CHAPTER XXIV
Nematode and Cestode Infections
Clyde Swartzwelder, Ph. D.
With the exception of filarial and hookworminfections, parasitism of United States Army troopsby nematodes and cestodes during World War II did not constitute a veryimportant militaryproblem. The total United States Army admissions during the years 1942through 1945 forinfections with selected parasites are shown in table 89. Thedistribution of hospital and quartersadmissions, in 1944, of troops infected with these parasites ispresented by area and theater intable 90. Except for trichinosis and tapeworm infections, a largemajority of the nematode andcestode infections apparently were acquired overseas.The number ofhospital and quartersadmissions is indicative of the problem of acute disease.Theseadmissions do not indicate, exceptindirectly perhaps, the number of troops infected.
The report of Stoll, entitled "This Wormy World," 1 represents a classic in the field of the geography of parasitism. The number of human helminthic infections in millions, calculated by Stoll, is shown in table 91. This table gives ample evidence of the presence of reservoirs of parasitic worms throughout the world which might provide a source of infection and a potential hazard to troops unless adequate protective sanitary measures were employed. Military organizations made numerous surveys of native groups living in the vicinity of troop concentrations; these surveys provide additional evidence of the presence of a source of infection for troops.2
NEMATODE INFECTIONS
Strongyloidiasis
There was a total of 1,242 admissions forinfection with Strongyloides stercoralis during theyears 1942 through 1945. In 1944, there were 336 recorded admissionsfor this infection.Ofthese, 237 represented admissions in overseas theaters. Ninety-ninecases were admitted in theUnited States during that year. The areas with the largest numbers ofreported cases in 1944 werethe Central and South Pacific, Southwest Pacific, Latin America,
1 Stoll,N. R.: This wormy world. J. Parasitol. 33: 1-18, February 1947.
2 (1)Hansen, M. F., and Bern, H. A.: A Roundworm Problem in the Philippines.Air Surgeon's Bull. 2: 377,November 1945. (2) Fink, H.: A Helminth Survey From an Autopsy SeriesonNatives of Okinawa, With Commentson Complications of Ascariasis. Am. J. Trop. Med. 28: 585-588, July1948. (3) History of Preventive Medicine, Headquarters, U. S. ArmyForces, Middle Pacific, December 1941-September 1945, pp.201-206. [Official record.]
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China-Burma-India, and the Mediterranean (table90).A single stool examination will fail todiagnose all cases of strongyloidiasis. Many infections requireduodenal aspiration fordemonstration of diagnostic forms. On a number of occasions, the writerobserved cases ofstrongyloidiasis erroneously
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diagnosed as hookworm infection in overseas areas. Thus the numberof infections acquired nodoubt greatly exceeded those, correctly diagnosed and recorded asstrongyloidiasis.
Maj. A. A. Liebow, MC, and 1st Lt. C. A. Hannum, SnC,3 reported that infection with S. stercoralis stood next in frequency to hookworm among admissions of troops from the Solomon Islands to the 39th General Hospital for helminthiases. Routine stool examinations which were performed at the hospital between February and December 1943 showed that 7.4 percent of 633 specimens were positive for rhabditiform larvae of S. stercoralis. Denhoff 4 pointed out the striking similarity between the symptoms of patients with strongyloidiasis and those of other troops with anxiety, neurosis. Delay in diagnosis of Strongyloides infections for long periods, without clinical relief, and the lack of a satisfactory treatment contributed to the difficulty in separating complaints from psychoneurosis and those from strongyloidiasis in troops. Denhoff called attention to the fact that duodenal intubation as a diagnostic method for Strongyloides infection lead not been stressed sufficiently. The 8th General Hospital, stationed at New Caledonia in 1944, reported that
3 Liebow,A. A., and Hannum, C. A.: Eosinophilia, Ancylostomiasis andStrongyloidiasis in the South PacificArea.Yale J. Biol. and Med. 18:381-403, May 1946.
4 Denbolf,E.: The Significance of Eosinophilia in Abdominal Complaints ofAmerican Soldiers. New England J.Med. 236: 201-206, February 1947.
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TABLE 91-Thecalculatednumber of human helminthic infections, in millions 1
1 Reproducedby permission of Norman R. Stoll, Sc. D.
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TABLE 91-The calculated number of human helminthicinfections, in millions- Continued
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hookworm and S. stercoralis were the commonest intestinalparasites encountered. Theinfections with S. stercoralis were more resistant to treatmentand appeared to be more clinicallysignificant than the hookworm infections.5 A prevalence ofstrongyloidiasis of 12 percent wasreported in 150 Puerto Rican enlisted men at Fort Brooke, P. R.6One infection withStrongyloides fulleborni, normally a parasite of monkeys, wasrecorded. 7 The patient hadkept a pet monkey while stationed on the island of Leyte in thePhilippines.
The following information supplied by Dr. C. A. Jones, chief of the medical service of the Veterans' Administration Hospital, New Orleans, La., provides excellent information on the problem of strongyloidiasis in veterans of World War I and World War II. Between 4 May 1946 and 11 October 1950, 21,784 patients were admitted to the hospital. The diagnosis of strongyloidiasis was established in 123 of these patients-approximately 0.6 percent of the total admissions. Forty-two of these patients were veterans of World War I. Of this group, 14 served in areas outside the United States. Thirteen had service within the continental limits of the United States. In 15 cases, data on foreign service were not recorded. The available records indicate that all except one of these patients had no military duty outside the continental limits of the United States for approximately 30 years. The World War I group of patients probably acquired their infections in areas around their homes. Most of these World War I veterans were farmers or had other occupations which brought them in close contact with the ground. The homes of 35 of these World War I veterans were in rural Louisiana, Mississippi, or Arizona. Seven lived in New Orleans. Each of this older group of patients had received an average of 66 days of hospital care. This prolonged period of hospitalization resulted from repeated admissions to the hospital and complicating or accompanying chronic degenerative diseases. The relative proportion of veterans of World War I and of World War II in the series of 123 cases was approximately the same as the ratio of their admission to the hospital.8
There were 81 patients whose service occurred during World War II. One of these had service in both the First and Second World Wars. In contrast to the patients of World War I, at least 46 had duty outside the continental limits of the United States. Twenty-five of this group served in England, France, Italy, North Africa, or in the Middle East. The remainder had duty in the Pacific. Twenty-three had service exclusively within the continental limits of the United States. In 12 cases, the precise location of military duty other than the United States was not stated. The World War II veteran group included farmers, laborers, truck drivers, and skilled mechanics. The majority of these veterans lived in rural areas of Louisiana, Mississippi, and Texas. Thirteen came from larger communities such as New Orleans,
5 AnnualReport of the Activities of the 8th General Hospital, New Caledonia,for the year ending 31 December1944.
6 History of Medical DepartmentActivities, Antilles Department, Preventive Medicine, p.67.[Official record.]
7 Wallace,F. G., Mooney, R. D., and Sanders, A.: Strongyloides FiilleborniInfection in Man. Am. J. Trop. Med. 28:299-302, March 1948.
8(1)Personal communication to author.(2) Jones, C. A.: Clinical Studies inHuman Strongyloidiasis; Semeiology.Gastroenterology 16: 743-756, December 1950.
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Birmingham, Ala., and Houston, Tex. The epidemiologic data indicatethat these patients, withfew exceptions, live in areas where strongyloidiasis is endemic. In thepatients who served inWorld War II, exposure to polluted soil in endemic areas in the UnitedStates is probable.However, over half of these veterans served outside the limits of theUnited States in areas wherestrongyloidiasis is also endemic and prevalent. The hazard of infectionwas probably greaterunder overseas combat conditions than in these men's civilianoccupations or around theirhomes.
Of the 123 patients in whom a diagnosis of strongyloidiasis was established, approximately 90 percent had gastrointestinal symptoms of mild or severe nature. These symptoms were mainly those of abdominal pain, diar rhea, and allergic manifestations such as urticaria and asthma. Many have had repeated recrudescences of symptoms requiring repeated hospitalization; this has already resulted in an average period of hospitalization of approximately 45 days for each of these World War II veterans. Many of this latter group had no other disease to account for their illness, in contrast to veterans of World War I, many of whom had other chronic diseases to prolong their hospital stay. Data on the first 100 patients with the diagnosis of strongyloidiasis have been reported by Dr. Jones in Gastroenterology.
It is interesting to note that Hall 9 reported in 1918 that Dr. C. W. Stiles recommended during World War I that soldiers infected with S. stercoralis should be discharged from the service. The reason for this recommendation was that no satisfactory treatment for this condition was known.
It is the opinion of the writer thatstrongyloidiasis constitutes an important postwar problemamong veterans. In many cases, the disease is difficult to diagnose,with the result that infectionmay be overlooked for long periods. The duration of some infectionsapparently may be 10 ormore years. The natural reduction or loss of infection withouttreatment appears to be lessmarked in strongyloidiasis than in many other intestinal helminthiases.Treatment ofstrongyloidiasis is not satisfactory, although clinical relief may beafforded by repeated coursesof gentian violet. The search for an effective therapeutic drug meritsinvestigation and support inorder to remove infections acquired during military service. Most ofthe measures designed toprevent hookworm infection in troops would also serve to preventstrongyloidiasis. The initialmode of infection, that is, penetration of the skin by larvae, issimilar in both infections.
Ascariasis and Trichuriasis
Maj. C. A. Kofoid, SnC, 2d Lt. S. I. Kornhauser,SnC, and 2d Lt. J. T. Plate, SnC, recorded aprevalence of 1 percent of ascariasis in overseas troops and a 0.3percent prevalence in home-service troops in World War 1. They alsoreported that there was a definite indication ofacquisition of Trichuris
9 Hall, M. C.: Parasites in WarTime. Scient. Monthly 6:106-115, February 1918.
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trichiura, the whipworm, in troops with overseas serviceduring the First World War.The studyinvolved 1,200 overseas and 300 home-service troops of the UnitedStates Army.The prevalenceof whipworm infection was 6 percent in the overseas troops and 2percent in the home-servicegroup. This threefold increase was all the more significant ifallowance was made for the factthat 5 of the 6 infections in home-service troops were in recentimmigrants from Italy andRussia. If these infections were deducted, the prevalence in theremaining home-service troopswas 0.3 percent.10
In World War II, there were 5,031 admissions of United States Army troops for ascariasis between 1942 and 1945. The admissions for infection with Ascaris lumbricoides in overseas theaters totaled 3,630. The remainder, 1,401, represents admissions in the continental United States. In 1944, the largest numbers of admissions for ascariasis occurred in the Mediterranean and European Theaters of Operations. No figures are available for hospital admissions for trichuriasis. Usually only heavy infections with T. trichiura produce clinical manifestations. Light infections, which ordinarily are subclinical, are not treated for lack of a completely satisfactory therapeutic agent.A few reports of experiences with these two intestinal nematodes in troops follow.
Capt. D. R. Lincicome, SnC, and 1st Lt. John R.Shaver, SnC, reported a 34.4 percent prevalenceof ascariasis in the 13th Engineer Battalion, 7th Infantry Division,which had been in combat onLeyte.11 An infantrybattalion stationed near Manila, P. I., were examined by personnel ofthe26th Medical Laboratory, who found 18 percent of the troops infectedwith A. lumbricoides and10.7 percent infected with T. trichiura.12 Incidentally, a prevalence of 83 percent infected withA. lumbricoides was recorded in a group of Philippine civilianswho lived adjacent to troops.13May 14 surveyed 400 American Soldiers interned by theJapanese andfound that 35 percent hadascariasis and 40 percent had trichuriasis. A. lumbricoideswas second in prevalence amongparasitic helminths in continental soldiers stationed in the CanalZone. The infection rate per1,000 per annum from 1940 to 1945 was 3.96.15Intestinal parasitism was found in about 80percent of 150 Puerto Rican soldiers examined at Fort Brooke. Theprevalence of T. trichiura,the whipworm, was 55 percent. 16 Othersurveys of Puerto Rican troops stationed in the UnitedStates revealed prevalence of 53 and 72 percent infected with T.trichiura despite postinduc-
10 (1)Kofoid, C. A., Kornhauser, S. I., and Plate, J. T.: IntestinalParasites in Overseas and Home Service Troops ofthe U. S. Army. J. A. M. A. 72:1721, June 1919. (2) The MedicalDepartment of the United StatesArmy in theWorld War.Communicable and Other Diseases.Washington: U. S. GovernmentPrinting Office, 1928, vol. IX, pp.529-549.
11 MedicalBulletin No. 19, Headquarters, Army Service Command 1, Office of theSurgeon, Okinawa, 17 Sept.1945.
12 EssentialTechnical Medical Data, Headquarters, U. S. Army Forces, Pacific,October 1945, p. 35.
13 SemimonthlyReport of Activities of the 19th Medical Service Detachment (GeneralLaboratory), U. S. ArmyServices of Supply, for the First Half of March 1945, to the ChiefSurgeon, Headquarters, U. S. Army Services ofSupply, Southwest Pacific, 17 Mar. 1945.
14 May, E.L.: Parasitologic Study of Four Hundred Soldiers Interned by theJapanese. Am. J. Trop. Med. 27: 129-130, March 1947.
15 ProfessionalHistory of Internal Medicine in World War II, 1 January 1940 to 1October 1945, the Panama CanalDepartment, vol. II, p. 252.[Official record.]
16 See footnote 6, p. 508.
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tion treatment.17 A routine stool surveyof 1,456 insular troops who were admitted to hospitalsin the Canal Zone revealed that 76 percent were positive for ova of T.trichiura. The whipwormrate in insular troops in the Panama Canal Department per 1,000 perannum as determined bystool examination during hospitalization (1943-45) was 21.31.18The 105th General Hospital,which was located in the -Southwest Pacific, received alarge number of patients who wereinfected with T. trichiura. The infections wereasymptomatic, and no treatment wasadministered. 19
In general, infections with A. lumbricoides, the large intestinal roundworm, and with T. trichiura, the whipworm, were of minor medical significance in United States Army troops during World War II. No deaths in troops were caused by either of these parasites. About 5,000 admissions for ascariasis were recorded. Effective anthelmintics were available for therapy of cases of ascariasis. The treatment is of short duration and does not require prolonged hospitalization. Trichuriasis was apparently prevalent in many overseas theaters. High prevalences were recorded in numerous surveys. Most cases of whipworm infection have light worm burdens which represent subclinical infections.Some of the 2,275 admissions listed under "Nematode infection, other" (table 89) possibly include clinical cases of trichuriasis. Since an effective anthelmintic for the treatment of whipworm infections is lacking, search for a satisfactory drug for use in clinical infections should be initiated and supported.
In countries where human feces are commonly used as fertilizer, troops generally were prohibited from serving and eating vegetables raw. The regulation probably prevented numerous cases of ascariasis. Embryonated eggs in feces-polluted soil frequently provide the source of infection.Troops often are, of necessity, in contact with soil from which their hands may easily be contaminated. Ingestion of these eggs will produce infection. Personal hygiene, therefore, is very important in the prevention of ascariasis. Proper disposal of excreta is necessary to prevent spread of the infection.
Enterobiasis
The total number of admissions for Enterobiusvermicularis, the pinworm, is recorded as 1,272(table 89). Of these, 889 occurred in overseas troops. The symptoms ofmany pinworminfections probably were not severe enough to induce men to seekmedical treatment. Anal-swabtechniques were not universally employed in military establishments forthe diagnosis ofEnterobius infections. Since stool examination is notoriouslyinefficient for the detection
17 (1)Report of Disinfestation Program in 762d and 891st Antiaircraft GunBattalion, by Lt. Col. G. H. Houck, MC,Capt. P. L. Burlingame, SnC, Capt. M. S. Watts, MC, and 1st Lt. G. T.Marconis, MC, Fourth AntiaircraftCommand, Post Office Box 3552, San Francisco 19, Calif., 5 Aug. 1945.(2) Letter, Lt. Col. G. H. Houck, MC,Army Air Forces Regional and Convalescent Hospital, Office of Chief ofMedical Service, Santa Ana Army AirBase, Calif., to the Surgeon, Headquarters, Fourth Air Force, SanFrancisco, Calif., 22 June 1945.
18 Seefootnote 15, p. 510.
19 AnnualReport of 105th General Hospital, Southwest Pacific, 29 Jan. 1944.
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of pinworm infections, the statistics probably do not reflect thedegree of parasitism even inclinical cases of enterobiasis in troops. The small number ofadmissions recorded suggests thatEnterobius infection was not a serious problem. Pinworminfection reaches high incidence underinstitutional conditions. Troops living in barracks or otherwise housedin large groups providesimilar conditions which might predispose to mass infection with E.vermicularis.Viablepinworm ova may occur in household dust, bedclothing, toilet fixtures,and innumerable otherobjects indoors. Rigid personal. hygienic measures and cleanliness oftroop quarters arenecessary to minimize and suppress this infection.
Trichinosis
There were only 285 hospital and quartersadmissions for trichinosis in the United States Armyrecorded from 1942 through 1945 (table 89). About three-fourths (208)of these admissionsoccurred in the United States. One death from trichinosis was recordedin 1944.Additional caseswere recorded in May 1941 by Maj. Alexander A. Marble, MC, Capt. AllenP. Skoog, MC, and1st Lt. Donald J. Bucholz, MC.20 Thirteen soldiers in LCompany, 104th Infantry Regiment, 26thInfantry Division, Camp Edwards, Mass., were admitted to the stationhospital with clinicaltrichinosis. Based upon the presence of eosinophilia, it was estimatedthat from one-third to one-half of Company L (142 troops) probably hadasymptomatic trichinosis.
The low incidence of trichinosis in United States Army troops suggests that pork and pork products generally were cooked thoroughly before being served in military installations.
Trichinosis was more of a problem in German prisoners of war than in United States Army troops. Several outbreaks occurred among interned prisoners. Many German prisoners of war preferred and were accustomed to eating meat raw. The outbreaks of trichinosis among these prisoners were due primarily to this habit and to the failure of prisoner-of-war cooks to comply with clear and precise instructions to cook all pork and pork products thoroughly before serving to their fellow prisoners. To obtain better compliance with orders for the proper preparation of meat to prevent trichinosis, closer supervision of mess personnel and oral as well as written instruction of all prisoners of war would be necessary. Section VII, Army Services Forces Circular No. 160, 4 May 1945, specifically prohibited permitting German prisoners of war to consume raw pork.
An outbreak of trichinosis occurred at Camp Atterbury, Ind., in December 1945. One hundred and three prisoners of war with trichinosis were admitted to Wakeman General Hospital. The clinical diagnosis was adequately substantiated by laboratory studies. Because of lack of hospital space, 77 others with symptoms similar to those exhibited by patients sent to the hospital
20 Marble, A., Skoog, A. P., andBucholz, D. J.: Trichinosis: Report of an Outbreak at CampEdwards, Massachusetts. Mil. Surgeon 90: 636-643, June 1942.
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were admitted to isolation barracks. In addition there were 409patients with similar but mildersymptoms who were kept in their quarters. There were no cases oftrichinosis reported inAmerican personnel at the camp. Epidemiologic evidence indicated thatcanned bacon and porkwhich were consumed without cooking caused the infections. Elevenprisoners of war from theprisoner-of-war camp at Austin, Ind., who had trichinosis were alsosent to Wakeman GeneralHospital in December 1945. 21
Eighty-three German prisoners of war with clinical trichinosis were admitted to an Army Air Force regional station hospital in the United States in December 1945.22 Uncooked sausage presumably provided the source of infection. An outbreak of trichinosis also occurred at Fort Custer, Mich.23 It resulted in the hospitalization of 256 German prisoners of war. Raw pork sausage which lead been made into sandwich spread and inadequately cooked meat loaf, prepared contrary to published orders, presumably were the sources of infection. A board of officers recommended that:
1. All meals should be inspected by Americanpersonnel at the time themeal is being served.
2. All mess personnel, American and German, should read, in the presence of the commanding officer of the respective company, all instructions relative to preparation and serving of food to prisoners of war.
3. All members of the respective mess detailsshould sign the aboveinstructions after readingthem.
4. Copies of these instructions should be posted in a conspicuous place in each messhall.
CESTODE INFECTIONS
There were 2,036 admissions for cestodeinfections recorded during the period 1942-45. Of thistotal, 1,349 admissions were in the United States. Twenty-twoadmissions for Echinococcusinfection occurred during the period. Cysticercosis was reported in onepatient during 1944 and1945.There were 2,013 other cases of cestode infection. Most of thesewere probably due toTaenia saginata, the beef tapeworm.Had any cases ofcysticercosis occurred in 1942 and 1943,which seems relatively unlikely, they would have been included among932 of the above 2,013cases of cestode infection (footnote 5 of table 89).
21 (1) Letter, Col. W. O.H. Prosser, MC, Post Surgeon, Camp Atterbury, Ind., to the CommandingGeneral, FifthService Command, Army Service Forces, Fort Hayes, Ohio, 29 Dec. 1945,subject: Investigation of Outbreak ofTrichinosis Among German Prisoners of war. (2) Davis, W. A., andCleland, R. R.: Trichinosis in Prisoners of War.Bull. U. S. Army M. Dept. 7: 973-976, November 1947.
22 Hathaway, F. H., andBlaney, L.: Trichinosis; Report of an Epidemic. Ann. Int. Med. 26:250-262, February1947.
23 (1) Annual Report,Surgeon, Sixth Service Command, Calendar year 1945, to the CommandingGeneral, ArmyService Forces, 27 Feb. 1946. (2) Report of Proceedings of Board ofOfficers, Army Service Forces, Sixth ServiceCommand, 1611th Service Command Unit, Prisoner of War Camp, FortCuster, Mich., 17 Mar. 1945. (3)Oppenheim, T. M., Whims, C. B., and Frisch, A. W.: Clinical andLaboratory Observations on 256 Cases ofTrichinosis.Bull. U. S. Army M. Dept. 6: 581-593, November 1946.
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Echinococcus Infection (HydatidDisease)
Military personnel were no doubt exposed to Echinococcusinfection in endemic areas such asNew Zealand, Australia, the Mediterranean littoral, andIceland.Although 15 of the 22 cases ofechinococciasis in United States Army troops were admitted to hospitalsin the United States,their origin may well have been in overseas theaters either prior to orduring World War II. Thedisease is endemic in the United States, but it is also rare inoccurrence.24 The incubation period insome cases of hydatid disease may be many years in duration. One deathfrom Echinococcusinfection occurred in 1944. In 1947, Mathieson 25reported a case of hydatid disease of the lungin a United States Army veteran of World War II. According to Magath,26the patient lead beenin Casablanca, French Morocco, 4 months, another 8 months elsewhere inNorth Africa, and 16months in and about Naples and elsewhere in southern Italy. The onlycontact which the patienthad with dogs was in Italy, where the soldier's infection was mostlikely acquired.
Occasionally troops kept dogs as pets and unit mascots in overseas areas where hydatid disease was endemic.Trained dogs were also used by military services.Dogs constitute the chief source of human infection with Echinococcus granulosus. Since the parasite may, in many cases, require years of development in man before clinical manifestations result, it is possible that this disease may occasionally be detected in the future in veterans. If troops were prohibited from keeping dogs as pets, the hazard of infection might be reduced. However, complete enforcement of such a regulation is difficult to attain.
Cysticercosis
The results of a recent statistical investigationof individual records of cysticercosis indicatedthat there was actually only one case of this disease. The admissionoccurred in theMediterranean theater in 1945. Cysticercosis is a relatively rareinfection with the larval stage ofTaenia solium.
Man is the only host of the pork tapeworm, T. solium. Since infection with Cysticercus cellulosae ordinarily originates from ingestion of T. solium eggs (except in cases of internal autoinfection), contamination of food or drink with human excrement must occur for cysticercosis to be transmitted. Proper disposal of excreta and rigid personal hygiene are necessary to avoid infection. In areas where T. solium is heavily endemic, care should be taken to avoid or minimize transmission of the infection from the native population to troops.
24 Swartzwelder,J. C.: Echinococcus Infection (Hydatid Disease) in Louisiana.NewOrleans M. & S. J. 99:617-619,June 1947.
25 Mathieson,D. R.: The Present Status of Tropical and Exotic Diseases AmongServicemen. Journal Lancet 67: 37-40, January 1947.
26 Personal communicationto author from T. B. Magath, Mayo Clinic. Rochester, Minn., 18 Aug.1950.
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Other Cestode Infections
The number of other cestode infections wasapproximately 2,000. T. saginata presumably wasthe commonest tapeworm in these cases. Two-thirds of these cases wereadmitted to hospitals inthe United States.In 1944, the European and Mediterranean theaters andthe Central and SouthPacific contributed most of the overseas admissions for cestodeinfections. Taenia infections areacquired from eating inadequately cooked beef or pork, depending uponthe species of tapeworminvolved. The necessity of cooking these meats and their productsadequately is obvious.Manyof the T. saginata infections in troops in the United Statesmay have been acquired by eating incivilian restaurants or in homes as well as in Army installations.
INTRODUCTION OF INFECTIONS INTO THEUNITED STATES
A survey for intestinal helminths in 4,000soldiers processed for separation at Fort McPherson,Ga., revealed that the prevalence of A. lumbricoides, T. trichiura,S. stercoralis, E. vermicularis,and Hymenolepis nana infection was less than 1 percent foreach. About two-thirds of the grouphad overseas service, and the remainder had service only in thecontinental United States. Theprevalence indicated a low acquisition rate of these intestinalhelminths.27 Mackie andSonnenberg 28 found a low prevalence ofinfection with most helminths in 484 veterans studied.The number of infections for each parasite was A. lumbricoides, 7;S. stercoralis, 10; T.trichiura, 22; and Taenia species, 1.
Wright and McCoy predicted that the return of infected troops would make little difference in the public health status of these infections in the United States .29 The relatively small number of hospital admissions of United States Army troops from 1942 through 1945 (table 89) and the apparently low prevalence of infection found in separatees with overseas service and in veterans, if representative, support the views of Wright and McCoy that these helminth cases in returned servicemen offer no basis for exceptional concern from a public health point of view. The helmintbs considered in this section are already endemic in this country. The slight increment of infection contributed by returned troops probably is extremely small in comparison with the number of infections already present in the civilian population. This does not necessarily apply to Ancylostoma duodenale, the Old-World hookworm.
27 SpecialArticle: Survey of Intestinal Parasites in Soldiers Being SeparatedFrom Service. Bull. U. S. Army M.Dept. 6: 259-262, September 1946.
28 Mackie,T. T., and Sonnenberg, B.: Tropical Disease Problems Among Veterans ofworld war II. Am. J. Trop.Med. 29: 443-451, July 1949.
29 (1) Wright, W.H.: Present andPost-War Health Problems in Connection With Parasitic Diseases. Science99:207-213, 17 Mar. 1944. (2) McCoy, O. R.: Public Health Implicationsof Tropical and Imported Diseases;Imported Malaria.Am. J.Pub. Health 34:15-19, January 1944. (3)McCoy, O. R.: Precautions by the Army to Prevent the Introduction ofTropical Diseases. Am. J. Trop. Med. 26: 351-355, May 1946.
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SUMMARY
Parasitism of United States Army troops bynematodes and cestodes, with the exception offilarial and hookworm infections, did not constitute a serious militaryproblem during WorldWar II. There is abundant evidence of a high incidence of helminthiasesin native inhabitants ofcertain overseas areas. The practice of basic sanitary preventivemeasures must have contributedto the over-all low incidence of infection in troops stationed in theseareas.
There were 1,243 recorded admissions for strongyloidiasis from 1942 through 1945. About two-thirds of these occurred in overseas theaters. Most of the diagnoses were based upon stool examination which is of limited value as a diagnostic measure for this infection. The similarity between the symptoms of patients with strongyloidiasis and those of troops with anxiety neurosis created a diagnostic problem. Of the common nematode and cestode infections, strongyloidiasis possibly represents the most potential postwar problem among veterans. Measures designed to prevent hookworm infections no doubt were to a great extent operative against strongyloidiasis.
Admissions for ascariasis during this 4-yearperiod numbered 5,031.Of this total, 3,630 were inoverseas theaters. In view of the high incidence of ascariasis innative inhabitants of manyoverseas areas, appropriate preventive measures must be taken tominimize transmission of thisinfection to troops. Whipworm infection, caused by T. trichiura,apparently was frequent introops in some overseas areas. The incidence of T. trichiurawas high in native troops fromPuerto Rico and the Canal Zone. Whipworm infections usually weresubclinical.
The small number of admissions for enterobiasis, 1,272, suggests that this infection did not constitute an important problem in troops during the war. It is known that pinworm infection attains high incidence under institutional conditions. Troops are often housed in large groups. This enhances the opportunity for dissemination of this parasite. Therefore, rigid personal hygienic measures and cleanliness of troop quarters are mandatory if the spread of this infection is to be prevented.
About three-fourths (208) of all hospitaladmissions for trichinosis (285) in United States Armytroops were in the United States. One death from trichinosis occurredin 1944. There were a fewoutbreaks of trichinosis in German prisoner-of-war camps. Theseresulted from the habit of someprisoners of eating pork raw and from the failure of prisoner-of-warcooks to comply withinstructions to cook all pork and pork products thoroughly. Closersupervision of prisoner-of-warmess personnel and instruction of all prisoners of war would havesecured better compliancewith orders for the proper preparation of pork to prevent trichinosis.Trichinosis was more of aproblem in these prisoners of war than in United States Army troops.
There were over 2,000 admissions for cestode infections in United States Army troops. The majority occurred in the United States. Echinococcus or
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hydatid infection was recorded 22 times. One death was caused byechinococciasis. The longincubation period of hydatid disease may result in the clinicalappearance of this infection inveterans in future years. The danger of acquiring this infection fromdogs should be emphasizedto troops.
At least one case of cysticercosis occurred in troops. In areas where T. solium, the pork tapeworm, is heavily endemic, care should be taken to avoid transmission of infection from natives to troops through fecal contamination of food and drink.
Troops should be instructed to eat only adequately cooked beef at Army installations or at civilian establishments to prevent T. saginata infection. The need for such instruction is indicated by the occurrence of approximately 2,000 admissions for cestode infections.
The number of infections with these helmintlhs in troops returned from overseas is small in comparison with the number already present in the civilian population of the United States where the infections are endemic.The return of the troops with these helminthiases probably will not make any significant difference in the public health status of the infections in this country.
