Sot Scr Me-d Vol 32, No 11, pp 1275-1281, 1991 Pnnted m Great Bntaln

0277-9536/91 $3 00 + 0 00 Pcrgamon FYess plc

KNOWLEDGE, ATTITUDES AND PERCEPTIONS (KAP) OF ONCHOCERCIASIS: A SURVEY AMONG RESIDENTS IN AN ENDEMIC AREA IN GUATEMALA TARGETED FOR

MASS CHEMOTHERAPY WITH IVERMECTIN

FRANK RICHARDS,’ ROBERT E KLEIN,~ CARLOS GONZALES-PERALTA,~ ROD~LFO ZEA FLOW,’ GUILLERMO ZEA FLORES~ and JULIO CASTRO RAMIREZ’

‘Medical Entomology Research and Trammg Umt, DiMsIon of Parasltlc Diseases, Center for Infectious Diseases, Centers for Disease Control, Pubbc Health Service, U S Department of Health and Human Services, Atlanta, Georga 30333, U S A, *Centro de Investlgaclones en Enfermedades Tropicales, Uruversldad de1 Valle de Guatemala, Apartado Postal 82, Guatemala, Guatemala, C A., ‘Department of Entomology, College of Agnculture, The University of Anzona, Tucson, Anzona 85721, U S A and 4Departamento de Enfermedad de Robles (Oncocercosls), Mlmsteno de Salud Pubhca y Aslstencla Social

Guatemala, Guatemala, C A

Abstract-If lvermectm dlstnbutlon programs are to have maximum impact on the morbldlty and transnusslon of human onchocerclasls there must be broad and sustamed acceptance wlthm the endemic commumtles Educational actlvltles, developed with careful consideration of commumty attitudes, should promote positive treatment seeking behavior while simultaneously addressing local reservations about the control effort To better understand the ambient knowledge, attitudes, and practices concernmg onchocerclasls m the context of lvermectm use m Guatemala, we conducted a survey among 145 heads of households m five endemic commumtles

Given the country’s long-standmg nodulectomy program, It was not surpnsmg that 100% of persons mtemewed had heard of the disease ‘la jlana’, which they defined as a skm nodule that could cause bhndness Ninety-five percent of respondents Identified surgery as the only cure for the condition Relatively few (39%) knew that la jlarla was caused by a worm, although slightly more (50%) knew that the condition was acquired by the bite of an insect The term mlcrofilana was not broadly recogmzed We also determined that onchocerclasls was not perceived as a senous health problem few persons (12%) mentioned la jlurra when requested to provide a complete list of illnesses that occurred m the community, and the gravity of infection (based on rank ordenng of common Illnesses) was similar to that of a bad cold Recommendations were made which m&t assist long-term acceptance of a natlonal chemotherapy mltlatlve against onchocerclasis m Guatemala

Key words-attitudes, therapy, onchocerclasls, lvermectm

The mtroductlon of the drug lvermectm will have a dramatlc Impact on the prevention of morbldlty due to human onchocerclasls [l-4]. Population-based chemotherapy programs using lvermectm are being developed that represent a radically different approach from previous (vector) control efforts Community drug distribution m many endemic areas m the Americas (m Mexico, Guatemala, Venezuela, Brazil, Ecuador, Colombia) [S] IS projected within the next few years, stimulated m part by the Merck & Co, Inc offer to provide lvermectm free-of-charge to approved control projects However, as lvermectm does not kill the adult stages of Onchocerca oolvulus, a drug program ~111 need to distribute lvermectm repeatedly, every 6-12 months The required duration of such repetitive therapy IS presently unknown, and IS a function of the impact of commumty lvermectm dehvery on transmission (I e the establishment of new human Infection)

The Guatemalan population affected by oncho- cerclasls resides m several hundred rural commumtles and pnvately owned plantations @cm) m three maJor endemic zones Northwest, Central, and Eastern [6] A vertical control program for onchocerclans, mltlated m 1935 by the Mmlstry of Health (MOH), IS based

on systematic ldentlficatlon of onchocercomata by palpation exammatlon and their surgical removal by small teams (brigades) of technicians who regularly vlslt much of the endemic area In heavily Infected areas, up to 10% of villagers have one or more nodules removed each year [7j The Impact the nodulectomy effort has had on prevalence and morbldlty of onchocerclasls IS debatable [7-lo] Unlike m Mexico, chemotherapy with dlethylcarbamazme has not been widely used m the Guatemalan control program [9, 111

The Guatemalan MOH ~111 begm lvermectm dlstn- butlon m endemic areas m 1991 The shift toward drug use as a primary onchocerclasls control strategy poses the questlon W11l lvermectm treatment be accepted over the short- and long-term m endemic commumtles? The MOH IS currently developmg a commumty mterventton program (which will comclde with the dlstrlbutlon process) almed at gaming com- munity partlclpatlon We report here the results of a survey m endemic commumtles that was destgned to explore local knowledge, attitudes, and practices (KAP) with respect to onchocerclans, or lajilar~a, as the mfectlon IS commonly called m Guatemala. Our obJectlve was to ldentlfy mdtgenous factors which

1275

1276 FRANK ~CHARLX er al

rmght Influence the acceptance of ivermectm, and thus pernut development of effective commumty education and orgamzatton m the context of the national chemotherapy program

hwrHODOLOGY

Household mtervtews were conducted m four coffee fincas and a nearby rural commumty m the Central Endemic Zone (Departments of Suchttepequez and Sololl) near Lake Atttlan Simuhum ochruceum, the prmctpal vector for onchocerciasts m Guatemala, bttes m this regton at rates ranging between 1 2- 112/hr [12] In the commumttes selected for study, MOH records showed prevalence of 0 volvulus nodules and mtcrofiladermta of 7-2 1% and 6-70%) respectrvely (Table 1)

The questtonnaue, admimstered to the male or female head of each household by one of three expenenced mtervtewers, focused on spectfic aspects of knowledge, attitudes, and behavior related to onchocerctasts, tts transrmsston and control The 40- mm mtervtew explored the followmg areas (1) Illness term recognztzon, (2) Outcome of untreated oncho- cereal mfectton, (3) Dejimtlon and cause of onchocer- coasts, (4) Treatment, (5) Attztudes toward the present Guatemalan nodulectomy program, and (6) Perceived serzousness of the mfectton The survey data were coded and placed on a microcomputer. Frequency dntnbutrons were generated for all the vat-tables, and later for collapsed categories.

Addtttonal studies of the mdigenous perception of onchocerctasts were carned out on a subsample (80 persons) of the study populanon To reduce the nsk of researcher btas m measurmg percepttons of tllness m a ‘foreign’ culture, we used mtervtewmg techniques that allow mformatton that 1s sahent to the mformant to be ehctted, while mmtmtzmg possible contammatton with a prrort assumpttons [ 131 Open-ended interviews were conducted to ehctt local terms relevant to health and illness m general From this list we selected 14 commonly mentioned illness terms Lafilurta was mcluded as the fifteenth disease term These were then presented m either patred or tnadtc comparison formats to a randomly selected group of 80 persons m two of the five commuruttes (La Ermtta and Coloma Santa Cruz Qutxaya) In the paired compartson format, each illness term was paired with every other

Table I Prevalence of onchoccrwsts m partxtpatmg commumtles based on MOH serves statlstlcs

Number Percent Percent exammed wth wth

Commumty (year’) nodules mxrofiladermla

La Ermlta 104 84 56 (1980)

Sta Cnstma (1985:)

74 29 6

San Lazaro ,I,&

444 70 4

Fmca Santa Cruz Qwaya

,,9;:, 14 3 57 I

Colonra Santa Cruz Qulxaya 114 21 9 35 I

(1990)

Total 313 166 28 4

‘Year of latest MOH data based on bngadc wslt to community

term These 105 pairs were randomized and presented orally to 40 persons who were asked to select the tllness m each pair they considered to be the most senous (gruue) Thts resulted m a rank order ofjudged senousness of the 15 tllnesses The tnadic comparison task was employed to explore conceptual structure and percetved stmilanty among the 115 tllnesses Thuty-five sets of three tllness terms were randomly generated such that each pazr of tllnesses appeared once among the tnads (lambda-one design [14]) The tnads were presented orally m random order to 40 adults, who were asked to select that tllness m each group of three which was most different from the other two The mtervtew process employmg oral presenta- tion of tnads has been proven accurate for collectmg data from illiterate SubJects [IS] The tnad data were analyzed by multtdtmenstonal scaling to explore the conceptual orgaruzatton of tllnesses, describe the tnter- relattonshlps between tllnesses, and locate onchocer- coasts wtthm the local conceptual structure [16-19)

RESULTS

One hundred and forty-five persons were mter- viewed for the KAP survey, 48 males and 97 females, representmg 84% of the heads of households m the selected commumttes (Table 2) The average age of the respondents was 39 (range 16-73 years) and the average duration of residence. m the commumty was 21 years (range 1 month-70 years)

(1) Illness term recogmtron

Lafilarla was a term recogmzed by one hundred percent of respondents, t.e all those mterviewed knew that there was an :llness calledjZurra The term$Zarza was as fanuhar to endemic populattons as were umver- sally occumng illnesses hke cold/mfIuenza (grrpe), diarrhea, mtestmal worms, and fever Complete recog- mtton of the term jifurra 1s explamed by the high prevalence of nodules and the extenstve contact of the populaton with the MOH nodulectomy bngades One hundred percent of the respondents reported that they, or a member of their family, had had direct contact with the nodulectomy brigades, indeed, 99% reported a prevtous palpation exammatton, 78% reported having had a previous skm biopsy (‘snip’) exammatton, and 76% a prevtous nodulectomy Ftfty-seven respondents (39%) believed someone in their immediate family was currently infected with onchocerctasts, generally because of the presence of a subcutaneous nodule, but, m a substanttal proportion (13%), because of visual complamts. When asked about symptoms, other than nodules, caused byfiZur!a,

Table 2 Sample sizes m parttctpatmg commumtles

Total Heads of number famdes % famhes

Commumty of famhes mtcrwewed mterwcwed

La Ermna 64 46 72 Sta Cnstma 22 22 I00 Sdn Lazaro IO 8 80 Fmca Santa

Cruz Qulxaya 27 22 81 Coloma Santa

Cruz Qmxaya 50 47 94

Total I73 145 a4

Knowledge, attitudes and perceptions (KAP) of onchocerclasls

SYMPTOM/ILLNESS

“M-RELATED”

BLINDNESS

DAMAGED VISION

YELLOW EYES

RED EYES

SWOLLEN MS

ITCHING EYES

CLOUDY EYES

0 20 40 60 60 100

PERCENT WITH AFFIRMATIVE RESPONSE

Fig 1 KAP survey m Guatemala percentage of respondents attnbutmg a symptom or an Illness to onchocerclasls. N = 145

1277

35% reported they had either a fnend or neighbor with visual symptoms attnbutable to onchocerclasrs

(2) Outcome of onchocerclasu

Survey ptiapants overwhehnmgly Identified bhnd- ness, visual detenoration, and/or abnormal coloration of the eyes with ‘untreated’fifana (Fig. 1). In contrast, skin-related conditions were less frequently (28~44%) associated with onchocerclasu

(3) Dejimtlon and cause

Fifty-seven informants (39%) ldenttfied lujikzrza as a worm, whereas the majonty (61%) defined the con- ditlon as a subcutaneous (non-fixed, non-discolored, and usually non-painful) nodule (Fig. 2) Half of the respondents (72 persons) believed that lafilarta was

DEFINITION N-1 45

caused by the bite of an insect. However, 23% had no idea about the cause. Some respondents believed that filanal nodules resulted from local trauma (14%), ‘germs’ (3%), or poor quality of food or water (6%) In 4%, la filana was felt to be due to ‘tradltlonal/ superstitious’ ideas, specifically, the relationstip of jlarla to avocado pits or wth proxmnty to one of the nearby volcanoes No respondent considered jilorla conta@ous m a person-to-person sense. Among the 95 mdlvlduals who provided etther the correct response for definition (worm) or cause (insect hte) offilarza, only 33 (35%) knew both facts (Fig 2)

The term ‘mlcrofilana’ was recognized by 25 (17%) of respondents Ten of these knew both the correct definition and cause of lafilarta, compared to 23 of the 120 persons who did not recognize the term

CAUSE N-1 45

OTHER 13%

GERMS SUPERSTITION FOOD/WATER

BRUIS

14%

23%

CORRECT DEFINITION %ET

“WORM” “INSECT” N = 56 N = 72

35% (23% of totol study)

Rg 2 KAP survey m Guatemala. Definition and theory of causation of onchocerclasrs

1278 FRANK Rmwws et al

‘mrcrofilana ’ The assocratton of the term mtcrofilana with a correct definition and knowledge of causatton of jlarza was stattstically significant (xf, = 4, P < 0 05)

(4) Treatment

When asked the question “When 1s treatment required after dtagnosts of Iafilarza,” 16% responded wtthm the tirst year Forty-four percent of respondents described specrfic nodule charactensttcs and palpauon techmques that were used to gauge the size and ‘npeness’ (maduro) of the nodule These served as to determme the immediacy of need for nodulectomy Another factor which influenced the acceptance of surgery was the fear of the consequences that might result from refusal of treatment when the bngade exammattons were made compulsory by the plantation admmtstratron

Surgical removal of nodules was identified as the only treatment for lafilarza by 95% of respondents Sixteen persons (1 1 %), however, considered nodul- ectomy dangerous (due to pam and concern of post- operatrve infection) These respondents felt tt was better to leave the nodules untreated Only four villagers (3%) believed that fafilarra could be treated with medrcmes, and fewer still mentioned the use of tradttronal treatment measures The only tdentrfiable or affordable source of treatment for 96% of respondents was the MOH nodulectomy brigades

An item analysis was conducted of specrfic questrons m the survey to determine tf there were subgroup differences m knowledge (of etrology, transmtsston, dlagnosts, treatment and outcome) of filarza No systematic differences were observed by sex, age, com- munity, time living m the endemic area. or number of MOH exammattons/nodulectomtes expenenced by the respondent

(5) Attztudes toward the h4OH nodulectomy program

When asked the question “Would you parttctpate m the national program d you had no symptoms of la filarza,” 45 of 48 (94%) males responded affirma- tively, compared to 74 of 97 (76%) females (XL = 6 7, P < 0 05) Skm snips and body palpatron (for the detection of nodules) were aspects of the program that were more distasteful to women (Table 3) Partial drs- robing gave feelmgs of shame and drscomfort (pena, mzedo, oerguenza) Skin snips were most disliked by both sexes but palpation was proportronately more disliked by females (at a female male ratio of 9 to 1)

(6) Percezved serzousness of onchocerczaszs

We measured the degree of senousness the respondents attnbuted to lafilarza by comparing rt to

Table 3 Attitudes toward skm smp and palpatmn exammatmns con- ducted by the Guatemalan national onchocerclws control program

Number answermg affirmatwely Females Males Total (N =97) (N = 48) (N = 145) x;,, Probabthty

Dlshke skm smps W) (Z) (2, (“5:)

6 <o 020

Dlsltke palpation exammatton W)

30 co 001 (ii, (i (Z,

Table 4 Percewcd senousness of onchocernasls as determmed by mentton of dlncss m ‘free hst’ and by poured comparison

Percent Number Judgmg mentlomng Illness as

Illness more serious m free hst m pared

(rank) comparison Illness N = 145 N=40’

1 Intestmal worms 14 (12) 424 (Lombrrces)

2 Measles 8(15) 398 3 Vomxtmg 33 (6) 376 4 Dysentery 17(10) 373 5 Pertussts 10 (14) 346

(Tosferma) 6 Diarrhea 75 (3) 342 1 BronchIus 4(16) 331 8 GI Illness 4(16) 292

(Empacho) 9 Fever 93 (I) 265

10 Anemia lO(l4) 264 I I Malaria 19 (9) 213 I2 Body/Jomt aches 22 (8) 194

(Reumarrsmo) I3 Onchocercrasls 12(13) 167

(Alana) 14 Urtimfluenza 55 (4) I52

mpe1 15 Skm drseases 23 (7) 63

(Gronos) Stomach ache 82 (2) -

Headache 54 (5) -

Chtlls (Fnos) 15(11) -

‘Theoretically, an tllness could achieve a maxImum score of 560 (40 x 14) If all 40 respondents consldered It to be more serious than the other 14 condltlons

other common tllnesses occurnng m the commumttes Compansons were accomplished using three different techniques The first was to elictt ‘free lists’ of tllnesses m response to the question “Tell me all the rllnesses which affect residents of this community?” Fifty-six different illness condttrons were mentioned by the 145 parttclpants m the mam study The 18 tllnesses that were cited by at least 4 respondents are shown m Table 4 (column 1) La jilarza was mentioned by 17 persons (12%), giving tt a ranking of thirteenth

Usmg the paired comparison format, where each illness was compared once with each of the other fourteen tllnesses, 40 villagers were asked which rllness m each pan was most serious Table 4 shows these tllness terms ranked m order of comparattve senous- ness, along with the number of times the vtllagers selected that illness as more serious than one of the other rllnesses m the pan As can be seen,Jilarza was constdered less senous than most of the rllnesses m the list, ranking thirteenth LaJilarza was ranked as stmtlar m senousness to a cold or influenza (grzpe) and somewhat more serious than skm condrttons (granos)

An addmonal group of 40 villagers was presented with randomly ordered triads of tllness terms and asked to select the rllness which was most different than the other two A stmtlanty matnx of the 15 illnesses was generated and analyzed by multrdtmen- sronal scaling [20] The two dtmenstonal solution, represented m Euchdean space, IS presented in Ftg 3 Stmtlanty among tllnesses is directly related to the distances between tllnesses m space of the plot Two groups of tllnesses were clustered together gastro- mtestmal illnesses (dysentery, diarrhea, blocked drges- tron [empacho] and mtestmal worms) and respiratory

Knowledge, attitudes and perceptions (KAP) of onchocerclasis

2 . I I ,

ONCHO j

1 - (‘flyw j_ . UEASLEX

- SKIN ols+s :w I

5 I aa?cHms

RHEIJM~Y ANEt+ I

ci 0 __._____._______________~__~___?~~~E_

z I E -NT i WMrnNC

DW * -1 -

WORhis :. ! BLOCKED DICESnON j (aPAcH0’)

I -2

I I

-2 -1 0 1 2

DIMENSION 2 WmwYEnKm !slREss 0287.

Fig 3 KAP survey in Guatemala similanty structure of fifteen illnesses, N = 40

1279

ailments (influenza, bronchitis, and Pertussis) Fever appeared to be more closely assoctated with the res- piratory iuhnents. Measles and malana were perceived as somewhat strmlar. The remammg two tllnesses, rheumatism and anemia, were not closely alhed with any of the others Lujilurm IS seen to be most similar to skm ailments and malana, and relatively dtssimilar to the other illnesses

DISCUSSION

Thu mvestigatton explored knowledge, attitudes and pracuces related to onchocerciasis among resi- dents of 5 endemic commumhes m Guatemala The study was pnnapally motivated by the need for solid mformation for planning a community education/ participation program to accompany the tvermectm chemotherapy campaign. The results of the study are discussed below, wrth spec& reference to the potential impact local KAP can have on the success of ivermectm distnbution

The term j2arta was umversally recogmzed m the endemic commumhes we surveyed and was commonly defined as a subcutaneous nodule which can cause eye disease The high degree of illness term recogmtion and the correct tdenttfication of disease outcome we mterpret to be the result of prolonged and extenstve contact with MOH nodulectomy bngades, as well as the high mcldence of nodules in the population. Smce the MOH has never mcorporated an explicit educa- tional component mto the nodulectomy campaign, the degree of recognmon is the result of informal communication between MOH brigades and local residents

Relative to illness term recognition and stated outcome of la jilana, understandmg of the hfecycle of the parasite was less complete While half of the respondents associated mfection with Insect bites, and 39% knew that the nodules contained worms, this knowledge was fragmentary, smce the overlap of these two groups was less than 40%. Not surpnsmgly, the term ‘microfilana’ was unfamiliar to most respondents.

Therapeutic alternatives to nodulectomy are few, traditional cures are rare. Treatment is not actively sought from other than MOH sources. Because nodulectomy ts percetved by some as a potentially dangerous process, we noted ambtvalence about the need to remove all onchocercomata. A local examm- atton termmology and technique has evolved which IS used to define the mdtgenous cntena for the treatment decision

These findings suggest that a drug promoted for the treatment of 1aJilar~a mtght be Judged pnncrpally on its ability to ‘cure’ nodules and deter nodulectomy. However, bemg a mrcrofilanadal agent, tvermectm IS unhkely to have any Immediate or noticeable impact on the nodules of a treated person For this reason, the drug must be effectively promoted if it is to be regarded as a potent treatment modahty. In addition, smce mtld to moderately severe adverse reactions (headache, fever, locahzed edema) frequently accom- pany ivermectm use m endemic areas [21-231, the drug could be Judged as undesirable or dangerous. A great challenge to the national dtstnbutton program will be to foster the concept that adverse reactions are a mmor and necessary discomfort that must be bone d the ocular consequences of la firarta are to be avoided. Probably, the mohvahon to accept repeutive treatment wtll be related to the fear of lafilaria, i.e. the perceived senousness of the condition

We found, however, that onchocerctasis IS not per- ceived as serious m these commumties. Psychologists have shown that more important tllnesses tend to appear with higher frequency across respondents’ list [24] In the free-hstmg of diseases elictted in this study, la j2arra was mentioned by only 17 persons (12%), giving it a rank order of thirteenth. The free hst find- mgs were corroborated by the ranked order of com- parative senousness In terms of perceived simtlanty, onchocerciasis is most hke skm ailments (grunos), probably because the nodules give skin-related symp- toms The simtlanty of lufiiar~a to malana probably IS a result of the fact that nodulectomy bngades wear similar uniforms as workers m the MOH Department of Malaria The low perceived seriousness of oncho-

1280 FRANK RICHARDS et al

cerclasls 1s somewhat paradoxzcal conszdenng the apparently serious ‘stated’ outcome of the condztzon (blmdness/vlsual zmpan-ment) This mcongruity may reflect the respondents’ desire to gzve what they conszder a ‘correct’ (vzsual impairment) answer to mtervzewers whom they associated with the MOH program The actual posltlonmg of onchocerclasls (thirteenth) IS consistent wth an Illness structure often observed m Third World rural commumtzes, acute, dzsablmg illnesses whzch prevent dally activities are conszdered to be more senous than chronic, more mszdzous condztzons

The zvermectm dzstnbutzon program m Guatemala ~111 be implemented wzthm the framework of the current MOH nodulectomy actzvztzes The results from this survey indicate that that program operates under a margmal level of commumty acceptance Skm snip exammatzons and upper body palpation are uncomfortable, especially for women The addztzon of another programmatic task (lvermectm dzstnbutlon) wzthout certain program modzficatzons may stress commumty acceptance of the drug dzstnbutzon effort

The findings from thus survey permzt us to make specific recommendatzons that could enhance the potential effectiveness of a national chemotherapy program (1) Health education should focus on the transmzsszon cycle of onchocerczans, particularly wzth respect to the disease organzsm and the role of mlcro- filanczdal drugs Accurate mformatzon needs to be communicated with respect to the nodule, the adult worm, and mzcrofilana so that there 1s baszs wzthm the commumty for understandmg what zverznectm does, (2) As an adjunct to any future chemotherapy campaign, nodulectomy mzght be offered on request, based on self-diagnosis, (3) If systematic palpation 1s to he mcluded m the program, women examiners rmght be used for female patzents, or palpatzon of women should be restncted to the head This IS reasonable since nsk to eyeszght appears related to the occurrence of head nodules [lo, 251, (4) Data (nodule and mlcrofiladermza rates and densztzes) for evaluatzon of drug impact on communzty parasite load might be collected from men rather than women, and, (5) The campagn would be enhanced by promot- mg the usefulness of zvermectm for treating intestinal parasites (lombnces), whzch are perceived as more serious (Table 4), and whose expulsion 1s a vzszble effect closely related temporally to therapy [21]

Over the past two decades, safe drugs that can be gven orally and m a smgle dose have become available for many helmmthzc mfectzons Penodzc commumty- based chemotherapy IS a key element in modem strategzes for controllmg schzstosomzaszs, Intestinal helmmthzases, and taenzasls/cystzcercoszs A common requirement 1s broad and sustained popular accep- tance of the programs. Early exploratzon of local knowledge, attitudes and practzces that mzght influence partzczpatzon can aid m the effectzve promotzon of such control efforts [26-281

Acknowledgements-We thank the followmg mdlvlduals for their mtervlewmg skills Sheha Gongora Roman, Vldahna Ramos Regalado, Mana Hortensla Morales Flares, and Jose Humberto Miguel, Centro de Investigaclones en Enfer- medades Tropicales, Umverstdad de1 Valle de Guatemala

Eduardo Chmctilla Solorzano Thus mvestlgatlon received pamal financial support from the UNDP/World Bank/WHO Special Programme for Research and Trammg m Troplcal Diseases (ID No 870340) and the Edna McConnell Clark Foundation (ID No 00787)

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We acknowledge the programmrng assistance of Manuel

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