Communicable Diseases, Table of Contents
CHAPTER XVIII
THE MALARIAL FEVERS
COMPARISON OF MALARIAL RATES FOR THE WORLD WAR WITH PREVIOUS
AND SUBSEQUENT MALARIAL RATES, UNITED STATES ARMY
Prior to the World War, malaria in the United States Army hadbeen controlled with a high degree of efficiency, as shown in Table 81.Satisfactory as had been the reduction in morbidity and mortality from malarialfevers, most apparent in our troops serving in the Philippine Islands, Panama,and Porto Rico, the results obtained by our medical officers and sanitarians inthe prophylaxis of these fevers during the World War were much better, despitethe fact that many of our great camps were located in regions where endemicmalaria was severe.
Year |
| Colored enlisted | Porto Rican | Filipino | ||||
| Philippine Islands | Hawaiian Islands | Panama | United States | Philippine Islands | Porto Rico | Philippine Islands | |
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1911 | 15.47 | 75.56 | 6.95 | 53.92 | 0.68 | --- | 131.03 | 242.12 |
1912 | 14.65 | 186.35 | 6.22 | 120.31 | 4.42 | 45.89 | 52.72 | 241.91 |
1913 | 8.82 | 126.27 | 9.05 | 145.55 | 7.67 | 38.65 | 31.99 | 193.49 |
1914 | 11.05 | 48.60 | 1.44 | 208.96 | --- | 30.35 | 12.73 | 201.80 |
1915 | 12.86 | 68.43 | 2.24 | 87.57 | 6.56 | 21.63 | 18.34 | 80.11 |
1916 | 22.43 | 60.74 | 2.40 | 66.50 | 10.56 | 87.83 | 269.63 | 43.38 |
1917 | 7.50 | 50.24 | 3.54 | 109.23 | 5.85 | 81.68 | 26.65 | 56.63 |
1918 | 3.91 | 22.11 | --- | 75.67 | 4.48 | 44.09 | 57.28 | 46.47 |
1919 | 3.58 | 14.68 | --- | 82.18 | 1.22 | 45.46 | 45.41 | 41.12 |
1920 | 7.54 | 8.37 | .80 | 55.13 | 2.06 | 51.36 | 24.79 | 26.32 |
| DEATHS |
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1911 | --- | .08 | --- | --- | --- | --- | --- | .57 |
1912 | - | .36 | --- | --- | --- | --- | --- | .55 |
1913 | --- | .21 | --- | --- | --- | --- | --- | .57 |
1914 | --- | --- | --- | --- | --- | --- | --- | --- |
1915 | .03 | --- | --- | --- | --- | --- | --- | --- |
1916 | .02 | --- | --- | --- | --- | --- | --- | --- |
1917 | .01 | .11 | --- | .25 | --- | .66 | --- | --- |
1918 | .01 | --- | --- | .24 | .04 | --- | .24 | .18 |
1919 | .01 | .26 | --- | .20 | .04 | --- | .48 | .12 |
1920 | --- | --- | --- | .23 | --- | --- | --- | --- |
1Includes National Guard officers.
2Includes officers.
There was a marked decrease in the admission rates formalaria for white enlisted men during the period 1911-1920, in the UnitedStates, the ratio for 1916 being 22.43 per 1,000; in 1917, 7.50 per 1,000; in1918, 3.91 per 1,000; and in 1919, 3.58 per 1,000, the latter rate having beenobtained despite the fact that during 1917 and 1918 hundreds of thousands ofuntrained and susceptible recruits were mobilized in camps situated in regionsof malaria endemicity. The admission rates for malarial fevers in the PhilippineIslands, Panama, and Porto Rico (all classes) were also reduced, although to alesser extent, the lower reduction in these countries being due undoubtedly tocontinuing greater
aUnless otherwise stated, all figures for the World War period are derived from sick and wounded reports sent to the Surgeon General.-Ed.
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exposure to infection, in spite of the rigid sanitarymeasures taken to prevent infection.
The rise in the United States malarial rate in 1920 was probably due to thenecessity of curtailing the antimosquito work in camps during the latter part of1919 and in 1920, owing to the lack of funds.
ADMISSION ANDDEATH RATES DURING THE WORLD WAR
In the period from April 1, 1917, to December 31, 1919, inclusive, the totalnumber of admissions for malaria was 15,555, this number including officers andenlisted men of both American and native troops. There were 36 deaths recordedas due to malaria and 28 discharges for disability. The total loss of timerecorded as caused by the malarial infections (primary cause of admission) was194,529 days.
The malarial fevers were not included among the 30 leading diseases for ourArmy, as a whole, either for admissions, deaths, discharges for disability, ortime lost. However, in Panama they ranked second for admissions, third fordeaths, and second for time lost, for American enlisted men. Among Filipinotroops, the malarial fevers ranked third for admissions, eleventh for deaths,and fourth for time lost, while for Porto Ricans (Porto Rico and Panama) thesefevers ranked eighth for admissions, third for deaths, and seventh for timelost.
The greatest number of cases of malaria occurred in the United States, butthe highest admission rate was in American troops serving in Panama. The nativePorto Ricans furnished the next highest admission rate and the highest deathrate.
The admissions, deaths, and discharges for disability for malaria, withratios per 1,000, are given in Table 82.
Rank and country |
| Deaths | Discharges for disability | |||||||||
Absolute numbers | Ratios per 1,000 strength | Per cent of total diseases | Relative standing among diseases1 | Absolute numbers | Ratios per 1,000 strength | Per cent of total diseases | Relative standing among diseases | Absolute numbers | Ratios per 1,000 strength | Per cent of total diseases | Relative standing among diseases | |
Officers: |
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| United States | 328 | 2.64 | 0.45 | --- | 1 | 0.01 | 0.12 | --- | --- | --- | --- | - |
| Europe | 60 | .81 | .16 | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Total (including other countries) | 437 | 2.12 | .38 | --- | 1 | .00 | .07 | --- | --- | --- | --- | --- |
American enlisted men: |
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|
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| United States | 10,182 | 4.82 | .43 | --- | 23 | .01 | .07 | --- | 25 | 0.01 | 0.02 | - |
| Europe | 890 | .56 | .10 | --- | 2 | .00 | .01 | --- | --- | --- | --- | --- |
| Philippine Islands | 639 | 29.79 | 3.27 | 10 | 2 | .09 | 2.74 | 12 | --- | --- | --- | --- |
| Hawaiian Islands | 24 | 1.23 | .20 | --- | --- | --- | --- | --- | --- | --- | --- | - |
| Panama | 1,739 | 88.34 | 11.30 | 2 | 3 | .15 | 9.38 | 3 | --- | --- | --- | - |
| Total (including other countries) | 13,674 | 3.52 | .41 | --- | 30 | .01 | .05 | --- | 26 | .01 | .02 | --- |
Native troops: |
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| Filipino | 843 | 45.38 | 6.93 | 3 | 2 | .11 | 1.71 | 11 | 2 | .11 | .56 | 0.12 |
| Porto Rican2 | 600 | 50.72 | 3.87 | 8 | 3 | .25 | 2.42 | 3 | --- | --- | --- | --- |
| Hawaiian | 1 | .18 | .30 | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Army total | 15,555 | 3.77 | .44 | --- | 36 | .01 | .06 | --- | 28 | .01 | .02 | --- |
1Thirty leading diseases; a dash indicates astanding below 30.
2Served in Panama as well as Porto Rico.
bOnly primary admissions are taken into account until Table 88 is considered.
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DISTRIBUTION IN THE ARMY
Of the total 15,555 primary admissions for malaria in theUnited States Army, no less than 10,510 were in the troops serving in the UnitedStates. Only 950 admissions are recorded as occurring in our troops serving inEurope, while 1,482 admissions were in the Philippine Islands, 1,739 in Panama(American troops), 600 in Porto Rico and Panama (Porto Ricans), and 24 in theDepartment of Hawaii. In addition to the above, 249 admissions for malaria wereamong officers and enlisted men serving in other countries.
Of the 36 deaths reported as due to malaria, 24 occurred inthe United States, 2 in Europe, 4 in the Philippine Islands, 3 in the Canal Zone(American), and 3 in Porto Rico and Panama (Porto Ricans).
The rate of admissions per 1,000 for officers serving in theUnited States was 2.64 and for enlisted men, 4.82; in Europe, for officers,0.81, and for enlisted men, 0.56; in Panama, for white enlisted men the ratioper 1,000 was 88.34; in the Philippine Islands 29.79, and in the HawaiianIslands, 1.23. For native troops the ratio per 1,000 was highest for PortoRicans, i. e., 50.72 and lowest, for Hawaiians, i. e., 0.18 per 1,000. The ratioper 1,000 for native Filipino troops was 45.38.
The low rate for troops serving in the Hawaiian Department isexplained by the fact that the malarial fevers are not present in the HawaiianIslands except as imported cases, there being no well-authenticated instance ofa case of malaria originating in the Hawaiian Territory. All malaria infectionsoccurring in our troops in these islands were, therefore, relapses of infectionsacquired elsewhere.
The malarial fevers caused 11.3 per cent of the sickadmission rate in American troops serving in Panama, 6.93 per cent of that inthe Philippine Islands, and 3.87 per cent of the admission rate in Porto Ricantroops. In the United States malaria caused less than 0.45 per cent of the totaladmission rate for disease in the Army, while in Europe these infections causedless than 0.15 per cent of our total admission rate for disease.
It is evident that in countries in which the chances forinfection were greatest, as in Panama, the Philippine Islands, and Porto Rica,the incidence was greatest, but even in such regions the rates, on the whole,were low when compared with the pre-war rates.
RACIAL DISTRIBUTION
The admission rate per 1,000 for officers was 2.12; for Americanenlisted men, 3.52; and for native troops, 40.09. There was, however, a greatdifference in geographical situation, native troops all serving in highlymalarious countries.
The absence of immunity to malaria in native troops appearsto be established by a comparison of the ratio per 1,000 for American andFilipino troops, both serving in the Philippine Islands, where the ratio per1,000 for American enlisted men was only 29.79 as compared with a ratio of 45.38for enlisted Filipinos.
However, caution should be used in drawing the conclusionfrom these data that native troops possess no immunity to the malarialinfections. In the absence
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of information regarding relative exposure to infectionbetween the two groups and whether the native troops had been exposed previouslyto malaria, it is impossible to state definitely that the native troops weremore susceptible to malarial infection than white troops; but it is fair toassume, in view of these figures, that such immunity as the native troopspossessed in the Philippine Islands was of little worth in protecting them fromthe infection and could not be depended upon as of any practical value inmilitary operations. The experience of our Army in this respect is similar tothat of other armies and demonstrates that there is no such thing as a trueracial immunity to the malarial infections.
|
| Ratios per 1,000 | ||||||
Admissions | Deaths |
| Days lost | Admissions | Deaths | Discharges for disability | Non- | |
White | 12,690 | 24 | 24 | 155,683 | 3.53 | 0.01 | 0.01 | 0.12 |
Colored | 861 | 5 | 2 | 15,299 | 3.00 | .02 | .01 | .15 |
Filipino | 843 | 2 | 2 | 9,120 | 45.38 | .11 | .11 | 1.35 |
Hawaiian | 1 | --- | --- | 5 | .18 | --- | --- | .00 |
Porto Rican | 600 | 3 | --- | 7,092 | 50.72 | .25 | --- | 1.64 |
Color not stated | 123 | 1 | --- | 1,926 | --- | --- | --- | --- |
| Total Army (enlisted men) | 15,118 | 35 | 28 | 189,123 | 3.85 | .01 | .01 | .13 |
In comparing American and native troops, the ratio per 1,000of admissions for malaria shown in Table 83 was greatest for Porto Ricans andsmallest for colored soldiers. For the former it was 50.72 per 1,000 and for thelatter only 3 per 1,000. The ratio per thousand for Filipino troops was 45.38;for Hawaiian soldiers 0.18, and for white soldiers 3.53. While this tableillustrates what actually happened so far as such statistics can show, it shouldnot be interpreted as proving any racial susceptibility to malaria, for bothPorto Rican and Filipino troops were serving in malarial countries, while thevast majority of our white troops were not exposed to malaria, and the troopscomposed of native Hawaiians in Hawaii were absolutely unexposed, malaria notbeing present in the Hawaiian Islands owing to the absence of anophelinemosquitoes.
DISTRIBUTION IN WHITE TROOPS IN THE UNITEDSTATES, PANAMA, PHILIPPINE ISLANDS, AND
HAWAIIAN ISLANDS
An inspection of Table 84 demonstrates that the admission anddeath rates from malaria for white enlisted men for the World War period washighest in Panama and lowest in Europe. In Panama the ratio per 1,000 formalaria was 88.34; in the Philippine Islands, 25.48; in the United States, 4.89;in the Hawaiian Islands 1.48, and in Europe, 0.47.
The malarial fevers were far more prevalent in white enlistedmen serving in Panama than in those serving in the Philippine Islands, the ratioper 1,000 for the former being 88.34 as compared with 25.48 for the latter.Thus, the
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ratio per 1,000 for Panama was over three times that for thePhilippine Islands. Without accurate knowledge of the local conditions affectingthe exposure of the men in the two countries, it would be unwise to attempt todraw any conclusions as to the cause of the much higher ratio in Panama.However, it is evident that during the period of the World War our whiteenlisted men serving in Panama were three times as apt to contract malaria asthose serving in the Philippines, as shown by the actual ratio per 1,000 ofmalarial infections. The cases of malaria recorded for the AmericanExpeditionary Forces doubtless were relapses of infection acquired in the UnitedStates as no evidence was obtainable that original infections were acquired inFrance.
TABLE 84.-Malarialfevers. Admissions, deaths, discharges for disability, and days lost, bycountries of occurrence, white enlisted men, United States Army, April 1, 1917,to December 31, 1919. Absolute numbers and ratios per 1,000
Country |
| Ratios per 1,000 | ||||||
Admissions | Deaths |
| Days lost | Admissions | Deaths | Discharges for disability | Non- | |
United States | 9,617 | 18 | 23 | 115,181 | 4.89 | 0.01 | 0.01 | 0.16 |
Europe | 697 | 1 | --- | 15,930 | .47 | .00 | --- | .03 |
Philippine Islands | 433 | 2 | --- | 5,982 | 25.48 | .12 | --- | .96 |
Hawaiian Islands | 24 | --- | --- | 282 | 1.48 | --- | --- | .05 |
Panama | 1,739 | 3 | --- | 16,867 | 88.34 | .15 | --- | 2.35 |
| Total Army (white enlisted men)1 | 12,690 | 24 | 24 | 155,683 | 3.53 | .01 | .01 | .12 |
1Includes figures for"Transports."
DISTRIBUTION IN WHITE AND COLORED ENLISTED MEN,BY CAMPS, IN THE UNITED STATES
From Table 85 it may be seen that the greatest number ofadmissions for malaria was at Camp Beauregard, La., (726); the second greatestnumber at Camp Pike, Ark., (703); the third (469) at Camp Jackson, S. C.; thefourth (356) at Camp Travis, Tex.; the fifth (344) at Camp Shelby, Miss.; thesixth (233) at Camp Johnston, Fla.; the seventh (223) at Camp Wheeler, Ga.; theeighth (206) at Camp Sevier, S. C.; the ninth (203) at Camp Gordon, Ga.; thetenth (163) at Camp Logan, Tex.; the eleventh (161) at Camp Taylor, Ky.; thetwelfth (122) at Camp Eustis, Va.; the thirteenth (115) at Camp McClellan, Ala.;the fourteenth (113) at Camp Bowie, Tex.; while a smaller number occurred at theother camps in the United States. Only one admission for malaria was reported atCamp Forrest, Ga., and one at Camp Greenleaf, Chickamauga Park, Ga.
While the camps mentioned stand in the above order as regardsthe actual number of admissions for malaria in the troops serving within them, astudy of the ratios per 1,000 admissions in these camps results in a verydifferent relative standing. Considered in this way, the camps mentioned standin the following order: (1) Camp Beauregard, La.; (2) Camp Shelby, Miss.; (3)Camp Pike, Ark.; (4) Camp Jackson, S. C.; (5) Camp Eustis, Va.;c(6) Camp Wheeler,
cOccupied only a part of war period.
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Ga.; (7) Camp Johnston, Fla.; (8) Camp Travis, Tex.; (9) CampMcClellan, Ala.; (10) Camp Sevier, S. C.; (11) Camp Taylor, Ky.; (12) CampGordon, Ga.; (13) Camp Humphreys, Va.; and (14) Camp Logan, Tex. It should notbe deduced from these statistics that the malarial infections all actuallyoriginated in these camps, as they do not distinguish between infectionscontracted in the camps and those due to relapse of previously acquired malaria.
Camps |
| Deaths | Discharges for disability | |||||||||
White | Colored | White | Colored | White |
| |||||||
Absolute numbers | Ratios per 1,000 | Absolute numbers | Ratios per 1,000 | Absolute numbers | Ratios per 1,000 | Absolute numbers | Ratios per 1,000 | Absolute numbers | Ratios per 1,000 | Absolute numbers | Ratios per 1,000 | |
Beauregard, La. | 694 | 34.35 | 32 | 75.83 | --- | --- | --- | --- | --- | --- | --- | --- |
Bowie, Tex. | 112 | 4.44 | 1 | 1.05 | --- | --- | --- | --- | --- | --- | --- | --- |
Cody, N. Mex. | 34 | 1.50 | --- | --- | --- | --- | --- | --- | 1 | 0.04 | --- | --- |
Custer, Mich. | 4 | .11 | 3 | 2.21 | --- | --- | --- | --- | --- | --- | --- | --- |
Devens, Mass. | 21 | .46 | 6 | 2.70 | --- | --- | --- | --- | 1 | .02 | --- | --- |
Dix, N. J. | 56 | 1.25 | 7 | 1.45 | --- | --- | --- | --- | --- | --- | --- | --- |
Dodge, Iowa | 28 | .84 | 4 | .69 | --- | --- | --- | --- | --- | --- | --- | --- |
Doniphan, Okla. | 82 | 3.07 | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
Eustis, Va. | 121 | 19.13 | 1 | 2.19 | --- | --- | --- | --- | --- | --- | --- | --- |
Forrest, Ga. | 1 | .11 | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
Fremont, Calif. | 43 | 2.79 | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
Funston, Kans. | 75 | 1.50 | 20 | 3.24 | 1 | 0.02 | --- | --- | --- | --- | --- | --- |
Gordon, Ga. | 185 | 4.86 | 18 | 2.64 | --- | --- | --- | --- | 1 | .03 | --- | --- |
Grant, Ill. | 8 | .19 | 14 | 2.02 | --- | --- | --- | --- | --- | --- | --- | --- |
Greene, N.C. | 33 | 1.26 | 4 | 1.13 | --- | --- | --- | --- | 1 | .04 | --- | --- |
Greenleaf, Ga. | 1 | .08 | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
Hancock, Ga. | 84 | 2.31 | 3 | 1.88 | 2 | .05 | --- | --- | --- | --- | --- | --- |
Humphreys, Va. | 40 | 4.10 | 9 | 2.92 | --- | --- | --- | --- | --- | --- | --- | --- |
Jackson, S.C. | 414 | 11.22 | 55 | 10.72 | --- | --- | --- | --- | --- | --- | --- | --- |
Johnston, Fla. | 115 | 5.79 | 18 | 7.46 | --- | --- | --- | --- | 1 | .05 | --- | --- |
Kearny, Calif. | 28 | 1.10 | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
Lee, Va. | 45 | .88 | 2 | .30 | --- | --- | --- | --- | 2 | .04 | --- | --- |
Lewis, Wash. | 55 | 1.16 | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
Logan, Tex. | 163 | 6.11 | --- | --- | 1 | .04 | --- | --- | --- | --- | --- | --- |
MacArthur, Tex. | 56 | 2.30 | 3 | 3.15 | 1 | .04 | --- | --- | 1 | .04 | --- | --- |
McClellan, Ala. | 97 | 3.66 | 18 | 8.45 | --- | --- | --- | --- | --- | --- | --- | --- |
Meade, Md. | 47 | 1.12 | 14 | 1.74 | --- | --- | --- | --- | 1 | .02 | --- | --- |
Mills, N.Y. | 83 | 3.62 | 2 | 1.59 | --- | --- | --- | --- | --- | --- | --- | --- |
Pike, Ark. | 639 | 15.64 | 64 | 7.34 | 2 | .05 | --- | --- | 1 | .02 | 1 | 0.11 |
Sevier, S.C. | 199 | 7.60 | 7 | 4.36 | --- | --- | --- | --- | --- | --- | --- | --- |
Shelby, Miss. | 317 | 11.01 | 27 | 16.34 | --- | --- | --- | --- | --- | --- | --- | --- |
Sheridan, Ala. | 79 | 3.08 | 5 | 5.65 | --- | --- | --- | --- | 2 | .08 | --- | --- |
Sherman, Ohio | 15 | .41 | 8 | 1.38 | --- | --- | --- | --- | --- | --- | --- | --- |
Syracuse, N.Y. | 4 | 1.19 | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
Taylor, Ky. | 140 | 3.29 | 21 | 4.79 | 2 | .05 | 1 | 0.23 | --- | --- | --- | --- |
Travis, Tex. | 327 | 8.72 | 29 | 4.41 | --- | --- | --- | --- | --- | --- | --- | --- |
Upton, N.Y. | 22 | .55 | 8 | 1.71 | --- | --- | --- | --- | --- | --- | --- | --- |
Wadsworth, S.C. | 43 | 1.43 | 2 | 1.79 | --- | --- | --- | --- | --- | --- | --- | --- |
Wheeler, Ga. | 213 | 8.91 | 10 | 5.51 | --- | --- | 2 | 1.10 | --- | --- | --- | --- |
Others | --- | --- | 3 | 8.85 | --- | --- | --- | --- | --- | --- | --- | --- |
DISTRIBUTION BY STATES
It does not follow that every man inducted or enlisted in aparticular State was a native of that State; nevertheless, it is true that themajority were and that practically all had been residing in the State from whichinducted or enlisted long enough to contract malaria infection if it werepresent. That this supposition is correct is borne out by the data shown inTable 86, which agree with the well-known distribution of the malarialinfections in the United States.
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State |
| |||||||||||
| Europe | Total United States and Europe | ||||||||||
| Absolute numbers | Absolute numbers | Ratios per 1,000 | |||||||||
| Deaths | Discharges | Admissions | Deaths | Discharges | Admissions | Deaths | Discharges | Admissions | Deaths | Discharges | |
Alabama | 815 | 2 | 1 | 47 | --- | --- | 862 | 2 | 1 | 19.57 | 0.05 | 0.02 |
Alaska | 1 | --- | --- | --- | --- | --- | 1 | --- | --- | .50 | --- | --- |
Arizona | 9 | --- | --- | --- | --- | --- | 9 | --- | --- | .89 | --- | --- |
Arkansas | 622 | --- | 1 | 23 | --- | --- | 645 | --- | 1 | 15.37 | --- | .02 |
California | 116 | --- | --- | 6 | --- | --- | 122 | --- | --- | 1.17 | --- | --- |
Colorado | 15 | --- | --- | 2 | --- | --- | 17 | --- | --- | .52 | --- | --- |
Connecticut | 32 | --- | --- | 4 | --- | --- | 36 | --- | --- | .78 | --- | --- |
Delaware | 6 | --- | --- | --- | --- | --- | 6 | --- | --- | 1.03 | --- | --- |
District of Columbia | 10 | --- | --- | 3 | --- | --- | 13 | --- | --- | 1.16 | --- | --- |
Florida | 204 | --- | --- | 7 | --- | --- | 211 | --- | --- | 11.21 | --- | --- |
Georgia | 570 | 1 | 3 | 29 | --- | --- | 599 | 1 | 3 | 12.88 | .02 | --- |
Idaho | 9 | --- | --- | --- | --- | --- | 9 | --- | --- | .52 | --- | --- |
Illinois | 555 | 2 | --- | 28 | --- | --- | 583 | 2 | --- | 2.59 | .01 | --- |
Indiana | 220 | --- | --- | 12 | --- | --- | 232 | --- | --- | 2.54 | --- | --- |
Iowa | 110 | --- | --- | 15 | --- | --- | 125 | --- | --- | 1.38 | --- | --- |
Kansas | 93 | 1 | 7 | --- | --- | --- | 100 | 1 | --- | 1.74 | .02 | .06 |
Kentucky | 326 | --- | --- | 21 | --- | --- | 347 | --- | --- | 5.75 | --- | --- |
Louisiana | 480 | --- | --- | 42 | --- | --- | 522 | --- | --- | 15.57 | --- | --- |
Maine | 17 | 1 | --- | 1 | --- | --- | 18 | 1 | --- | .79 | .04 | --- |
Maryland | 65 | --- | --- | 2 | --- | --- | 67 | --- | --- | 1.80 | --- | --- |
Massachusetts | 103 | --- | --- | 11 | 1 | --- | 114 | 1 | --- | .95 | .01 | --- |
Michigan | 96 | --- | 1 | 15 | --- | --- | 111 | --- | 1 | .91 | --- | .01 |
Minnesota | 70 | --- | --- | 9 | --- | --- | 79 | --- | --- | .86 | --- | --- |
Mississippi | 1,279 | 1 | 2 | 57 | --- | --- | 1,336 | 1 | 2 | 49.04 | .04 | .07 |
Missouri | 360 | --- | --- | 27 | --- | --- | 387 | --- | --- | 3.47 | --- | --- |
Montana | 4 | --- | --- | 1 | --- | --- | 5 | --- | --- | .15 | --- | --- |
Nebraska | 41 | --- | --- | 8 | --- | --- | 49 | --- | --- | 1.13 | --- | --- |
Nevada | 1 | --- | --- | --- | --- | --- | 1 | --- | --- | .21 | --- | --- |
New Hampshire | 9 | --- | --- | --- | --- | --- | 9 | --- | --- | .66 | --- | --- |
New Jersey | 116 | 1 | --- | 7 | --- | --- | 123 | 1 | --- | 1.29 | .01 | --- |
New Mexico | 21 | 1 | 1 | 1 | --- | 1 | 22 | 1 | 1 | 1.02 | .08 | .08 |
New York | 319 | --- | 1 | 42 | --- | --- | 361 | --- | 1 | 1.87 | --- | --- |
North Carolina | 241 | 1 | --- | 13 | --- | --- | 254 | 1 | --- | 5.28 | .02 | --- |
North Dakota | 10 | --- | --- | --- | --- | --- | 10 | --- | --- | .41 | --- | --- |
Ohio | 157 | --- | 1 | 26 | --- | --- | 183 | --- | 1 | 1.01 | --- | .01 |
Oklahoma | 153 | --- | 1 | 9 | --- | --- | 162 | --- | 1 | 2.30 | --- | .01 |
Oregon | 20 | --- | --- | 2 | --- | --- | 22 | --- | --- | .79 | --- | --- |
Pennsylvania | 223 | --- | 1 | 19 | --- | --- | 242 | --- | 1 | .92 | --- | --- |
Rhode Island | 25 | --- | --- | 4 | --- | --- | 29 | --- | --- | 1.69 | --- | --- |
South Carolina | 161 | --- | --- | 8 | --- | --- | 169 | --- | --- | 6.82 | --- | --- |
South Dakota | 20 | --- | --- | 1 | --- | --- | 21 | --- | --- | .75 | --- | --- |
Tennessee | 473 | 2 | --- | 32 | --- | --- | 505 | 2 | --- | 9.33 | .04 | --- |
Texas | 626 | 2 | 3 | 32 | --- | --- | 658 | 2 | 3 | 5.32 | .02 | .02 |
Utah | 1 | --- | --- | 2 | --- | --- | 3 | --- | --- | .19 | --- | --- |
Vermont | 8 | --- | --- | 1 | --- | --- | 9 | --- | --- | .91 | --- | --- |
Virginia | 134 | --- | 1 | 5 | --- | --- | 139 | --- | 1 | 3.08 | --- | .02 |
Washington | 13 | --- | --- | 1 | --- | --- | 14 | --- | --- | .34 | --- | --- |
West Virginia | 50 | --- | --- | 4 | --- | --- | 54 | --- | --- | 1.15 | --- | --- |
Wisconsin | 70 | --- | 1 | 8 | --- | --- | 78 | --- | 1 | .85 | --- | .01 |
Wyoming | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
Others or not stated | 538 | 3 | 5 | 103 | --- | --- | 641 | 3 | 5 | --- | --- | --- |
| Total | 9,617 | 18 | 23 | 697 | 1 | 1 | 10,314 | 19 | 23 | 3.29 | .01 | .01 |
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TABLE 86.-Malarial fevers. Admissions, deaths, discharges for disability by State of induction, white and colored enlisted men, United States Army, United States and Europe, April 1, 1917, to December 31, 1919-Continued
State |
| |||||||||||
| Europe | Total United States and Europe | ||||||||||
| Absolute numbers | Absolute numbers | Ratios per 1,000 | |||||||||
| Deaths | Discharges | Admissions | Deaths | Discharges | Admissions | Deaths | Discharges | Admissions | Deaths | Discharges | |
Alabama | 54 | 1 | --- | 8 | --- | --- | 62 | 1 | --- | 2.60 | 0.04 | --- |
Arkansas | 38 | --- | --- | 4 | --- | --- | 42 | --- | --- | 2.55 | --- | --- |
District of Columbia | 1 | --- | --- | --- | --- | --- | 1 | --- | --- | .23 | --- | --- |
Florida | 23 | --- | --- | 1 | --- | --- | 24 | --- | --- | 2.00 | --- | --- |
Georgia | 75 | 2 | --- | 9 | --- | --- | 84 | 2 | --- | 2.71 | .06 | --- |
Illinois | 2 | --- | --- | 1 | --- | --- | 3 | --- | --- | .32 | --- | --- |
Indiana | 1 | --- | --- | --- | --- | --- | 1 | --- | --- | .23 | --- | --- |
Iowa | 1 | --- | --- | --- | --- | --- | 1 | --- | --- | .82 | --- | --- |
Kansas | --- | --- | --- | 1 | --- | --- | 1 | --- | --- | .49 | --- | --- |
Kentucky | 10 | --- | 1 | 3 | --- | --- | 13 | --- | 1 | 1.19 | --- | 0.09 |
Louisiana | 73 | --- | 1 | 8 | --- | --- | 81 | --- | 1 | 3.09 | --- | .04 |
Maryland | 5 | --- | --- | 2 | --- | --- | 7 | --- | --- | .77 | --- | --- |
Massachusetts | 1 | --- | --- | --- | --- | --- | 1 | --- | --- | .84 | --- | --- |
Minnesota | --- | --- | --- | 1 | --- | --- | 1 | --- | --- | 2.05 | --- | --- |
Mississippi | 70 | --- | --- | 21 | --- | --- | 91 | --- | --- | 4.16 | --- | --- |
Missouri | 6 | --- | --- | --- | --- | --- | 6 | --- | --- | .70 | --- | --- |
Nebraska | 2 | --- | --- | --- | --- | --- | 2 | --- | --- | 3.25 | --- | --- |
North Carolina | 28 | --- | --- | 4 | --- | --- | 32 | --- | --- | 1.67 | --- | --- |
Ohio | 4 | --- | --- | --- | --- | --- | 4 | --- | --- | .53 | --- | --- |
Oklahoma | 2 | --- | --- | 1 | --- | --- | 3 | --- | --- | .55 | --- | --- |
Pennsylvania | 3 | --- | --- | --- | --- | --- | 3 | --- | --- | .21 | --- | --- |
South Carolina | 62 | --- | --- | 4 | --- | --- | 66 | --- | --- | 2.84 | --- | --- |
Tennessee | 27 | 1 | --- | 2 | --- | --- | 29 | 1 | --- | 1.75 | .06 | --- |
Texas | 57 | 1 | --- | --- | --- | --- | 57 | 1 | --- | 1.87 | .03 | --- |
Virginia | 9 | --- | --- | 3 | --- | --- | 12 | --- | --- | .56 | --- | --- |
Wyoming | 2 | --- | --- | --- | --- | --- | 2 | --- | --- | 22.22 | --- | --- |
Others or not stated | 9 | --- | --- | 2 | --- | --- | 11 | --- | --- | --- | --- | --- |
| Total | 565 | 5 | 2 | 75 | --- | --- | 640 | 5 | 2 | 1.85 | .01 | .01 |
As regards the absolute number of admissions for malaria, astudy of Table 86 shows that Mississippi led the States in the number ofadmissions (1,427), and this is also true as regards the ratio per 1,000.Arranged in order of relative total admissions for malaria the States showingthe greatest number stand in the following order: (1) Mississippi, 1,427; (2)Alabama, 924; (3) Texas, 715; (4) Arkansas, 687; (5) Georgia, 683; (6)Louisiana, 603; (7) Illinois, 586; (8) Tennessee, 534; (9) Missouri, 393; and(10) New York, 361.
Though the various States of the Union stand in the aboveorder as regards the absolute number of admissions for malaria occurring in theenlisted men inducted or enlisted from them, the true incidence of the malarialinfections can be determined only by a consideration of the ratio per 1,000 ofinducted or enlisted men from each State. A study of the table shows that theStates stand in the following order as regards the actual percentage or ratioper 1,000 for malaria, the figures applying only to white enlisted men, thesmall number of infections in colored troops being negligible for the presentpurpose: (1) Mississippi, 49.04; (2) Alabama, 19.57; (3) Louisiana, 15.57; (4)Arkansas, 15.37; (5) Georgia, 12.88; (6) Florida, 11.21; (7) Tennessee, 9.33;(8) South Carolina, 6.82; (9) Kentucky, 5.75; (10) Texas, 5.32.
519
The relative prevalence of malaria in enlisted and inductedmen, as shown in the above list of 10 States, agrees almost perfectly with whatis known regarding the relative prevalence of malarial infections in the civilpopulation of the United States. It is noted that inducted and enlisted men fromthe States of Mississippi, Alabama, Louisiana, and Arkansas showed the highestratios per 1,000 for malaria, and it is well known that malaria is moreprevalent in these States than in any other States of the Union. It will also benoted that the ratio per 1,000 for men from Mississippi is three times that formen from any other State, and this also agrees with other observations regardingthe relative frequency of malaria in the Southern States of the Union. Theratios per 1,000 shown for the other States in the above list agree well withwhat was known regarding the distribution of malaria in the United States beforethe World War, and it can not be said therefore that our records have addedanything new to our knowledge as to the distribution of malarial infections inthis country. While this is true, the data are of value in demonstrating whatmay be expected as regards the incidence of malaria in men enlisted or inductedfrom the various States in the Union. It is certain from Table 85 that a veryconsiderable proportion of the malaria occurring in our camps was not due tolocal infections but to relapses of infections contracted before arrival in thecamps. These relapses occurred in men coming from States well known to beheavily infected with this disease. Therefore it is evident that a considerableamount of malaria, in the form of relapses, must be expected in troops recruitedin the States of Mississippi, Alabama, Louisiana, Arkansas, and other SouthernStates, while practically no malaria will occur in the form of relapses introops recruited in New Hampshire, Wyoming, Arizona, Nevada, and other States ofthe northern and western groups. It must also be remembered that most of therelapse cases are "carriers" of malarial infection. This subject, soimportant from the standpoint of prophylaxis, will be considered below.
SEASONAL PREVALENCE
Malarial fevers were present in our troops throughout theyear, but were most prevalent during the summer and autumn months (Table 87). In1917 and 1918 the greatest prevalence of malaria was in May, June, July, August,and September, the highest ratio per 1,000 occurring in 1917 in June (14.31),and in 1918 in July (8.36). In 1919, the highest ratio per 1,000 occurred inNovember (15.64), probably due to the fact that the majority of relapsesoccurred at this time.
Due to climatic conditions in the States whose men showed thegreatest number of admissions for malaria, it may be stated that most of thecases admitted during the months of November, December, January, February,March, and April were relapses of infections contracted during the other monthsof the year. It is also undoubtedly true that a certain proportion of the casesadmitted during May, June, July, August, and September were "relapse"cases; admitting these facts, however, the table demonstrates beyond questionthat there was a great increase in malaria in our troops, commencing in May andreaching its acme in 1917 in June; in July in 1918; and in November in 1919. Thehigher prevalence of the malarial infections in November, 1919, is probably
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partially due to the fact that prior to that time funds forthe prosecution of antimosquito work had been greatly curtailed coincident withdemobilization of the Army.
As a whole, Table 87 demonstrates that malarial infections inour troops were most prevalent during the months of June, July, August, andSeptember, and this agrees perfectly with what was previously known regardingthe seasonal prevalence of these infections in the parts of the United States inwhich our various camps were situated.
|
| Colored | Total | |||
| Ratios | Absolute numbers | Ratios | Absolute numbers | Ratios | |
| 1917 |
|
|
|
|
|
|
April | 151 | 9.86 | 1 | 2.46 | 152 | 9.67 |
May | 222 | 10.85 | 1 | 2.06 | 223 | 10.65 |
June | 375 | 14.55 | --- | --- | 375 | 14.31 |
July | 414 | 10.83 | 1 | 1.80 | 415 | 10.95 |
August | 428 | 9.13 | 6 | 8.45 | 434 | 9.10 |
September | 921 | 14.23 | 9 | 11.48 | 930 | 14.20 |
October | 858 | 9.97 | 15 | 8.26 | 873 | 9.94 |
November | 349 | 3.95 | 32 | 9.79 | 381 | 4.15 |
December | 156 | 1.66 | 9 | 2.93 | 165 | 1.70 |
| 1918 |
|
|
|
|
|
|
January | 118 | 1.29 | 8 | 1.89 | 126 | 1.32 |
February | 117 | 1.28 | 4 | .96 | 121 | 1.27 |
March | 233 | 2.48 | 7 | 1.53 | 240 | 2.43 |
April | 287 | 2.95 | 12 | 2.44 | 299 | 2.92 |
May | 567 | 5.68 | 39 | 5.34 | 606 | 5.66 |
June | 813 | 7.48 | 47 | 6.32 | 860 | 7.41 |
July | 919 | 8.30 | 93 | 8.92 | 1,012 | 8.36 |
August | 761 | 7.11 | 124 | 8.83 | 885 | 7.31 |
September | 592 | 5.38 | 81 | 5.90 | 673 | 5.43 |
October | 178 | 1.59 | 20 | 1.31 | 198 | 1.56 |
November | 107 | 1.02 | 13 | 1.04 | 120 | 1.02 |
December | 48 | .61 | 10 | 1.15 | 58 | .67 |
| 1919 |
|
|
|
|
|
|
January | 31 | .55 | 4 | .70 | 35 | .57 |
February | 33 | .84 | 3 | .55 | 36 | .80 |
March | 36 | 1.06 | 3 | .81 | 39 | 1.04 |
April | 53 | 1.87 | 2 | .81 | 55 | 1.79 |
May | 44 | 1.81 | 7 | 4.04 | 51 | 1.96 |
June | 44 | 2.14 | 2 | 1.29 | 46 | 2.08 |
July | 102 | 5.69 | 2 | 1.20 | 104 | 5.31 |
August | 134 | 10.26 | 3 | 2.00 | 137 | 9.41 |
September | 117 | 9.40 | 4 | 4.24 | 121 | 9.04 |
October | 153 | 13.13 | 1 | 1.32 | 154 | 12.40 |
November | 182 | 16.49 | 2 | 2.73 | 184 | 15.64 |
December | 74 | 6.56 | --- | --- | 74 | 6.15 |
|
| 9,617 | 4.89 | 565 | 3.88 | 10,182 | 4.82 |
MORTALITY
In the period between April 1, 1917, and December 31, 1919, 36 cases ofmalaria were reported as having died. These figures include all deaths from thiscause (primary admission) in the entire Army, and it is believed that neverbefore in the history of the world has so small a number of deaths from the malarial infections been recorded in any army in time of war.
PREVENTIVE MEASURES
The principal prophylactic method employed in the United States Army, and theone that gave the best results, was the prevention of the breeding of
521
mosquitoes.d The efforts of the medical officersof the Army in this direction were ably seconded by those of the officers of theSanitary Corps and, in the extra-cantonment area, by those of the United StatesPublic Health Service. An immense amount of time, labor, and money was expendedin ditching, dredging, draining, and filling in, but the results obtained wellrepaid the effort and the funds expended, as shown by the low malaria rates inour training camps which were situated in infected localities.
In certain camps mosquito control was never complete, andother prophylactic measures were employed. Thus, at Camp Beauregard, La., wheremosquito control was not satisfactory, it was found that the proper treatment of"carriers" and of cases contributed greatly to the control of thedisease.1
RELATIVE EFFICIENCY OF PROPHYLACTIC MEASURES
The relative efficiency of the various methods of prophylaxisemployed for the prevention of malaria has always been a subject of controversy.No data of value in the settling of this question are available in our recordsof the World War, as only two methods of prophylaxis were extensively employedin the Army; i. e., the prevention of mosquito breeding and screening. Ourexcellent results were due then almost entirely to the prevention of thebreeding of the mosquitoes transmitting malaria in this country, plus screening.By reason of the magnitude of our antimosquito operations and their success, theexperience of our Army probably furnishes the most striking example of theefficiency of antimosquito prophylaxis of malaria on record, an experiment sogigantic and so successful that it should end for all time any doubt as to thevalue of this form of prophylaxis in the prevention of malarial infection.
PRESENT STATUS OF PROPHYLACTIC MEASURES
As stated, the measures directed toward the prevention of thebreeding of mosquitoes, plus screening, proved to be the most efficient in thecontrol of malarial infections, but it should be remembered that ourexperience with the use of other methods was very limited, too much so to be ofany real weight in the evaluation of the various methods generally employed.Screening and the treatment of "carriers" of malaria resulted inalmost absolute protection at Ebert Field,2 and had it been possibleto apply these methods on as great a scale as the antimosquito methods wereapplied, it would be possible for a definite statement to be made regardingtheir relative value.
The following extracts from a report on the prophylaxis ofmalaria at Ebert Field, Ark., are of great interest as showing the value ofquinine treatment of "carriers" and screening in the prophylaxis ofthese infections:
The control of malaria at Ebert Field, Ark., represented anunusually difficult problem due to the extensive area, the high rate of malariaamong natives, and particularly the problem of the rice fields which extendedfor many miles around the camp. It can truly be said that malaria was controlledin this zone, but that mosquitoes were not under control.
The total number of cases of malaria reported from EbertField was 33. On these no cases were contracted in camp. The results on malariacontrol are indicated as follows:
Control of mosquito production being humanly impossible solong as the rice fields were within flight distance of any and all parts of thearea, it is interesting to compare the mortality
dSee Vol. VI, Sanitation, Chap.X. V.
522
and the history incidence of malaria in 1917 withthe casereports, mortality, and September check index of 1918. In 1917 there occurred 4deaths from malaria in the control area as against none in 1918. The historyincidence index, 29 per cent, or expressed in the number of cases, 522, the onlyavailable record for 1917, when compared with the actual development of only onecase in 1918, is conclusive proof of the efficiency of the control.
Since, in spite of the attempt to control production, A.quadrimaculatus, recognized as an efficient transmitter of malaria, waspresent in large numbers about the residences of the community, this diminutionof malaria can be ascribed only to screening and the sterilization of the human"carriers"-the latter being probably the main factor.
* * * * * * *
The use of 10 grains of quinine sulphate by mouth forsterilization of the blood of malaria carriers is evidently sufficient for onemalaria season if used actively over a period of 30 days.
British experience in Macedonia showed3 that the bestresults in the prophylaxis of malaria were obtained when antimosquito measuresand prophylactic quinine were combined, owing to local conditions which madeanti-mosquito measures impossible. So far as the prevention of breeding placeswas concerned, Wenyon states4 protection from the bites of mosquitoeswas the most efficient prophylactic measure; he found that it was impossible toget rid of the mosquitoes and that the following were the most effective methodsof prophylaxis under the existing conditions:
Evacuation of infected individuals -The evacuation ofinfected individuals-i. e., those that showed by their history that they had apersistent infection-reduced the number of cases by removing the most heavilyinfected and also removed the "carriers" of the infection, thuspreventing the infection of mosquitoes. The results of this measure alone heestimates as reducing the admissions by from 60 to 70 per cent. Over 25,000 menwere thus evacuated, and he believes it no exaggeration to state that had thesemen remained they would have caused at least from fifty to sixty thousandadditional admissions to hospital from malaria.
Quinine prophylaxis -Inhis experience this method wasdisappointing, due to poor application. The dosage varied greatly in differentcommands and was generally insufficient, and no proper methods were adopted tosee that the men actually took the drug distributed to them.
Mosquito nets - Of all the methods tried, Wenyon regardsthe mosquito net as by far the most efficient in preventing infection. Head netsand gloves are also valuable.
When troops are engaged actively in campaign in a malarialregion the main effort should be to protect the men from the bites ofmosquitoes; the mosquito net, properly used, will accomplish this.
No data accumulated during the World War have changed ourviews regarding the relative value of the methods of malaria prophylaxis. Theprevention of the breeding of the transmitting mosquitoes and protection fromtheir bites are still the most efficient methods of prophylaxis, whileprophylactic quinine, the segregation and proper treatment of"carriers," and the proper treatment of initial malarial infectionsare all considered valuable methods which should be combined with antimosquitomeasures. Especially important in malaria prophylaxis is the detection andtreatment of "carriers" and the treatment of initial infectious inorder that the "carrier" state may be prevented.
523
ETIOLOGY
Despite the considerable amount of research work connectedwith the etiology of malaria that was accomplished by our medical officers andsanitarians during the period of the World War, no new facts of fundamentalimportance were discovered regarding the etiology of these infections.
THE SPECIES OF MALARIA PLASMODIA
Our experience with malaria during the World War wasconfirmatory of the existence of at least three species of the malariaplasmodia; i. e., Plasmodium vivax, the benign tertian plasmodium; Plasmodiummalario, the quartan plasmodium; and Plasmodium falciparum, theestivoautumnal or malignant tertian plasmodium. There was a tendency among someobservers in the British and French Armies to urge the unity of all malariaplasmodia, basing their arguments upon the apparent merging of one type ofmalarial infection into another, with a corresponding change in the morphologyof the plasmodia observed in the blood of the patients. However, there isnothing in the published observations of any of the adherents of this theorythat would indicate that mixed infections with more than one species ofplasmodium could be eliminated, and at the present time it may be stated that noobservations made during or since the World War have shaken, in the least, theevidence upon which is based the generally accepted belief in the plurality ofspecies among the malaria plasmodia.
As regards the existence of more than one species ofestivoautumnal plasmodium, little that is new was added to our knowledge as aresult of the war.
In March, 1921, some new data were published by the writerregarding the species of the estivoautumnal plasmodia secured from the study ofmaterial from malarial patients in some of our camps.5These datawere confirmatory of the existence of more than one species of this plasmodiumand of the previous conclusions of the same writer that the estivoautumnalplasmodium should be divided into two types, one the species known as Plasmodiumfalciparum and the other, a subspecies, which this writer, in 1909, called Plasmodiumfalciparumquotidianum.6 The evidence that these two forms exist rests upondistinct differences in morphology, in the length of the life cycle in man, andin the clinical picture of the infections which are produced by them. Themorphological differences are as constant and distinctive as those between Plasmodiumvivax and Plasmodium malario, while the striking difference in thetemperature curve still further serves to differentiate them.
SPECIES OF ANOPHELES CONCERNED IN THE TRANSMISSION OF MALARIA IN CAMPS IN THE UNITED STATES
Early in the war the Surgeon General directed thatcollections be made of the prevailing mosquitoes in the training camps in theUnited States, and these collections were forwarded to the entomologist of theArmy Medical Museum for diagnosis and preservation.7 Thesecollections were not carefully made in many instances, so that it is impossibleto state what species of anopheline
524
mosquitoes were most prevalent in certain of our camps, butthe following list gives the anopheline mosquitoes common to certain camps inwhich malaria was most prevalent:
Camp Beauregard, La. | Anopheles quadrimaculatus. |
Camp Dix, N.J. | Anopheles punctipennis. |
Camp Eustis, Va. | Anopheles quadrimaculatus. |
Camp Gordon, Ga. | Anopheles punctipennis. |
Camp Greene, N.C. | Anopheles punctipennis. |
Camp Jackson, S.C. | Anopheles crucians. |
Camp Logan, Tex. | Anopheles quadrimaculatus. |
Camp McClellan, Ala. | Anopheles puntipennis. |
Camp Pike, Ark. | Anopheles quadrimaculatus. |
Camp Travis, Tex. | Anopheles pseudopunctipennis. |
Camp Wheeler, Ga. | Anopheles quadrimaculatus. |
Of these mosquitoes, Anopheles punctipennis is theleast active as a carrier of malaria, and where it is noted as occurring aloneit is probable that other more active species also occurred but were notincluded in the collections. Anopheles quadrimaculatus is the most activetransmitter of malaria of the anophelines reported, with Anopheles crucians secondin importance in this respect. Anopheles walkeri and Anopheles barberihave not been recorded as hosts of the malaria plasmodia.
THE LENGTH OF FLIGHT OF ANOPHELINE MOSQUITOES
The question of the length of flight of anopheline mosquitoeshas always attracted much attention because of the importance of an accurateknowledge of this subject in prophylaxis. Craig,8 in 1906, was thefirst to call attention to the fact that anopheline mosquitoes will fly over 2miles in order to obtain a feeding of blood, although at that time it wasgenerally believed by entomologists that anophelines did not fly for a greaterdistance than half a mile. It was not until the observations upon the Isthmus ofPanama regarding the long-distance flight of anophelines that these findingswere confirmed. During the World War some interesting and valuable observationsalong this line were conducted at Ebert Field, Ark.2 The experimentsconsisted in catching and staining anopheline mosquitoes, liberating them atvarious distances from the camp, and then recatching as many as possible. Duringthe time covered by the experiments there were only light air currents, so thatthe distances covered by the mosquitoes could not be explained by their beingcarried by winds. More than 5,000 mosquitoes were experimented with, andrecatching was done at 37 different stations. It was found that the distancescovered by the flight of anophelines varied all the way from one-quarter of amile to 2? miles, the
525
greatest number being caught at distances of from one-half to1? miles. The conclusion was that in this locality a flight distance of at least1 mile could be expected, but the range of Anopheles quadrimaculatus, themost common mosquito caught, could be as much as 2? miles.
The observations detailed above amply confirm those made in1906,8 which were received at that time with incredulity by entomologists andsanitarians, and render it evident that little dependence can be placed uponprophylactic methods based upon the supposed short-flight distance ofanophelines.
THE "CARRIER"
The importance of the "carrier"-i. e., the humanbeing apparently well but whose blood contains the malarial gametocytes-wasdemonstrated again and some work was done, especially at Ebert Field, showingthe importance of discovering and treating "carriers" in theprophylaxis of malaria. It was demonstrated also that "carriers" maybe freed from their infection by persistent quinine treatment.
SYMPTOMATOLOGY
Nothing new was added to our knowledge of the symptomatologyof malarial infections by observations made during the World War.
ASSOCIATION WITH OTHER DISEASES
The association of malaria with other diseases is shown inTable 88. A study of this table indicates that it possesses little scientificvalue as proving that any of the diseases in which malaria was secondarypredispose to the latter infections to any great extent or that the malarialinfections are more often associated with any one particular disease in anyevent. The number of cases is too small to base any important conclusions uponthem, and the table is chiefly of interest as demonstrating that malariaactually was associated with the conditions mentioned.
TABLE 88.-Malarial fever, secondary to other diseases. Enlisted men, United States and Europe, April 1, 1917, to December 31, 1919. Absolute numbers, ratios per 1,000, and percentage rates
Primary diseases |
| Case rates (secondary) | Death rates (secondary) | Fatality rates (secondary) | |
| Deaths | ||||
|
|
|
|
| Per cent |
Measles | 47 | --- | 0.50 | --- | --- |
Influenza (epidemic) | 366 | 11 | .50 | 0.01 | 3.01 |
Meningitis, cerebrospinal | 5 | 3 | 1.08 | .65 | 60.00 |
Mumps | 72 | --- | .33 | --- | --- |
Typhoid vaccination | 41 | --- | 1.20 | --- | --- |
Tuberculosis of lungs | 24 | 1 | .77 | .03 | 4.17 |
Acute miliary tuberculosis | 2 | 2 | 8.40 | 8.40 | 100.00 |
Syphilis (all) | 22 | --- | .35 | --- | --- |
Gonococcus infection | 80 | --- | .33 | --- | --- |
Tonsillitis, acute | 40 | --- | .24 | --- | --- |
Pharyngitis, acute catarrhal | 21 | --- | .43 | --- | --- |
Bronchitis | 172 | --- | .73 | --- | --- |
Pneumonia: |
|
|
|
|
|
| Broncho | 20 | 2 | .65 | .06 | 10.00 |
| Lobar | 62 | 7 | 1.44 | .16 | 11.29 |
Intestines, other diseases of | 21 | --- | .35 | --- | --- |
All others | 380 | 8 | --- | --- | 2.11 |
| Total malarial fevers (secondary) | 1,375 | 34 | --- | --- | 2.47 |
Total malarial fevers (primary) | 11,072 | 25 | 2.99 | .01 | .23 |
526
PATHOLOGY
There were no new contributions to our knowledge of thepathology of malarial infection by our medical officers during the period of theWorld War.
DIAGNOSIS
During the war the diagnosis of malaria was based, in thevast majority of cases, upon the results of microscopic examinations of theblood of the infected individual. This is the first time in the history of ourArmy in war that the diagnosis of the malarial infections was made by anexamination of the blood, for in our previous wars, with the exception of theSpanish-American War, such a method of diagnosis was not feasible, as themalaria plasmodia had not been discovered. In the Spanish-American War, as amatter of fact, the diagnosis of malaria was very largely based upon clinicalsymptoms, with the result that our statistics concerning the actual occurrenceof malaria during that war are very inaccurate. During the Philippineinsurrection the use of the microscope in the diagnosis of malaria became moregeneral, but owing to lack of facilities and trained observers it did not becomea general practice there except in our larger hospitals. However, for severalyears prior to the World War the diagnosis of malaria in our Army had been basedentirely upon the results of blood examinations, and this wise practice wascontinued during the war. Every home camp was furnished with a splendidlyequipped laboratory and specially trained officers and men, so that it wasalways possible to diagnose malaria by the examination of the blood. Conditionsin this respect were equally favorable abroad.
No new method of diagnosis of malarial infections wasevolved during the war by our medical or sanitary officers.
TREATMENT
In our Army, as well as in those of other nations, quininecontinued to be the drug par excellence in the treatment of malarial infections,and no new substitute for quinine had been discovered. There was some differenceof opinion as to the best method of administering this drug, but in our Army itwas generally given by the mouth, with excellent results. In cases exhibitingpernicious symptoms the drug was administered intravenously.
In the British Army in Macedonia many medical officersfavored the intramusculur use of quinine, but this method was rarely used by ourmedical officers. It is very questionable if the intramuscular injection ofquinine should be adopted in preference to intravenous administration and ourmedical officers found that the administration of the drug by the mouth answeredall purposes in the vast majority of the malarial infections that theyencountered.
Some pessimistic papers were written during the war period bymedical officers of the British Army as to the value of quinine in the treatmentof malaria. The opinion is expressed that this spirit of doubt regarding theefficiency of quinine as a specific is entirely due to the results that havefollowed its administration in a faulty manner or to individuals who did notabsorb the drug from the stomach when administered by the mouth. The opinion isalso expressed that quinine properly administered and continued for a sufficient
527
period of time, will cure any case of malarial infection, provided thepatient can take the drug; the experience of the British in treating invalidedsoldiers for malaria and returning them to duty is proof of this assertion.
REFERENCES
(1) Reports on mosquito control at Camp Beauregard, La. On file, Record Room, S. G. O., Correspondence File, 725.11 (Camp Beauregard) (D).
(2) Report on the activities of the malaria control section, division of sanitation, S. G. O., February 20, 1920, by Maj. George R. Bascom, Sanitary Corps. On file, Record Room, S. G. O., 725.11-1.
(3) Proceedings of the medical conference, held at the invitation of the Committee of Red Cross Societies, Cannes, France, April 1-11, 1919. Published by the League of Red Cross Societies, Geneva, Switzerland, 1919, 132.
(4) Wenyon, C. M., and Anderson, A. G.: Malaria in Macedonia, 1915-19, Journal of the Royal Army Medical Corps, London, 1921, xxxvii, 81.
(5) Craig, C. F.: The Classification and Differential Diagnosis of the Aestivo-autumnal Malarial Plasmodia. American Journal Tropical Medicine, Baltimore, 1921, 1, No. 2, 57.
(6) Craig, C. F.: The Classification of the Malarial Plasmodia. Boston Medical and Surgical Journal, 1909, clx, 677.
(7) Cir. Letter, Surgeon General's Office, March 21, 1918.
(8) Craig, C. F.: Observations upon Malaria; latent infection in natives of the Philippine Islands; intracorpuscular conjugation. Philippine Journal of Science, Manila, 1906, 1, 523.
