Communicable Diseases, Table of Contents
CHAPTER XVI
INFECTIOUS JAUNDICE; TYPHUS FEVER; TRENCH FEVER
INFECTIOUS JAUNDICE
Infectious jaundice is not a new disease, epidemics havingbeen reported upon as far back as the first half of the eighteenth century.1In 1914 certain Japanese investigators isolated a spirochete from cases intheir own country to which they gave the name Spiroch?taicteroh?morrhagi?.1 Theintermediate host of the parasite is the brown rat. This spirochete is to-daygenerally accepted as the specific cause of the disease.
The United States Army reported a total of 452 cases ofspirochetal jaundice during the period of the World War, with a resultant lossof 9,251 days and 15 deaths. The distribution of these cases by countries isindicated in the following table: United States, 279; Europe, 108; PhilippineIslands, 15; Panama, 9; other countries, 5; transports, 1; total officers, 35;total Army, 452. To these 452 original admissions must be added 80 instances inwhich the same malady occurred concurrently with other diseases, making a grandtotal of 532 cases.
TYPHUS FEVER
Typhus fever has been long known, and the World War addedlittle, if anything, to clinical knowledge concerning it. Its transmission bythe louse is accepted. Its incidence in the Army during the World War was asfollows: United States, 15; Europe, 7; other countries, 19; officers, 1; total,42. To the 42 original admissions for typhus fever must be added 5 more cases inwhich this malady appeared as a concurrent disease. Three of these individualsdied and the disease was responsible for 1,335 days lost.
Although the war did not, properly speaking, advance inmeasurable degree the clinical, epidemiological, and etiological phases of theavailable knowledge concerning typhus fever, nevertheless, the startlingepidemics of the disease which occurred in Russia, Poland, and other countriesduring the war period served to stimulate the labors of the Typhus ResearchCommission of the League of Red Cross Societies to Poland, the results of whoseinvestigations became available in the main report of this commission whichappeared in 1922.2 This commission looked upon"the determination of the exact nature of the specific cause of the disease* * * as the most important goal."2
The transmission of typhus fever by the louse was accepted atthe start. The one organism found to be most definitely and uniformlydemonstrable in lice that had fed upon typhus patients was Rickettsiaprowazeki. This Rickettsia was identified in each instance upon itsappearance as observed in serial sections of lice. It was found in the lice of27 out of 52 experiments.3 Changesin technique based upon experience secured positive results in practically everyone of the last third of the experiments.
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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Rickettsia pediculi was found occasionally.Microorganisms other than Rickettsia did not appear in any of the 52 experimentsin which lice were nourished upon typhus patients. Animal experimentationdesigned to prove Rickettsia prowazeki the specific cause of typhus feveris reported in detail. The authors' conclusions are as follows:4
The presence of Rickettsia prowazeki inlice in our experience is proof of the presence of the virus of typhus.
A variable percentage only of lice nurturedupon typhus patients acquire the virus of typhus; and this holds true in boxeswhere all lice have equal opportunities to become infected.
After allowing for the technical difficultiesin making adequate search for Rickettsia and injections from the same louse andfor the uncertainty of the reaction of guinea pigs to typhus blood in the testfor immunity, we believe that the data from the above experiments are sufficientproof that the virus of typhus and Rickettsia prowazeki are inseparable.
Concerning Rickettsia, it is stated5that this "is the group name given by da Rocha-Lima (1916) to minutemicroorganisms with certain peculiarities found in lice. The name honors thememory of Howard Taylor Ricketts, who first described microoganisms possibly ofthis type in connection with studies upon typhus (Ricketts and Wilder,1910)." The present knowledge of Rickettsia is summarized as follows:6
A satisfactory definition of Rickettsia is notpossible at present. The properties in common of the 13 or 14 microorganisms sofar described under this name are as follows:
Morphology.-Bacteriumlike on thewhole. They are smaller than bacteria and occur characteristically in pairs.Large forms, bacillary and filamentous, have been described in connection withtwo carefully studied Rickettsias-Rickettsiaprowazeki and Rickettsialectularius-and it seems probable that a simple cycle or sequence inmorphological development is a characteristic of the pathogenic forms.
Staining reactions -Difficultyof staining with the common staining solutions used for bacteria is a strikingfeature, as is the failure to retain the stain by Gram's method. The onlysatisfactory staining methods are the modifications of Romanowsky's method; ofthese, the most satisfactory is Giemsa's solution.
Mobility -Motileforms have not been seen.
Cultivation -Sofar all have resisted cultivation with the exception of the Rickettsia fromthe sheep louse. It grows on a relatively simple glucose blood agar medium.
Resistance to physical and chemical agents -Notenough work has been done to generalize. The viruses of typhus (da Rocha-Lima,1919, p. 240) and Rocky Mountain spotted fever (Wolbach, 1919) are extremelysusceptible to heat, drying, and chemical agents. On the other hand, the virusof trench fever resists 80? C. of dry heat for 20 minutes and drying for manymonths (Byam and Lloyd, 1919).
Host specificity -AllRickettsias have insect hosts which in the case of the pathogenic ones arethe vectors. All are highly specific for their insect host, while the pathogenicones may infect widely separated mammals.
Hereditary transmission -Inevery instance where careful study has been made it has been found-with theexception of the Rickettsia of typhus-that the organisms pass down throughsuccessive generations in the eggs. Da Rocha-Lima has offered some evidence thatthis is also true of Rickettsia prowazeki, and Sergent, Foley, andVialette, 1914 (quoted by Nuttall, Parasitology, vol. 10), accidentallycommunicated typhus to a monkey and a man with the offspring of lice which weresupposed to be infected only with relapsing fever.
Classification is ofcourse impossible, and it is probable that we have already included underRickettsia a number of very different microorganisms. The Rickettsia of thesheep louse has little to distinguish it from bacterium; yet we believe theRickettsia of typhus has a number of peculiarities which necessitate itsseparation at present. The Rickettsialike
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cause of Rocky Mountain spotted fever, whichwe prefer for the present to consider under a distinctive name, while resemblingin many ways Rickettsia prowazeki, is very unlike the morphologicallysimple Rickettsia of trench fever.
At the present the opinion seems generally held that Rickettsiaprowazeki is the specific cause of typhus fever. This knowledge may becredited to the epidemiological opportunities indirectly afforded by the WorldWar.
TRENCH FEVER
In 1915 there made its appearance among British troops on theWestern Front a disease7 which cameto be known as "Trench fever"8 andwhich gradually was recognized as a specific infection. The armies in Salonikalikewise reported cases of this disease.9 Thereis no available evidence indicating that this disease had ever been recognizedas a clinical entity before 1915.
OCCURRENCE IN THE ARMY
The following figures, which represent the occurrence of trenchfever in the Army, include a number of experimental cases, but do not embracerelapses from either experimental or natural causes. The total number of primaryadmissions was 798, divided as follows: Officers, 54; white enlisted men, 531;colored enlisted men, 2; color not stated, 211. All of these cases, except 12,occurred in our forces in Europe; the 12 cases were admitted in the UnitedStates. To the 798 primary admissions are to be added 103 cases which wereconcurrent with other diseases for which admission was made, thus giving a totalof 901. Among these, there were 2 deaths, 1 white enlisted man and 1 color notstated. Both deaths were in Europe.
The foregoing figures suggest a point of interest as regardsthe racial distribution of this disease. The admission rate per 1,000 was, forwhite enlisted men in the whole Army, 0.15, as against 0.01 for colored enlistedmen; and in Europe 0.35 for white enlisted men and 0.02 for colored enlistedmen. Assuming the probability that essentially the same conditions as to louseinfestation obtained in both white and colored combat troops, this notabledifference in race incidence would seem at first glance to indicate a relativelyhigher immunity on the part of the colored man. On the other hand, coloredtroops had relatively much less service in the trenches than did white troops,and it is probably much nearer the truth to assume that lice infected with thevirus of trench fever were largely, if not wholly, confined to the combat areas.
ETIOLOGY AND TRANSMISSION
The researches of the trench fever research committee of theAmerican Red Crossb whosereport was issued in 1918 afforded at the time of publication the last word onthe etiology and transmission of this disease.10For the investigation of the problems concerning the etiology and transmissionof the disease, human subjects were necessary, since the disease was nottransmissible to animals. The consent of the commander in chief, A. E. F., tothe use of soldiers
bThe members of the commission were as follows: Maj. Richard P. Strong, M. C.; Maj. Homer F. Swift, M. C.; Maj. Eugene L. Opie, M. C.; Capt. Ward J. MacNeal, M. C.; Capt. Walter Baetjer, M. C.; Capt. A. M. Pappenheimer, M. C.; Capt. A. D. Peacock, R. A. M. C. (T); and Lieut. David Rapport, M. C.
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who might volunteer for this human experimentation was secured by the chiefsurgeon, A. E. F. Out of hundreds who volunteered, 82 were selected. All thesevolunteers were subjected to detailed physical examination to exclude any unfit,and bacteriological examinations were then made of the blood, urine, and fecesto eliminate those who might be suffering from chronic infections, and carriers.The whole detachment was strictly segregated, and the most complete records asto temperature and condition of skin and clothing were made. A semiweekly bathand weekly sterilization of clothing were a part of the routine.
In seeking the specific etiological factor, the first step was an inquiryinto the possibility of infection with any members of the enteric group ofbacteria. Briefly, the examinations of blood, urine, and feces in cases ofspontaneous and experimental trench fever by methods adopted in the search forthe typhoid and paratyphoid bacilli were consistently negative. Serologicalreactions gave no indication that any of these organisms was culpable.Structures resembling spiroch?tes had been previously found by at least oneworker on the hematology of trench fever.11He looked upon the possibility of their being the causative factor in thedisease as not incompatible with the filterability of its virus since "somespiroch?tes are known to be filterable * * *." Otherwise the search forspiroch?tes in the blood (as conducted by the members of the Red Crosscommission by the method of anaerobic cultures) was entirely unsuccessful. TheWassermann test likewise was consistently negative, and thus failed to give anysuggestion that trench fever might be a modality of syphilis, or due to anyspiroch?te of close biological relationship to Spiroch?ta pallida. Thecommission confirmed the earlier experiments of McNee, Brent, and Renshaw thatthe disease was infectious and transmissible by the blood. Thirty-fourvolunteers who previously had been studied with great care were inoculated withblood or some constituent portion thereof taken from trench fever patientsduring the febrile paroxysms. Of these, 23 contracted the disease with anincubation period of from 5 to 20 days. Careful consideration of the results ofexperimental inoculation brought the commission to the conclusion that "Thevirus or organism of trench fever is present particularly in the fluid portionof the blood, and is not contained within the blood corpuscles themselves."
Investigation of the filterability of the virus resulted in proof that"at least one stage of the development of the virus of trench fever isfilterable and ultra-microscopic," though elsewhere it is stated that the"virus is not filterable with ease in centrifuged plasma or serum."
Concerning the thermal death point of the virus, it was found that the virusresists a temperature of 60? C. moist heat for 30 minutes, and is fullyvirulent after such treatment, but is killed by a temperature of 70? C. moistheat for 30 minutes. Obviously, therefore, a temperature of 55? C. for30 minutes, which destroys the Pediculus humanus and its ova, does notsuffice to destroy the virus of trench fever which may be present on theunderclothing of trench fever patients. Furthermore, its stability is perhapsone of its most striking characteristics. Immediate suspension of the thoroughlydried virus in a large volume of saline solution for several hours does notattenuate its virulence, and it has already been pointed out that it resistsdrying in the urinary
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sediment of trench fever cases and in louse excrement. For these reasons theorganism causing trench fever may apparently be most appropriately classified asa resistant filterable virus. The virus is invariably present in the blood inthe early stages; it is not present in the feces; it is present in the urine;sometimes it appears to be present in the mixture of saliva and sputum, asindicated by successful inoculation experiments.
Thirty-eight of the 82 volunteers were employed inexperimental investigation of the transmission of trench fever by the louse. Apure-bred strain of lice was obtained from the Lister Institute for thispurpose. The so-called "box method" of handling these lice was madeuse of. When lice were to be allowed to feed upon trench fever patients thesmall, round, cardboard box in which they were confined was placed, afterremoval of the cover, upon the surface of the skin of the forearm. The period offeeding was in each instance not less than 30 minutes and was repeated threetimes a day. Lice were placed upon healthy volunteers at varying intervals oftime after removal from the patients, with intent to exclude direct mechanicaltransmission through the medium of the parasite's biting mouth parts, and aswell to obtain information with regard to the length of time the louse mightremain infective. These experiments led to the conclusion that the disease"is transmitted naturally by the louse, Pediculus humanus, Linn.,var. corporis, and that this is the important and common means oftransmission; that the louse may transmit the disease by its bite alone (theusual manner of infection), or the disease may be produced artificially byscarifying the skin and rubbing in a small amount of the infected louseexcrement." Also "that a man may be entirely free from lice at thetime he develops trench fever, the louse that infected him having left him sometime previously as its host, and that the louse need only remain upon theindividual for a short period of time in order to infect him." It wasfurthermore shown that no evidence could be obtained pointing to the hereditarytransmission of the virus of trench fever in the louse; and finally there isevidence that, if the virus undergoes development in the louse, it requires 6 to10 days to do so; there is a little evidence that suggests the minimumincubation period to be about 4 days and that "lice may remain infected forat least 10 days and possibly 13."
The most suggestive discovery in all attempts to identify thespecific cause of this disease has been Rickettsia bodies. Swift12states that "while it is difficult not to believe that there is a causalrelationship between the virus of trench fever and the Rickettsia bodies, itwill be difficult to establish definitely such a relationship until it ispossible to obtain pure cultures of the bodies and with them to reproduce thedisease. In this connection it must be recalled that the relation of Rickettsiabodies to other microorganisms has not been established. They may be specificmicroorganisms; they may be a granular stage through which some othermicroorganism is passing; or, finally, they may be cell inclusions, the resultof the action of some invisible virus on the cell protoplasm, and thus resemblethe Guarnieri bodies in vaccinia, the Negri bodies of rabies, the molluscumbodies in molluscum contagiosum, and the cell inclusions in trachoma."Ledingham13 succeeded in producingagglutination of Rickettsia in emulsions prepared from dried lice excreta by theuse of immune
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sera from four experimental rabbits and one guinea pig. Hefound, however, that agglutination disappeared beyond a dilution of 1 in 40.
From critical consideration of the foregoing it would seemthat the final conclusion as to the specific cause of trench fever must be thatit is not yet indubitably known, although available evidence now points moresuggestively to a Rickettsia than in any other direction.
SYMPTOMS
The period of incubation in louse-borne trench fever varies from14 to 30 days, though the suggestion is offered that this might be shortened incases of infection resulting from large amounts of virus.10Certain vague prodromata-headache, fever of a low grade, and pain in theextremities-are complained of by a minority of individuals. Otherwise theonset is sudden and characterized by dizziness, headache, retrobulbar pain,particularly on movement of the eyeballs, nystagmus when the eyes are directedto either side, conjunctivitis, and a sudden elevation of temperature to 103?or 104? F. The febrile reaction varies much in its characteristics. It may lastabout a week, to be followed by a period of defervescence and a short relapse,or it may persist for several (often six) weeks and be marked during that periodby indefinite relapses; and, finally, it may assume quite distinctively the formof a regularly relapsing fever with apyretic intervals lasting six or sevendays. A less frequent picture is that of a low continued fever which persists,with only slight remissions, or none at all, from one to two months. The skin inthree cases out of four presents an eruption consisting of erythematous spots orpapules, most intense on the ventral and dorsal surfaces of the torso. Theindividual lesions average 3 or 4 mm. in diameter, are pink in color, and thecolor disappears under pressure. The period of their duration is short, often nomore than 24 hours. Most characteristically they first appear during the initialstage, but they are sometimes first seen during a relapse.
The blood picture is variable. Many cases show a moderateleucocytosis (13,000 to 17,000), which recurs with each relapse. On the otherhand, in certain cases the leucocytes are normal, while a few manifest aleucopenia (occasionally as low as 3,500). The urine frequently contains albuminin small amounts, but there is no other evidence of true inflammation of thekidney. The spleen is enlarged in a considerable majority of instances.
The most impressive subjective symptoms of trench fever arepain and tenderness. These are referred particularly to three regions or systems-thebones, the head, and the muscles. The "shin pains" are present in 75per cent or more of all patients. They are boring or lancinating in characterand increase in severity so much at night as seriously to interfere with sleep.They appear most characteristically on the third day of the disease or later,but in certain cases do not occur until the first or second relapse. They areaccompanied by marked tenderness of the tibia to pressure. Pain of a similarcharacter occurs in the scapula in many cases. Joint pains occur with afrequency equal to that of shin pains in both the upper and lower extremity. Theheadache is a universal symptom. It is commonly frontal or postorbital, thoughit may be generalized, and it lasts for two or three days, usually recurringwith
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each relapse. It is accompanied by a peculiar tenderness topressure in the supraorbital region which occasionally involves the entirescalp.
Muscle pain is complained of in the lower extermities, in theabdominal wall (either localized or generalized), in the lumbar region where itoccurs in 80 per cent of all cases, in the muscles of the shoulder girdle, andin the cervical muscles. It is accompanied by tenderness on palpation.
Anorexia and coated tongue are the most prominent of thegastrointestinal symptoms.
Although the pain is so constant and so marked and thereflexes are exaggerated, it is not believed that the central nervous system isdirectly attacked by the virus of trench fever. The nervous manifestations areprobably no more than may be accounted for on the basis of toxemia.
The pulse usually parallels the temperature in the firststages of the disease, but later shows a tendency to acceleration. The dyspnea,tachycardia, precordial pain, increase in the size of the heart, all indicatemarked involvement of that organ. It has been assumed either "that trenchfever virus has a selective action on the heart muscle such as we see inrheumatic fever or in the specific infiltration in syphilis 'of the heart,'or that the 'toxin in trench fever acts upon the heart muscle in a similar wayto that seen in pneumonia, typhoid fever, influenza, bronchitis, or other acuteinfections.'"10
COMPLICATIONS AND SEQUEL?
The most important of these is concerned with the heart, andhas been variously termed "effort syndrome," "disordered actionof the heart," and "tachycardia." The circulatory manifestationsof trench fever have already been described. The persistence of the indicatedcardiac condition after the apparent cessation of activity is probably to beascribed-at least, in large measure-to the desire of medical officers toreturn soldiers to duty as soon as possible. Convalescence appears to beessentially a lengthy procedure in this disease, as in dengue fever, andacceptance of such a view in the management of convalescence will allow forcomplete recovery without the appearance in any marked degree of this cardiacdisorder. Thus, the American Red Cross commission, previously quoted, statesthat-
Among our patients, we feel that up to thepresent time none have shown a condition of D. A. H. after the infection wasovercome. This probably is due to the fact that our subjects were carefullychosen, and those who had previously shown symptoms of cardiac weakness were notinoculated. The subjects were all young and strong, and at the time ofinoculaton were not suffering from other infections, nor had their resistancebeen lowered by long duty in the trenches or exposure to other forms ofstrenuous work * * * On the other hand, the absence of permanent effect upon theheart may have been due to the opportunity we had of holding the patients untilwe felt they were fit for active duty.
Except for the cardiac complications and sequel? of trenchfever, the concurrent diseases in the Army were widely various, and were notsuch as to indicate a pathological relationship between themselves and theoriginal infection.
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PATHOLOGY
Since the disease uncomplicated is never fatal, and since itis not transmissible to animals, the pathology is a sealed book. The clinicalevidence of changes in the heart and spleen, as well as the blood findings, havebeen referred to under symptoms.
DIAGNOSIS
Diagnosis is to be made upon the symptoms and signs hereinabovedescribed, of which the shin pains and shin tenderness are perhaps the mostessentially characteristic.
From influenza, trench fever may be differentiated by theabsence of respiratory symptoms and signs, by the characteristic pain andtenderness, by the relapses, by the splenic enlargement, and by the eruption.
Typhoid and paratyphoid fevers are of gradual onset, areaccompanied by certain digestive disorders, present a spleen which is lessenlarged (if at all) and softer than is the case in trench fever, lack thecharacteristic pains and tenderness, show a leucopenia, and give a blood serumcapable of agglutinating the causative organism in high dilution. Bacillustyphosus and Bacillus paratyphosus may also be recovered from theblood, feces, and urine.
Trench fever and malaria differ very characteristically intheir temperature charts, in the matter of febrile paroxysms, in the skineruption, pains, and tenderness which are present in the former disease, and inthe absence of the malarial parasite in the blood of trench fever cases unlessthe two diseases coexist.
Relapsing fever, because of its mode of onset, its pain, andrash, may be confused with trench fever; but a crisis on the seventh day with arelapse at the end of another seven-day period in relapsing fever indicates adifference between the febrile processes. Both liver and spleen are enlarged inrelapsing fever, the spleen alone in trench fever. The causative spirochetes arepresent in the blood of relapsing fever and absent therefrom in trench fever.Salvarsan exerts a marked effect upon relapsing fever, but none on trench fever.
Dengue fever may suggest trench fever in its mode of onsetand distribution of painful areas, but the acute stage of dengue is short, withan intermission occurring on the third to fifth day. The rash in dengue fever iserythematous or scarlatiniform during the first paroxysm and measleslike in thesecond paroxysm. Dengue is invariably characterized by a marked leucopenia;trench fever presents a moderate leucocytosis in a great majority of cases.
In typhus fever the onset is more gradual than in trenchfever and is accomplished in successive steps. Toxemia becomes increasingly moreprofound as typhus fever progresses, while the toxic manifestations of trenchfever-such mild ones as there may be-are more intense within the first fewdays after onset and rapidly subside. The characteristic relapses of trenchfever are not found in typhus fever. The skin eruption in typhus appears on thethird to the fifth day and is macular in character, changing to petechial.Typhus fever has a high mortality; trench fever is never fatal.
Malta fever is to be differentiated from trench fever, first,by the different temperature curve, by the absence of the eruption andcharacteristics pains
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and tenderness, by recovery of the causative organism fromthe blood and urine, and by serological methods.
There is, however, no serological or other laboratoryprocedure which is specific for the diagnosis of trench fever.
PREVENTIVE MEASURES
General preventive measures during the war consisted essentiallyin the delousing of officers and men, together with their effects, a detaileddescription of which is in Volume VI, Sanitation.
No attempts, apparently, were made to attenuate by heat thevirus of this disease as it occurs in louse excrement and in the urine oftrench-fever patients, and to vaccinate experimentally with such material. Sincethe infection of laboratory animals is not possible, such experimental attemptsat vaccination could hardly lead to results of practical value for the reasonthat the source of such vaccine could only be trench-fever patients themselves,of whom a very considerable number would undoubtedly be necessary to supplymaterial sufficient in amount for large bodies of troops. Again, no referencecan be found to the attempted protection of noninfected individuals by the useof serum from convalescent patients.
The relatively small number of cases of trench fever reportedfor the whole United States Army can not bespeak efficiency of the preventivemeasures in operation among American troops, in view of the fact that the majorportion of our combat troops were louse infested at the time of the signing ofthe armistice. But other considerations must be taken into account. A study ofthe statistics of trench fever in the Third Army shows that three-fourths of allits cases occurred in two divisions, as follows:14
Incidence of trench fever in troops of ThirdArmy, January 1 to March 1, 1919
| Cases |
| Cases |
42d Division | 143 | Third army troops | 9 |
2d Division | 55 | Third Corps troops | 2 |
1st Division | 16 | Fourth Corps troops | 1 |
52d Division | 11 | Total | 251 |
4th Division | 8 | ||
3d Division | 6 |
Again, the Third Army alone reported within only two months(January 1 to March 1, 1919) nearly a third of all the cases in the wholeAmerican Expeditionary Forces for the entire period of the war. That thesefigures represent the actual state of affairs is difficult to believe. They tendto suggest rather that in reality the cases in the Army exceeded the reportednumber of 901, and that many diagnoses were missed either because of transfer ofthe infected individuals from one station to another or-more especially-"becausemedical officers were not acquainted with the manifestations of thedisease."14 This impression isdefinitely reinforced by a consideration of the far greater uniformity withwhich trench fever is shown to have invaded the various units of the BritishExpeditionary Force.
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TREATMENT
No specific method of treatment is available. Salvarsan andthe other antisyphilitic arsenicals are without effect. A symptomatic therapyconsisting of complete rest in bed during the infectious period, a diet of goodnutritive value, and the exhibition of such drugs as aspirin and Dover'spowder in doses sufficient to control the pains are indicated. The mostimportant factor in treatment is the recognition of the necessity for prolongingthe convalescent period until the cardiac condition and action have becomeentirely normal. Patients should be kept in bed until all probability of arelapse is at an end. The amount of time allowed out of bed should then beginwith a few hours and gradually be increased daily, provided no return of thecardiac symptoms is noticed. As soon as the patient reaches the point ofremaining up and about all day, guarded and carefully supervised exercises areto be begun. These must be carefully controlled and the appearance of dyspnea,cardiac palpitation, dizziness, pain, fatigue, headache, excessive increase inpulse rate, and cyanosis are the signal for moderation in the amount of exercisetaken. The exercises employed are of two kinds: Setting-up exercises andpractice marches. As soon as the patient can endure a practice march of 5 mileswith full field equipment and return therefrom without evidence of undueweakness his convalescence is looked upon as completed
REFERENCES
(1) Jobling, James W., and Eggstein, A. A.: TheWild Rats of the Southern States as Carriers of the Spiroch?taIcterohemorrhagi?. The Journal of the American Medical Association, Chicago,1917, lxix, 1787.
(2) Wolbach, S. Burt; Todd, J. L.; and Palfrey,F. W.: The Etiology and Pathology of Typhus. (Report of the Typhus ResearchCommission of the League of Red Cross Societies to Poland). Harvard UniversityPress, Cambridge, Mass., 1922, 3.
(3) Ibid., 43.
(4) Ibid., 112.
(5) Ibid., 116.
(6) Ibid., 123-4.
(7) Graham, J. H. P.: On a Relapsing FebrileIllness of Unknown Origin. The Lancet, London, September 25, 1915, ii,703.
(8) Hunt, G. H., and Rankin, A. C.: IntermittentFever of Obscure Origin. The Lancet, London, 1915, ii, 1133. Also, Hunt,G. H., and McNee, J. W.: Further Observations on Trench Fever. QuarterlyJournal of Medicine, Oxford, 1915-16, ix, 442.
(9) Hurst, A. F.: Trench Fever. Journal of theRoyal Army Medical Corps, London, 1917, xxxviii, 207.
(10) Report of Commission of American Red CrossResearch Committee on Trench Fever. Oxford University Press, 1918.
(11) Coles, Alfred C.: Spiroch?tes in the Bloodin Trench Fever. The Lancet, London, March 8, 1919, i, 375.
(12) Swift, Homer F.: Trench Fever. Archivesof Internal Medicine. Chicago, 1920, xxvi, 76.
(13) Ledingshaw, J. C. G.: AgglutinationExperiments with Trench Fever Riekettsia. The Lancet, London, June 12,1920, i, 1264.
(14) Swift, Homer L.: Trench Fever in theAmerican Expeditionary Forces. The Journal of the American MedicalAssociation, Chicago, 1919, lxxiii, No. 11, 807.
