Contents

CHAPTER XIV

Statistics of Malaria

Fred H. Mowrey, M.D.

Malaria, one of the world's greatest causes of morbidity, hasplayed a dominant role in many military campaigns, although not so devastatinglyas the pestilential diseases of typhus, plague, the dysenteries, and smallpox.

HISTORICAL NOTE

Malaria played a vital part in Caesar's campaigns during theRoman civil wars. Malaria was the savior of Rome from the Germans on manyoccasions. Celli¹ writes: "TheQueen of the World suffered much at the hands of these Barbarians, but, in herdethronement, she found ample revenge. For in the swamps around Rome therelurked swarms of mosquitoes eager for fresh healthy blood, and they it was thatnow attacked the foreign invaders. These Northern warriors, who were forced tospend the summer within or outside Rome, died, or lingered on for years weakenedby daily fever, and this happened over and over again for centuries with aterrifying regularity. The various German troops made their departures more inthe manner of a funeral procession than in a victor's triumph." Cellireferring to Otto I in 964 writes, "The Emperor, however, celebrated theNativity of St. John (June 24) and the Feast of the Holy Apostles (June 29) andturned homewards from the Roman Land. But he was overcome by a fate more unhappythan he could ever have looked for, for in his army there broke out so great anddeadly a pestilence that almost all died, and those who still kept their healthonly dared to hope to live from one evening to the next morning." In 1167,Emperor Frederick I failed to conquer Rome. "Suddenly, such a deadly feverbroke out in his Army that, within seven days, almost all the princes who foughtwith him against the Church were unexpectedly snatched away by a miserabledeath." He was forced to flee leaving uncounted dead.

Malaria was ever-present during the Siege of Mantua in1796-97. Prinzing² states that malaria brokeout with great severity and acquired virulent forms which played a decisive rolein the result.

A typical example of the effect of malaria in military campaigns occurredamong British and French troops in Macedonia in 1918. Some 80 percent of 120,000French troops were hospitalized. Over 25,000 British troops were invalided homewith chronic malaria, and more than 2 million

¹Celli, Angelo : The History of Malaria in the Roman Campagna. London: John Bale, Sons & Danielsson, Ltd., 1933.
²Prinzing, Friedrich: Epidemics Resulting From Wars. Oxford: At The Clarendon Press, 1916.

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man-days were lost in the British Macedonian Army during 1918 because ofmalaria.³

Malaria also has been a problem to the U.S. Army. There are no availablestatistics on malaria prior to 1818, but we know it was prevalent before then."As early as 1776 the Continental Congress ordered the Medical Committee toforward 300 pounds of Peruvian bark to the Southern Department for the use oftroops."⁴

During the War Between the States, one-half of the whitetroops and four-fifths of the Negro troops in the Northern Armies contractedmalaria annually. There were 10,063 deaths due to malaria. In addition, morethan 1,000 Confederate troops died of malaria in Northern prisons. The incidenceof malaria during the U.S. Civil War, in Northern troops, per 1,000 per annum,is shown in the following tabulation:⁵

Fiscal year	White troops	Negro troops
1861-62	390.7	(1)
1862-63	428.3	(1)
1863-64	535.9	811.6
1864-65	496.6	703.2
1865-66	829.5	920.6

¹No Negro troop strength.

During the Spanish-American War, there were 90,461 admissionsfor malaria during the calendar year 1898, with 349 deaths. The annual admissionrate was 611.78 per 1,000. A rate of 1,924.78 per 1,000 per annum occurred inCuba with a mortality rate of 14.02 per 1,000 per annum.⁶Theodore Roosevelt stated that malaria was the chief enemy in Cuba. Everyofficer in his regiment, except himself, was down at one time or another withmalarial fever. "Though the percentage actually on the sicklist never gotabove twenty, there were less than fifty percent who were fit for any kind ofwork."⁷

In the First World War, from 1 April 1917 to 31 December 1919, there were15,555 admissions for malaria, 36 deaths, 28 discharges for disability, and194,529 man-days lost. Most of the malaria occurred among troops engaged intraining in facilities located in endemic malarious areas in the United States.Only 950 admissions for malaria occurred in Europe.⁸

³Wenyon, C. M., Anderson, A. G., McLay, K., Hele, T. S., and Waterston, J.: Malaria in Macedonia, 1915-1919. J. Roy. Army M. Corps 37: 81-108, August 1921.
⁴Blanton, W. B.: Medicine in Virginia in the Eighteenth Century. Richmond, Va.: W. Byrd Press, 1931.
⁵Medical and Surgical History of the War of the Rebellion. Medical History. Washington: Government Printing Office, 1888, pt. III, vol. I.
⁶Annual Report of The Surgeon General, U.S. Army. Washington: Government Printing Office, fiscal year, 1900.
⁷Major, Ralph H.: Fatal Partners: War and Disease. Garden City, N.Y.: Doubleday, Doran & Co., Inc., 1941, p. 195.
⁸The Medical Department of the United States Army in the World War. Washington: U.S. Government Printing Office, 1928, vol. IX, p. 512.

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The incidence of malaria among U.S. troops was of littlesignificance following World War I, occurring chiefly among troops stationed inPanama, Puerto Rico, and the Philippine Islands. The incidence for the entireArmy during 1941 was 4.74 per 1,000 per annum.

WORLD WAR II

The disease became, however, a problem of serious importanceduring World War II, when U.S. Army troops campaigned in highly malarious areasin many parts of the world. Never before had the Medical Department been calledupon to combat a problem of such magnitude. It is indeed a tribute to thepreventive measures adopted that the menace of malaria did not more seriouslyinterfere with military operations. However, these sanitary measures were notimmediately available to combat troops in such areas as Guadalcanal, New Guinea,China, Burma, India, North Africa, Sicily, Italy, and elsewhere. Accordingly,malaria exacted its toll in morbidity and man-days lost.

Malaria assumed a dominant role in many Pacific areas-GreenIsland, Emirau, Bougainville, Vella Lavella, Suaba, Efate, Esp?ritu Santo,Guadalcanal, Tulagi-Florida, Russell Islands, Munda, and the Treasury Islands-seriouslydepleting combat effectiveness and increasing the workload of the MedicalDepartment. This was best illustrated in Guadalcanal where there were 10,206primary cases of malaria among U.S. Army troops during March-December 1943:⁹

19431	Number of primary cases
March	845
April	3,374
May	1,926
June	1,117
July	1,123
August	608
September	566
October	315
November	177
December	155
Total	10,206

¹Data are not available for primarycases occurring in January and February.

The 1st Marine Division ceased to be an effective combat unit for many monthsowing to the hospitalization for malaria of approximately 80 percent of thecommand.¹⁰ Four out of five units had to beremoved from combat for rehabilitation. The Americal Division was transferredfrom New Cale-

⁹Essential Technical Medical Data, South Pacific Base Command, for March 1945. Inclosure 13-4, unnumbered table entitled "Primary Cases of Malaria, Army, Guadalcanal, 1942-44."
¹⁰Essential Technical Medical Data, Southwest Pacific Area, for January 1944.

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donia to Guadalcanal during November and December 1942. Owingto the exigencies of combat and failure to appreciate the problem, few, if any,antimalarial measures were taken. The number of cases of malaria rapidlyincreased, weekly rates as high as 2,500 per 1,000 per annum being reported. Thedivision had to be transferred to Fiji in March 1943 for rehabilitation. Masstherapy of the division was undertaken between April and June, when allmedication was discontinued. The hospitalization rate promptly rose to 4,220 inAugust. It was still 2,948 in late October when suppressive therapy withAtabrine (quinacrine hydrochloride) was reinstituted, with a consequent drop to80 by late December 1943.¹¹

The 25th Infantry Division engaged in combat on Guadalcanal in January 1943.This division also failed to take proper antimalarial measures. As aconsequence, the malaria rate rose to 2,385 per 1,000 per annum during the lastweek of April. This division was transferred to New Zealand in December 1943 forrehabilitation, and thence to New Caledonia in February 1944 for reorganization.It is estimated that approximately 46 percent of the division had one or moreattacks of malaria during 1943.

The 43d Infantry Division entered Guadalcanal in March 1943 and subsequentlyparticipated in the Russell Islands and New Georgia campaigns. This divisionrequired rehabilitation in New Zealand during February and March 1944. In orderto determine the amount of seeding in the division, a small control group wastaken off Atabrine. The malaria rate for this group rose to 2,000 per 1,000 perannum; whereas the rate for the remainder of the division, which continued onAtabrine suppression, did not exceed 236 per 1,000 per annum.

Malaria was a great problem in the Southwest Pacific Area, 47,663 attacksoccurring during 1943 alone. Sixty-seven percent of the 32d Infantry Divisionhad malaria during the 10-month period following their withdrawal from NewGuinea. The effectiveness of malarial control was demonstrated in the Milne Bayarea of New Guinea where the rate was 3,308 in January 1943. Following theinstitution of control measures, the rate dropped to 100 by May and to only30.72 by January 1944.¹²

There were 9,160 cases of malaria in the China-Burma-Indiatheater during 1943, with nearly 115,000 man-days lost. Of the first 2,400patients admitted to the 20th General Hospital, located near Ledo in Assam, 73percent had malaria. At one time, 55 percent of the beds were occupied bypatients with malaria.¹³ The effect on troops of exposure to the endemicdisease is illustrated by 92 men of the 900th Airborne Engineer Company whotraveled from Ledo to Tagap. En route, 54 were hospitalized with malaria; out

¹¹Essential Technical Medical Data, South Pacific Area, for April 1944.
¹²Essential Technical Medical Data, Southwest Pacific Area, for May 1944.
¹³Essential Technical Medical Data, China-Burma-India Theater, for August 1943.

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of the 38 who reached Tagap, 20 had malaria on arrival.¹⁴An epidemic of malaria occurred at the 1306th Air Force Base Unit, Air TransportCommand, located in Karachi, India, in 1944. There were no cases during August,but the rate rose rapidly to 1,202.3 per 1,000 per annum during the first 2weeks of October. The rate dropped to 148 during the first 2 weeks of Novemberfollowing the institution of malaria control methods.¹⁵

Malaria was a serious problem to North African theater forces. It wasprevalent in the areas of Rabat and Port Lyautey in Morocco, the Constantinearea in Algeria, the Tunis-Bizerte-Ferryville area in Tunisia, Catania inSicily, Corsica, Sardinia, Salerno, Paestum, and the Pontine Marshes in Italy.There were 69,000 cases during 1943-44 with 944,000 man-days lost. One andtwo-tenths percent of patients with malaria were evacuated to the United States.¹⁶During the Sicilian campaign, the Seventh U.S. and British Eighth Armies lost,from malaria alone, the equivalent of the fighting effectiveness of two infantrydivisions. In fact, there were more losses due to malaria than there were battlecasualties; the Seventh U.S. Army reported 9,892 cases of malaria and 8,375battle casualties and the British Eighth Army reported 11,590 and approximately9,000, respectively.¹⁷

It is interesting to note that nearly all of the total malaria cases (32,796)in the European theater were imported by troops who had originally served in theNorth African theater. There were 4,806 cases of malaria among U.S. troopsstationed in England before D-day 1944.

Altogether, during the period 1942-45, there were 492,299 cases of malaria,410,727 of these occurring overseas; the total attack rate per 1,000 averagestrength per annum was 19.43 and was highest during 1943 and 1944 (table 53).Data on the noneffective rates for malaria are not presently available, but from8 to 9 million man-days were estimated to have been lost because of malariaduring 1942-45, at an average daily noneffective rate of 1 per 1,000 averagestrength; the estimated rate based on the average duration multiplied by thenumber of admissions and readmissions is 0.94.

Of the 492,299 cases of primary malaria occurring during 1942-45 with a rateof 19.43 per 1,000 average strength (table 54), the greatest number of casesoccurred in the Southwest Pacific followed by the Central and South Pacific, theMediterranean, and China-Burma-India theaters. The highest incidence rate,98.46, occurred in the China-Burma-India theater.

¹⁴Recorded Interview, Office of the Surgeon General, 20 Apr.1944, subject: Report of Medical Department Activities in China-Burma-India byMaj. John H. Grindlay, MC, Chief, Surgical Service, 20th General Hospital,India.
¹⁵Annual Report, Surgeon, India-China Division Air Transport Command, 1944.
¹⁶Golz, Harold H.: Human Malaria in the North African and MediterraneanTheaters of Operations, U.S. Army. [Official record.]
¹⁷Essential Technical Medical Data. North African Theater of Operations,U.S. Army, for October 1943.

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TABLE 53.-Total attack rate¹for malariain the U.S. Army, by area,² type of plasmodium, and year,1942-45

[Preliminary data based on sample tabulations of individual medical records]
[Rate expressed as number of cases per annum per 1,000 average strength]

Type of plasmodium	1942-45		1942		1943		1944		1945
	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number of  cases	Rate
	Continental United States
Vicax (tertian) malaria	74,197	5.02	1,387	0.52	4,625	0.89	27,045	6.81	41,140	13.80
Falciparum (estivo-autumnal) malaria	761	.05	186	.07	245	.05	175	.04	155	.05
Malaria, mixed type	248	.02	23	.01	20	.00	130	.03	75	.03
Malariae (quartan) malaria	294	.02	34	.01	45	.01	120	.03	95	.03
Malaria, unclassified and other	6,072	.41	427	.16	1,300	.25	2,055	.52	2,290	.77
Total	81,572	5.51	2,057	0.77	6,235	1.20	29,525	7.43	43,755	14.68
	Overseas
Vivax (tertian) malaria	267,079	25.33	10,048	17.15	87,596	51.90	102,765	26.90	66,670	14.98
Falciparum (estivo-autumnal) malaria	50,519	4.79	4,295	7.33	28,054	16.62	12,750	3.34	5,420	1.22
Malaria, mixed type	3,196	.30	193	.33	1,173	.69	1,020	.27	810	.18
Malariae (quartan) malaria	1,583	.15	88	.15	640	.38	680	.18	175	.04
Malaria, unclassified and other	88,350	8.38	6,586	11.24	51,169	30.32	21,415	5.61	9,180	2.06
Total	410,727	38.96	21,210	36.20	168,632	99.91	138,630	36.30	82,255	18.48
	Total Army
Vivax (tertian) malaria	341,276	13.47	11,435	3.53	92,221	13.42	129,810	16.66	107,810	14.51
Falciparum (estivo-autumnal) malaria	51,280	2.02	4,481	1.38	28,299	4.12	12,925	1.66	5,575	.75
Malaria, mixed type	3,444	.14	216	.07	1,193	.17	1,150	.15	885	.12
Malariae (quartan) malaria	1,877	.07	122	.04	685	.10	800	.10	270	.04
Malaria, unclassified and other	94,422	3.73	7,013	2.16	52,469	7.64	23,470	3.01	11,470	1.54
Total	492,299	19.43	23,267	7.18	174,867	25.45	168,155	21.58	126,010	16.95

¹Includes admissions for the first time for malaria, readmissions, andadmissions for other causes, but in which malaria existed concurrently ordeveloped subsequently.
²Area of admission to medical treatment, but not necessarily the area in which the disease was acquired.

TYPES OF MALARIA

Malaria due to Plasmodium vivax, Plasmodium falciparum, andPlasmodium malariae occurred in all theaters. Malaria caused by P. vivax had thehighest incidence rates in the China-Burma-India theater, the Southwest Pacificand the Central and South Pacific Areas. The majority of the cases in the UnitedStates were of this type. The highest incidence rates due to P. falciparum occurred in the Middle East and the China-Burma-India the-

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TABLE 54.-Attack rates¹ of malaria, allforms in the U.S. Army, by area and year, 1942-45

[Preliminary data based on sample tabulations of individual medical records] 

[Rate expressed as number of cases per annum per 1,000 average strength]

Area2	1942-45		1942		1943		1944		1945
	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate
Continental United States	81,572	5.51	2,057	0.77	6,235	1.20	29,525	7.43	43,755	14.93
Overseas:
Europe	32,796	7.81	69	0.83	662	2.48	17,585	10.49	14,480	6.66
Mediterranean3	80,532	52.60	735	32.06	33,232	72.76	38,830	59.78	7,735	19.25
Middle East	10,715	80.53	746	123.39	6,669	125.73	2,900	62.75	400	14.41
China-Burma-India	44,052	98.46	1,077	123.14	9,160	231.21	26,265	155.68	7,550	32.78
Southwest Pacific	124,109	78.25	4,451	62.49	47,663	250.98	33,475	62.08	38,520	49.03
Central and South  Pacific	95,828	66.53	2,934	19.44	65,489	224.62	17,275	39.38	10,130	18.12
North America4	200	.41	71	.71	89	.46	25	.19	15	.22
Latin America	17,891	47.05	11,042	108.34	4,874	40.34	1,245	14.51	730	10.19
Total overseas5	410,727	38.96	21,210	36.20	168,362	99.91	138,630	36.30	82,255	18.48
Total Army	492,299	19.43	23,267	7.18	174,867	25.45	168,155	21.58	126,010	16.95

¹Consists of new admissions and readmissions for malaria as well asadmissions for other causes, but in which malaria existed concurrently ordeveloped subsequently.
²Area of admission to medical treatment, but not necessarily the area in which the disease was acquired. 
³Includes North Africa.
⁴Includes Alaska and Iceland.
⁵Includes cases on board transports.

ater. Ninety-seven percent of malaria acquired in Liberia wasdue to P. falciparum.¹⁸ P. malariae was found chiefly in theMediterranean, the Southwest Pacific, China-Burma-India, and the Central andSouth Pacific Areas. The incidence rate of clinical P. malariae infectionswithout classification was highest in China-Burma-India, the Southwest Pacificand the Central and South Pacific Areas.

P. vivax was the etiological agent in 341,276 cases; P.falciparum, in 51,280; P. malariae, in 1,877; and there were 3,444 cases withmixed type infections, or a total of about 397,000 in which plasmodia wereidentified. The remaining 94,442 cases were unclassified, the diagnosis beingmade on clinical signs and symptoms without microscopic verification. (Seetables 55, 56, 57, 58, and 59.)

RELAPSE IN MALARIA

There are no accurate statistical data available on relapse rates. However,it is well known that malaria ascribed to P. vivax was prone to relapse underthe therapeutic regimens in use during World War II. The relapse rate of malariadue to P. falciparum was markedly lower than that caused by P. vivax, althougha significant number did relapse.

¹⁸Annual Report, U.S. Army Forces in Liberia, 1943.

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TABLE 55.-Attack rates¹of vivax(tertian) malaria, in the U.S. Army, by area and year, 1942-45

[Preliminary data based on sample tabulations of individual medical records] 
[Rate expressed as number of cases per annum per 1,000 average strength]

Area2	1942-45		1942		1943		1944		1945
	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate
Continental United States	74,197	5.02	1,387	0.52	4,625	0.89	27,045	6.81	41,140	13.80
Overseas:
Europe	26,011	6.19	42	0.51	299	1.12	14,060	8.39	11,610	5.34
Mediterranean3	55,489	36.24	371	16.18	15,818	34.63	32,310	49.74	6,990	17.39
Middle East	2,349	17.65	95	15.71	934	17.61	1,125	24.34	195	7.03
China-Burma-India	26,122	58.38	412	47.11	4,010	101.22	15,335	90.90	6,365	27.63
Southwest Pacific	83,076	52.38	884	12.41	27,902	146.92	24,215	44.91	30,075	38.28
Central and South  Pacific	58,600	40.69	499	3.31	34,866	119.59	14,260	32.52	8,975	16.05
North America4	119	.24	48	.48	36	.19	20	.15	15	.22
Latin America	12,657	33.29	7,672	75.27	3,430	28.39	990	11.54	565	7.88
Total overseas5	267,079	25.33	10,048	17.15	87,596	51.90	102,765	26.90	66,670	14.98
Total Army	341,276	13.47	11,435	3.53	92,221	13.42	129,810	16.66	107,810	14.51

¹Consists of new admissions and readmissions for malaria as well asadmissions for other causes, but in which malaria existed concurrently ordeveloped subsequently.
²Area of admission to medical treatment, but not necessarily the area in which the disease was acquired. 
³Includes North Africa.
⁴Includes Alaska and Iceland.
⁵Includes cases on board transports.

TABLE 56.-Attack rates¹ of falciparum (estivo-autumnal)malaria in the U.S. Army, by area and year, 1942-45

[Preliminary data based on sample tabulations of individual medical records]
[Rate expressed as number of cases per annum per 1,000 average strength]

Area2	1942-45		1942		1943		1944		1945
	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate
Continental United States	761	0.05	186	0.07	245	0.05	175	0.04	155	0.05
Overseas:
Europe	391	0.09	5	0.06	176	0.66	135	0.08	75	0.03
Mediterranean3	7,446	4.86	144	6.28	6,257	13.70	965	1.49	80	.20
Middle East	7,502	56.38	568	93.95	5,299	99.90	1,515	32.78	120	4.32
China-Burma-India	8,265	18.47	280	32.01	2,265	57.17	5,250	31.12	470	2.02
Southwest Pacific	13,624	8.59	233	3.27	5,166	27.20	3,945	7.32	4,280	5.45
Central and South  Pacific	8,756	6.08	248	1.64	7,628	26.16	730	1.66	150	.27
North America4	29	.06	5	.05	24	.12	---	0	---	0
Latin America	4,326	11.38	2,803	27.50	1,173	9.71	200	2.33	150	2.09
Total overseas5	50,519	4.79	4,295	7.33	28,054	16.62	12,750	3.34	5,420	1.22
Total Army	51,280	2.02	4,481	1.38	28,299	4.12	12,925	1.66	5,575	0.75

¹Consists of new admissions and readmissions for malaria as well asadmissions for other causes, but in which malaria existed concurrently ordeveloped subsequently.
²Area of admission to medical treatment, but not necessarily the area in which the disease was acquired. 
³Includes North Africa.
⁴Includes Alaska and Iceland.
⁵Includes cases on board transports.

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TABLE 57.-Attack rates¹ of malariae (quartan) malaria, in the U.S. Army, by area and year, 1942-45

[Preliminary data based on sample tabulations of individual medical records] 
[Rate expressed as number of cases per annum per 1,000 average strength]

Area2	1942-45		1942		1943		1944		1945
	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate
Continental United States	294	0.02	34	0.01	45	0.01	120	0.03	95	0.03
Overseas:
Europe	192	0.05	1	0.01	21	0.08	140	0.08	30	0.01
Mediterranean3	473	.31	3	.13	330	.72	135	.21	5	.01
Middle East	125	.94	3	.50	32	.60	90	1.95	---	0
China-Burma-India	241	.54	9	1.03	77	1.94	145	.86	10	.04
Southwest Pacific	274	.17	4	.06	60	.32	115	.21	95	.12
Central and South  Pacific	146	.10	7	.05	84	.29	45	.10	10	.02
North America4	2	.00	2	.02	---	0	---	0	---	0
Latin America	102	.27	59	.58	33	.27	5	.06	5	.07
Total overseas5	1,583	0.15	88	0.15	640	0.38	680	0.18	175	0.04
Total Army	1,877	0.07	122	0.04	685	0.10	800	0.10	270	0.04

¹Consists of new admissions and readmissions for malaria as well asadmissions for other causes, but in which malaria existed concurrently ordeveloped subsequently.
²Area of admission to medical treatment, but not necessarily the area in which the disease was acquired. 
³Includes North Africa.
⁴Includes Alaska and Iceland.
⁵Includes cases on board transports.

TABLE 58.-Attack rates¹of malaria,mixed type, in the U.S. Army, by area and year, 1942-45

[Preliminary data based on sample tabulations of individual medical records] 
[Rate expressed as number of cases per annum per 1,000 average strength]

Area2	1942-45		1942		1943		1944		1945
	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate
Continental United States	248	0.02	23	0.01	20	0.00	130	0.03	75	0.03
Overseas:
Europe	67	0.02	1	0.01	6	0.02	40	0.02	20	0.01
Mediterranean3	540	.35	2	.09	213	.47	250	.38	75	.19
Middle East	67	.50	4	.66	18	.34	25	.54	20	.72
China-Burma-India	427	.95	20	2.29	112	2.83	225	1.33	70	.30
Southwest Pacific	1,168	.74	26	.37	267	1.41	315	.58	560	.71
Central and South  Pacific	724	.50	13	.09	521	1.79	150	.34	40	.07
North America4	1	.00	---	0	1	.01	---	0	---	0
Latin America	161	.42	127	1.25	29	.24	5	.06	---	0
Total overseas5	3,196	0.30	193	0.33	1,173	0.69	1,020	0.27	810	0.18
Total Army	3,444	0.14	216	0.07	1,193	0.17	1,150	0.15	885	0.12

¹Consists of new admissions and readmissions for malaria as well asadmissions for other causes, but in which malaria existed concurrently ordeveloped subsequently.
²Area of admission to medical treatment, but not necessarily the area in which the disease was acquired. 
³Includes North Africa.
⁴Includes Alaska and Iceland.
⁵Includes cases on board transports.

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TABLE 59.-Attackrates¹ of malaria, unclassified andother,²in the U.S. Army, by area and year, 1942-45

[Preliminary data based on sample tabulations of individual medical records]
[Rate expressed as number of cases per annum per 1,000 average strength]

Area3	1942-45		1942		1943		1944		1945
	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate	Number  of  cases	Rate
Continental United States	6,072	0.41	427	0.16	1,300	0.25	2,055	0.52	2,290	0.77
Overseas:
Europe	6,135	1.46	20	0.24	160	0.60	3,210	1.92	2,745	1.26
Mediterranean4	16,584	10.83	215	9.38	10,614	23.24	5,170	9.96	585	1.46
Middle East	672	5.05	76	12.57	386	7.28	145	3.14	65	2.34
China-Burma-India	8,997	20.11	356	40.70	2,696	68.05	5,310	31.47	635	2.76
Southwest Pacific	25,967	16.37	3,304	46.38	14,268	75.13	4,885	9.06	3,510	4.47
Central and South  Pacific	27,602	19.16	2,167	14.35	22,390	76.79	2,090	4.76	955	1.71
North America5	49	.10	16	.16	28	.14	5	.04	---	0
Latin America	645	1.70	381	3.74	209	1.73	45	.52	10	.14
Total overseas6	88,350	8.38	6,586	11.24	51,169	30.32	21,415	5.61	9,180	2.06
Total Army	94,422	3.73	7,013	2.16	52,469	7.64	23,470	3.01	11,470	1.54

¹Consists of new admissions and readmissions for malaria as well asadmissions for other causes, but in which malaria existed concurrently ordeveloped subsequently.
²Other than vivax, falciparum, malariae, and mixed type.
³Area of admission to medical treatment, but not necessarily the area in which the disease was acquired. 
⁴Includes North Africa.
⁵Includes Alaska and Iceland.
⁶Includes cases on board transports.

The problem of relapses can best be illustrated by citing theexperience in several areas. Approximately 30 percent of the troops of the 43d,37th, 25th, and Americal Divisions had over four attacks of malaria by June1944.¹⁹ Twenty percent of these relapses occurred within 2 months ofthe primary attack. The overall relapse rate in the China-Burma-India theaterwas estimated at 25 percent for vivax infections.²⁰ The 26th FieldHospital reported that approximately 60 percent of the malaria admissions wererecurrences. Some of these patients had had 8, 10, and 14 previous attacks ofmalaria.²¹ Forty percent of 11,343 cases of malaria studied in theMediterranean theater from 1 January to 1 December 1944 were recurrent cases.The relapse rate in this theater was estimated to be from 50 to 55 percent.²²In the Southwest Pacific Area, 392 cases of primary malaria were studied.

¹⁹Report, Capt. James E. T. Hopkins, MC, Surgeon, 3dBattalion Medical Detachment, 5307th Composite Unit (Provisional), 22June 1944, subject: Preliminary Report of Physical and Mental Condition ofMen and Officers of the 3d Battalion With Recommendations.
²⁰Essential Technical Medical Data, China-Burma-India Theater, for June 1944. 
²¹Annual Report, 26th Field Hospital, Persian Gulf Command, 1944.
²²See footnote 16, p. 453.

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Of the total, 153 cases had relapses, the first relapseoccurring on an average of 50 days after the primary attack. In 49 of the 153cases, the second relapse occurred on an average of 54 days after the firstrelapse. In 18 of the 49 cases, 3 or more relapses each, occurred: 14 had 3relapses, 2 had 4 relapses, and the remaining 2 had 5 relapses.²³

The following tabulation gives the percentage of relapses in a group ofpatients studied in Italy during January 1945.²⁴

Number of previous attacks	Percent
1	39.2
2	21.4
3	21.4
4	10.7
5	5.3

Eighteen hospitals in the Mediterranean theater reported the number of relapses experienced by 3,512 recurrent cases of malaria, as follows:

Number of previous attacks	Number of patients	Percent
1	1,685	48.0
2	777	22.1
3	435	12.4
4	267	7.6
5	138	3.9
6	79	2.2
7	69	2.0
8	31	.9
9	16	.5
10	7	.2
11	8	.2
Total	3,512	100.0

DURATION OF HOSPITALIZATION

Data on the average duration of hospitalization for malariain the entire Army were available only for the years 1942, 1943, and 1945, atthe time this analysis was made.

The average stay in hospital and quarters varied from a lowof 13.6 days in 1945 to a high of 22.2 days in 1943 (table 60). Malaria due to amixed type of infection required a longer period of hospitalization than didmalaria due to a single species of Plasmodium. It is perhaps significant thatthe duration of hospitalization for fever of undetermined origin was much lessthan that due to malaria.

²³Essential Technical Medical Data, Southwest Pacific Area, for July 1944.
²⁴Essential Technical Medical Data, Mediterranean Theater ofOperations, for February 1945.

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TABLE 60.-Average number of days in hospital and quartersfor admissions and readmissions due to malaria and fever of undetermined origin,U.S. Army, 1942, 1943, and 1945

[Preliminary data based on sample tabulations of individual medical records]

Diagnosis	1942	1943	1945
Malaria, all forms	16.6	22.2	13.6
Vivax (tertian) malaria	16.7	25.3	13.7
Falciparum (estivo-autumnal) malaria	15.6	18.6	14.0
Malariae (quartan) malaria	19.0	21.8	10.8
Malaria, mixed type	22.5	61.1	16.6
Malaria, unclassified	16.8	17.9	11.5
Fever of undetermined origin	8.1	7.5	6.9

DEATHS DUE TO MALARIA

There were 302 deaths due to malaria during the period1942-45; 292 of these deaths occurred among oversea admissions; of this total,157 deaths occurred in Pacific areas: 113 deaths recorded for the SouthwestPacific and 44 deaths for the Central and South Pacific Areas, table 61. Theannual rates per 100,000 average strength were highest in China-Burma-Indiafollowed by the Middle East, Southwest Pacific, and Latin American areas. Therates varied from year to year, the highest, 20.19 per 100,000 average strength,occurring in the China-Burma-India theater during 1943.

The majority of deaths, 125, and the highest annual rate per 100,000 averagestrength, 0.49, were due to P. falciparum. P. vivax accounted for 68

TABLE 61.-Deaths due to malaria, allforms,¹ in the U.S.Army, by area of admission and year of death, 1942-45 

[Preliminary data based on tabulationsof individual medical records] 
[Rate expressed as number of deaths per annum per100,000 average strength]

Area	1942-45		1942		1943		1944		1945
	Number	Rate	Number	Rate	Number	Rate	Number	Rate	Number	Rate
Continental United States	10	0.07	1	0.04	3	0.06	2	0.05	4	0.13
Overseas:
Europe	5	0.12	---	0	---	0	4	0.24	1	0.05
Mediterranean2	57	3.72	3	13.09	40	8.76	13	2.00	1	.25
Middle East	12	9.02	1	16.54	5	9.43	3	6.49	3	10.81
China-Burma-India	40	8.94	1	11.43	8	20.19	25	14.82	6	2.60
Southwest Pacific	113	7.12	5	7.02	23	12.11	31	5.75	54	6.87
Central and South  Pacific	44	3.05	2	1.32	28	9.60	9	2.05	5	.89
North America3	---	0	---	0	---	0	---	0	---	0
Latin America	18	4.73	12	11.77	5	4.14	1	1.17	---	0
Total overseas4	292	2.77	24	4.10	110	6.52	87	2.28	71	1.60
Total Army	302	1.19	25	0.77	113	1.64	89	1.14	75	1.01

¹There were no deaths due to malariae (quartan) malaria. 
²Includes NorthAfrica.
³Includes Alaska and Iceland.
⁴Includes one death each year on transports, 1943, 1944, and 1945,respectively.

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deaths and mixed infections for 6. No deaths were caused by P. malariae. There were 103 deaths due to unclassified malaria. (See tables 62,63, 64, and 65.)

TABLE 62.-Deaths due to vivax(tertian) malaria, in theU.S. Army, by area of admission and year of death, 1942-45

[Preliminary data based on tabulations of individual medical records] 
[Rate expressed as number of deaths per annum per 100,000 average strength]

Area	1942-45		1942		1943		1944		1945
	Number	Rate	Number	Rate	Number	Rate	Number	Rate	Number	Rate
Continental United States	5	0.04	---	0	1	0.02	2	0.05	2	0.07
Overseas:
Europe	4	0.10	---	0	---	0	3	0.18	1	0.05
Mediterranean1	14	.91	1	4.36	6	1.31	6	.92	1	.25
Middle East	---	0	---	0	---	0	---	0	---	0
China-Burma-India	5	1.12	---	0	---	0	4	2.37	1	.43
Southwest Pacific	25	1.58	1	1.40	8	4.21	4	.74	12	1.53
Central and South  Pacific	10	.69	---	0	8	2.74	---	0	2	.36
North America2	---	0	---	0	---	0	---	0	---	0
Latin America	5	1.32	3	2.94	2	1.66	---	0	---	0
Total overseas	63	0.60	5	0.85	24	1.42	17	0.45	17	0.38
Total Army	68	0.27	5	0.15	25	0.36	19	0.24	19	0.26

¹Includes North Africa.
²Includes Alaska and Iceland.

TABLE 63.-Deaths due to falciparum (estivo-autumnal)malaria, in the U.S. Army, by area of admission and year of death, 1942-45

[Preliminary data based on tabulations of individual medical records] 
[Rate expressed as number of deaths per annum per 100,000 average strength]

Area	1942-45		1942		1943		1944		1945
	Number	Rate	Number	Rate	Number	Rate	Number	Rate	Number	Rate
Continental United States	3	0.02	1	0.04	1	0.02	---	0	1	0.03
Overseas:
Europe	---	0	---	0	---	0	---	0	---	0
Mediterranean1	27	1.76	2	8.73	22	4.82	3	.46	---	0
Middle East	11	8.27	1	16.54	5	9.43	2	4.33	3	10.81
China-India-Burma	20	4.46	---	0	6	15.14	12	7.12	2	.87
Southwest Pacific	43	2.71	---	0	5	2.63	11	2.04	27	3.43
Central and South  Pacific	8	.56	---	0	5	1.71	2	.46	1	.18
North America2	---	0	---	0	---	0	---	0	---	0
Latin America	10	2.62	7	6.87	2	1.66	1	1.17	---	0
Total overseas3	122	1.15	10	1.71	46	2.73	32	0.83	34	0.77
Total Army	125	0.49	11	0.34	47	0.69	32	0.41	35	0.46

¹Includes North Africa.
²Includes Alaska and Iceland.
³Includes one death each year on transports, 1943, 1944, and 1945,respectively.

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TABLE 64.-Deaths due to malaria, mixed type, in the U.S.Army, by area of admission and year of death, 1942-45

[Preliminary data based on tabulations of individual medical records]
[Rate expressed as number of deaths per annum per 100,000 average strength]

Area	1942-45		1942		1943		1944		1945
	Number	Rate	Number	Rate	Number	Rate	Number	Rate	Number	Rate
Continental United States	---	0	---	0	---	0	---	0	---	0
Overseas:
China-Burma-India	2	0.45	---	0	---	0	1	0.59	1	0.43
Southwest Pacific	2	.13	---	0	1	.53	--	0	1	.13
Central and South  Pacific	2	.14	---	0	---	0	2	.46	---	0
Other theaters	---	0	---	0	---	0	---	0	---	0
Total overseas	6	0.06	---	0	1	0.06	3	0.08	2	0.04
Total Army	6	0.02	---	0	1	0.01	3	0.04	2	0.03

TABLE 65.-Deaths due to malaria, unclassified and other,¹ in the U.S. Army, by area of admission and year of death, 1942-45

[Preliminary data based on tabulations of individual medical records]
[Rate expressed as number of deaths per annum per 100,000 average strength]

Area	1942-45		1942		1943		1944		1945
	Number	Rate	Number	Rate	Number	Rate	Number	Rate	Number	Rate
Continental United States	2	0.01	---	0	1	0.02	---	0	1	0.03
Overseas:
Europe	1	0.02	---	0	---	0	1	0.06	---	0
Mediterranean2	16	1.05	---	0	12	2.63	4	.62	---	0
Middle East	1	.75	---	0	---	0	1	2.16	---	0
China-Burma-India	13	2.91	1	11.43	2	5.05	8	4.74	2	.87
Southwest Pacific	43	2.70	4	5.62	9	4.74	16	2.97	14	1.78
Central and South Pacific	24	1.66	2	1.32	15	5.15	5	1.13	2	.35
North America3	---	0	---	0	---	0	---	0	---	0
Latin America	3	.79	2	1.96	1	.82	---	0	---	0
Total overseas	101	0.96	9	1.54	39	2.31	35	0.92	18	0.41
Total Army	103	0.41	9	0.28	40	0.58	35	0.45	19	0.26

¹Other than vivax, falciparum, malariae, and mixed type. 
²Includes NorthAfrica.
³Includes Alaska and Iceland.

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SUMMARY

The role of malaria in military campaigns was reemphasized once more duringWorld War II. The magnitude of the problem is illustrated by a briefpresentation of statistical data giving the incidence of malaria, the types ofmalaria, the relapse problem, and the number of deaths due to malaria. It isindeed a tribute to the Medical Department of the U.S. Army, that the menace ofmalaria did not more seriously interfere with military operations.

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