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GENERAL SUMMARY OF EXPERIENCE
Experience of the United States Army during World War II would seem to justify continued inclusion of the diarrheas and dysenteries among so-called tropical diseases. Certainly the incidence was highest in those theaters and areas in tropical and semitropical positions and was lowest in theaters, or their major subdivisions, closer to the poles. Incidence was lowest in the Alaskan and North American areas. It was lower in northern than in southern service commands among troops stationed in the continental United States. In the Latin American area, the South Atlantic Division located on the Equator experienced rates among the highest attained in the several theaters and areas. In the Southwest Pacific, incidence was lower in Australia than in New Guinea or the Philippines. The northerly situated European theater experienced low rates. In general, 40 degrees north latitude was the dividing line between relatively good and bad experience with these diseases. South of this line lay the China-Burma-India theater, the Middle East theater, the North African and Southern Italy portions of the Mediterranean theater, and the Southwest Pacific area. These all had high incidence and contributed a great preponderance of the total cases of World War II. The notable exception to this pattern is found in the Panama Canal Department, located only a few degrees north of the Equator, where the monthly rates for diarrheal diseases were among the lowest reported. The emphasis on good sanitation in this tropical, fixed base resulted in this record and demonstrates that control of these diseases can be accomplished even in the Tropics.
Severe mass problems of diarrheal disease can occur north of 40 degrees north latitude. The experience of German: prisoners of war in the European theater is an example of high morbidity with quite high mortality. Diarrheal diseases occur endemically and epidemically in the civilian populations of Iceland, Greenland, and Alaska. United States Army Troops were deployed during World War II in these areas adjacent to the Arctic Circle in rapidly constructed but quite well- sanitainod bases and stations. There was little diarrheal disease. Deployment of large numbers of troops under actual combat conditions in such northern latitudes conceivably could result in an altogether different situation. Little is known about field conditions in the Arctic and their relation to mass problems of diarrheal diseases. Expeditions into the Arctic during World War II have yielded information which suggests sanitary disposal of feces and provision of safe water supply could become difficult problems for large populations in permafrost or constantly frozen areas. Despite the relatively favorable experience during World War II in northern latitudes, diarrheal diseases may become special problems of an army in com-
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bat in the Arctic. The history suggests that research and field tests are needed.
Highest rates were encountered when United States Army troops intermingled in densely populated areas with Eastern peoples, as in China-Burma India, the Middle East, North Africa, and the Philippines. It was at these points of contact with Eastern civilizations that highest rates of diarrheal disease occurred. Diarrheal disease was hyperendemic in these locations into which United States troops were introduced. The criticism was often made that United States troops, accustomed to the advanced sanitary practices of Western civilization, were not sufficiently briefed regarding precautions necessary to prevent personal and mass diarrheal disease in these Eastern locations. Should United States troops again be required to contact these peoples, much diarrheal disease could be prevented by adequate advanced training of personnel, by early availability of sanitation facilities and materials, and by not permitting the use of natives as foodhandlers in military messes.
Critical Periods of Risk
The critical times and circumstances in which increased or epidemic incidence of diarrheal disease occurred during World War II among United States Army troops fell into the following major categories:
1. Within a few days or weeks of the first entry of troops (either first arrivals or rotated personnel) into hyperendemic areas, especially under conditions which enabled contact with native populations.-In several theaters, it did not take long, following the arrival of large numbers of United States Army susceptibles, for epidemics to occur. Troops among the early arrivals were not always able to provide ideal sanitation for themselves because of shortage of the necessary supplies. Education of these troops in personal measures to be taken to prevent diarrheal disease in these foreign environments often was lacking or inadequate.
The employment of natives as foodhandlers (as in the China-Burma-India theater) or eating with friendly natives (as reported in the Philippines) or eating in unauthorized native restaurants (as reported in North Africa and the Middle East) were frequently considered by preventive medicine authorities to be associated with high incidence. Minimizing or neutralizing these causes by training, regulation, and adequate advance planning could conceivably result in prevention of a large amount of diarrheal disease.
2. While troops were engaged in combat, especially in war of movement.-Under such conditions, excreta disposal, provision of safe food and water, fly control, and messgear sanitizing became difficult problems. This was particularly the case when troops were pinned down by enemy fire. There was typically a correlation between actual combat and increased incidence of diarrheal disease (as is well documented for the European theater).
The consistent observation that there was much less incidence when troops
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in actual combat were subsisting on individual packaged rations indicates at least one important preventive measure.
Additional research is needed, pointing toward better field sanitation techniques and facilities for frontline troops during actual combat.
3. During training maneuvers when troops had not yet had sufficient education in field sanitation practices.-The obvious preventive measure is to schedule first the necessary instructions in field sanitation and in personal hygiene under field conditions.
4. During transportation of troops by rail (for example, as in the travel across India to Assam and as in Australia from the fixed bases to training areas) or by excessively overcrowded overwater transport.-Provision en route of adequate facilities for messing, prohibition of unauthorized use of native restaurants or food vendors, and planning for adequate safe drinking water supplies are important whenever troops must be transported by rail if outbreaks of diarrheal disease are to be prevented.
Overcrowding of troop transports, with resulting overtaxing of toilet and messing facilities, and with increased opportunity for contact spread should be avoided. If overcrowding is necessary, additional emergency sanitary facilities for excreta disposal should be provided. Research toward development of a shipboard item for this purpose would be worthwhile. Messing facilities should not be overtaxed. Instead they should be utilized for only one prepared meal daily-other meals being provided, for example, from individual packaged rations. Nor are the diarrheal diseases the only ones for which there is increased risk with overcrowding. It is better to prevent the basic cause unless a drastic military situation contraindicates.
5. Prior to or during the construction of fixed bases.-At such times, construction and engineer personnel especially are at risk. The troops involved are apt to be existing under difficult sanitary conditions. Primitive excreta disposal and messing facilities must be used for a prolonged period of time. Often the water supply is limited in per capita volume and requires special care because of an untreated and untested source. Special emphasis on training for and enforcement of good field sanitation practice are indicated for personnel to be assigned such duty.
6. During the taking and holding of such terrain as coral atolls where conventional field sanitation techniques were found to be inadequate.-Problems of excreta disposal and safe water supply development in adequate amounts, often under combat conditions, were especially difficult on the smaller atolls. The eventual development of impervious concrete sewage holding pits and disposal of the collected sewage at sea was a solution to the problem during World War II. Provision of large stills for distilling sea water enabled a safe but paucivoluminous supply in contrast to the often brackish and easily contaminated water supply from the fresh water lens of the pervious coral atolls.
The Arctic is another example of terrain where conventional techniques are inadequate.
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Doubtless better methods await needed research and development for use when large numbers of troops enter such specialized environments if future unnecessary diarrheal disease in the Army is to be prevented.
7. Among prisoners of war when overcrowding was increased in emergency enclosures or camps.-This was true of both United States and enemy prisoners of war. Overcrowding associated with inadequacies of water supply and sanitation facilities was typical in emergency enclosures or camps. Characteristic of prisoners of war is a demoralization and lack of discipline. Sanitary disciplines must be very stringent at the very time of the demoralization if much morbidity and mortality is to be avoided. Senior officers and men captured by the enemy should insist upon the best possible sanitation discipline among their own personnel. Briefing of men prior to combat situations, in which they might become prisoners, should include information regarding the prevention of enteric diseases which so notoriously occur in such situations.
Prevention and Control Specific immunization.-Specific preventive measures were not developed for the various diseases included in the category of diarrheas and dysenteries during World War II. Research was conducted which led to the preparation of a polyvalent dysentery vaccine, but no successful evaluation was accomplished. Further research and controlled evaluation seem indicated. The high rates for diarrheas and dysenteries in several theaters where typhoid and paratyphoid A and B fevers also were endemic in native populations but amazingly infrequent among vaccinated United States Army troops, seems to emphasize the value of the triple typhoid vaccine. Development of a successful specific prophylactic for the dysenteries could result in lowering the incidence of not only reported bacillary dysentery but also that significant proportion of unclassified dysentery and the common diarrheas which is caused by the dysentery bacilli. More could be gained by such research if successful, than a simple perusal of reported bacillary dysentery incidence would suggest.
Isolation and treatment of recognized cases and carriers.-Early diagnosis and isolation was considered important to the control of the specific dysenteries. Adequate treatment to eliminate infection was considered fundamental for both control and good medical practice. Isolation was quite regularly utilized for the recognized bacillary dysentery cases but not so regularly for the common diarrheas. A significant proportion of the latter were doubtless unrecognized cases of Shigella or E. histolytica infection. This latter fact was not invariably appreciated nor was it always realized that most of the cases of the common diarrheas are infectious and are subject to the same general control measures as are effective for the specific dysenteries.
Surveillance of recognized carriers of specific dysenteries was quite routinely accomplished. In several locations, mass attempts at bacteriologic
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discovery of bacillary dysentery carriers and their treatment with the sulfonamide drugs was attempted. Such methods proved cumbersome and were impractical or impossible with the available facilities in outbreaks involving large populations.
Experimentally, in a few units with high incidence of recognized cases and carriers of bacillary dysentery, a mass prophylaxis using the sulfonamide drugs was attempted, and results seemed quite encouraging; but none of the experiments were well controlled. Sulfanilamide and its related compounds which at first seemed to be of such great value in therapy of bacillary and unclassified dysenteries later gave variable results. Doubtless the development of some resistant strains of dysentery bacilli contributed. Antibiotics, other than penicillin, which offer so much promise as therapeutic and prophylactic agents were not available during World War II.
Sanitary excreta disposal, fly control, and food and water sanitation.-The basic principles entailed in the sanitary disposal of human feces; in insect (especially common fly) control; in the sanitary supervision of the preparation, processing, and serving of foods (especially those which are moist or eaten raw); in the attainment of good personal hygiene of troops and particularly of foodhandlers; in the protection and purification of water; and in the development of adequate volumes of water supply for the literal washing away of the potentials of contact spread, were important to the prevention and control of both the specific dysenteries and the common diarrheas.
It is one thing to know that the efficient application of these basic principles can effectively prevent or control this group of diseases; it is another to apply them efficiently throughout a vast military organization dispersed in varied environments where local situations require particularized methods for rapidly achieving the desired objectives. From the history of the diarrheas and dysenteries in the United States Army in World War II, many lessons may be learned which will be of value in minimizing future incidence.
