza. The figures in parentheses are those for London itself. there
and Worcester each reported a fatal of enteric fever. There were 5 deaths from diphtheria at Liverpool, 4 each at Huddersfield and Leeds, 3 at Barking, each at East Ham, Southampton, Bradford, Burnley, Hull, Middlesbrough, Newcastle-on-Tyne, Oldham, Birmingham, and
Manchester, Leicester,
case
MerthyrTydfil. The number of stillbirths notified during the week was 246 (corresponding to a rate of 35 per 1000 total births), including 40 in London.
4Spec. Report
Series No. 195, H.M.
Stationery Office, 1934.
UNITED STATES OF AMERICA
(FROM
AN
OCCASIONAL
CORRESPONDENT)
THE SHOCKING WORD
SYPHILIS
THE National Advisory Council on Radio in Education has organised for the current radio season a course of lectures on "Doctors, Dollars, and Disease " dealing for the most part with problems of medical economics. An extra lecture in this course was delivered over the long-distance telephone by Sir Arthur Newsholme in London. The fifth lecture in this series was to be on the subject " Public Health Needs," by Dr. Thomas Parran, Jnr., health commissioner of New York State. Dr. Parran had prepared a manuscript in which the possibility of saving life from various diseases was reviewed, and amongst the causes of preventable disease he mentioned syphilis, devoting a short paragraph to the hopeful fact that syphilis can be prevented. At the last moment the Columbia broadcasting system insisted that syphilis must not be mentioned. Dr. Parran refused to cut out the paragraph and the address was not given. The Columbia system issued an explanation in the course of which they point out that " broadcasting reaches persons of widely varying age levels and reaches them in family and social groups." Dr. Parran retorts: "A hopeful view of relief from this dangerous malady might be more welcome to the half million persons in the United States who acquire this disease each year than the veiled obscenity permitted by Columbia in the vaudeville acts of certain of their commercial
programmes." The position taken by Columbia, while typical enough, is not adopted by all American broadcasting stations. Your correspondent has given more than one address over the air in which the word syphilis has been used freely and without objection. The newspapers also are becoming more liberal than in the past and syphilis may sometimes be found now even
in the headlines. HEALTH OF THE NEGRO
Dr. Louis I. Dublin has recently brought up to date and republished his study on the health of the negro (Metropolitan Insurance Co. Press, New York). The results of displacing the African negro to an entirely foreign geographical and social-environment are generally recognised to have had some serious physical consequences. Dr. Dublin shows that in 1930 the coloured death-rate in the United States was 82 per cent. higher than the white ; in the cities 95 per cent. higher. The most pronounced difference between white and coloured death-rates is found in the age-group 15-25 years, at which ages the death-rates for coloured males and for coloured females are respectively two and a half and three times those of the whites. In 1933 organic heart disease was the leading cause of death among coloured policy-holders of the company. Second came tuberculosis with a rate of 175-3, more than three times as high as the white death-rate from this cause. Syphilis is only prevalent among negroes and is much more important as a cause of death among them than amongst the white population. Against this unfavourable showing must be placed the remarkable decline in the mortality of the American negro that has taken place in the last two decades. The future holds out a bright prospect for him, so Dr. Dublin believes. The high mortality which he has suffered from such causes as tuberculosis, typhoid fever,
PUBLIC HEALTH THE
PROBLEM
OF
DIPHTHERIA
Prevalence A YEAR ago we drew attention1 to the sharp rise in diphtheria which took place during the autumn of 1933. The number of notifications was about 20 per cent. in excess of those received during the corresponding period of 1932, and, for each week, between 10 and 20 per cent. above the average (as measured by the median value) of the corresponding weeks of the preceding nine years. We then suggested that the incidence and mortality might be serious during the winter 1933-34, and this has proved to be true. Throughout the late winter and spring of 1934 the notifications remained at a high level but, more important, the usual summer decline of incidence was arrested, so that the excess of cases beyond expectation became higher at the season when prevalence is normally low. When the subsequent course of events is examined (Chart 1), it will be seen that there was again a rapid rise in prevalence from the already high minimum in August, 1934, and in the last two weeks of the year the number of notifications received has, in fact, exceeded expectation by 60 per cent. The actual number of notifications in the 118 great towns of England and Wales during 1934 was 44,367, as compared with 32,585 in 1933. For the whole country they numbered 69,009 as against 47,435 in the previous year, an increase of 45 per cent. The incidence is likely to fall after the end of January, but at what rate cannot be easily predicted. In passing it may be noted that scarlet fever has behaved in a similar way, this concurrence of the two diseases having been constantly observed but never satisfactorily explained. Recent experience cannot be seen in true perspective without reference to the past behaviour of diphtheria. The Registrar-General gives us each year a statement of the proportion of cases notified in England and Wales to the total estimated population of the country, and these rates are presented in Chart 2 for the years 1911 to 1933. During this period there were two waves of high prevalence, culminating respectively 1 THE LANCET, 1933, ii., 1288.
in 1920 and 1930, but the latter declined a little more rapidly than the former. While the interval between them was ten years, a notification-rate almost as high as either of them (1-7 per 1000) has been reached
CHART 2. COMPARATIVE PREVALENCE Notification-rates of diphtheria per 1000 of population during the years 1911 to 1933. (From the Registrar-General’s Statistical Review.)
in 1934-i.e., within the short spell of four years. It is very unlikely that the rise will be continued for a further six years-if it were, public health departments would be faced with a grave problem-but it is at least probable that 1935 will not see any marked abatement. To illustrate what these notification-rates mean, we have charted them also for two areas where they have tended in recent years to be higher than in the whole country-viz., London and the Welsh county boroughs. The consistently high rates in London during the post-war years are attributed by the Registrar-General rather to better observance
of
the
statu-
tory duty of notification than to any pronounced excess of prevalence, and this contention is borne out by the crude fatality-rates based upon deaths and notifications in London which are consistently lower than elsewhere. So far as Wales is concerned, however, this does not appear to be the case, and the principality seems to than have been more usually affected since 1928.
Mortality While Chart 2 shows
no
CHA.RT 1. GENERAL PREVALANCE
pronounced tendency on the part of notification-
Notifications of diphtheria in the 118 great towns of England and Wales in each week from August 5th, 1933, to December 29th, 1934. (From the Registrar-General’s Weekly Returns.)
rates to fall during the last 23 years, a similar illustration (Chart 3) of the death-
PUBLIC HEALTH
rates from diphtheria in England and Wales, although it has peaks corresponding with those of Chart 2, shows the mortality during the last ten years to be much lower than the prevalence would have led It is difficult to say how much of this us to expect. in fall fatality is due to better notification apparent
illustrated 118
great
171
by the deaths-to-notifications rates in the towns during 1932, 1933, and 1934 :-
proportion is definitely, if not strikingly, increasing. It is possible therefore that diphtheria is taking The
a rather more serious form. Even if any increase of virulence were only slight, its association with a continued rise in prevalence would swell the death-rate from the disease. The actual number of deaths in England and Wales during 1934 is not yet available, but if they have increased in the same proportion as in the great towns they will exceed anything recorded during the last ten years, and this in spite of a steady fall in the number of children at the most susceptible ages.
The Seed and the Soil
CHART 3. DEATH-RATE IN THE YOUNGER POPULATION Deaths from diphtheria and croup in England and Wales per million under 15 years of age from 1911 to 1933.
and the use of bacteriological aids to diagnosis, how much to better treatment or how much to a real decline in virulence. The present epidemic may afford evidence which will help to a conclusion. At present we can only record the facts as they appear in statistical returns. A rough-and-ready measure of the fatality of the disease from year to year may be found in the number of deaths per 1000 notifications in England and Wales (Chart 4). Here the impression gained from examination of the notification- and death-rates is confirmed. The rate during the war years appears inflated owing to defective notification as a result of
CHART 4. CASE MORTALITY
Deaths from diphtheria in England and Wales per thousand notified cases from 1911 to 1931.
the absence of a large proportion of practitioners on service. If however the decline were entirely due to improved notification, it should be continuous or at least the rate should not increase, since any falling off in this respect is now unlikely to occur. A slight upward tendency since 1930 may therefore be genuine evidence of an increase of virulence which is reported from some parts of the country. The point is further
In certain parts of Great Britain and Ireland there has been, as remarked above, an increase in the severity as well as in the amount of diphtheria. Anderson, McLeod, and their colleagueswere the first to show (1931) that the exacerbation of diphtheria morbidity and fatality at Leeds was associated with. an increased prevalence of special types of diphtheria bacilli-and observation since confirmed in many other localities. It now becomes justifiable to explain variations in the clinical picture, complications, and epidemiological phenomena by observed changes in the types of infecting organisms ; one need no longer assume that these variations are caused wholly by unobserved changes in the susceptibility or environment of the human community. The demonstration that severe and epidemic diphtheria tends to be associated with one type of diphtheria bacillus, mild and endemic diphtheria with another kind, is a notable step forward in the epidemiology of the disease. This advance is quite independent of any claim that the epidemic " virulent variants (so-called gravis) and the endemic " milder (so-called mitis) types of diphtheria bacilli are constant in their cultured character or other attributes, when and wherever they are encountered. Why, at certain intervals and places, the more infective and invasive strains of diphtheria bacilli should appear, or originate from milder endemic strains, is not known. It is however worth recalling that 40 years ago Sir Arthur Newsholme correlated2 diphtheria epidemics in England, and many other countries, with deficient rainfall. Nevertheless, most authorities did not think that rainfall was a factor of consequence in determining fluctuations in diphtheria rates in comparison with variations in population density and environmental hygiene. No doubt these latter factors would have a greater effect than the weather on the periodicity of diphtheria, provided that they themselves varied. But during the last 20 years in England, environmental and hygienic conditions have, on the whole, improved or remained unchanged. Again Schick-test surveys made during the last decade have given no evidence of any significant decline in the mean susceptibility of the population to diphtheria. It is noteworthy that the very dry summer of 1921 was followed by many local outbreaks of diphtheria, and the present epidemics have materialised during the recent long 1 Anderson, J. S., Happold, F. C., McLeod, J. W., and Thomson, J. 2G.: Jour. Path. and Bact., 1931, xxxiv., 667. Epidemic Diphtheria, London, 1898.
PUBLIC HEALTH
172
deficient rainfall. There may well be in Newsholme’s theory ; dry weather may in some indirect way favour the dissemination of the more invasive strains of diphtheria bacilli. If this be so, the present predominance of the virulent " epidemic " types of C. diphtherice may be expected to subside gradually with the re-establishment of normal rainfall.
period of something
Cases and Carriers Far more diphtheria infections are caught from earriers than from cases of the disease, because the former so greatly outnumber the latter. Moreover although under identical conditions the case may be a more dangerous source of infection than the carrier, yet most cases are rendered harmless by being isolated in hospital, or at least immobilised in bed, while the vast majority of carriers remain undiscovered and wander freely among their fellows. Carriers are found to be infected with exactly the same types of bacilli that are found in the cases which are seen at the same time and place. Whether certain kinds of diphtheria bacilli are more prone to produce carriers rather than cases is not known with certainty ; but it is possible at one time to have a great prevalence of carriers accompanied by few diphtheria cases, and at another time to have a sharp outbreak of diphtheria with a relatively low carrierrate-although at both times the percentage of the population having positive Schick reactions is about the same. Certainly some of the " epidemic " strains of C. diphtherice which are now causing anxiety can produce just as high carrier-rates as are caused by any endemic strain which has been investigated. The carrier-rate depends on a host of known and unknown factors, but other things being equal the rate should be directly proportional to the percentage of the population which is Schick-immune. In practice it can be assumed that all carriers of virulent diphtheria bacilli have negative Schick reactions. On the other hand those in whom the Schick reaction remains positive are susceptible to diphtheria and cannot harbour virulent diphtheria bacilli for any length of time without exhibiting symptoms of the disease. The exceptions to this working rule are too few to invalidate the argument which follows. Further, a Schick-susceptible when attacked by virulent diphtheria bacilli often becomes Schick-immune so rapidly as to escape without noticeable symptoms. This phenomenon, known as latent immunisation, must occur more frequently than attacks of clinical diphtheria, because in urban areas there are only about one in six to one in ten persons who having acquired negative Schick tests have also had clinical diphtheria. There is yet another possibility. When attacked by a virulent diphtheria bacillus the Schick-susceptible may remain Schick-susceptible, but the virulent bacillus becomes "
"
avirulent., It is now easy to see that the greater the proportion of Schick-immunes in a community the greater will be the number of potential diphtheria carriers in that community. It is a peculiar fact that, while artificial active immunisation is an almost absolute protection against clinically recognisable diphtheria, it has no effect whatever in preventing subsequent carrier infection ; at the same time and place the virulent carrier-rate is just as high among the artificially immunised as among those with natural negative Schick tests. When a number of children in a school or community are made Schick-immune by inoculation with a diphtheria prophylactic, the density of virulent diphtheria carriers may be correspondingly increased.
Such an increase in the carrier-rate has been shown to have followed the artificial immunisation of at least one institution. The Individual and the Herd Should any increase in the density of diphtheria carriers follow on the protection of a part of the community, it will of necessity increase the risk of infection tb those who remain Schick-susceptible. This accounts for the well-established observation that an antidiphtheria campaign is in general followed by no significant fall in the diphtheria rates until over a certain percentage of the population has been immunised. American experience is definite on this point. Three years ago E. S. Godfrey showed3 that the incidence of diphtheria in all of ten American towns did not fall, even after 50 per cent. or more of the school-children had been immunised ; directly 30 per cent. of the pre-school children had been
protected, diphtheria practically disappeared.
Every
effort should therefore be made to inoculate children as young as possible, especially as the disease is so much more fatal at the pre-school age. For the same reason it is advisable to immunise all the susceptible children of the same household. If some are protected and others not, the former, should they subsequently become carriers, are liable to infect the latter under the intimate conditions of home life. The attitudes of the medical officer of health and general practitioner toward antidiphtheria inoculation should be somewhat different. The health authority wishes to reduce the number of diphtheria cases in his whole district. He must therefore prepare a scheme whereby he will ensure that enough children under 5 are protected to achieve this end. Otherwise if he conducts a half-hearted compaign, especially if it is limited to the school-children, he may fail to produce any favourable effect on the diphtheria rates, or conceivably increase them. The general practitioner need not be swayed by such considerations. Every individual has the right to have his children protected on request, even if the risk of infection to those whose parents are too ignorant, or too indifferent, to do likewise is increased thereby. Moreover, provided antidiphtheria inoculation is made available for everyone who demands it, the protection of sensible human stocks from the ravages of C. diphthei-ice at the expense of foolish human strains may commend itself on eugenic grounds.
Necessarily Immunisation pressing the artificial immunisation
Inoculation is not
The necessity of of young children becomes more urgent in view of the " fact that the illness, caused by some of the " epidemic strains of the diphtheria bacillus which are in evidence to-day, is relatively irresponsive to diphtheria antitoxin, unless it is given very early in large doses. If a child has been made Schick-immune it is practically safe from severe diphtheria, whatever the type of infecting bacillus. Admittedly mild cases of diphtheria do occasionally develop in subjects whose Schick test is negative. In such cases the causative organisms nearly always belong to the so-called gravis or intermediate varieties of C. diphtheria. Fatal or severe cases are practically unknown in those whose Schick reaction is known to have become It is, negative after antidiphtheria inoculation. however, quite improper to use the word " inoculated " as a synonym for " immunised " in antidiphtheria work. Some 5 to 10 per cent. of children, according to circumstances, are not made Schick3
Amer. Jour. Pub. Health, 1932, xxii., 237.
173
UNITED STATES OF AMERICA
immune by a single course of antidiphtheria inoculation. It is just those few children who, because of their inability to respond to the artificially introduced products of the diphtheria bacillus (toxoid, &c.), are the most likely to have a poor response to infection with the living diphtheria bacillus, and who are therefore most likely to contract a severe form of diphtheria. This is the great argument for using the Schick test after each course of inoculation, in order to find out if immunity has resulted, and, if it has not, to go on giving inoculations until Otherwise repeated the reaction becomes negative. of of severe cases diphtheria among children, reports who have been inoculated but never immunised, may cause antidiphtheria inoculation to fall into
disrepute. In a proportion
of successfully immunised children the Schick test may become positive again, but this is not of much consequence. Provided a child has once had a negative Schick reaction he has been sensitised against diphtheria toxin ; should he subsequently become infected with toxigenic diphtheria bacilli, even though his Schick reaction has relapsed to positive, he responds so rapidly and effectively that he generally escapes symptoms altogether, or only gets a trivial illness. This is not true of inoculated children in whom Schick immunity has never been successfully stimulated. For the sake of brevity and lucidity many of the questions touched on above have been dealt with dogmatically. For scientific exactitude some of the statements would require qualification. The evidence on which they are based is critically discussed in a recent report4 by S. F. Dudley, P. H. May, and J. A. O’Flynn to the Medical Research Council.
INFECTIOUS DISEASE IN ENGLAND AND WALES DURING THE WEEK JAN.
ENDED
5TH, 1935
Notifications.-The following cases of infectious disease were notified during the week : Small-pox, 0 ; scarlet fever, 2861 ; diphtheria, 1907 ; enteric fever, 17 ; acute pneumonia (primary or influenzal), 1029 ; puerperal fever, 43 ; puerperal pyrexia, 109 ; cerebro-spinal fever, 25 ; acute poliomyelitis, 8 ; acute polio-encephalitis, 2 ; encephalitis lethargica, 5 ; continued fever, 1 (Tottenham) ; dysentery, 12 ; ophthalmia neonatorum, 81. No case of cholera, plague, or typhus fever was notified during the week. The number of case" in the Infectious Hospitals of the London County Council on Jan. 14th-15th was as follows : Small-pox, 0 under treatment, 0 under observation ; scarlet fever, 1413 ; diphtheria, 2244 ; measles, 171 ; whooping-cough, 280 ; puerperal fever, 19 mothers (plus 7 babies) ; encephalitis lethargica, 268 ; poliomyelitis, 8 ; " other diseases," 290. At St. Margaret’s Hospital there were 18 babies (plus 11 mothers) with ophthalmia neonatorum.
Deaths.-In 121 great towns, including London, was no death from small-pox, 3 (0) from enteric fever, 3 (0) from measles, 5 (0) from scarlet fever, 8 (3) from whooping-cough, 65 (10) from diphtheria, 54 (13) from diarrhoea and enteritis under 2 years, and 54 (9) from influenza. The figures in parentheses are those for London itself. there
and Worcester each reported a fatal of enteric fever. There were 5 deaths from diphtheria at Liverpool, 4 each at Huddersfield and Leeds, 3 at Barking, each at East Ham, Southampton, Bradford, Burnley, Hull, Middlesbrough, Newcastle-on-Tyne, Oldham, Birmingham, and
Manchester, Leicester,
case
MerthyrTydfil. The number of stillbirths notified during the week was 246 (corresponding to a rate of 35 per 1000 total births), including 40 in London.
4Spec. Report
Series No. 195, H.M.
Stationery Office, 1934.
UNITED STATES OF AMERICA
(FROM
AN
OCCASIONAL
CORRESPONDENT)
THE SHOCKING WORD
SYPHILIS
THE National Advisory Council on Radio in Education has organised for the current radio season a course of lectures on "Doctors, Dollars, and Disease " dealing for the most part with problems of medical economics. An extra lecture in this course was delivered over the long-distance telephone by Sir Arthur Newsholme in London. The fifth lecture in this series was to be on the subject " Public Health Needs," by Dr. Thomas Parran, Jnr., health commissioner of New York State. Dr. Parran had prepared a manuscript in which the possibility of saving life from various diseases was reviewed, and amongst the causes of preventable disease he mentioned syphilis, devoting a short paragraph to the hopeful fact that syphilis can be prevented. At the last moment the Columbia broadcasting system insisted that syphilis must not be mentioned. Dr. Parran refused to cut out the paragraph and the address was not given. The Columbia system issued an explanation in the course of which they point out that " broadcasting reaches persons of widely varying age levels and reaches them in family and social groups." Dr. Parran retorts: "A hopeful view of relief from this dangerous malady might be more welcome to the half million persons in the United States who acquire this disease each year than the veiled obscenity permitted by Columbia in the vaudeville acts of certain of their commercial
programmes." The position taken by Columbia, while typical enough, is not adopted by all American broadcasting stations. Your correspondent has given more than one address over the air in which the word syphilis has been used freely and without objection. The newspapers also are becoming more liberal than in the past and syphilis may sometimes be found now even
in the headlines. HEALTH OF THE NEGRO
Dr. Louis I. Dublin has recently brought up to date and republished his study on the health of the negro (Metropolitan Insurance Co. Press, New York). The results of displacing the African negro to an entirely foreign geographical and social-environment are generally recognised to have had some serious physical consequences. Dr. Dublin shows that in 1930 the coloured death-rate in the United States was 82 per cent. higher than the white ; in the cities 95 per cent. higher. The most pronounced difference between white and coloured death-rates is found in the age-group 15-25 years, at which ages the death-rates for coloured males and for coloured females are respectively two and a half and three times those of the whites. In 1933 organic heart disease was the leading cause of death among coloured policy-holders of the company. Second came tuberculosis with a rate of 175-3, more than three times as high as the white death-rate from this cause. Syphilis is only prevalent among negroes and is much more important as a cause of death among them than amongst the white population. Against this unfavourable showing must be placed the remarkable decline in the mortality of the American negro that has taken place in the last two decades. The future holds out a bright prospect for him, so Dr. Dublin believes. The high mortality which he has suffered from such causes as tuberculosis, typhoid fever,