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Chapter 15

Table of Contents

Chapter 15

Gastrointestinal Diseases: Background and Buildup

Colonel Ralph F. Wells, MC USA (Ret.)

* * * comfort may be derived from a knowledge that some of the best work of the profession has come from men whose clinical field was limited but well-tilled. The important thing is to make the lesson of each case tell on your education. The value of experience is not in seeing much, but in seeing wisely. [Osler (1894)].

Perhaps the ultimate medical irony of the Vietnam conflict is the paucity of substantial new information generated in the field of gastrointestinal disease. Areas which might have been, but were not, studied include the natural history of peptic ulcer in combat troops and the effect of new drugs, such as metronidazole, on the clinical course of the common enteric pathogens as well as on tropical sprue and amebiasis. The effect of antimalarial chemoprophylaxis on gut flora, though often the subject of speculation, was not investigated. Radioisotope capability was not available in Vietnam and was only belatedly available in offshore hospitals; thus, it remained for physicians in USAMCJ (U.S. Army Medical Command, Japan) or in CONUS (continental United States) to delineate the resolution time of amebic hepatic abscess. While the indirect hemagglutination test for amebiasis became available in 1965, neither this method nor other contemporary serologic methods were systematically investigated.

Several reasons for this lack of investigative accomplishment are apparent. The rapid buildup of troops and medical facilities meant that adequate laboratory support and diagnostic tools were not initially available. The short tour of duty militated against longitudinal study. Therefore, meaningful data were best collected by specifically designated teams. Although one might legitimately observe that the Vietnam conflict was not a vehicle for gastroenterologic research, the fact is that studies of gastrointestinal problems are mission-oriented, and the solution of these problems could contribute substantially to combat effectiveness in future conflicts. This is exemplified by the reduction in man-days lost from hepatitis resulting from classical clinical research conducted at the 6th Convalescent Center.


Enteric diseases, including salmonellosis, shigellosis, and amebiasis, had a profound impact on the U.S. effort in World War II. It is estimated that over a


million man-days were lost because of the latter disease alone (MD-MS, p. 408). Merrill's Marauders in the CBI (China-Burma-India) theater sustained 424 battle casualties and 1,970 casualties from disease; amebic dysentery, of which there were 503 cases, led the list of serious illnesses (War D-MM, p. 114). In Korea, days lost from duty because of diarrhea and dysentery totaled 78,970, of which 15,795 were for amebiasis (AR-TSG). Dysentery showed a distinct seasonal pattern, reaching a peak in August 1950 with morbidity rates of 120 per 1,000 per year and ranking second only to neuropsychiatric casualties (HOA, pp. 16, 22).   

In 1958, American troops were sent to Lebanon to help stabilize a deteriorating political situation. Task Force 201 was formed, and the first troops landed in late July. Enteric disease became a problem early, and diarrhea, although of short duration, caused significant morbidity. Specific morbidity rates per 1,000 troops per year are shown in table 57. In separate papers, Moore (1959) and Hurewitz (1960) analyzed the factors related to enteric disease incidence and assessed the sequelae as troops (particularly the 187th Airborne Battle Group) returned to Europe. They noted a breakdown of sanitation measures, improper food handling, a failure to load necessary preventive medicine equipment, and a critical shortage of preventive medicine personnel. An alarming shigella carrier rate approaching 5 percent was noted in troops returning to Germany. Shigella boydii (Type IV) was a common offender.

In May 1962, the 1st Battle Group, 27th Infantry Division, and marine units were airlifted to Thailand to meet a political crisis and experienced similar high diarrheal disease rates. The 1st Battle Group, 35th Infantry Division, relieved the 27th Division unit in September, and a further serious outbreak of diarrhea was prevented by rigid sanitation measures (Giffin and Gaines 1964).


Some indications of the problems to be expected in Vietnam could be found in the French publication, Revue Internationale des Services de Santé des Armées de Terre, de Mer e t de l'Air (Black). Between November 1945 and June 1954, there were 1,609,989 troops in Indochina: 614,981 European, 187,703 North African (Arab or Berber), 101,744 Black African, 704,131 Indochinese, and 1,400 from French India. A total of 193,380 cases of amebiasis were reported, most of which were diagnosed clinically; 88,568 amebiasis patients were hospitalized, 4,900 were repatriated, and 192 died. Other diseases of importance included shigellosis and viral hepatitis.

When the buildup of American forces in Southeast Asia began in 1965, the picture had changed little in the decade since the French experience ended. The magnitude of the diarrhea problem among U.S. personnel was evidenced by the rate of hospital admissions for diarrheal diseases in the first 7 months of 1965 (table 58). Accordingly, The Surgeon General dispatched a team from the AFEB (Armed Forces Epidemiological Board) Commission on Enteric Infections, composed of Doctors Horace M. Gezon, Franz J. Inglefinger, and Albert V. Hardy, to do an onsite survey in September 1965. The team was briefed by Col. (later Maj. Gen.) Spurgeon Neel, MC, Col. Samuel Gallup, MC, and Dr. Hugh Randel. Areas


TABLE 57.-Weekly disease admissions, Army Task Force 201, Lebanon, 1958 [Rates per 1,000 average strength per year]

TABLE 58.-Diarrheal disease admissions, U.S. military personnel in Vietnam, January-July 1965 [Rates per 1,000 per annum]

of major military activity, including Saigon, Bien Hoa, Da Nang, Nha Trang, and Cam Ranh Bay, were visited. Doctor Hardy studied patients in the hospitals and outpatient facilities in the Saigon area; Doctors Inglefinger and Gezon, accompanied by Maj. (later Col.) Robert Joy, MC, and members of the WRAIR (Walter Reed Army Institute of Research) Medical Research Team, examined patients, cultured specimens, and interviewed medical officers at the other four bases. Doctor Gezon wrote the final report (1966), an extensive summary of which follows.    

Although diarrheal disease was present throughout the country, severe debilitating disease was seen in only three places: Saigon, Nha Trang, and Cam Ranh Bay. The team questioned troops in the Bien Hoa area about their experience with diarrheal episodes since arriving in Vietnam. Nearly half of those who had been in the country for as long as two months reported having had an attack of diarrhea; about one-third of those reporting disease had had multiple attacks within four months. Only one-fifth of those with diarrhea had felt ill enough to seek medical attention. Reported rates clearly did not reflect the magnitude of the problem although they probably did reflect accurately that of


the more severe disease.    

According to dispensary records at Bien Hoa and Da Nang, enteric complaints accounted for roughly 10 to 20% of dispensary visits. Skin, respiratory, and venereal disease complaints were comparable in frequency. However, there were not sufficient data to calculate accurate diarrheal disease rates for an extended period of time. There was no evidence of an epidemic in units at these two locations; this observation was confirmed by the medical officers.

Two kinds of disease were recognized, one in which no bacterial pathogen was present and a more severe variety apparently caused by Shigella. Gezon described them as follows (pp. 9-10):

Typically those with the first variety complained of a sudden onset of mild abdominal discomfort soon followed by watery diarrhea, with perhaps three to five stools a day. Usually there was tenesmus, some cramps and occasionally mild vomiting, but without fever and with a total duration of perhaps two or three days. On examination these patients were not in great discomfort nor did they show dehydration. On proctoscopic examination the mucosa of the rectum appeared to be normal. The stool frequently was greenish liquid with no red or white cells present on microscopic examination. Culture revealed no pathogens. Fresh smears showed no Entamoeba histolytica.

Patients with the second type of disease also gave a history of sudden onset of symptoms but frequently with vomiting, fever as high as 105°F, chills, and numerous liquid stools per day. Stools usually were described as mucoid, liquid, and bloody. A maximum frequency of upwards of 20 stools per day was reported. These patients on examination appeared to be acutely ill, quite toxic, and sometimes moderately dehydrated. On proctoscopic examination the mucosa was found to be hyperemic, edematous, friable, but with no distinct ulcerations present. Mucus obtained at proctoscopy or direct stools obtained on these patients sometimes was grossly bloody. Microscopic examination frequently showed large amounts of cellular exudate with innumerable white cells. Frequently innumerable red cells were also seen. On culture approximately 60% of these patients were positive for Shigella.    

The severe form was found particularly among patients from Cam Ranh Bay and Nha Trang, but only in a limited number of units. The patients in Nha Trang were mainly recent arrivals who were quartered in an area known as "Tent City." In Cam Ranh Bay they were largely from one company, the 611th Ordnance, also recently arrived. Nearly one-half of this unit developed diarrhea within a three or four day period; the outbreak was attributed to the mistaken use of untreated bay water for dishwashing.

The results of cultures from the 176 patients examined by the team are given in table 59. Nine serotypes of Shigella were isolated altogether, and as many as seven serotypes were found to be present simultaneously in a given area. Sh. flexneri 2A, which predominated, was isolated largely from one group in the Nha Trang area. All of the Shigella isolates were found to be resistant to sulfadiazine and most to tetracycline; only a few were resistant to chloramphenicol or kanamycin. The results of drug trials are shown in table 60.    

Amebiasis was reported to be the principal etiologic agent of diarrhea in hospitalized patients. The incidence varied during different periods but the disease had been reported steadily during most of 1964 and 1965. The team was told that 600 amebiasis patients were diagnosed at the Navy Hospital alone in


TABLE 59.-Enteric pathogens cultured from 176 U.S. military personnel with acute diarrheal disease in Vietnam, September 1965

the first six months of 1964 and again in the first six months of 1965. Most of these, of course, were seen as outpatients. Amebiasis was treated with emetine, carbarsone, Diodoquin, Entero-Vioform, and tetracycline, singly or in combination; in some instances as many as four drugs were used on a given patient. Patients were said to respond promptly to the anti-amebic therapy.

Gezon, Inglefinger, and Hardy made a direct microscopic examination of freshly obtained stool or proctoscopic specimen, with and without iodine staining, from approximately 90% of the 176 patients they studied; no E. histolytica cysts or trophozoites were seen. A portion of the specimen was placed in


TABLE 60.-Antibiotic sensitivity of Shigella strains isolated in 176 U.S. military personnel in Vietnam, September 1965

polyvinyl alcohol/Schaudinn's solution and sent to Dr. Elvio Sadun at WRAIR for a definitive parasitological diagnosis. Only 37 specimens were in satisfactory condition when received in his laboratory after a nearly 3 month delay in transit; none was positive for E. histolytica

On several occasions the team was able to reexamine the stool and perform another proctoscopy on the patient on the same day that the clinical laboratory found E. histolytica cysts or trophozoites in his stool; in no instance could they confirm the diagnosis of amebiasis either clinically or parasitologically. In at least two of the laboratories, white cells and macrophages were being called cysts and trophozoites of E. histolytica, and in some instances both trophozoites and cysts were reported in the same specimen. It was evident that amebiasis was being grossly overdiagnosed. Undoubtedly many patients who had been treated for intestinal amebiasis had either nonspecific diarrhea or shigellosis.

Casual inspection of the several bases revealed numerous environmental problems caused largely by the rapid buildup of personnel and overuse of existing facilities. Dishwashing and handwashing facilities were inadequate in most activities. Frequently there were not enough latrines and those which were available were unsanitary. Water in the field was of questionable quality; much of it was surface water which was treated in an Erdlator. Thus it seemed that much of the diarrheal problem could be attributed to inadequate environmental control and only a small fraction of it to food obtained off base. The most obvious environmental difficulties were in areas where troops arrived in large numbers and facilities for receiving them were inadequate. This was true particularly in Nha Trang and Cam Ranh Bay and to some extent in Saigon.

The final recommendations made by the team were as follows (p. 12):

(1) That a competent parasitologist instruct the laboratory technicians in the correct diagnosis of amebiasis and that the diagnosis of acute amebic colitis be made only when multiple trophozoites


were found in the stool. These trophozoites should have a clear cytoplasm, definite directional motility and at least some with ingested red cells.

(2) That the acute diarrheal disease accompanied by fever and with WBC's in the direct stool smear be considered as probably due to a bacterial agent. When feasible the treatment instituted should be based on cultural studies. If cultural facilities are unavailable these should be treated as bacterial infections.

(3) That handwashing facilities, more adequate dishwashing facilities and screening of mess halls and kitchens be procured and tighter policing of kitchens be instituted.

(4) That the Commission on Enteric Infections prepare a proposal to continue this investigation, which began as a scouting visit, and attempt to carry out a definitive study on etiology, therapy and control of diarrheal disease in our troops in Vietnam.

The rate of admission to hospital or quarters in Vietnam for diarrheal disease in comparison to malaria and total disease admissions is given in table 61. Diarrheal disease rates were relatively constant, while the rates for malaria and other diseases seemed to fluctuate in relation to combat or geographic factors. Some indication of the difficulty encountered in identifying the specific causes of diarrheal disease is seen in table 62, which compares all reported diarrheal disease with amebiasis and bacillary dysentery. Amebiasis was diagnosed with decreased frequency in early 1966 as a direct consequence of the AFEB report's sharp criticism of diagnostic standards. In fact, diagnostic criteria became so stringent that amebic colitis was probably underdiagnosed, resulting in a disproportionate number of hepatic abscesses being encountered for the number of reported cases with intestinal involvement (Sheehy 1968). It remained for Col. Hinton Baker, MC, commander of the 9th Medical Laboratory, to carry out an intensive educational program for laboratory personnel to correct the situation.

TABLE 61.-Admissions to hospital or quarters, U.S. Army active-duty personnel in Vietnam, January 1965-March 1966 [Rates per 1,000 average strength per year]


TABLE 62.-Number of diarrheal cases reported to USARV medical consultant, January-March 1966

In 1967 and 1968, it was noted that diarrheal diseases among the troops increased significantly during the "dry season" (March through June). Studies were conducted in 1969 to further clarify the etiology of these disorders. A team under the direction of Lt. Col. John Kalas, MC, conducted an extensive study at hospital and troop level. Their report (Kalas and Bearden 1969) describes the first part of the study, which was conducted at the 3d Field Hospital in Saigon, the 8th Field Hospital in Nha Trang, and the 17th Field Hospital in An Khe, as follows (p. 2):    

Two hundred and four hospitalized and/or dispensary cases were studied. All of the cases were sigmoidoscoped; a biopsy taken; mucosal scraping for wet mount preparation was performed; and cultured for bacteria. Fecal smears were also fixed in Schaudinn's solution, PVA, and 10% buffered formalin; all for later confirmation of parasites after exposure to appropriate staining. Many of the hospitalized patients were also intubated for duodenal drainage for parasites, and small intestinal biopsy.

Results were as follows:

(1) No etiologic agent could be identified in 80% of the cases.

(2) Shigella and salmonella organisms were isolated from the stool specimens of 29 (14%) of 204 cases; 23 patients had shigella organisms and 6 had salmonella organisms.

(3) Upon initial examination, 57 of 204 patients were believed to have a bacterial enterocolitis (history of elevated temperature, bloody diarrhea, sigmoidoscopic evidence of grossly involved colon, and a wet prep exam of stool revealing clumps of WBC's with no evidence of E. histolytica). However, a possible etiologic bacterial agent was found in only 29 cases.

(4) Parasites were found in 17 of 204 cases (8%). Amebiasis was identified in four patients and was considered responsible for the symptoms in all of them. Four cases of hookworm were found, only one of which was symptomatic. Two


patients (from Puerto Rico) had eggs of Schistosoma mansoni in their stools but their symptoms were not believed to be related to the intestinal parasites. Only one patient had pinworm infection, which was asymptomatic. Five patients had Giardia lamblia infections, four of which were symptomatic.    

(5) "Pathogenic E. coli" was isolated from 16% of the patients. However, it was also isolated from the stool specimens of 19% of control patients (patients without diarrhea and not subjected to antibiotics within the past month).

The second part of the study was conducted at three battalion aid stations in Bong Son and in one clearing company of the 173d Airborne Brigade there; at the battalion aid station and the clearing company at Bao Loc (173d Airborne Brigade); in the 43d Medical Group; and at four battalion aid stations in Qui Nhon (55th Medical Group). The method of study used was inquiry, since the caseload at this level was not sufficient to make the results significant. The fact that diarrheal diseases were not a problem at this level explained the low rate of diarrheal disease reported in the Command Health Report.

Six platoons of the 173d Airborne Brigade in Bong Son were also studied, using an extensive questionnaire and cultures obtained by rectal swab. It was evident that diarrheal disease was a significant problem at the platoon level. About 60% of the 100 troops interviewed had diarrhea at the time of the questioning. A similar situation was believed to exist throughout the country, based on verbal reports from troops in units in other areas (III, and IV Corps).

One possible explanation for the high incidence of diarrhea was the failure of the combat troops to use their water purification tablets properly; 54% of those interviewed admitted they did not use them as directed while on patrol. The major objection to the halazone tablets was the taste they imparted to the water, although some individuals attempted to solve this problem by adding concentrated fruit flavoring. The second important objection was that troops really had no satisfactory method of carrying the tablets with them on combat missions. It is noteworthy that 94% of the same combat troops stated they faithfully used the weekly chloroquine-primaquine tablets as directed.

The authors of the report made the following recommendations (pp. 4-5):

(1) This is the second disease which has been investigated at the platoon level, the first being skin diseases in the delta [Allen et al. 1972]. Neither of these diseases has ever received the necessary attention, and neither appears significant in the Command Health Report. It appears that platoon level epidemiology is necessary for the adequate management of diseases at the combat troop level.

(2) A more complete search for bacterial and viral etiology in enteric disease in troops is necessary since 80% of the cases do not have a demonstrable etiology.

(3) A more complete understanding of the altered physiology of diarrheal diseases is necessary for immediate treatment of the patient, regardless of etiology. At least for the foreseeable future many of the cases of gastroenteritis will not have a demonstrable etiologic agent. These diseases should be classified according to altered physiology and treatment adjusted accordingly.


Allen, A. M.; Taplin, D.; Lowy, J. A.; and Twigg, L. 1972. Skin infections in Vietnam. Mil. Med. 137: 295-301.

AR-TSG-Medical statistics of the United States Army. 1955. Annual Report of the Surgeon General. Calendar year 1953. Washington: Office of the Surgeon General.

Black, Lt. Col. Robert H., Royal Australian Army Medical Corps, Consultant in Tropical Medicine, AHQ. An account of the health aspects of the French campaign in Indo-China, 1945-1954. Medical Liaison Letter, undated.

Gezon, H. M. 1966. Special report on the visit to Cairo and S.E. Asia in August and September, 1965. Report, Armed Forces Epidemiological Board, Commission on Enteric Infections, 22 Apr. 66.
Giffin, R. B., Jr., and Gaines, S. 1964. Diarrhea in a U.S. battle group in Thailand. Mil. Med. 129: 546-50.

Health of the Army. See HOA.

HOA-Office of the Surgeon General, U.S. Army. 1953. Korea: A summary of medical experience, July 1950-Dec. 1952. Health of the Army, Jan., Feb., and Mar. 53. Copies at Uniformed Services University of the Health Sciences.

Hurewitz, S. 1960. Military medical problems of the Lebanon crisis. Mil. Med. 125: 26-35.

Kalas, Lt. Col. John P., MC, and Bearden, Maj. James H., MC. 1969. Trip report to Vietnam, 18 February 1969 to 8 June 1969; to evaluate the problem of gastroenteritis in combat troops at the hospital, battalion aid station, and platoon (or company) level. Report to commander, U.S. Army Medical Research and Development Command, Washington, D.C., 25 Jul. 69.

Long, Col. Arthur P., MC, Chief, Preventive Medicine Division, Office of the Surgeon General. 1960. Preventive medicine lessons learned in Lebanon. Disposition Form to Director, Historical Unit, 26 Jan. 60.

MD-MS-Medical Department, U.S. Army. 1975. Medical statistics in World War II. Washington: Government Printing Office.

Medical statistics in World War II. See MD-MS.

Medical statistics of the United States Army, Annual Report of the Surgeon General. See AR-TSG.
Merrill's Marauders. See
War D-MM.

Moore, W. S. 1959. Lessons learned from the Lebanon crisis. M. Bull. U.S Army Europe 16: 61-65.
Osler, Dr. William. 1894. The Army surgeon. Graduation address presented at the Army Medical School, Washington, D.C., 28 Feb. 94.

Sheehy, T. W. 1968. Digestive disease as a national problem. VI. Enteric disease among United States troops in Vietnam. Gastroenterology 55: 105-12.

USARV surgeon. Monthly Command Health Reports to USARV commander, Jan. 1965-Apr. 1966. On file at the U.S. Army Center of Military History.

War D-MM-U.S. War Department, Military Intelligence Division. 1945. Merrill's Marauders (February-May 1944). American Forces in Action Series. Copy at U.S. Army Center of Military History.