Complete investigation of localized outbreaks and comprehensive studies of large groups of cases indicate that the case fatality rate was approximately 11 per cent and were exact data available it doubtless would be found to have been less than 10 per cent.

DISCHARGE ON ACCOUNT OF DISABILITY

A total of 24 men were discharged from the service on account of disability resulting from an attack of typhoid. Of the total number of individuals discharged for disabilities resulting from diseases, only 0.014 per cent were discharged for disabilities incident to typhoid, and in the list of the 30 diseases most frequently resulting in discharge for disability typhoid does not appear. NONEFFECTIVE RATES

A total of 1,529 primary admissions for typhoid were reported and these men were absent from duty a total of 109,374 days. The average loss of time from duty per case of typhoid was, therefore, 72 days.

SEASONAL DISTRIBUTION

In general, the seasonal distribution in troops during the World War conformed to the well-known seasonal distribution of typhoid fever in temperate and cold climates-highest incidence in the late summer and fall months, particularly for cases developing in the United States. In Europe, however, a very considerable proportion of the cases arose during the winter months-November, 1918, to March, 1919, inclusive due, doubtless, to increasingly constant exposure to massive doses of the infective agent.

GEOGRAPHICAL DISTRIBUTION

The recorded mortality rate for the civilian population of Manila, Philippine Islands, for the period 1917 to 1919, inclusive, was 1.84 12 per 1,000 per annum, while that for American and Filipino troops serving in the Philippines during the same period of time was practically nil (1 case, or 0.05 per 1,000, for the period).

The admission rate per 1,000 for total enlisted strength for the period was 2.57 for Hawaii, 0.54 for Europe, and 0.25 for the United States. Expressed in comparative ratios these figures mean that for every one case of typhoid fever occurring in troops in the United States approximately two cases occurred in troops in Europe and ten cases in troops serving in Hawaii.

TYPHOID FEVER IN HAWAII

An explosive outbreak of typhoid fever, definitely traced to the water supply, occurred at Schofield Barracks, Hawaii, in the fall of 1917. The following abstract summarizes the epidemiology of this outbreak: 13

Schofield Barracks, the largest Army station in Hawaii, is located on the northern end of the island of Oahu, about 23 miles from Honolulu. The regular water supply for the station was obtained from two sources. The old section of the station was supplied mainly with water collected in tunnels and brought down through a system of tunnels and pipes from a range of mountains adjacent

to and to the west of the station. The new section of the station, about 1 mile distant, was supplied by a gravity system having its main intake in the Koolau Mountain Range in the headwaters of the fork of the Kaukonahua River on the opposite side of the island. This supply was not subject to contamination except that certain sections of the tunnels in the upper reaches were open. Overflow and additional small streams came together, below the intake for the regular supply, forming a stream at the bottom of the ravine. On this stream, below the intake for the permanent water supply, was located a pumping station to augment the permanent supply, when necessary. This auxiliary supply was not supposed to be used without previously informing the sanitary authorities, through whom instructions would emanate as to the proper treatment of the water. At times water from the auxiliary supply for the new post also was pumped to the old post to augment the permanent supply, but at no time was this done during the course of the epidemic to be reviewed. The pumping station for this auxiliary supply was located at the lowest point of the watershed and the water itself was subject to constant contamination from camps of Japanese laborers engaged in construction work on the water supply system at the time the outbreak of typhoid occurred. These camps were on the hillside below the water mains and about 45 feet above and 55 to 100 yards distant from the bed of the stream constituting the auxiliary supply.

In the early days of August, 1917, a Japanese laborer arrived at one of the camps and, though he did not report for treatment, it was learned at a later date that he was ill for some time with a continued fever that doubtless was typhoid. While ill, he was visited by a Japanese friend (Mizusawa) employed at one of the construction camps. Mizusawa had not been inoculated against typhoid fever and came down with typhoid fever during the latter part of August. He worked for several days after he became ill, continuing to live at the camp, and he failed to report for treatment. He stopped work on September 1, but remained at camp until September 7. He was admitted to hospital in Honolulu on September 15 and was having hemorrhages from his intestines at that time. This patient was interrogated at the time the epidemic was under investigation and examination of his blood gave a positive agglutination reaction with B. typhosus in high dilution. While at the quartermaster construction camp this man had used an insanitary privy located on the drainage shed of the stream constituting the source of the auxiliary water supply for the new section of Schofield Barracks.

From the middle of August to the middle of September, 1917, the rainfall on the watershed of the regular water supply system for the newer part of the post was so low that it became necessary, more or less constantly, to supplement the regular supply with water from the auxiliary system. The sanitary authorities at Schofield Barracks had no knowledge of the fact that this was being done. On September 13 and 14 rather heavy rains occurred on the watershed used as an auxiliary water suppy and following these rains it was noted at Schofield Barracks that the water from the source was quite muddy. Within 10 days after these heavy rains fell cases of typhoid fever began to appear, and within a comparatively short period of time 100 cases had occurred. All individuals. who contracted the disease gave a history of drinking the contaminated water

within the incubation period of the disease. Of the total population-military and civilian-exposed to infection, 4,087 had been vaccinated with antityphoidparatyphoid vaccine and 812 had not been so protected. No persons living in the older section of the post contracted typhoid except an occasional individual who gave a definite history of drinking water in the newer section of the post on the evening of September 14 or the following day. The comparative morbidity and mortality rates from typhoid fever in these two groups are shown in Table 5.

TABLE 5.-Typhoid fever. Schofield Barracks, Hawaii. Vaccinated and unvaccinated groups, population, admissions and deaths. Absolute numbers, with rates per 1,000 and case fatality a

Source of information: Russell, F. F.: Typhoid fever in the American Army during the World War. The Journal of the American Medical Association, Chicago, Ixxii, Dec. 20, 1919, 1863.

These statistics demonstrate conclusively the protective value of prophylactic vaccination, the relative morbidity rate for the nonvaccinated to vaccinated being approximately 4 to 1. They show also that the complete eradication and prevention of typhoid can be accomplished only by a combination of prophylactic vaccination and efficient environmental sanitation and personal hygiene. The lower case mortality rate in the vaccinated group is confirmatory of other observations that appear in medical literature.

TYPHOID FEVER IN EUROPE (RUSSIA EXCEPTED)

The greater frequency of occurrence of typhoid in American troops on active service in France than in the United States justifies a somewhat detailed discussion of the epidemiology of the disease in the former area of activity. In the United States many of the cases occurred in unvaccinated individuals, but all troops in Europe presumably had been vaccinated; in the United States environmental sanitation in mobilization camps was excellent, while in Europe many defects existed, particularly so in the battle areas where the military objectives necessary of attainment prevented proper attention to sanitation; and general exposure to typhoid infection was much greater in France than in the United States.

The prevalence of typhoid fever in American Expeditionary Forces for the period of the World War is shown in Table 3. The total number of cases. recorded as primary admissions was 885 (0.53 per 1,000). The occurrence of the cases by months is presented graphically in Chart IV.

The data incorporated in Chart IV pertain to all bacteriologically proven, as well as clinically diagnosed but not bacteriologically proven, cases of typhoid fever reported to the chief surgeon's office, A. E. F. They include also cases reported as primary admissions for typhoid fever as well as cases of typhoid

complicating, or concurrent with, other diseases or battle injuries, and represent very closely the actual prevalence of typhoid fever in France. This chart shows that, prior to June, 1918, practically no typhoid fever occurred in American troops in France (there was a total of nine cases only); that an increase in the disease occurred in June, 1918, bringing the morbidity rate up to 0.03 and that again in December, 1918, and January to March, 1919, increases in rates occurred. The various elevations of the morbidity curve referred to above correspond with the occurrence in a few organizations located in various parts of France and more particularly the somewhat widespread but limited occurrence of the disease from November, 1918, to January, 1919, inclusive, in certain of the divisions that had taken part in the Meuse-Argonne operation.

That the origin and spread of typhoid fever in the American Expeditionary Forces were due to defects in sanitation that usually operate to initiate and disseminate the disease is well shown in the review of the epidemiology of the more important of the outbreaks, namely, those occurring in

Company No. 4, Camp Cody replacement unit, July, 1918. 77th Division, December, 1918, to January, 1919_

79th Division, December, 1918, to March, 1919_

88th Division, January, 1919, to March, 1919..

Medical Department units at Curel, December, 1918, to January, 1919.

Motor Transport Camp, Marseille, March, 1919..

Cases

95

122

61

21

72

64

TYPHOID FEVER IN COMPANY No. 4, CAMP CODY REPLACEMENT COMPANY On June 15, 1918, three replacement units left Camp Cody, Deming, N. Mex., for Camp Merritt, N. J., en route to France.1 Company No. 4, with an enlisted strength of approximately 248 men, was a provisional one, both commissioned and enlisted personnel being made up of individuals casually attached by transfer. All three companies arrived at Camp Merritt, N. J., on June 21, and none reported any serious illness. Company No. 4 was the only one of the three in which typhoid fever occurred.

Company No. 4 sailed for England on June 28, arriving in Liverpool on July 11. During the passage across the Atlantic many cases of so-called seasickness were reported, of which doubtless a considerable proportion were in reality typhoid fever. The company left Liverpool on July 11 and arrived in St. Aignan, France, via Cherbourg, shortly thereafter. During this trip, typhoid suspects transferred to hospital were as follows: July 11, Liverpool, England, 3; July 12, Romsey, England, 4; July 14, Southampton, England, 34; July 15, Cherbourg, France, 17; July (date unknown), St. Aignan, France, 3. Men continued to be taken ill for a period of 10 days after the arrival of the company at St. Aignan, the last case of typhoid having been admitted to hospital on July 28.

The following information is summarized from reports of investigation of the outbreak in England 14 and France.15

The incubation period of a large proportion of the cases was of such length as to indicate that most of the men contracted the disease while traveling by train from Camp Cody, N. Mex., to New York. The three companies traveled on the same train, but cases of typhoid arose in Company No. 4 only. So far as could be ascertained by inquiry, general sanitary conditions on the train were alike for the three companies.