HISTORY AND EPIDEMIOLOGY OF INFLUENZA
ByJames I. Johnston, M. D.
ByJames I. Johnston, M. D.
ByJames I. Johnston, M. D.
The history of epidemic influenza extends back with definite authenticity to the Middle Ages, with a fair amount of assurance to the beginning of the Christian Era and with presumptive reliability even before that period. Beyond this statement, nothing definite can be said until the first epidemic reported by Short and found in the English Annals in the year 1510. This, the first reliable record, presented some features not unlike those occurring in the present epidemic. Two or three striking things stand out in this record—namely, the presence of nose bleed, pneumonia and the very great danger to gravid women. Here, for the first time, the meteorological conditions were elaborately studied and persistently dwelt upon. One other impressive thing, also reported by Short, was that in 1580 the disease showed a tendency to return after a period of quiescence. Attention is called to this because the epidemic, while it was exceedingly prevalent in the months of August and September, became pandemic in October and November. Another feature was that during the years intervening between 1580 and 1658 sporadic cases of this disease were frequently reported. During the latter year another epidemic appeared in the month of April. In 1657 and 1658 at London the summer was very warm, the winter came on early, there was much snow and the spring was very moist.
The prevailing opinion at this time, and the first stated by Willis, was that the widespread disease was due to the weather influences on the circulation, poisoning the blood of the patients, and “not blasts of malignant air.” The disease prevailed in the large cities, recurring again in the autumn in an extensive form through the villages and country. Sydenham, in his communication on the epidemic in 1675, wrote emphatically on the influence of the infection on pregnant women, and here used the term “tussis epidemicus” as a name for the disease. The summer of 1675 was wet with an inconstant autumn. La Grippe prevailed inFrance and Germany, according to Atmuller. In England in 1676, the autumn was pleasant, but suddenly became cold and moist. La Grippe then started in Germany during September after a summer and a beginning autumn which was very rainy. Molyneux in his description of the epidemic of 1693 in Dublin called attention to a feature, very striking to the recent pandemic, that the aged to a great extent escaped the infection. This would seem a somewhat unique feature until that epidemic is compared with the present one. In 1729 Morgagni and others stated that over all Europe the winter of 1728 was very rigorous, the spring was cold and the summer and autumn very variable, while January and February of that year were very moist. Huxham in his record of 1729, the fifth extensive one on record in the English Annals, which extended into 1733, stated from his study at Plymouth that the epidemic was exceedingly mild in the year 1733, and, with the exception of infants and consumptive old people, the mortality was very low. Like many of his predecessors, he emphasized greatly the conditions of the weather at the time and presented an elaborate study of it. The epidemic of 1732 was one of the longest and most persistent, extending up to 1737. All authors do not hesitate to attribute as a cause the very frequent variations of temperature which characterized this period. Of this epidemic Arbuthnot also emphasized the importance of the air, assigning the prevalence and widespread features of the disease to the thick and frequent fogs. From November, 1732, until March, 1733, this disease spread from Germany to Italy and thence to England. He called attention to a very striking feature—namely, that people in prisons and in hospitals escaped the disease. This, as we know, where such institutions are placed under preventive quarantine, is not such a unique feature during this present scourge. He, more than former writers, devoted pages to the elaborate and accurate description of instruments for meteorological observation and their findings, which meteorological records were published in detail, covering the whole period of a year—June, 1732, to June, 1733—with almost daily regularity. Huxham in 1737 in his record first used the term “epidemic catarrhal fever”—a name often used subsequently to describe this disease. Here attention was first called to the prostration which characterized the convalescents, and his belief that consumption frequently followed the disease. Thenext epidemic, which occurred in 1742 and 1743, was also reported by Huxham, who stated that the weather was very rigorous. This disease, according to his description, extended over all Europe, and the term “influenza” seems to have been first used by him during this time. The cases were mild in England, but more severe in Southern Europe. Whytt in his record of the epidemic of 1758 was the first who did not consider that the air condition or the seasons had the significance attributed to them by former writers, since the weather conditions during the prevalence of the disease were generally mild and dry. In Edinburgh at this time not even one out of seven escaped. Nevertheless, he did not hesitate to express his opinion that the disease did not spread by contagion from one person to another. One other observation of his is worthy of note, which is: that frequent relapses occurred when patients were re-exposed too soon after the first infection and such relapses were much more severe than the original disease.
The epidemic of 1762 called forth the opinion of Baker, emphasizing an opinion already expressed by Whytt, that the origin of epidemic disease is not due to changeable winds nor to their nature or character as recorded by the barometer. This epidemic also prevailed over all Europe and appears to have begun following sharp alterations of cold and moisture. In 1766 in Spain, France and other parts of Europe the epidemic appears to have begun after a warm summer, followed by an autumn moist and cold. In 1767 Heberden placed on record his observations during this period, but nothing new was reported. In 1775 the disease began in Germany in the summer after a dry and warm spring and spread over all Europe. During the prevalence of the disease in 1775 a questionnaire was sent to the leading English physicians, and letters from Fothergill, Sir John Pringle, Heberden, Reynolds and others seemed to express a consensus of opinion that weather conditions had nothing to do with the prevalence or spread of the disease, and that the cause and reason for its spread were unknown. Following sharp alterations in temperature in 1780, the disease appeared in France and then throughout the world. The epidemic of 1782 began in Russia, starting January 2 at St. Petersburg. The thermometer underwent a variation of 40 degrees and the same day 4,000 were afflicted with La Grippe. It reached Koenigsburg in March, Copenhagen in April, London in May, France in June and July, Italy in July and August, Spainand Portugal in August and September, and then reached America. Edward Gray, writing of the epidemic of 1782 for the first time, expressed emphatically his opinion on the contagiousness of the disease and stated what we now know—that close contact is necessary. To him also is attributed the opinion first mentioned by him, that there is a possibility of carriers in this disease. During this time Dr. Hamilton, in a published letter, protested against venesection in influenza, a practice long prevalent, and Hogarth called attention to the fact that the disease began in cities and villages first and that it was brought to these places by visitors from without.
The first American writer on this subject was Noah Webster in 1647 and 1655. Following him was Warren, writing of the epidemic of 1789 and 1790, just 100 years before the last and greatest epidemic which preceded the present one. Rush and Drake also reported this epidemic. During that epidemic which prevailed in America from September to December, 1789, and appeared again in the spring of 1790, President Washington suffered a very severe attack. The year before, in 1788, when the epidemic prevailed abroad, the summer temperature in Paris was very variable, variations of 8, 10 and 12 degrees occurring on various days. La Grippe predominated all the time. The same variations were true in Vienna. At the end of the year 1799 the epidemic struck Russia, following very cloudy, misty weather, was prevalent in Lithuania in January of the year 1800 and in Poland during February.
The next great epidemic occurred in 1802 and 1803, was very general, beginning in France and coinciding with a cold and moist autumn following a very dry summer. It was of six months’ duration in England. Many schools, jails, asylums and workhouses, although located in the area swept by this plague, at first escaped. As mentioned before, this striking feature has not been so unique in subsequent epidemics. One feature noticed here and commented upon freely was that elsewhere throughout the country there seemed to arise endemic foci. During this time there was also the prevailing belief that the disease was followed by phthisis. One other observation made here, which was accurate, lasting and is accepted today, was that no family was affecteden masse, but always one individual case occurred first, to be followed by general infection of the others. At this timeearly bleeding was still adhered to. The French spoke of seven varieties of the disease, but one can only see in the classification emphasis laid on certain individual symptoms in this disease of complex symptomatology. During this epidemic pneumonia is said to have been very infrequent. The disease was particularly fatal to pregnant women, and the patients suffering from pulmonary tuberculosis were hurried off by the influenza.
Burns, writing of the epidemic of 1831, mentioned that in 1810 the disease was very widespread in China and Manila, and also emphasized the fact mentioned in many works that certain epidemics prevailed among animals at the same time, stating that in 1831 these diseases were of choleric nature. This epidemic began in 1830 in the East, reached Paris in the summer of 1831, reappeared in Europe in 1833, following the same route that cholera had taken in 1832. In the epidemic of 1833, Hingeston also laid great stress on the fact that horses were often affected. These features, as mentioned by Burns and Hingeston, are frequently quoted by authors, and such observations seem to have been widely accepted.
One of the greatest epidemics of influenza began in 1836 and extended until 1837, and was called at this time epidemic catarrh. It began in England in January, spread to France, and during all the time that it was in Paris there were continual penetrating rains with cold and humidity. At Montpelier on February 20, 1837, the thermometer passed from 12 to 15 degrees above to 2 and 3 degrees below zero, and it was then that La Grippe appeared suddenly. In reply to the circular letter sent out by the Council of the Provincial Medical Association of England, comprising 18 questions, the following opinions prevailed. The disease was greatest from September to February; the great prevalence of the epidemic in all parts of the kingdom was recognized—attacks were irrespective of age, sex or temperament; it was milder in children, and the aged suffered most from it. Further, the disease was extensive in all neighborhoods; the mortality was 1 in 50, old age predisposed to fatal termination, and the duration of the disease occupied two periods, one terminating in 4 or 5 days and one in 5 to 14 days. Also relapses were frequent; those exposed to employment in the open air were not more liable to the disease than others; there was no proof of the disease being communicated from one person to another, and influenzaaggravated an existent pneumonia or pulmonary phthisis. And finally previous attacks of influenza offered no protection; the symptoms were uniform; the most common of unusual symptoms were those of meningitis, inflammation of the lungs and syncope, and aside from ordinary care and treatment, general venesection was not endorsed. Evidence of fine weather and good telluric conditions were at this time also appended. The same symptoms and complications, particularly those of the lungs, occurred irrespective of seasons, civilization or place. It was believed and stated that the plague described in Homer was probably influenza. For the first time there is noticed here a point well worth consideration—the association of other epidemics with influenza, either anticipating, following or superseding. That some such association may follow the present pandemic is not to be entirely ignored. For example, cholera is already reported as prevailing abroad, following an earlier influenza outbreak. During the period, as if anticipating bacteriology, one writer explained the epidemic in an article called “The Dust of Regular Winds,” and Groves (1850) wrote on “Epidemics Examined, or Living Germs as a Source of Disease.”
In 1846 and 1847 a slight epidemic occurred in London, Paris, Nancy and Geneva. In France during the last week of 1857, and extending into January and February, 1858, there was a mild epidemic. During this period there alternated frequent frosts with soft weather, misty and humid. Among the numerous small epidemics between 1837 and 1889, one occurred on the continent of Europe in 1860, but little of value or interest was noted. In Paris in March, after great and sharp variations in temperature, a series of epidemics extended from 1870 to 1875. These were unimportant. Atmospheric modifications occupied first rank in the minds of some as a cause for the outbreaks. Rapid changes from hot to cold or from cold to hot were given weight. Other undetermined modifications of conditions were probably important.
In a recent article published by Loy McAfee (J. A. M. A., 1917, 72, 445) he discussed the confusion which existed between the diagnosis of cerebro-spinal meningitis and epidemic influenza in 1863. These were believed the same by some—that is, the same disease of varying degree. There was a great diversity of opinion among clinicians at this time, and the American Medical Associationappointed a committee to make an investigation. McAfee quotes from the Medical and Surgical History of the War of the Rebellion that in 1861 and 1862 an epidemic existed among the troops called epidemic catarrh, which was afterward changed to read acute bronchitis. In September, 1861, there existed an epidemic of influenza in one of the regiments which lasted more than two weeks, and in another camp there was a similar epidemic at the same time. It is stated that there were in all 168,715 cases among the white troops, with a mortality of 650, and 22,648 among the negro troops, with a mortality of 255, making about 4 per thousand, and over 11 per thousand, respectively.
The next great epidemic, and the last until the present, occurred in the years 1889 and 1892, and was pandemic in its nature. The death rate during this time was lower in the cities than in the country. This was probably due to the fact that the greatest mortality was among children and old people, and as old people were generally left in the country, this explains the observation. The highest number of deaths was among males, believed to be due to the exposure and fatigue of work. Forty per cent. of the world’s population was said to have been attacked during this period. The yearly or seasonal repetition, as shown in this pandemic, had occurred in other epidemics. In the great pandemic of 1889 and 1890, five decades after the last important epidemic, it was stated that the medical profession found itself confronted by a new disease of which it had knowledge through medical history, so also in our time few physicians recognized at first the reappearance of influenza. This 1889 epidemic is extensively reported in the literature, and has been elaborately worked out by many observers. One important feature has been emphasized by Leichtenstern, which, although recognized by the profession after the last epidemic had been fully reported and recorded, is not appreciated by the profession during the present epidemic—namely, that while shortly after the last epidemic there were smaller relightings of the infection throughout various parts of the country, those diseases which we erroneously call grippe or influenza, occurring commonly in the spring and fall, are in no way connected with the disease with which we are dealing, and which occurs at rather long intervals. Any speculation in regard to these periods, which history has shown to be fairly wide apart, has very little basis. This pandemic, likemany of former days, is believed to have originated in Asia, and from there to have spread over Europe and hence over the world. The disease spread rapidly over countries, affected probably about 40 per cent. of the world’s population, disappeared rapidly after several weeks, was thought to have had nothing to do with weather conditions, had a great morbidity but small mortality, and affected all ages and occupations. There is no doubt, as stated by some, that the development of traffic and travel was a large factor in the rapid and extensive spread of influenza during this pandemic. The course which the disease followed, springing from its supposed beginning in Asia, has been fully and amply described by writers after that period, but the great rapidity of its dissemination over all countries is the most remarkable feature in the epidemiology of any disease. This, during 1889, made many prominent physicians disregard the opinion that influenza spread by contagion and accept again the opinion expressed by observers of epidemics in former ages, that miasma as a pathogenic agent was responsible for its distribution; but anyone who reads closely the history of this epidemic, and in the light of modern medical science, must feel that the rapidity of distribution was nowhere greater than the most speedy means of transportation. This very necessary close connection was demonstrated also in regard to the mode of spread of the disease; the large cities and the commercial centers were affected earlier, smaller and country districts followed later, railroad towns were more frequently attacked than isolated villages, and even from jails, prisons and workhouses, where quarantine was immediately attempted, as well as from remote villages where the disease had been brought, there could be traced a zone of infection spreading into the country. One interesting point was raised at this time—namely, that in some places it seemed to spread by leaps and bounds, and at other places radiating as stated above.
The old controversy of whether influenza is distributed in a radiating manner or in so-called leaps and bounds is believed to be settled by consensus of opinion that it occurs in both ways. An opinion expressed by the study at this time as to whether influenza spreads more rapidly than any other infectious disease is found in the statement that the contagion is markedly virulent, the micro-organisms are easily conveyed from their original seatin the mucous membrane by coughing, sneezing and expectoration, the great number of persons who, though slightly affected, carried on their ordinary way of life without hindrance, the probable longevity of the organisms in convalescents, the brief period of incubation of two or three days, the susceptibility of all people of every age and vocation, and the possibility of carrying the contagion by merchandise and even through short distances in the air, are all suggestive reasons for this. No one at present accepts the so-called miasmatic nature of the contagion. Proofs are ample to show that one case must be present in a locality or even family, although it may be frequently overlooked, from which the epidemic spreads. During this period of 1889 and 1890 the duration of the actual epidemic period in different localities in Europe was from four to six weeks. This was subsequently shown to be consistent with the recorded reports from the various cities in the United States. Following this pandemic in the first part of the year in 1891 there were numerous epidemic outbreaks in various parts of America, including New Orleans, Chicago, Boston, and simultaneously in England. Strange to say, at this time neither Germany nor France had such epidemics, although both were exposed by travelers, particularly from England and America. The question was raised at that time whether the Germans, French or other continental nations were more immune than Americans and English. In the fall of 1891 and the entire winter of 1892 the disease was extensively prevalent both in Europe and Northern America. In these later epidemics there was no definite direction of spread. They probably would come more clearly under the so-called radiation from numerous rural districts. In almost every case at the point of its origin in these countries the epidemic developed and spread slowly, lasting months and with very varying morbidity and mortality. They had none of the explosive characteristics of the pandemic. The general diminished morbidity of the later epidemic, the diminished geographic distribution of the disease and the scarcely recognizable character of its contagion, its slow development and extension over several months, the continuous diminution in frequency and in intensity since its onset in 1889, have been explained by presumptive successive lessening of susceptibility of the population, possibly due to acquired immunization. Observers at that time, as well as ourselves, could question this last statement.
There was observed one noteworthy thing about seasons. While the great pandemic of 1889 and 1890 had no definite connection with seasons, the epidemic types which followed in 1891 and 1892 seemed to show a lighting up in either spring or fall, remaining dormant in the summer months. It has also been shown by the history of former epidemics that almost all the pandemics started from Russia in the fall, winter and spring months. Such was the case in 10 of the great pandemics of 1729 to 1889. This, no doubt, was the reason so many of the former historical writers were impressed by seasons and meteorological conditions. The statement made by observers during the epidemic that influenza presented two phases, one pandemic and the other endemic, and that each follows different epidemiological rules, seems possible. The question raised during the last epidemic of the spread of the disease in families, the disease occurring at high altitudes and even at sea, we know does not interfere with the recognition of its spread by direct contagion. Definite examples of families or villages being infected by a returned member of such family or citizen from abroad are reported frequently, and even the appearance of the disease in isolated places has often been traced and verified from a definite source, to say nothing of the question of carriers and those supposed to be suffering from other diseases.
Striking examples are shown also in this epidemic that many institutions, frequently those isolated from the world, were markedly exempt until, through servants or outside visitors, the disease gained access to them. This gave a most favorable field for the study of invasion, spread and decline of the disease. Observations made at this time in regard to hospitals seemed to suggest that certain institutions were more or less exempt, although not closed institutions, while others suffered from the first. These two types of hospital invasion are hard to reconcile.
Great stress was laid in this epidemic upon the very great morbidity and the low mortality. Simple, uncomplicated influenza at this time was looked upon as a disease that was rarely dangerous to life. Studies have shown that after this period there seemed to have been lessened morbidity. As previously stated, nearly all the numerous pandemics at various times have had their origin in Russia and arose in the late autumn or winter months. This pandemic of 1889 and the succeeding severe epidemicsin Europe and North America in the years of 1891 and 1892 occurred almost exclusively in the cold weather, the summer remaining free. It is generally believed now, and was at the end of that pandemic, that atmospheric or telluric conditions had nothing to do with the spread. The origin of epidemics following the pandemics seemed to be influenced in their recurrence by the season of the year. It was conceded by observers in that pandemic also that contagion might be carried by merchandise and even flies and healthy individuals.
In the city of Boston during the week ending August 28, at the Naval Station at the Commonwealth Pier, 50 cases of influenza occurred and within the next two weeks more than 2,000 were reported in the naval forces of the First Naval District. Of these 5 per cent. developed broncho-pneumonia with a mortality of more than 60 per cent. From here it probably spread to Camp Devens and thence ran rapidly over the country. There can hardly be a question that it spread along the lines of traffic. Up to November 9 there were reported 3,339 cases among the civilian population of Boston. There were 3,430 deaths from influenza, the presumption being that these were due to bronchial pneumonia, although not reported as such. The deaths from all forms of pneumonia were reported as 942, making in all 4,372 deaths from September 7 to November 9. This discrepancy—that is more deaths than reported cases of influenza—is due to the fact that influenza was not made a reportable disease until the date of October 4, fully a month from the time the epidemic appeared. The weather conditions were generally fair and no noted abnormality is recorded as compared with other years. The statement of the Health Department of this city was that, after a practical disappearance of influenza in October, there was a slight recurrence in November and a more pronounced recurrence about the first of December, since which time the cases have slowly but steadily decreased, until at present—December 21—the fatalities attributable to influenza are about 20 daily.
In the city of New York the epidemic first appeared September 18. Up to and including December 27 there were reported to the Department of Health 136,061 cases of influenza and 21,388cases of pneumonia. The number of deaths since September 18 was 11,725 attributed to influenza in the death certificates filed in the Health Department and 11,601 attributed to pneumonia. The epidemic reached its peak during the week of October 19, slowly subsided and was practically at an end on November 9. While the epidemic is reported as ending on this date, the mortality rate from influenza and pneumonia is still very much above normal. No particular features concerning the meteorological conditions were noted, except that in this city the weather was clear and delightful during the months of September and October when the epidemic was rampant.
In the city of Philadelphia on July 22 the Health Department issued its first health bulletin on so-called Spanish influenza, announcing the possible spread of this disease into the United States. On September 18 a warning was issued against an epidemic, the department starting a public campaign against coughing, sneezing and spitting. On September 21 the Bureau of Health made influenza a reportable disease. At this time the authorities stated an epidemic of influenza was recognized as existing among the civil population of similar type to that found in the naval stations and cantonments; that a large percentage of cases was accompanied by pneumonia; that patients should be isolated and attendants wear masks; that isolation be practiced for a period of ten days after recovery to prevent carriers; that patients be guarded against relapse and that the public be cautioned against large assemblages and crowded places, as well as to avoid coughing, sneezing and spitting. On October 3 the churches, saloons and theatres were closed, funerals were made private and food handlers were required to protect their wares. The number of cases reported from September 23 to November 8 was 48,131, but the Bureau states, from a rough estimate, the number of cases was probably 150,000. The total number of deaths reported was 7,915 from influenza and 4,772 from pneumonia in all its forms, the presumption being that the deaths during this period were due to influenzal pneumonia. The weather condition during this time is recorded as mild and fair.
The influenza cases began to be reported in Cleveland on October 5, and up to December 20, 22,703 cases had been recorded. Certificates recording deaths due to influenza alone numbered 2,497, while pneumonia amounted to 833. The epidemic was atits height in the latter half of October and the weather was spoken of as pleasant fall weather. During the week of October 26 the epidemic reached its greatest height, abated in the week ending November 23, increased later, but showed a drop for the week ending December 21.
The epidemic first reached Chicago on September 21, and from that date on it rapidly increased throughout the city for a period of 26 days until October 17, when it reached its maximum both in the number of deaths from influenza and from pneumonia. On that day the total number of deaths from influenza and from pneumonia reported was 2,395. From September 21 until November 16 there were reported 37,921 cases of influenza and 13,109 cases of pneumonia. On September 8 at the Great Lakes Naval Training Station, which is 32 miles north of the city, an extensive outbreak of influenza occurred. This was 13 days before the outbreak in the city of Chicago itself. Camp Grant, located at Rockford, 92 miles northwest of the city, suffered an outbreak on September 21. A suggestion of the likelihood that influenza was prevalent in this country in a mild and unrecognized form in the spring of this year is shown by the fact that numerous local outbreaks of acute respiratory diseases were brought to the attention of the Health Department of Chicago. These occurred especially in large office buildings and in industrial departments. The total number of deaths from influenza and pneumonia during 14 weeks was 51,915. This would indicate that a very great number of cases were not reported to the Bureau of Health until they died or else there must have been a large number of deaths due to lobar pneumonia. One naturally obtains from these figures the impression that the disease was not recognized for a long time, that the pneumonia must have been called lobar pneumonia, and that the actual figures gathered by this city, as well as others, must have been greatly confused at the onset of the epidemic. It is not unlikely that records from many of the army cantonments and naval stations may be considered from the same viewpoint. Weather conditions were considered normal at the height of the epidemic, the weather being dry. There has been a flare-up of influenza recently, but not in sufficient numbers to justify calling it epidemic.
In the city of Louisville, Ky., the epidemic started September 26, and the total number of cases up to December 21 is reportedas being 9,445. Out of this number 772 deaths occurred from pneumonia. No distinction is made here between broncho-pneumonia and lobar pneumonia, but the presumption from the records of other cities at this time is that these were cases of broncho-pneumonia following influenza. The weather was described as being delightful fall weather. The statement is made by the authorities that while the epidemic is still prevalent, it is confined largely to children and is rapidly abating.
The first case in the city of St. Louis was reported about October 7, and up to December 23 there had been 31,531 cases reported to the Bureau of Health. They recorded 1,920 deaths with influenza given as a contributing cause. Preceding the time when the epidemic was at its height the weather was fair and warm, and the statement is made that, “without going into the matter exactly, we have been of the opinion that damp, rainy weather has been a help in controlling the disease.” The opinion was expressed by the Commissioner of Health that the disease had now abated.
No information could be obtained as to when the epidemic first reached the city of New Orleans, but during the months of October and November 43,954 cases of influenza were recorded. Of this number 2,188 died from a combination of influenza and pneumonia. They stated in their health report that during the period from January 1 to December 31 there were 239 deaths attributable to broncho-pneumonia. The weather was mild and on December 24 the epidemic was stated to have abated.
The city of Minneapolis recorded its first case on October 7, but the authorities expressed their belief that a few cases had appeared before that date. Up to December 21, 15,000 cases had been reported to the Bureau of Health and of these there had been 735 deaths from broncho-pneumonia. They had in their city a late, rainy fall and up to that period they had had no cold weather.
The record obtained from the city of San Francisco stated that the epidemic first appeared September 23 and that it was very widespread in that city early in October. There were two invasions and 53,260 cases reported. At the height of the epidemic more than 2,000 cases were reported in one week; 188 deaths occurred from influenzal pneumonia. The following week, after the institution of mask wearing, in which between 80 and 90 per cent. of the population concurred, it was stated that the numberof cases decreased to about 200. It was stated that the weather was generally very fair during the epidemic.
From the city of Portland, Oregon, the following information was obtained: The epidemic first appeared October 11, with a second one toward the end of the year. There were 8,079 cases reported, with 658 deaths from influenza and 250 from pneumonia. Weather conditions were stated to be varied, but the health officer believed that during the worst wave the weather was clear and dry, with easterly wind. He believed that a decrease in influenza was noticed immediately after a Chinook wind and warm rain. Similar observations were made by Coutant in Manila.
A weather comparison of 12 large cities, well distributed over the United States, studied during this pandemic of influenza and checked with normal weather during that of many years, shows: Boston, fair with no abnormality; New York, clear and delightful, no abnormality; Philadelphia, mild and fair; Pittsburgh, mild and cloudy; Cleveland, pleasant fall weather; Chicago, normal and dry; Louisville, delightful fall weather; St. Louis, fair and warm-damp, rainy weather later seemed to control the epidemic; New Orleans, mild; Minneapolis, a rainy fall and no cold weather, which is unusual there; San Francisco, generally fair, and Portland, Oregon, clear and dry.
At Bryn Mawr College, in Pennsylvania, an institution devoted to the higher education of women, located within 10 miles of the city of Philadelphia, the epidemic occurred at the beginning of the college year—October 1. This college at the time had an enrollment of 465 students. There were 85 cases of influenza, with an additional 25 who suffered from influenza in their homes. There were no deaths from pneumonia. The weather conditions were clear and warm, and since November 29 there have been no new cases occurring in the college and only three or four of the students have been ill at their homes since that time.
Dates of the Appearance of Influenza Endemic in various Cities of theUNITED STATES1918.
Dates of the Appearance of Influenza Endemic in various Cities of theUNITED STATES1918.
Dates of the Appearance of Influenza Endemic in various Cities of theUNITED STATES1918.
The enrollment at Smith College, Northampton, Mass., was 2,103, and the first case of influenza appeared with the arrival of the students on September 18 and reached its height on September 30. All group gatherings indoors were stopped from October 3 to October 18, and the epidemic was over by October 20. A recurrence began November 15 and continued until December 17. There were 182 cases in the first epidemic and 100 cases in the second. There were only two deaths from influenza pneumonia. During the rise of the epidemic the weather was rainy, followed by good, clear weather. The change in weather conditions seemed to make no difference. The second epidemic was still prevalent when the students left for their holidays.
In Wellesley College, where there were enrolled 1,593 students, the epidemic first appeared on September 18. Up to the middle of December they had had 280 cases. During six weeks of the epidemic 265 cases were reported and only one death occurred from broncho-pneumonia. For the most part, bright and sunny days were present, with only a few cloudy and rainy days. This college has not been without cases since September, but the epidemic lasted only about six weeks.
In a communication from Columbia University it is stated that the epidemic appeared during the week beginning September 22. No records were available for the student body at the time of inquiry, but in the Student Army Training Corps of 2,200 men between 8 and 9 per cent. had the disease during the period from October 1 to December 14. In this army group during this period two deaths from influenza and pneumonia occurred. The weather conditions in the city during this time were considered normal for fall weather—that is, mostly clear, with high winds. The opinion expressed was that the epidemic was still prevalent and increasing, and that a return wave seemed to be more virulent and affected the children of the city more than had the first one in the early fall.
There were enrolled at Harvard on October 1, 3,193 students. The first case of influenza occurred on September 20. There were 227 cases of influenza reported; of these there were 46 cases of broncho-pneumonia, with five deaths. There were two waves to the epidemic; the first wave height was in October and the second the last of November. The weather conditions were not severe nor particularly unfavorable at either time. The epidemic abated at the university largely because of the demobilization of the Student Army Training Corps. At that time it was still prevalent in Cambridge and Greater Boston.
At Yale University the disease first appeared in the New Haven Hospital on September 21. There were registered in all departments of the university 2,265 students. Up to the date of December 24, 1,013 cases have been treated. The number of deaths from broncho-pneumonia has been 249. At the height of the epidemic, which occurred in the third week of October, typical fall weather prevailed. An unusually clear, dry October with very little rain, much sunshine and rather low humidity was the weather report.
During the period of the epidemic at Princeton that university had 1,050 students, and the first cases appeared shortly after the opening of the college term on September 24. As a precautionary measure, every case, when even only suspicious, was sent to the infirmary. In all, there were about 70 cases in the university and about 45 cases from the United States School of Military Aeronautics. Only one member in the latter school died of pneumonia. There were no deaths among the students at the university. In this part of the country the weather was most delightful all autumn, being warm and dry, very little rain having occurred since the end of July. At the date of the inquiry the epidemic had disappeared—that is, about December 21—there being only two very mild cases under suspicion. In the town of Princeton, outside of the university, the conditions were much more serious than in the university itself. Influenza appeared in the homes of many of the poor people of the immigrant class, so that it was not uncommon for four or five members of one family to be infected at once. In one family of seven, five serious cases of pneumonia developed. An emergency hospital was opened by the authorities and 40 cases of pneumonia were treated. Of these approximately one-half died. At the time this report was furnished the epidemic seemed to have disappeared.
The number of students enrolled at the University of Virginia was 957. The first cases occurred as early as September 24. There were 290 of these in number, and three died of broncho-pneumonia. The epidemic was reported as having abated on December 15, but a few cases appeared after that date.
At the Army General Hospital No. 24, located at Hoboken, a few miles outside of the city of Pittsburgh, on September 28two soldiers were taken ill and, with the disease unrecognized, they were removed to the cantonment hospital at Point Breeze, within the city proper. The men were found a few days later to be suffering from influenza, and from this presumable source an epidemic spread rapidly among the troops and student soldiers located here.
From September 28 until November 20, 1,392 cases of influenza occurred among the enlisted men. How the infection reached the first two cases at Hoboken is not known. The command here consisted of the Student Army Training Corps of the University of Pittsburgh, and Carnegie Institute of Technology, Motor Mechanics of the University of Pittsburgh and the Ordnance and Quartermasters’ Department on detached service. The strength of this command was approximately 7,000. The first case appeared on September 30 and the diagnosis was made on the following day. Beginning October 13, all soldiers of this group were inoculated with two 1 cc. doses of vaccine, obtained from the New York State Board of Health. At the height of the epidemic there were about 840 soldier patients in the several hospitals of the city at one time. Cubicles were used in the hospitals, and in the barracks a floor space of 50 square feet was allowed to each man. The men slept alternately head to foot, with paper screens intervening, which were changed daily. In company formation they were instructed to gargle their throats and clean their teeth morning and night under the supervision of their officers. Strict military quarantine was maintained throughout the entire camp, no congregating was allowed, classes were suspended and only open-air drills were permitted. For the entire command there were 220 cases of pneumonia, with 99 deaths, an average mortality of 44 per cent. The dishes were boiled in the hospitals, and sanitary dishwashers were used in all mess halls. The kitchen help and personnel were inoculated with influenza vaccine, with apparently good results. The Magee Hospital, with 375 beds, was under strict military control. When this was full, all others were treated in the civilian hospitals.
In the city of Pittsburgh the disease was not made reportable until October 5. However, one case was reported on October 1, and it was known that there were a few isolated cases in Pittsburgh previous to that date. During the months of October, November and up to December 21 there were 23,268 cases of influenza reported, and the deaths were 1,374 from lobar pneumoniaand 678 from broncho-pneumonia. We cannot but feel that most of the deaths reported during the period of the epidemic as lobar pneumonia were broncho-pneumonia associated with influenza. It was well known among civilians that true lobar pneumonia was exceedingly rare and has remained so up to the present time. This is especially noticeable, as this is the time of the year when lobar pneumonia is usually widespread in Western Pennsylvania. This district was particularly favored with a mild fall and winter. On October 1 the first case was reported, on October 15 the epidemic reached its peak—on that day 957 persons being reported ill with the disease. From October 16 until October 28 it maintained an average of 600 cases daily; from October 29 until October 31 there was a sharp decline from 600 cases daily down to 200 cases daily. From November 1 until December 21 the decline has been uniform, and on this latter date 58 cases of influenza and 7 of pneumonia were reported. The height of the epidemic was reached between October 15 and October 29. During the period of the epidemic in Pittsburgh, from October 1 until December 15, 62 days were recorded as cloudy, or partially cloudy, and only 14 days as clear, although the cloudy days seemed distributed and not in decided groups. The mean temperature for October was 58 degrees, with normal 54.9; for November, 44 degrees, normal 42.9; for December, 41 degrees, normal 34.7. The precipitation in October was 3.08, as against a normal of 2.36; in November, 1.79, with normal 2.55; and in December, 3.50, normal 2.73. From a study of these weather reports we see that the epidemic occurred during a period of abnormally warm, cloudy and slightly more moist autumnal season than usual, but these variations were relatively slight and far from decided. The confusion of diagnosis between lobar pneumonia and broncho-pneumonia, associated with or following influenza, occurred in the Pittsburgh health reports as well as in other cities. The presumption that almost all, if not all, of the cases reported as pneumonia of different types were really cases of influenzal pneumonia, seems justified.
During the time the epidemic was at its height in Pittsburgh the Western Pennsylvania Institution for the Blind was in session.This school is located in the heart of the educational center and was surrounded by the barracks of the Student Army Training Corps of the University of Pittsburgh and the Carnegie Institute of Technology. When the influenza was recognized as epidemic in this neighborhood, the attending physician at this institution advised a quarantine against the public. The children were refused visitors in the buildings, and the usual week-end trips home were forbidden. This school was continuously in session from September 24 until November 30. During this time there was not a single case of influenza in the school and the children were free from any infectious disease. On December 1 the pupils returned to school after the Thanksgiving holiday, and one week later, on December 8, the first case of influenza appeared. In a period of five days following 15 cases developed. It was considered wise to close the school, and all well children were sent to their homes. The institution was kept closed until January 1, since which time no cases have developed. Very few of these children had influenza at home, and only one death occurred.
A reliable report, subsequently confirmed by the health officer, stated that in Masontown, Pa., the start and course of the epidemic were very striking. A dance was held in the town and the musicians were brought from nearby cities. One of the musicians employed was not very well upon his arrival, and became so ill that after the dance he was put to bed in the hotel. He was found to be suffering from influenza when examined the following day, and from him as the primary case the town was swept by the epidemic.
In Mercer, Pa., the physician to the Board of Health reported that during September they had a general epidemic of coryza and sneezing, with slight fever, which lasted for three or four days. This was looked upon by the people as hay fever. In the midst of this, or about September 16, a man, 74 years of age, who had been away from home, developed true influenza, followed by pneumonia, from which he recovered about October 10. Another man, employed in Greenville, a nearby town, where influenza was already prevalent, returned to his family here suffering from the disease. The whole family and all who were exposed to this family were infected. From this family as a focus the disease spread rapidly in every direction. There wereabout 350 cases in the town of 2,000 inhabitants, and there were 9 deaths. Sporadic cases have occurred since, ranging in number from one to a dozen at a time. These numbers do not include scores of cases called colds by the people, but it seems that all these cases had an influenza element.
In the town of New Castle it was not possible to trace the onset of the influenza epidemic to a definite case. As the health officer stated, several cases were reported at once.
The first case of influenza in Indiana, Pa., of which there was any definite knowledge occurred on September 15. A clothing merchant who had just arrived from New York, where he had been buying stock for his store, was the first case identified. The next case occurred several weeks later, the disease being contracted at the mining town of Coal Run, in Indiana County.
A man resident in Sharpsburg who had suffered from influenza visited friends in Fraser Township, Allegheny County, to convalesce. Previous to his coming that section had been free from the disease. He was still coughing at the time, and, moreover, he is said to have been a great talker and visited largely among the neighbors of his host. Threshings in that part of the township were going on and these he also attended. The date of his coming was October 13. By October 15 his hostess was taken ill. By October 16 some of the threshers were affected, and by October 17 enough were sick to break up the work of threshing. Eventually all the men engaged became ill, and 11 families were infected from this source.
Reviewing the history of former epidemics and pandemics, I have gained the impression, as have many others, that we are not dealing with any new disease. Further, our knowledge of this pandemic with its high incidence of broncho-pneumonia shows that it is in no way markedly different from that of former manifestations of influenza. One is impressed by the fact that in different outbreaks of this disease of complex symptomatology certain symptoms or complications have been prominent, overshadowing others, and making such complications the striking feature at the time. The failure to recognize that these varying features are merely different manifestations of one disease hasresulted in much confusion. The observation made in the last epidemic—and one which can be endorsed during the present plague—is that influenza has been and is the most widespread, rapid and extensive of all diseases. One thing also that attracts attention at the present time is the long period existing between the several pandemics. Whether, as one observer during the present pandemic has stated, it requires a long period for the infection to become active and easily carried, or whether any possible reason can be suggested for these phenomena, admits of no satisfactory explanation. The outstanding feature during this epidemic is the complication of broncho-pneumonia, and yet, from very early times, this complication has been repeatedly spoken of as a striking characteristic. Reviewing the health reports from the large cities of deaths from pneumonia, the presumptive opinion seems justified that almost all, if not all, pneumonias reported as associated with influenza were of the broncho-pneumonia type. The infrequent presence, indeed the rare finding, of lobar pneumonia during this period in Pittsburgh seems to verify the aforesaid opinion. The great frequency and the high mortality of broncho-pneumonia were particularly noted during the present epidemic. During the present epidemic the great mortality among pregnant women was another striking feature, and yet this is by no means new, having been recorded by some of the earliest writers. Such also may be said of the recurrence of the disease in the same patient. One important observation brought out in the study of the pandemic of 1889 to 1892 was that the ordinary infections occurring in the spring and fall known as grippe or La Grippe are in no way connected with the pandemics which have occurred. There seems to be a consensus of opinions among the records of the more recent epidemics, as well as during the present pandemic, that weather conditions in no way influence the spread of the disease. Furthermore, a study of weather conditions throughout the United States, and particularly those of our own city, seem to bear out the truth of this observation. While clinicians during other epidemics expressed their belief in the incident of a primary case producing infection, it has only been during the present one that such an opinion has not been assailed. The large number of military training camps and cantonments have undoubtedly offered splendid opportunity for the spread of influenza. Thefutility of attempting to control it even under normal conditions is still questionable. Consistent with former reported invasions of the disease, the present epidemic lasted a definite period. This period was about six weeks in most of our large cities, colleges and institutions, extending approximately from October 1 to November 15.
It is imperative to note the accurate clinical observations recorded from the numerous epidemics of the past by men with far less data to go upon than is available at the present day. The high morbidity among the personnel of many of our hospitals and institutions where the infection occurred and the relatively low mortality deserve attention. This may be partly explained by the methods of treatment of those infected, but not entirely. The great likelihood of carriers of influenza, who either are not ill or who are suffering from very mild infection, is an observation also noted by former writers which cannot be ignored. The value of the masks has not been established, although they have been extensively used in many parts of the country. Frequent throat lavage was generally accepted as a rational preventive measure. Relightings of the disease have been noted in most of our cities after the subsidence of the epidemic. Vaccination against influenza is fully discussed in Dr. Haythorn’s paper in this series.
The presence of influenza in San Quentin prison, California, in April, 1918 (Public Health Reports, May 9, 1919); an epidemic of respiratory disease in Chicago in the spring of 1918; the report of Soper of influenza in our army camps in March and April, 1918; the occurrence of influenza in Porto Rico in June; influenza on a United States Army transport from San Francisco, as reported by Coutant, seem to point to the possibility that influenza had a footing in America long before the disease became pandemic. The view held by some that the beginning of influenza was in America, subsequently being transferred to Europe and then reimported here, is worthy of consideration. Coutant believed the disease originated in Manila, others that it traveled from “a permanent endemic focus in Turkestan,” and there are many other theories which attempt to discover the original source of the disease. The question is today an unsettled one. The pandemic of influenza in its severest form swept so suddenly over the world that before the profession realized it or had becomestabilized it had changed its character and the great plague was gone. The consequence has been that we have really learned little that is new and have done scarcely more than establish on a firm basis many of the opinions formed after the great outbreak of some 30 years ago. Because transportation is today more rapid than it was at that time, so the spread of the disease has been correspondingly swift. Our modern life, the congregating crowds in theatres, moving-picture houses and in lecture halls, as well as of the men in our training camps, the development of street cars and the more frequent traveling by train—these and many more changes in our mode of living have served to aggravate the conditions favoring the widespread distribution of the infecting agent. A higher proportion of the population was, therefore, attacked than in any previous pandemic, and the period during which the disease was widely prevalent has for the same reason been relatively much shorter.
The characters differed somewhat in different regions, but the evidence shows clearly that we are not dealing with any new disease. It will be years before we are able to fully analyze the data that have been collected from such wide sources and by so large a body of trained men, so that important epidemiological facts may still be forthcoming from the material already at hand. We are too close to the events to get the most helpful perspective, and the object of this report has been to add, in however small a degree, to the general knowledge of this great pandemic as it has appeared to us in Pittsburgh and its surroundings.