THE INFLUENZA PNEUMONIA PANDEMIC IN THE AMERICAN ARMY CAMPS DURING SEPTEMBER AND OCTOBER, 19181

THE pandemic of influenza which has been prevalent in Europe and which swept over the United States in the spring of 1918, causing much suffering and disability in industrial plants and loss of training time in American army camps, reappeared with greatly intensified violence in September and October. Within a month of its recognition it had been reported from nearly every quarter of the United States, civil and military.

The army and navy camps suffered severely from the outset. Rarely before in the history of war has infection exhibited a more explosive character or has so large a proportion of troops been infected in camps under conditions of abundant shelter and food and freedom from the strains and anxieties of conflict. The epidemic has been attended by an unusual fatality.

The data and deductions contained in this report are such as are warranted by daily telegrams and other sources of information collected during the course of the pandemic. The final and complete statistics will not be available until after the outbreak is completely over.

During the period September 12-October 18, 1918, inclusive, there were 274,745 cases of influenza reported among the troops in America. During the same period there were 46,286 cases of pneumonia and 14,616 deaths.

The incidence of influenza and pneumonia among all troops in the United States, week by week, from the outbreak to and including October 18, 1918, follows:

1 Published by permission of the Surgeon General of the U. S. Army.

THE OUTBREAK OF THE PANDEMIC

The first report that a serious epidemic existed in any camp came from Devens, at Ayer, Mass. On September 16 the camp sanitary inspector, reporting through the camp surgeon to the Surgeon General of the Army, announced that an epidemic of so-called "Spanish influenza" had broken out at Devens as a part of a general epidemic which had attacked Boston and the neighboring states and towns some weeks before.

The Devens epidemic is supposed to have commenced on September 7, 1918, in D Company, 42d Infantry. On that date a case of supposed meningitis was sent to hospital from this company; on the following day twelve cases were sent for observation. These proved to be influenza. By the sixteenth 37 cases had gone from the same company. One death from pneumonia had occurred. Almost simultaneously, other cases appeared in other organizations. By September 12 the total number of cases which had been admitted was 599. The disease spread rapidly, in spite of the measures taken to check it. On September 20 the epidemic reached its maximum intensity. that day 1,543 new cases were reported as having been admitted to sick report. After reaching this high point the number of new cases

On

rapidly became less, so that by the end of the month there were less than 100 new cases reported per day.

Meanwhile, pneumonia had become a frequent and fatal accompaniment of the influenza at Devens. Fifty new cases were reported September 19, less than three weeks after the influenza had broken out. The number rapidly increased; on September 24, there were 342 new cases. The number each day remained at about 200 for four days; then there was a decrease, until, before the end of the month, 40 per day had been reached. Since October 4 there have been less than five new cases daily.

The Devens outbreak, so far as may be understood from the records at hand, could be divided into 4 parts as shown in the following table:

affections to which the term influenza has been generally applied for the last twenty years.

The leading symptoms in the typical cases are: severe headache; chills or chiliness; pains in the back and legs; temperature sometimes as high as 104; great prostration; drowsiness. Occasionally there are nervous symptoms; sometimes, but not always, the eyes and the air passages of the nose and throat are affected; there may be gastro-intestinal disturbances. The onset is sudden. The patient can often tell the exact moment of his attack. In the typical case he is very sick-wholly incapacitated for exertion. He lies curled up and can hardly be roused for food. In two or three days the fever usually disappears by crisis and the patient feels that he is rapidly recovering. It is highly important that he be well cared for and kept comfortably warm during the next week. Pneumonia occurs in about 18 per cent. of the cases; it proves fatal in over one third of those attacked.

The fact that an epidemic existed in a camp has generally been recognized when the number of new cases has amounted to 100 or more per day. The incidence then increases rapidly. Sometimes the records show a great number of cases at the start, and there are marked fluctuations in the daily incidence as the epidemic continues. Striking irregularities do not represent the way in which the disease occurs but are to be accounted for by the stress and difficulty with which the returns are collected. The greatest number of new cases reported for any day has often considerably exceeded 1,500 in a camp. At Devens the maximum was 1,543. At Grant, 1,810 and Custer, 2,800. The high point has often been reached on about the tenth day of the epidemic.

Epidemics commonly subside almost as rapidly as they arise. Within from 16 to 20 days after the outbreak the number of new cases per day falls to 200 or less, after which there is a more gradual decline to the end. In its epidemic aspect, as in the individual case, the disease is characterized by sudden onset, great intensity, and rapid recovery.

Within about a week after the outbreak of the influenza there occurs an ominous prevalence of pneumonia. The pneumonia does not exist as a separate epidemic, but is always a follower of the influenza. How the two diseases are related is not positively known. It is clear that the influenza paves the way for the pneumonia, if it does not actually produce it. Most of the pneumonia is of the lobular type and presents various unusual aspects. The time of greatest incidence is usually about a week after the greatest incidence of influenza.

SPREAD OF THE PANDEMIC

The second camp to report an epidemic following Devens, was Upton, on Long Island, N. Y.; the third was Lee, in Virginia. Dix, in New Jersey, and Jackson, in South Carolina, followed immediately. Hoboken, N. J., Syracuse, N. Y., Gordon, in Georgia and Humphreys, in Virginia, all reported on the same day. Within a week from the start, nine large camps in widely separated parts of the country were attacked. Others followed in rapid succession. The table on the following page gives the order in which the camps were attacked. In addition there were many epidemics reported from posts, aviation stations and other troop centers.

THE OUTLOOK FOR THE FUTURE

How far the pandemic will spread will apparently depend only upon the material which it can feed upon. It is too early to foretell the end or to measure the damage which will be done before the pandemic disappears. Enough is known to show that hereafter influenza is not to be ranked merely as an endemic disease of civil life, but an infection of first-class military possibilities. It is not improbable that the present pandemic may disappear as rapidly as it came, although most persons hold the opinion that its final disappearance will be gradual, the extinction of the disease being postponed for many months. In the pandemics which sweep over the earth at long intervals, recurring waves of the disease in greater or less degree commonly occur. If this rule holds

Wherever it occurs its presence is startling. The consternation and alarm which it produces frequently lead to irrational and futile measures to check it.

In theory and practise influenza is preventable but it is very difficult to control under municipal and military conditions. It rarely happens that the necessary measures-chiefly isolation are taken in time. In the present pandemic the disease has, on more than one occasion, been confined to certain wards of hospitals to the exclusion of others. It is not possible as yet to state to what extent it has been restricted in camps. No large camp has escaped it.

The following table gives the numbers attacked and the deaths recorded up to October 18 in twenty of the largest camps and canton

ments:

TABLE OF CASES AND DEATHS AMONG 20 CAMPS
GROUPED IN THEIR CHRONOLOGICAL ORDER
OF ATTACK

true now we may look forward to another pandemic before many months are past. It is to be remembered that the present is the second, not the first, great wave which has occurred here this year.

The pandemic now raging may truly be termed an epidemic of epidemics. However desirable it may be to ferret out the cause to the first case this can not be done. Like all great outbreaks of this most infectious of communicable diseases, the epidemics now occurring appear with electric suddenness, and, acting like powerful, uncontrolled currents, produce violent and eccentric effects. The disease never spreads slowly and insidiously.

As the pandemic has progressed the propor tion of soldiers attacked has increased, and the proportion developing pneumonia has increased while the fatality of the pneumonia has diminished. These differences have been slight, but they seem to be unmistakable. If these figures are fully substantiated by later 2 Devens, Upton, Lee, Dix, Jackson.

3 Grant, Taylor, Sevier, Pike, Newport News. 4 Sherman, Dodge, Shelby, Custer, Travis. Cody, Forrest, MacArthur, Wadsworth, Greenleaf.

and more complete returns, the facts and inferences to be drawn from them will be of great moment.

The disease is carried from place to place by persons, not things or by the general atmosphere, as was once supposed. Its rapidity of spread is due to its great infectivity, short period of incubation, missed cases and absence of timely precautionary measures. It would appear that an epidemic does not easily start, but once the flame is well kindled a conflagration occurs which can not be stopped. epidemics stop themselves. This they do either by the exhaustion of the susceptible material, by a reduction in the virulence of the causative agent, or both.

The

The causative agent is believed to be the bacillus of Pfeiffer; the means of transfer; the air and objects recently contaminated by the buccal and nasal secretions of those who harbor the virus. It is a fundamental assumption that influenza is produced when, and only when, material from the mouth or nose of infected persons gets into the mouth or nose of someone who is susceptible. As is plainly recognized in respect to intestinal infections, the hand probably plays an important part in the transmission of influenza. Coughing and sneezing help greatly to spread infection.

CHANGES IN VIRULENCE

It has long been known that interchanges of bacteria occur commonly from mouth to mouth under ordinary conditions of social intercourse. Most of the organisms are harmless under normal conditions of health. That their virulence is sometimes increased, sometimes reduced, according to circumstances, appears to be certain. But what the circumstances are which raise or lower the virulence is conjectural. The Pfeiffer bacillus is no stranger to America; it was believed to be present in many healthy persons before the present pandemic. To account for the pandemic it has been suggested that something must have happened to increase its virulence or a new and more active strain has appeared, or the susceptibility of those attacked has become greater.

The conditions which govern susceptibility

are not understood. Good general health, absence of fatigue and avoidance of cold and hunger are standard methods of prevention for the individual. Vaccination against pneumonia is practicable but such preventive treatment is in the experimental stage as respects influenza.

The belief that immunity is conferred by an attack is partly confirmed by the observation that in Europe and America a preponderance of persons who have suffered in the present pandemic are relatively young persons, few of whom could have experienced the disease during the pandemic of 1889-90.

The weather has always been supposed to exert an influence upon influenza-the very name is derived from the effect which extraterrestrial conditions were supposed to exert upon it. But although there has been a great deal of study of this subtle matter, little is known concerning it. It seems probable that the weather this fall has aggravated the disease and contributed to the incidence of pneumonia.

The epidemics which occurred in the spring of 1918 were like those which are taking place now, except that the disease was milder and there was less pneumonia. Until recently the influenza reported from Europe was of this mild type. It seems to have been as infectious as it is now. Reports coming from all parts of Europe indicate that the percentage of persons attacked was about the same at that at present.

Something seems to have occurred during the summer greatly to increase the virulence of the disease. During July and August a number of vessels plying between Europe and America experienced intense outbreaks of influenza, accompanied by very fatal pneumonia. That cases of the disease were being brought into the country in this manner was stated in the daily press and in official reports in July.

COMPARISON WITH OTHER PANDEMICS

It is interesting to compare the present pandemic with others, but it is impossible to say