The prophylaxis of malaria with special reference to the military service

Front matter

Class

Book

I

Preface

In the sundry civil act tor 1914, under the appropriation for printing and binding for the War Department, it was provided:

That the sum of $3,000, or so much thereof as may be necessary, may be used for the publication from time to time of bulletins prepared under the direction of the Surgeon General of the Army, for the information of medical officers, when approved by the Secretary of War.

Similar provision was made in the sundry civil act for 1915, and it is hoped that this appropriation will be continued from year to year in the future. It is intended that these bulletins shall be used for the publication to the Medical Corps of the special technical work of the service laboratories, the reports of the boards for the study of tropical diseases, and other work of medical officers which is of too special or technical a character to make it acceptable for publication in the medical journals and the Military Surgeon.

The bulletin will be published, if possible, at least quarterly. Officers of the corps are requested to submit suitable articles to this office for use in the bulletin, with the understanding that they may be published elsewhere by the author if found not suitable for the bulletin.

'i • .* William C. Gorgas, Surgeon General ', United States Army.

September 24, 1913.

ORDER.

A board of officers of the Medical Corps, representing the Sanitary and Statistical Division and the Library of the Surgeon GeneraTs Office and the Laboratory of the Army Medical School, is hereby convened for the purpose of collecting materials and arranging for the publication of the bulletins for the instruction of medical officers authorized by the act approved June 23. 1913.

Detail for the board :

By order of the Surgeon General:

Chas. M. Gandy,

Lieutenant Colonel , Medical Corps , United States Army.

Table Of Contents

Page.

Introductory Remarks. 9

Illustrations of successful malaria prophylaxis. 10

Results in the Army.;. 10

Chapter I. The malaria plasmodia. 17 Methods of demonstrating the plasmodia. 17

Apparatus. 17

Living specimens. 17

Method of staining. 18

Staining reactions. 20

Ross thick film method. 20

Morphology and life cycle. 21

Classification. 21

Plasmodium vivax. 22

Unstained specimens. 22

Plasmodium malariae. 24

Unstained specimens. 24

Plasmodium falciparum. 26

Unstained specimens. 26

Plasmodium falciparum quotidianum. 27

Living specimens. 27

Development of plasmodia in the mosquito. 28

Morphology of the sexual forms of the plasmodia. 30

Gametes of Plasmodium vivax. 31

Gametes of Plasmodium malariae. 34

Gametes of aestivo-autumnal plasmodia. 34

Differential diagnosis of the malarial plasmodia. 36

Objects which may be mistaken for the plasmodia. 37

In fresh blood. 38

In stained preparations. 39

Chapter II. The malaria mosquitoes. 41 Geographical distribution. 41

Number of infected mosquitoes. 42

Species of mosquito in relation to malaria. 43

Classification. 42

External anatomy. 44

Internal anatomy. 45

Life cycle of anophelines. 46

The ova. 46

The larvae. 47

The pupae. 48

The adult mosquito. 48

Contents

Chapter II. The malaria mosquitoes—Continued.

Habits. 48

Of the larvae. 48

Chapter III. Prophylactic methods based upon the destruction of malaria

mosquitoes. 58

General remarks. 58

Drainage. 59

The blind drain. 59

The cement-lined open drain. 60

Subsoil drainage with tiles. 60

Filling. 60

Removal of shelter. 60

Larvicides. 61

Kerosene (fuel oil). 61

Canal Zone larvicide. 63

Other larvicides. 64

Destruction of larvae by fish. 64

Abolition of breeding places about barracks and quarters. 65

Destruction of the adult mosquito. 67

Sulphur dioxide. 67

Smudges. 68

Pyrethrum powder. 68

Other fumigants. 68

Mosquito catching as a prophylactic method. 68

Chapter IV. Prophylactic methods based upon the protection of man from the

bites of mosquitoes. 72

General remarks.:. 72

Screening. 72

Selection of screening material. 73

Size of the mesh. . 73

Method of screening. 75

Mosquito nets. 75

Head nets and gloves. 76

Use of odorous substances on the skin. 76

Results of screening. 77

Screening of malarial patients. 78

Chapter V. Prophylactic methods based upon the destruction of malaria

plasmodia (quinine prophylaxis). 80

General remarks. 80

Action of quinine upon the plasmodia. 82

Form of quinine to be used in prophylaxis. 84

CONTENTS. 7

Chapter V.—Prophylactic methods, etc.—Continued.

Methods of administration and dosage. 86

Celli’s method. 86

Sergent’s method. 86

Zieman and Noclit’s method. 86

Plehn’s method. 86

Koch’s method. 86

Service method. 86

Quinine-fast strains of plasmodia. 87

Treatment of infections and “carriers”. 88

Discovery and treatment of latent infections, i. 89

Proportion of latent infections. 90

Methods of diagnosing latent infections. 94

Treatment of latent infections. 94

Discovery of gamete carriers. 96

Time of occurrence of gametes. 97

Percentage of individuals showing gametes. 97

Estimation of number of gametes in prophylaxis. 98

Effect of quinine upon gametes. 99

Treatment of gamete carriers in prophylaxis. 99

Treatment of initial and recurrent infections in prophylaxis. 100

Results of quinine prophylaxis. 103

Chapter VI. The application of the methods of malarial prophylaxis to the

military service. 107

General remarks. 107

Malaria prophylaxis in the field. 107

Malaria prophylaxis in semipermanent camps. 108

Malaria prophylaxis in permanent posts. 109

References. 113

THE PROPHYLAXIS OF MALARIA.

INTRODUCTORY REMARKS.

The discovery by Laveran of the parasites concerned in the etiology of the malarial fevers, and by Ross of the method of transmission of these parasites from man to man by the mosquito, has placed the prophylaxis of these infections upon a firm scientific basis; while the discovery of cinchona and its alkaloid, quinine, placed in our hands a true specific against the parasites. In many countries these dis¬ coveries have been taken advantage of in extensive campaigns against malaria, and such campaigns have been successful in proportion to the thoroughness with which measures based upon etiological facts have been applied in prophylaxis.

In this bulletin, prepared at the request of the editorial board appointed by the Surgeon General of the Army, special stress will be laid upon those measures that are most applicable in the prophylaxis of malaria in the military service, including service in the field as well as in semipermanent camps and permanent posts. It is obvious that methods of prophylaxis that would he suitable in a permanent post might be impracticable upon the march, in bivouac, and in camps lasting only a day or two, so that it will be necessary to con¬ sider somewhat in extenso the prophylactic measures suitable under the special conditions brought about by military operations as well as those suited to preventing infection in permanent posts.

At the present time our knowledge of the etiology of malarial in¬ fections is so extensive and accurate that no matter how badly a region may be infected or how difficult the local conditions may make the application of prophylactic measures some method may be adopted that will result in success. It is now proven beyond controversv that the malarial fevers are transmitted from man to man by mosquitoes belonging to the Anophelince; that these mosquitoes in order to become infective must have bitten an infected individual; that the malaria parasites undergo a definite cycle of development in both man and the mosquito, which, if interrupted at any stage, will result in the death of the parasites; and that these parasites, so far as we know, exist only in man and mosquitoes, so that it is unnecessary to consider other animal or insect hosts in the prophy¬ laxis of malaria. Therefore it follows that if it were possible to destroy all malaria-carrying mosquitoes or kill all the plasmodia in the blood of all infected individuals we would succeed in the

PROPHYLAXIS OF MALARIA.

eradication of these fevers in every locality. Unfortunately, we must admit that in practice we can only hope for a partial success if we depend upon one method of prophylaxis alone, and it is gen¬ erally necessary to combine methods looking to the destruction of mosquitoes, the protection of man from the bites of these insects, and the destruction of the malaria plasmodia.

That methods based upon the discoveries of Laveran and Koss, when properly applied, are successful has been proven by numerous sanitarians. The success achieved by Gen. Gorgas and Col. Kean, of the Medical Corps, in Habana; of Gen. Gorgas in the Canal Zone; of Celli in Italy; of Watson in the Federated Malay States; and of the Sergents in Algeria in the prevention of malaria has demon¬ strated for all time the wonderful value of prophylactic measures against these infections, and there is no more striking illustration of what may be expected from intelligent prophylaxis than is shown in Chart No. I, giving the malarial rates in the Canal Zone since 1906 to 1913. As will be noted, during 1906 nearly T per cent of the entire working force on the canal entered hospital each month suf¬ fering from malarial infections, while in 1912 less than 1 per cent per month entered hospital from these infections.

In the Army there has been a gradual and continued reduction in the number of cases of malaria since 1898, as shown by Chart No. II. It should be understood, however, that the enormous number of admissions from malarial fevers in 1898, 1899, and even in 1900, as shown in this chart, can not be taken as representing the actual facts, for it is well known that a very large percentage of the cases of typhoid fever occurring during these years, and especially during 1898 and 1899, were diagnosed as remittent malarial fever and so entered upon the records. However, if Ave accept the year 1901 as representing accurate statistics of this disease, it will be noted that the admission rate for all American troops, serving both at home and in our tropical possessions, has been reduced from 365.39 per 1,000, the rate for 1901, to 24.75 per 1,000, the rate for 1913.

The noneffective rate from malarial infections, the best index we possess of the influence of the disease upon the efficiency of the Army, has likewise fallen greatly. This rate for all American troops, as shown in Chart III, serving both at home and abroad, Avas 4.46 in 1903, while in 1913 it was only 0.53, the loAvest noneffec¬ tive rate from these feA^ers since 1898.

In the troops serving in the United States the reduction in malaria, as would be expected, has been more marked than in the Philippines. In Chart No. IV is given the admission and noneffective rates for these fevers since 1904, and it will be noted that there has been a steady decrease in both rates, until in 1913 we

Chart No. 1.

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PROPHYLAXIS OF MALARIA.

Chart No. II.

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PROPHYLAXIS OF MALARIA.

Chart No. III.

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PROPHYLAXIS OF MALARIA.

reached the very small noneffective rate of 0.18 and the admission rate of 8.79. In the Philippines on the other hand (Chart No. V) the decrease has not been as steady, and in 1912 and 1913 the ad¬ mission rates are higher than in 1910 or 1911. The exact reason for this increase during the years mentioned is not known but it was probably due to more exposure in the field because of local maneuvers or expeditions.

The decrease of malaria in the Army has been brought about largely by measures directed against the mosquitoes transmitting the disease, and the protection of man from the bites of these insects. Quinine prophylaxis has probably had but little to do with this re¬ duction, as the use of this method has been very limited. Neither has the control of treatment by microscopic examinations of the blood and the treatment of “ carriers " and latent infections operated to any extent in reducing the disease in the Army, as these methods have been very little used, and it is believed that had these methods been widely employed the reduction of malaria would have been much more marked and much more rapid than it has been.

The methods of prophylaxis adopted in different localities must vary with the peculiar conditions present in each region, and com¬ mon sense must be used here as in every other procedure for the prevention of disease. High-flown theories must give place to a calm study of the situation and the means most applicable and best adapted to fighting the infection. Under some conditions we may be able to practically eradicate mosquitoes, while under others this measure may be impossible, and quinine prophylaxis will have to be substituted, together with measures for the protection of man from the bites of mosquitoes. In many, if not most, localities the best results will be secured by the combination of several prophylactic measures, and I am not at all in sympathy with those who insist that •either upon the destruction of mosquitoes or the prophylactic use of quinine alone we must depend for success in the prevention of the malarial fevers.

The prophylaxis of malaria, to be successful, must rest upon a thorough knowledge of the etiolog}^ of these infections. In the past much effort has been wasted and money uselessly expended in fool¬ ish attempts at prophylaxis by individuals possessing a very super¬ ficial knowledge of either the parasites causing the disease or the insects transmitting the infection, and most of the unfavorable re¬ ports regarding various methods of prophylaxis, if carefully studied, will be found to be based upon insufficient evidence furnished by those unacquainted with the real facts regarding the etiology of malaria.

A knowledge of the morphology and life cycle of the parasites causing malaria and of the mosquitoes transmitting the disease is

PROPHYLAXIS OP MALARIA.

Chart No. IV.

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PROPHYLAXIS OF MALARIA.

Chart No. V.

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PROPHYLAXIS OF MALARIA.

absolutely essential to one who hopes to achieve success in prophy¬ laxis. This does not mean that one must be a professional protozo¬ ologist or entomologist, for a good working knowledge of these sub¬ jects may be obtained from the careful study of the blood from a few cases of malaria and from the investigation of the structure and habits of a few species of mosquitoes. One should be able to recog¬ nize the various forms of the malaria plasmodia occurring in the blood of man and also be able to differentiate mosquitoes belonging to the Anophelina ? from other mosquitoes, and, fortunately, this knowl¬ edge may be easily acquired by anyone who has access to the neces¬ sary material.

As the first step in any successful attempt at the prophylaxis of malaria is the diagnosis of the presence of infection either in man or the mosquito, it is necessary to consider as briefly as is consistent with the importance of the subject the methods of demonstrating the parasites and their morphology and life cycle. The discovery of “ carriers v of the infection, so important from a prophylactic stand¬ point, and the proper treatment of all malarial disease, depends upon the recognition of the plasmodia in the blood of man, while no mala¬ ria survey can be called complete which does not include the demon¬ stration of the plasmodia within the mosquitoes of the locality in¬ vestigated. In the following sections dealing with the plasmodia and the mosquitoes transmitting them I have endeavored to give the facts that are most essential to one working along the line of prophylaxis; and while it has been necessary to describe the morphology of the plasmodia I have limited myself as much as possible in the descrip¬ tion, placing special emphasis upon the forms of the plasmodia that infect the mosquito and that may also be demonstrated in the blood of man, i. e., the gametes. No attempt has been made to describe in detail the anatomy of mosquitoes, but special attention has been paid to the broad points differentiating the Anophelinai from other mos¬ quitoes and to the habits of certain species transmitting the malarial fevers. The methods of demonstrating the plasmodia are those that I have found most useful and can be easily applied by anyone hav¬ ing a knowledge of the microscope and of microscopical technique.

Fort Leavenworth, Kansas,

July, 191