experimental chancroid - postgraduate medical...

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EXPERIMENTAL CHANCROID IN MANRelative Effectiveness of Various Drugs Tested by Three Methods *

By R. R. WILLCOX, M.D.St. Mary's Hospital, London

IntroductionDuring I949, at the invitation of the Govern-

ment of Southern Rhodesia, the author spent sixmonths in that country undertaking a venerealdiseases survey, specifically .to determine how newmethods of treatment could, consistent with costand local conditions, be extended to the Africannative. The project was financed by means ofa grant from the Rhodesian State Lottery Trustees.It was found possible, however, to exceed theseterms of reference and make a venereal diseasessurvey of the country as a whole.On arrival in that country it was evident that,

although penicillin was in use in some places forgonorrhoea, this was not the case in the treatmentof early syphilis-for which disease a course offour to six weeks, varying upon the clinic, of neo-arsphenamine with or without bismuth was beinggiven. Of necessity, also, facilities for dark fieldexaminations, and sometimes serum tests inaddition, were often lacking and every case ofpenile sore, including chancroid which was some-times unsuspect, was given such treatment withoutattempts to arrive at a more precise diagnosis.As it appeared probable that the introduction

of penicillin for routine use for early syphilis inthe African native would be a more costly methodof treatment than the one already in use, it wasfelt necessary to show that the current method wasunsatisfactory. That it was not a thoroughlysound treatment for the syphilitic patient wasobvious, although it could be argued that it wasnot unsatisfactory as a treatment of the masses(the so-called ' public health cure ' aimed purelyat the eradication of infectious lesions). More-over, many local doctors were satisfied with thetreatment, claiming that the penile sores ultimatelyhealed during the not inconsiderable period thatthe patients spent in hospital.

* Being the substance of a thesis approved by theUniversity of London for the Doctorate of Medicinee-xamination.

Attention was, therefore, focused on the effectsof neo-arsphenamine upon chancroid, for thisdisease, as is noted in the report, was at oncefound to be of great prevalence and, in the absenceof sufficient diagnostic equipment, all sufferersfrom this disorder were being treated as forsyphilis. It was helpful, therefore, if penicillinwas to be recommended for the treatment ofsyphilis, to show convincingly that the existingtreatment was inefficient for chancroid.The effectiveness of penicillin in the treatment

of early syphilis in the African native had also tobe put to the test under Rhodesian conditions.It was soon show that, if penicillin was used, thesyphilitic lesions healed quicker and the time thatthe patient had to be retained in hospital (admis-sion to hospital of patients with open sores beinggenerally insisted upon) was reduced from up-wards of six weeks to only one week. In addition,quite apart from the virtual absence of toxic effects,the ultimate results of penicillin therapy could,according to all published figures, be confidentlyexpected to show an improvement on thoseobtained by the truncated arsenical and bismuthcourses previously in force. Moreover, default,which had precluded all hope of increaslng thelength of the older regime if patients were to bedischarged from hospital, then became of littleimportance.

Realizing that more adequate diagnostic facilitiescould only be generally applied after a consider-able period of time, it had to be expected that thetreatment schedule recommended for early syphiliswould, in practice, also be applied to soft sore.Thus it was necessary to ascertain whether thepenicillin course was likely to be effective in thatdisease.

Previously held opinions concerning the efficacyof penicillin on chancroid were contradictory, andthe little-published work referred only to smallnumbers of cases. The reason for this' is that theuse of penicillin for soft sore is rightly discouraged

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POSTGRADUATE MEDICAL JOURNAL

in medically advanced countries, in which a funda-mental principle of venereology is properly toexclude syphilis and then adequately to treat andfollow each individual proved 'infected, whilethose cases not showing positive findings areobserved without receivinng any drugs whichwould tend to mask or conceal syphilis which hasremained undetected. t Sulphonamides are usefulfor these latter cases,7 as they are very effectiveagainst chancroid, but have no influence on thedark field positive lesions of early syphilis. Suchan approach to the problem, the desirability ofwhich cannot be gainsaid, infers not only thatthere is an adequate provision for proper diagnosisbut also that the patients will cooperate in attend-ing the clinic while the tests are being carried out.Neither criterion is met in tropical Africa.

Therefore, if penicillin could be shown also togive an adequate routine cure for chancroid, nogreat harm would result if this antibiotic is pre-scribed indiscriminantly for all African cases ofgenital sore, even in the' absen'ce of confirmatorymicroscopical diagnosis, provided that a curativedose for syphilis is given at the same time. Such anarrangement would be entirely justified, and wouldrepresent in many respects an ideal treatment foruse in the many rural clinics in which there are nosuitable diagnostic aids and the organization of anysort of follow-up is practically impossible.The collection of adequate data as to the relative

effectiveness of various drugs on clinical cases ofsoft sore, in which syphilis had first been excludedby repeated dark field and appropriate serumtests before treating with penicillin, would haverequired many months if the numbers so obtainedwere to be statistically convincing. This wouldhave been impossible to achieve in SouthernRhodesia during the time available for the survey,if -the many other aspects concerning venerealdisease in the African were to be covered.

However, by experiments employing inoculationof chancroidal matter into relatively small num-bers of human volunteers, results were mostrapidly obtained ; results which, at the same time,were far more easily controlled than those achievedby the more prolonged method employing clinicalcases, had this been feasible.

After a few trials, employing an inoculum ofmatter taken from chancroidal sores, a change wasmade.to an inoculum of bubo fluid. This material,when injected intradermally, produces a control-lable but marked reaction on the forearm of anuntreated person, but evokes no such reaction ina patient treated at the time of inoculation withan adequate dose of an effective drug. At first thedonors of the bubo fluid were the sole recipientsbut, once the technique had been perfected insuch a way that unpleasant reactions were reduced

to a minimum,.inoculation into others was alsoperformed. By this means a.number of personswere inoculated simultaneously with the samematerial, some being left untreated and othersbeing treated with the different drugs to be tested.The experiments were then rechecked using

a different method whereby the donors, whoseability to infect others had first been proved, werethemselves then treated with one of the drugs tobe tested. At 24-48 hours after the onset oftreatment a specimen of bubo fluid was againaspirated and injected intradermally into untreatedvolunteers, in order to ascertain whether or notthe treatment given had caused it to lose itsvirulence. These further experiments yieldedalmost identical findings with those of the otherseries and, in all, the results. were well defined.As was expected, !-oth streptomycin and the

sulphonamides were entirely successful in pre-venting experimental chancroid. Penicillin wasalso successful in the doses given for syphilis, aswere aureomycin and chloramphenicol (facts atthat time unknown to the author but which sincehave been substantiated in America by work onthe clinical infection (Greenblatt, et al., 1950)).Neo-arsphenamine, bismuth and antimony provedof little value.The experiments produced convincing evidence

that the treatment schedules- previously in force-were inefficient both for syphilis and chancroid,that penicillin. administered in doses effectiveagainst early syphilis was also effective against softsore, and that penicillin is a suitable drug for bothdiseases in localities without diagnostic aids, pro-vided that sulphonamides are given in addition tothose patients whose sores fail to heal.

Recomm.endations based on these observationswere accepted and a course of eight daily injectionsof 6oo,ooo units of procaine penicillin (with orwithout 2 per cent. aluminium monostearate) hasbecome a standard treatment for the African withearly syphilis (Southern Rhodesian Govemment,1950). A further recommendation suggested thatcases clinically suspicious of chancroid, or patientswhose sores were unhealed at the completion oftreatment, should be given sulphonamides inaddition.

Finally, although cross inoculations with chan-croid have been used on countless occasions in thepast, especially for the so-called ' syphilization'treatment of the. previous century, at a time when.chancroid was .still confused. with syphilis inEurope (Abraham, I944; Lancereux, i868), it isbelieved that their employment for testing therelative value of anti-chancroidal drugs is original.It certainly is an extremely useful method by-which to extract controlled data. within a shortperiod of time. The experiments helped materially

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February 1952 WILLCOX: Experimental Chancroid in Man log

x

FIG.I

in framing the conclusions of the venereal diseasessurvey of the African in- Southern Rhodesia, whichwas one of the few, if not the only one undertakenin English-speaking Africa by an independentobserver freed from routine duties since that'ofLambkin (I908; I9II), which itself led to thedevelopment of the medical service in Uganda(Davies, 1947).

TechniqueThe effectiveness of different drugs in the

experimental infection of chancroid may be com-pared in various ways. Testing their efficacyagainst the experimental ulcer once produced haslittle advantage over treating the clinical infectionexcept; of, course, if inoculated subjects are em-ployed, larger numbers of cases may more readilybe obtained.' Moreover, all volunteers utilized insuch experiments are de facto ' takes,' and suchan outcome is to be avoided if possible. Moresatisfactory 'results, therefore, are achieved byproducing conditions in which 'takes 'only occurdeliberately in the controls and if ineffective drugs

..:.

- a W i i A;

FIG. 2

are administered, but in which no adverse reactionsare encountered when effective treatment is given.

First attempts of the author at inducing theexperimental infection in humans were made byintradermal injection of material squeezed fromthe patient's own chancroidal sores, smears .fromwhich were shown to contain H. ducreyi, into theforearms of two untreated volunteers. One ofthese inoculations resulted *in an angry localulceration (which- responded to treatment), andboth reactions were too severe to justify theapplication of such a method to the substantialnumbers required for adequate test to be made.

Trials were next undertaken employing fluidaspirated from chancroidal buboes, and it becameevident that, if the amount of fluid injected intra-dermally into an untreated person is kept as smallas 0.05-.1I c.c., the reaction is slight and easilycontrolled. This reaction consists first of anerythema, followed rapidly by the formation ofa small tender papule -which appears within 24-48hours, at the end of which time it is firm andraised. Within 48-72 hours it becomes a pustule

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which, if :.the patient remains untreated, thenproceeds to chancroidal ulceration (Figs. i and 2).

However, if the head of the pustule is removedby a sterilized needle and the patient treated witheffective drugs, the subsequent ulceration may bekept to a minimum. It was later found that, ifthe papule is needled as soon as it is consideredpus may be present and if the patient is. thentreated with effective drugs, the ulcerative stagemay be avoided altogether. If the inoculum isgreater than 0.05 c.c. the reaction is of the samepattern but the lesions are proportionately larger,and the use of a small inoculum is advisable.

If, however, inoculated persons are treated with*effective drugs.at-the time of inoculation, or thedonors with chancroidal buboes whose material is-to be used are treated prior to aspiration, suchreactions may be avoided completely, and nothingabnormal is observed in the recipient apart froman occasional small, non-tender papule at z4-48hours, persisting.in a few cases for 72-96 hours.If the drugs used are only partially effective, su.chpapules may persist for a longer time, apparentlyin a'state of suspended animation, only to reviveand progress to ulceration once the influence ofthe drug has been removed. Thus it is consideredwise subsequently to treat all persons with per-sistent papules with a course of drugs of provenvalue as soon as surveillance is deemed to becomplete.Employing this technique the effectiveness of

different drugs may be tested by three methods(a) By auto-inoculation of bubo fluid into the

arm of the patient himself, treating him with oneof the drugs to be tested and noting whether theexperimental infection does or does not appear.As a method this is quite satisfactory, but itrequires for its use- one case of chancroidal bubofor each person injected and it therefore takestime to establish a series of reasonable size.

(b) By hetero-inoculation of bubo fluid froman untreated person into other volunteers, somebeing given no treatment and others being treatedby various drugs from the time of inoculation.Scientifically, this method is perhaps the mostsatisfactory as, in theory, it is only the responseto the call for volunteers which limits both thenumber of controls and the number of drugs whichcan be tested on any one day-for only one patientwith chancroidal bubo is required for a wholebattery of tests.

(c) By hetero-inoculation (and auto-inoculationalso) of bubo fluid taken 24 or more hours afterthe donor has been treated with one of the drugsunder consideration.. This method is satisfactory,but requires at least one donor for each of thedrugs to be tested. It may be controlled beforetreatment by emploving method (b) using un-

treated volunteers, but this has the objection thatsuch controls are not inoculated on the same dayas the others.

All three methods were used by the author.Auto-inoculation (method a) was givqn to 35patients, nine of whom were untreated and actedas controls, not only for this series but for methodsb and c as well. (There was a certain degree ofoverlap both as regards controls and donors withall three methods.) The 26 treated cases weregiven either sulpha drugs, penicillin, chloram-phenicol, aureomycin, streptomycin or neo-arsphenamine. The detailed results have alreadybeen published (Willcox, 195oa).Method b was employed in ten exper'iments

involving i I4 volunteers. There were 30 controls,but six of these were common to method a.Ninety volunteer recipients. were treated eitherwith sulphathiazole, streptomycin, aureomycin,chloramphenicol, antimony, neo-arsphenamine orwith penicillin-either as oil-beeswax in dailydoses, single injections of procaine penicillin Gwith aluminium monostearate, or as oral calciumpenicillin. The results obtained in this series ofexperiments have also been described (Willcox,I950b).Method c was used for iz experiments employ-

ing material from i i treated donors who hadpreviously been given either sulphathiazole,streptomycin, aureomycin, chioramphenicol, neo-arsphe'namine or penicillin-after which -bubofluid was aspirated and injected intradermallyinto 75 recipients (Willcox, 1950C). Several of thedonors had already been used in the experimentsinvolving methods a and b as had many of thecontrols.The results obtained by the three methods are

complementary and show general agreement.This paper groups the results of all three sets ofexperiments, adds some additional data and drawsconclusions on the whole.

The SubjectsThe Donors

All 35 donors used received auto-inoculationsby method a. Material taken before treatmentfrom io was inoculated into I14 others (methodb), and material from i i was inoculated into 75others after treatment had been given to the donor(method c), and also into three additional controlsbefore treatment. Bubo fluid from four donorswas used in both methods b and c.The donors were all African Negroes with

obvious clinical soft sores which. gave negativefindings for syphilis by repeated dark fieldexamination in all but two with mixed infections;these latter patients were used for auto-inoculationonl.y. The buboes were unilateral in all but four

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Feoruary 1952 WILLCOX: Experimental Chancroid in. Man I II

with an equal distribution for left and right; allwere fluctuant. The reports.of the Wassermannreactions on z5 of the donors were available andthese showed negative results in. all but -two.Ide and Kahn. tests were performed on ii withnegative results in IO. The Lygranum skin test(for lymphogranuloma venereum) was negative inII of 12 persons tested. Organisms resemblingDucrey's bacillus were found in 70 per cent. ofsores examined (see later note) and, of 32 receivingthe Dmelcos skirn test for chancroid (Ito reaction),I7 were positive, 3 weakly positive and I2 werenegativem

The RecipientsThirty-five volunteers received auto-inoculation,

114 received hetero-inoculation from untreateddonors and 75 others received material fromtreated donors. Adding three additional controls(method c), we have a total of 227.individual tests.

All. of the recipients were African Negroeswith Venereal diseases consisting usually of earlysyphilis, soft sore, or both, chancroid being par-ticularly prevalent in the area in which the experi-ments were conducted. Of the 227 recipients,the results of the Wassermann reaction wereknown i i68 and were positive in 5 i and negativein I 17. The results of the Dmelcos skin ,testswere positive in 58, weakly positive in I2, negativein 14I and there is no record of I6.

The Experimen4sOne hundred and ninety-one persons were

inoculated either. with their own bubo or sore

flud and then. treated by various means (methoda); with bubo fluiid. aspirated from .another. un-treated person, the recipient then. being treated(method b); or with bubo fluid taken from atreated person (method c). There were also 36completely untreated controls. The numbersinvolved and the various treatments given to thoseinoculated by the three methods are portrayed inTable I.

ResultsControls (36 cases)

Thirty-four persons received bubo fluid fromthemselves or from an untreated donor, and twopersons received material from their own sores.All were left untreated in order to assess thevirulence of the fluid. Of nine untreated personsgiven their own material there were 'takes' ineight (method a). Thirty controls were used formethod b, but six of.these were comnmon to theforegoing. Of the remaining 24 controls no lessthan 2I showed 'takes.' Although the experi-ments employing method c had 36 controls themajority were taken from the donors used inmethods a and b and there were actually onlythree additional controls in this series. Of thesethere was a 'take ' in all three.Thus of a total of 36 controls used in the entite

investigation there were 'takes in 32. Thefindings of the Dmelcos skin tests of the cortrolswere as follows positive 8, weakly positive I,negative 26, no record i. The results -of theWassermann tests were: postive 5, negative 27and no record 4. Of the four controls who failed

TABLE I.NUMBERS OF RECIPIENTS INOCULATED AND NATURE OF TREATMENT GIVEN

Method A Method B Method C

Hetero- Hetero-Drug Auto- inoculation. inoculation. Total

inoculation Donor not Donortreated treated

Sulphonamides . . .. .. .. II I 10 36Streptomycin .. .. .. .. .. 3 7 II 21Aureomycin .. .. .. .. .. 1 0 1 3 24Chloramphenicol .. .. .. .. I 4 5 10PenicillinPOB 2.. .. .. .. .. 20 12 32PAM .. .. .. .. .. I6 3 2I!Oral .. .. .. .. .. - 4 - 4With sulpha drugs .. .. .. 2 - - 2

Neo-arsphenamine* .. .. .. .. 6 II 21 38Antimony .. .. .. .. .. 3 3

Totals .. .. .. .. 26 90 75 I9IControls (see notes below) .. .. .. .. .. 36

Total inoculated .. .. .. .. .. .. .. . . 227

* Three of these patients received bismuth also.

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to ' take,' the Wassermann reaction was negativein all and the Dmelcos skin test was negative inthree with no record in one.

Sulphonamides (36 cases)Of i i persons receiving auto-inoculation during

a 5-7-day course of sulphathiazole, sulphadiazineor ' prontosil,' only one developed a ' take.' Often recipients inoculated with material taken fromthree of these persons 24-72 hours after treatmenthad been commenced with 4 g. sulphathiazoledaily, there were 'takes ' in none. Of I5 othervolunteers, treated with sulpha drugs after inocula-tion of material of proved virulence from fouruntreated donors, there were no definite ' takes,'but two doubtful reactions which subsided as thecourse of sulpha drugs was continued. Thus ofthe 36 recipients in the sulphonamide-treatedgroup there was a 'take ' in only one and therewere two doubtful reactors; Thus the' effective-ness of sulphonamide drugs in preventingexperimental chancroid is evident.

Streptomycin (2I cases)Of ten persons treated with I.s-6.o g. of strepto-

mycin given over 2-5 days, and inoculated withbubo fluid-of proved virulence, three'by auto-inoculation and seven by hetero-inoculation, therewere ' takes' in none, although one showed apeksistent non-tender papule at 96 hours. Materialfrom'two donors treated as above was inoculated24-72 hours after treatment had commenced intoeleven others with negative results in all, althoughone patient showed a persistent non-tender papulewhich was aspirated on the sixth day and foundnot 'to contain pus. Thus streptomycin alsoproved effective in aborting the experimentalinfection.

Aureomycin (24 cases)One person receiving auto-inoculation and

being treated with 2,000 mg. aureomycin orallyover three days developed a delayed 'take ' withulcer formation at seven days. Material from thebubo of this patient was inoculated into I3 others24-120 hours after treatment had commenced andthere was a 'take ' only in one (inoculated at 24hours). In addition, hetero-inoculations withmaterial of proved virulence, taken from fouruntreated donors, were performed on ten personswho were then given 500-I,250 mgm. of aureo-mycin orally over 2-4 days. There was a ' take'in none.Aureomycin thus proved effective in preventing

the experimental infection, although possiblyslightly less so than the sulphonamides orstreptomycin.

Chioramphenicol (io cases)One person, receiving auto-inoculation and

treated with 250 mg. of chloromycetin orallythree times a day for three days, showed a localbump at 48 hours which was not tender butpersisted until I2o hours, when it was needledbut found not to contain pus. Four personsreceiving hetero-inoculations of material of provedvirulence from three untreated donors, the re-cipients then each being given 7-ia capsules of250 mgm. of chloramphenicol orally over 3-5days, all failed to show a 'take.' Bubo fluid fromthe patient receiving auto-inoculation was inocu-lated into five others, 24-48 hours after treatmentof the donor had commenced, with a '.take ' innone. Thus chloramphenicol also possesses pro-phylactic properties against the experimentalchancroidal infection.

PenicillinFour methods of penicillin administration were

tested: (ia) Eight daily injections of penicillin inoil beeswax (POB) ; (b) The same in combinationwith sulphonamides ; (c) Single injections ofprocaine penicillin in oil with 2 per cent. alu-minium monostearate (PAM) ; and (d) 'Oralpenicillin. The results show that, in adequatedoses, penicillin is an efficient prophylactic againstchancroid but in inadequate doses it is not.Whether a given dosage is or is not adequatedepends on the method of administration, and thevarious methods employed are, therefore, con-sidered separately.

Penicillin G in OilBeeswax (32 cases). Twentypersons were inoculated with bubo fluid of provedvirulence while under treatment with eight dailyinjections of 6oo,ooo units of penicillin G in oil-beeswax; 14 had received o-a doses and six 3-5doses at the time of inoculation. There weredefinite ' takes 'in none, although three volunteersexhibited non-tender papules persistent at 96-120hours after inoculation, and who had receivedtwo, three and four doses of penicillin respectivelyat the time of inoculation. Another person whowas treated with considerable doses of neo-arsphenamine without any loss of virulence of thebubo fluid (as evidenced by the results of hetero-inoculation into others) was then given eight dailyinjections of 6oo,ooo units of penicillin in oilbeeswax. Material from this case taken at 48-72hours after the commencement of penicillintreatment, and inoculated into Iz others, produceda ' take ' in none.Thus eight daily injections of 6oo,ooo units of

penicillin G in oil-beeswax proved efficientlvanti-chancroidal. It may be noted here that oneof the volunteers in the control series had com-pleted such an eight-day course two days prior to

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February 1952 WILLCOX: Experimental Chancroid in Man

TABLE 2

SUMMARY OF 'TAKEs' BY ALL METHODS

TotalTreatment persons 'Takes' No 'takes' % 'takes'

inoculated

Controls .. .. .. .. 36 32 4 88.gSulphonamides . .. * 36 I 35 z.8Streptomycin .. .. .. 22 O NilAureomycin .. .. .. 24 2 22 8.3Chloramphenicol .. .. . . o o IO NilPenicillinPOB alone .. .. .. 32 0 32 NilPOB with sulpha .. .. 2 ° 2 NilPAM .. .. .. 21 9 1I2 42.8Oral .. .. .. 4 I 3 25.0

Neo-arsphenamine .6. . 38 25 I3 65.8(Bismuth) .. .. .. (3) (2) (I) 66.6Antimony .. .. .. 3 3 0 100.0

-: 227 73 - 54

inoculation. This case showed a 'take,' but itwas very much delayed in its appearance, frankulceration being discovered 35 days later.

Penicillin and Sulphonamide Drugs Combined (zcases). Two volunteers, treated with eight dailyinjections of 6oo,ooo units of penicillin G in oil-beeswax, plus 4 g.' of sulphathiazole daily, alsoreceived auto-inoculations. Both failed to showa ' take.'

Procaine Penicillin with Aluminium Monostearate(2I cases). The so-called 'single-shot ' treatrmentof syphilis, employing one intramuscular injectionof 2.4 mega units of procaine penicillin G in oilwith 2 per cent. aluminium monostearate (1.2mega units in each buttock) was tested as to itspowers of aborting experimental chancroid atvarying time intervals after'administration.Two persons received auto-inoculation; one

who was given 'the penicillin injection simul-taneously with inoculation showed 'no take,' butanother, receivng the inoculation six days afterthe penicillin injection, did so. Fluid from thelatter case, aspirated after treatment, was inocu-lated into 'two others without result, and bubomaterial from the former was inoculated into oneother 24 hours after being given penicillin, alsowithout result.

Hetero-inoculations with material of previouslyknown virulence were performed on i6 volunteers.Of eight inoculated o-4 days after penicillin hadbeen given to the donor there were 'takes' inonly tivo, but of eight ino'culated 5-8 days after-wards there were ' takes in no less than six.One of those, who was inoculated five days afterreceiving penicillin, did not 'take ' at once, buta large ulcer had appeared when the patient wasseen 35 days later.

These results shows that single injections of 2.4mega units of procaine penicillin with 2 per -cent.aluminium monostearate given simultaneously withinoculation of bubo fluid offers fair protectionagainst the experimental infection. Of ten personsconcerning whom the inoculations took placewithin o-4 days after being given such a dose ofpenicillin there were only two '.takes,' while ofeleven, persons receiving inoculations 5-8 days afterinjection 'takes ' were noted. in no less than seven.

Oral Penicllin (4 cases). Four, persons givenhetero-inoculation of material, of proved virulencereceived 400,ooo-600,000 units, of calcium -peni-cillin orally each day for 3-4 days. There wasa 'take ' in one.Thus when there was an adequate serum con-

centration of penicillin there 'was an effectivesuppression of the experimental infection.

Neo-arsphenamine (38 cases)The tests with neo-arsphenamine provided.the

raison d'etre for' the investigation. In manycountries of the world, even today, neo-arsphen-amine is still the' drug in routine use for syphilis,and 'syphilis-' is often taken to mean any- case ofpenile sore. In the area in which'these experi-ments were undertaken the drug' was geerallyemployed in such a manner and, although clinicalchancroid was very prevalent, the-loc,al medicalofficers frequently stated that all sores so treatedhealed, albeit slowly, and there was' not at thetime any widespread disatisfaction with its action,which had not then been thrown into.relief by themore dramatic effects of penicillin. Thus if neo-arsphenamine was actually effective in the treat-ment of soft sore of the African, many of theobjections to 'the use of'this drug in proper dose>,

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114 POSTGRADUATE MEDICAL JOURNAI, February 1952

for all cases of penile sore became invalid, andsuch treatment could not be criticized on thera-peutic grounds alone, apart from the considera-tions of default, toxicity and economy of timespent in hospital. It was, therefore, consideredimportant that proper evidence should be securedso as to be able to refute any possible suggestionthat the use of neo-arsphenamine for soft sore hadanything to recommend it over the use of moremodem drugs as the sulphonamides and anti-biotics. The results obtained by the experimentswere completely effective in so doing, although, infact, the demonstration of the success of penicillintherapy for early syphilis in the African nativewas so convincing that it never became necessarvto present the experimental data.

Employing auto-inoculation into three personsreceiving up to o.9 g. of neo-arsphenamine duringthe week prior to inoculation, and continuingafterwards, and into three other persons commenc-ing treatment simultaneously (one of whom had1.2 g. during the ensuing six days), there werefour ' takes ' in' the six volunteers inoculated.Bubo fluid from one of these not showing a'take' on himself was inoculated into another 24hours after receiving a neo-arsphenamine injection-also with no result. However, the patientreceiving 1.2 g. in less than a week had furtherspecimens of bubo fluid taken on different days24-i68 -hours after the onset of treatment andthese were inoculated into 20 others with no lessthan 15 'takes.' Actually there were 'takes ' inthree out of four persons inoculated with this bubofluid on the seventh day after treatment, by whichtime the virulence of the fluid had evidently noteven been reduced. This donor was then .treatedwith eight daily injections of 6oo,ooo units ofpenicillin G in oil-beeswax and, as has alreadybeen described, further specimens were aspirated48-72 hours later and inoculated into 12 personswith a subsequent 'take-' in none. In addition,hetero-inoculations from untreated donors ofproved virulence were made into eleven recipientswho were all treated with neo-arsphenamine.Three had already received before inoculation i-6weekly doses of 0.45-o.6 g. of neo-arsphenamine(with o.2, g. .of bismuth in addition), and in eightthe arsenical treatment commenced simultaneouslywith inoculation and consisted of 0.45-0.9 g. ofneo-arsphenamine given over 24-72 hours. Noless than six showed a 'take '-frequently thosepersons receiving the larger amounts.

Neo-arsphenamine thus proved a most in-efficient prophylactic against the experimentalchancroidal infection.

Bismuth (3 cases)Three of the persons receiving neo-arsphen-

amine prior to inoculation of bubo fluid from anuntreated donor had had, respectively, one, threeand six weekly injections of 0.2 g. of bismuth inaddition. These persons, therefore, carried a smalldepot of bismuth in their buttocks. However, inspite of this, 'takes ' were noted in two and thusbismuth likewse proved an iqeffectual prophylactic.

TABLE 3

'TAKES' BY METHODS

Method Method Method Total_A B C

Takes .. 15 39 9 73No ' takes' .. 20 75 59 154

Total.. .. 35 114 78 227

Antimony (3 cases)Material of proved virulence from one donor

was inoculated into one volunteer receiving dailyinjections of z c.c. of antiomaline at the time ofthe third dose, and into two other persons receiv-ing i g. of sodium antimony tartrate on alternatedays. ' Takes ' were noted in all three. Antimonylikewise is not considered an effective prophylactic.

Summary and Conclusions(i) The effectiveness of different drugs in

aborting the experimental infection of chancroidin man was tested by three methods:

(a) By intradermal auto-inoculation of bubofluid and treating the recipient with one of thedrugs to be tested simultaneously with inocula-tion;

(b) By hetero-inoculation of material fromthe untreated donor; and

(c) By hetero-inoculation from the treateddonor.(2) Material from chancroidal sores was em-

ployed as the inoculum in two cases, but thesevere reactions which followed its use prompteda change to bubo fluid, after which, provided thatthe quantities of this inoculum were kept small(o.os c.c.), the reactions observed were easilycontrolled.

(3) Some 227 persons were inoculated, 35 byauto-inoculation, I I4 by hetero-inoculation ofmaterial from ten untreated donors, and 78 othersin a series employing hetero-inoculation ofmaterial from ii treated donors; 36 volunteersacted as controls and there were 'takes ' in 32.

(4) The drugs tested included various sulphon-amides, steptomycin, aureomycin, -chlorampheni-col, neo-arsphenamine and antimony. PenicillinG was also used, either as daily injections of anoil-beeswax preparation (alone or in combinationwith sulphonamides) as a single injection of 2.4

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mega units of procaine penicillin G with alu-minium monostearate, or as oral calcium penicillin.

(5) Sulphonamides, streptomycin and chlor-amphenicol proved entirely effective in preventingthe experimental infection. Aureomycin was alsosuccessful, but not in all cases.

(6) Neo-arsphenamine, bismuth and antimony,on the other hand, proved ineffective in preventingexperimental chancroid.

(7) Penicillin in high and sustained dosage, aswhen given in the form of daily injections of anoil-beeswax mixture, was also completely success-ful. When the inoculation was given near to thetime of injection a single dose'of 2.4 mega unitsof procaine penicillin with 2 per cent. aluminiummonostearate was fairly but not completelysuccessful, but the effectiveness of this treatmentrapidly deteriorated as the'time interval betweeninjection and inoculation was lengthened.

(8) The 73 'takes ' occurred irrespective of theresults of the Wassermann reactions or Dmelcosskin tests of the recipients, and there was noevidence to suggest that the presence or absenceof a positive Dmelcos (Ito) test indicated anyform of increased immunity against the experi-mental infection.

(9) Seventy-five per cent. of the ' takes'occurred within 72 hours and, in most cases, thosenoted as occurring later could have been anti-cipated at this time. In five instances the 'take '

was delayed for a week or longer in patients show-ing persistent papules ; three of these showed lateulceration. As it was evident in such cases tnatthe infection might be dormant, under temporaryinfluence of the drug that was being tested, only toreactivate as its influence was removed, it was laterconsidered advisable to treat all patients withpersistent papules with an effective drug as soonas surveillance had been concluded.

(io) Both aureomycin and chloramphenicolwere shown to have a definite action in preventingexperimental chancroid in man. It is of interestto note, on this account, that Wetherbee, et al.(I949) reported that aureomycin exerts only atransient inhibitory effect on H. ducreyi in vitroand that 'streptomycin is possibly the only (anti-biotic) agent with therapeutic possibilities in thisdisease.' Since then Zheutlin and Robinson(1950) and Greenblatt, et al. (195o) have reported'success in the clinical infection.

(ii) It is noted that aureomycin and chlor-amphenicol both have some action upon all ofthe common venereal diseases, namely soft sore;syphilis (O'Leary, et al., I948; Irgang and Alexan-der, I948; and Willcox, I949); gonorrhoea(Collins, et al., 1949); granuloma inguinale(Greenblatt, et at., I948); lymphogranulomavenereum (Wright, et al., I948); and also non-

specific urethritis (Finland, et al., 1948; Willcoxand Findlay, 1949). It would seem propitious,therefore, to employ these drugs on a large scalein experiments on systemic prophylaxis.

(12) The technique of employing intradermatinoculation of bubo fluid into volunteers treatedwith various drugs gave rapid and clear-cut resultsin a far shorter time than if a comparable numberof clinical cases had been collected and treated.Moreover, the experimental condition undertreatment is more standardized than is the clinicalcase of soft sore.

(13) The results of these experiments gavehelpful information as to the dose of penicillinwhich should be recommended for the treatmentof African syphilis in circumstances in which noproper diagnosis, confirmed by dark field andserological examination, is possible, and in which,therefore, chancroid would in practice be treatedas for svphilis.

(14) The conclusions were put to the testclinically. Eight daily injections of 6oo,ooo unitsof procaine penicillin G, with or without 2 percent. aluminium monostearate, or of penicillin inoil-beeswax, gave entirely satisfactory results inboth early syphilis and chancroid (i.e. on nearly allpatients with genital sores). This schedule was,therefore, recommended as the standard for earlysyphilis. The recommendation was accepted andhas since been implemented (Southern RhodesianGovernment, 1950).

(i5) On paper the employment of a singleinjection of 2.4 mega units of procaine penicillinwith 2 per cent. aluminium monostearate (PAM),which dose will give a detectable serum level for7-9 days, has much to recommend it as it is mostconvenient for isolated rural African clinics visitedonly occasionally by a doctor.Such treatment has been tried in the United

States of America (Thomas, et al., I949), and arecent appraisal by Bauer, et al. (1950) suggeststhat the results so far are not significantly inferiorto those obtained by the eight-day course. Aftera personal trial of this method it was recom-mended in the report that it be tried experimentally.Of I9 patients with soft sore, personally treated

in Southern Rhodesia with single injections of 2.4mega units of procaine penicillin G with 2 percent. aluminium monostearate (syphilis beingproperly excluded), only three required additionaltreatment with sulphonamides. Eighty suspectedsyphilitics in the same series of consecutivepatients, proved by dark field in 30 and suggestedby serum tests in 22 others, many of whom hadmixed infections with chancroid, received singleinjections of 2.4 mega units of procaine penicillin.with 2 per centA,aluminium monostearate. Only12 required additional treatment (Willcox, 195od).

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POSTGRADUATE MEDICAL JOURNAL February 1952

(I6) It is considered that, if single injectionmethods are used in the treatment of syphilis inmedically undeveloped areas, a dose of not less than2.4 mega units of procaine penicillin G with 2 percent. aluminium monostearate should be employed.

Although it has been suggested that syphilismight actually be cured with even a lesser amount,for many years yet chancroid will, in many of themore primitive countries of the world, continue

to be treated in the same manner as early syphilis.As an adequate serum level, sustained for somedays, is necessary to cure soft sore, it is, therefore,asserted that the dose given for syphilis, should not'be less than 2.4 mega units.

(I7) It is re-emphasized that the. recommenda-tions made are applicable only to places like tropicalAfrica and are not necessarily suited to localconditions in Europe or America.

BIBLIOGRAPHY

ABRAHAM, J. J. (1944), Brit. Y. Surg., 32, 236. -

BAUER, T. J., USILTON, L. J., PRICE, E. V. (I950), Y. vener.Dis. Inform., 3I, 65.

COLLINS, H. S., TROUSDALE, H., KAISER, T. F., REGAN,F. G., and FINLAND, M. (I949), Amer. Y. Syph., 33, 263.

DAVIES, J. N. F. ('947), East African med. Y., 24, 437.FINLAND, M., COLLINS, H. S., and PAINE, T. F. (1948),

. Amer. med. Ass., 138, 946.GREENBLA^TT, R. B., DIENST, R. B., CHEN, C. H., and

WEST, R. M. (1948), South. med.J., 41, I121.GREEN-BLATT, R. B., WAMMOCK, V. S., CHEN, C. H.,

DIENST, R. B., and WEST, R. M. (i950), J. vener. Dis.Inform., 31, 45.

IRGANG, S., and ALEXANDER, E. R. (x948), Harlem Hosp.Bull., I, 9I.

LANCEREUX, E. (i868), A Treatise on1 Syphilis, New SydenhamSociety, London.

LAMBKIN, F. J. (I908), Y. Roy. Arny med. Corps., 2, 149.LAMBKIN, F. J. (i9IxI), A System of Syphilis, Oxford Medical

Publications, 2, 329.MOORE, J.- E. (I947), 'A Modern Treatment of Syphilis,' G. C.

Thomas, Illinois.

O'LEARY, P. A., KIERLAND, R. R., and HERRELL, W. E.(I948), Proc. Mayo Clinic., 23, 574.

SOUTHERN RHODESIAN GOVERNMENT (I950), 'De-partment of Health Circular No. 4S.'

THOMAS, E. W., REIN, C. R., and KITCHEN, D. K. (I949),Amer. J. Syph., 33, S23.

WETHERBEE, D. G., HENKE, M. A. ,AN-DERSON, N. I., andPULASKI, E. J. (I949), Amer. J. Syph., 33, 462.

WILLCOX, R. R. (I949), Report of a Venereal Diseases Survey ofthe African in Southern Rhodesia, Southern Rhodesian Govern-ment.

WILLCOX, R. R. (I949}, Brit. med. Y., ii, 1076.WILLCOX, R. R. (ig50a), Amer. J. Syph., 34, 378.WILLCOX, R. R. (igsob), Arch. Dermat. and Syph. Chicago, 62,

533.WILLCOX, R. R. (195oc), Brit. Y. vener. Dis., a6, 13I.WILLCOX, R. R. (xgsod), Y. Roy. Army med. Corps., 9x, 26.WILLCOX, R. R., and FINDLAY, G. M'. (I949), Brit. med. J.,

iR 257.WRIGHT, L. T., SANDERS, M., LOGAN, M. A., PRIGOT,

A., and HILL, L. M. (I948), J. Amer. med. Ass., 138, 408.ZHEUTLIN, H. E. C., and ROBINSON, R- C.-V. (I950), Amer.

3'. Syph., 34, 71.

A Clinic for the diagnosis and treatment of Internal Diseases (except Mental or Infectious Diseases). TheClinic is,provided with a staff of doctors, technicians and nurses.

The surroundings are beautiful. The climate is mild. There is central heating throughout. The annualrainfall is 30.5 inches, that is, less than the average for England.

The Fees are inclusive and vary according to the room occupied.

For particulars apply -to THE SECRETARY, Ruthin Castle, North Wales.

Telegrams: Castle, Ruthin. Telephone: Ruthin 66.

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