Secondary Reservoir Role of Domestic Animals Other Than Sheep and Cattle in Fascioliasistransmission Inthenorthern Bolivian Altiplano

SECONDARY RESERVOIR ROLE OF DOMESTIC ANIMALS OTHER THAN SHEEP AND CATTLE IN FASCIOLIASISTRANSMISSION INTHENORTHERN BOLIVIAN ALTIPLANO

1 1 I 3 S. MAS-COMA',A. RODRIGUEZ , M.D. BARGUES , M.A. VALERO , J.R. COELLd & R. A GLES IDeportamento de Parasitologia, Facultad de Farmacia, Universidad de Yatencia,

AI'. Yicente Andres Estelles Sill, 46100 Burjassot - Yalencia, Spain 2LaboralOrio de Biologia, Colegio "Sail Calixto», Casilla 283, La Pa; Bolivia 3Ullidad de Parasitologia, lnstltuto Nacional de l.aboratorios de Salud «Nestor Morales Yillaton» (INLASA). Pasaje Rafae/Subieta No. 1889, Miraj7ores, La Pat; Bolivia

Received 29 March 1997; accepted 25 May 1997 REFERENCE:MAS-COMA(S.), RODRIGUE(ZA.), BARGUES(M.D.), VALERO(M.A.), COELLO(J.R.) & ANGLES(R.), 1997.- Secondary reservoir role of domestic animals other than sheep and cattle in fascioliasis transmission in the Northern Bolivian Altiplano. Research and Reviews in Parasitology, 57 (I): 39-46. ABSTRACTR: esearch studies were undertaken to analyse the possible reservoir role played by pigs, donkeys, horses, llamas and alpacas present in the Fasciola hepatica human endemic region of the Northern Bolivian Altiplano. Coprological analyses showed liver fluke eggs in the stools of 27, I% of 59 pigs, and 15,4% of 65 donkeys.Egg output (eggs per g of faeces: epg) was 4-65 epg (mean: 21,6 epg) in pigs and 3-10 I epg (mean: 38,8 epg) in donkeys. No positive samples were found in horses, goats and llamas. A comparison with a coprological control study performed in sheep (61,5% of 26 sheep infected, with a range of 3-145 epg and a mean of 44,7 epg) and with literature data on alpacas and cattle from the same endemic region is carried out. According to the populations of pigs, donkeys. horses, goats, llamas and alpacas present in the endemic region, it may be concluded that only pigs and donkeys represent potential reservoir hosts of the parasite in the orthern Bolivian Altiplano. The need to take pigs and donkeys into account within preventive and control measures is pointed out. KEYWORDS:Fasciola hepatica. transmission, pigs, donkeys. horses, goats. llamas, alpacas, prevalences, egg output. human fascioliasis, orthern Bolivian Altiplano.

I TRODUCTION cies concomitantly parasitizing F. hepatica-infected human subjects (ESTEBAN et al., I997a, c, d). Besides its well-known veterinary importance (MA- Multidisciplinary studies were undertaken to unders- LEK, 1980; BORAY, 1982), fascioliasis by Fasciola hepa- tand how this digenean parasite is able to reach such tica (Linnaeus, 1758) (Trematoda: Fasciolidae) has also high transmission rates in the orthern Bolivian Alti- proved to be a great worldwide health problem (CHE & piano, a region of a very high altitude of 3800-4100 m. MOTT, 1990; MAS-COMA et al., 1997; MAS-COMA, BAR- Up to the present, the Altiplanic liver fluke has shown no GUES & ESTEBAN, 1997). Recent papers estimate human significant difference when compared to European F. infection up to 2,4 million (RIM et al., 1994) or even 17 hepatica, both at genotypic (MARQUEZ & MAS-COMA, million people (HOPKINS, 1992). Studies carried out in 1993) and phenotypic levels (VALERO et al., 1997). Con- recent years have demonstrated that the most important cerning the intermediate snail host, despite initial reports human fascioliasis endemic regions are located in South of two different Iymnaeid transmitting species (Lymnaea America (MAS-COMA et al., 1995; WHO, 1995; HILL- viatrix d'Orbigny, 1835 and Lymnaea cubensis Pfeiffer, YER & APT, 1997; MAS-COMA, BARGUES & ESTEBAN, 1839 variety) in the Bolivian Altiplano (UENO et al., 1997). 1975), it has been recently demonstrated that only one Among the human fascioliasis endemic regions, the transmitting species is there. Shell morphology Northern Bolivian Altiplano has shown to be the area in (OVIEDO, BARGUES & MAS-COMA, 1995a; ROUMEGOUX which the highest human prevalences and intensities are et al., 1997), visceral mass anatomy (OVIEDO, BARGUES known. Different studies have reported human prevalen- & MAS-COMA, 1995a; ROUMEGOUX et al., 1997), mole- ces of up to 70% in coprological surveys (MAS-COMA et cular (BARGUES & MAS-COMA, 1997; BARGUES et al., al.,1995;ESTEBA et al., 1997a,b;A GLESetal., 1997) 1997) and isoenzyme (JABBOUR-ZAHAB et al., 1997) and even higher in immunological surveys (HILL YER et studies have proved that this species is the European al., 1992; MAS-COMA et al., 1995; BJORLAND et al., Lymnaea truncatula (MUlier, 1774), most probably in- 1995; STRAUSS et al., 1997). lntensities in Bolivian chil- troduced by Spanish colonizers long ago. dren, measured as egg output in stools, ranged from 24 Veterinary surveys performed by both coprological and to 5064 eggs per gram (epg), with arithmetic and geome- serological tests have shown that sheep and cattle present tric means of 474-100 I and 201-309 epg, respectively high F. hepatica infection prevalences and intensities in (ESTEBAN et al., 1997b). Moreover, the human fasciolia- the Altiplanic endemic zone (UENO & MORALES, 1973; sis problem in the Altiplano is increased by the presence UE 0 et al., 1975; MAS-COMA et al., 1995; BUCHON & of many other pathogenic protozoan and helminth spe- MAS-COMA, 1995; HILLYER et al., 1996; BUCHON et al., 40 S. MAS-COMA et al.

1997). At any rate, these prevalences and intensities To consider a mammal species able to play a signifi- found in Altiplanic sheep and cattle are similar to those cant role in the transmission of the liver fluke in a given known in other non-human endemic regions, that is, not zone, different aspects must converge: A) the parasite as high as to constitute a very large environmental conta- must be able to develop, mature and produce eggs that mination with liver fluke eggs. It must be taken into ac- are expelled with faeces; B) prevalences must be suffi- count that Iymnaeid snail populations in the Altiplano do cient and not sporadic in time; C) egg output must be not appear to be numerous and dense (OVIEDO, BARGUES sufficiently high; D) populations of the mammal species & MAS-COMA, I995b) enough to explain by themselves in question must be sufficiently numerous and dense; E) the very high human infection rates. parasite eggs shed with stools must prove to be viable, With the aim to investigate other factors that can im- that is, able to embryonate, hatch, the miracidium capa- prove liver fluke transmission in the orthern Bolivian ble to infect a susceptible Iymnaeid snail, intramolluscan Altiplano, research studies were undertaken to analyse larval stages be able to develop, cercariae to be produ- the possible reservoir role which could be played by ot- ced, shed in sufficient number and metamorphose into her domestic animal species present in the endemic encysted metacercariae, and the latter be able to success- zone. In the Altiplano, Aymara inhabitants markedly de- fully infect a susceptible definitive host species. pend upon livestock, owing to the agricultural difficul- The present paper deals with aspects A, B, C and 0 ties proper to the high altitude. That is why numerous ot- concerning large mammal species. Studies being pre- her domestic mammal species are present in the region sently carried out on aspect E in large mammals, as well (MAS-COMA et al., 1995): large mammals such as pigs, as on all aspects concerning small mammals, will be the donkeys, horses, goats, llamas and alpacas; small mam- objectives of further papers. mals such as lagomorphs (rabbits, hares) and even ro- dents (guinea pigs). All these species have already de- MATERIAL ANDMETHODS monstrated their capacity to be successfully infected by F. hepatica (BORAY, 1982; MAS-COMA et al., 1987, Animal samples: Animals surveyed were in localities where the 1988). presence of Iymnaeid snails assuring F. hepatica transmission was

Fig. 1.- Map of the fascioliasis human endemic region in the Northern Bolivian Altiplano showing localities in which domestic animal stool samples were obtained. I = Queroni; 2 = Huacullani; 3 = Chojasihui; 4 = Lacaya Baja; 5 = Chiripujo; 6 = Korila; 7 = Caleria; 8 = Chi- jipata Alto; 9 = Batallas; 10= Chirapaca; II = Palcoco; 12 = Ancocagua: 13 = Tambillo. Secondary reservoirs of fascioliasis in the Bolivian Altiplano 41 previously verified (Fig. I). Localities in areas where human pre- Although familial herds comprising only one animal can valences and intensities have proved to be high were preferentially be observed (most usually sheep or cattle, sometimes surveyed, such as the Chirapaca-Batallas-Chijipata Alto-Cutusuma pigs, rarely donkeys), they almost always include more area in the so-called «corridor of Batallas» (MAs-CoMA et al .. than one species (two, sometimes three, rarely four diffe- 1995;ESTEBAN et al., 1997b; ANGLES et al., 1997; STRAUSS et al., 1997), and the Chiripujo-Chojasihui-Lacaya Baja-Huacullani- rent species together), among sheep, cattle, pigs and Queroni area in the so-called «corridor of Huacullani» (ESTEBAN et donkeys (Fig. 2 B, D, H). In the endemic zone a family al., 1997a). Stool samples from llamas could only be obtained at a has approximately 1-2 cattle, sheep, pigs, and 4-5 birds. weekly trade fair of llamas in the locality of Paicoco. Estimates of After official data, the estimated animal population in- the populations of all domestic animal species were made during cludes 6 sheep and 3,4 cattle per family. In the locality numerous visits to all zones of the Northern Bolivian Altiplano en- of Ancocagua, for instance, familial herds include 0-50 demic region carried out in the 1992-1997 period. sheep (mean 14,6), 0-17 cattle (mean 8, I), and 0-4 don- Stool collection and preparation:Stool samples were obtained keys (mean 0,9). In Chijipata Alto, herds sometimes from pigs, donkeys. horses, goats and llamas in the month of comprise up to 4 sheep, II cattle, 9 pigs and 3 donkeys. March 1997 (March is usually the last month of the rainy season). In Cullucachi, there is an average of 0,08 sheep, 1,28 For comparison purposes, several sheep faeces samples from the cattle, 1,4 pigs and 0,12 donkeys per family. In given same localities were obtained from different months of the year. places of the Northern Altiplano endemic region the No stool samples could be obtained from alpacas; hence, preva- number of animals owned by an Aymara family was lence and egg output data from alpacas are taken from previous work carried out by other authors in the same endemic region. pronouncedly higher 10 years ago, sometimes even sur- Fresh faeces were collected off the ground as animals were obser- passing 200-250 sheep; whereas today it does not reach ved defecating. Stool samples were put in a plastic bag and trans- 15-20 animals (see review of MAS-COMA et al., 1995). ported to the ILASA Institute of La Paz within the following 5 These data do not significantly differ from similar data hours. At the INLASA Institute, a qualitative technique was first from the Central Bolivian Altiplano except in the absence applied to all stool samples. Those which showed to be positive of llamas. In the locality of Huaraco, 130 km south of La (detection of F. hepatica eggs) were appropriately fixed and trans- ported to the Parasitology Department of the University of Valen- Paz on the route to Oruro, each family owns a mean of 2- cia, Spain. for a quantitative analysis. 10 cattle, about 20-50 sheep, as well as several donkeys; but certain families also have 5-15 llamas (FISEL, 1989). Coprological techniques: For a first qualitative analysis, a small but sufficient amount of faeces was homogenized with 10% formaline. The mixture was then strained through a funnel with a ste- Pigs rile gauze into an assay tube. The assay tube was afterwards allo- wed to stand for 2 h for sedimentation. Finally, several drops of the Stool samples of 59 pigs were analysed: 6 pigs from sediment were taken with a Pasteur pipette and deposited on 2 mi- the locality of Tambillo; 7 from Lacaya Baja; 18 from croscope slides. After covering each sample with a cover slide. Chijipata Alto; I from Batallas; 14 from Queroni; 3 from both preparations were examined under 10x magnification with a Huacullani; 2 from Chiripujo; 5 from Chojasihui; 2 from microscope. Korila; I from Caleria. A total of 16 pigs (27, I%) pre- In cases in which F. hepatica eggs were found. 3 g from the re- sented F. hepatica eggs in their faeces: I from Tambillo; mainder of the original stool sample were fixed with 50 ml of 10% 12 from Chijipata Alto; 2 from Queroni; I from Chiri- formaline for a later quantitative study. For the quantitative analysis, the sedimentation test of DENNls, STONE & SWANSON (1954) pujo. The number of eggs per gram of faeces ranged bet- was performed with the modification of using water without deter- ween 4 and 65 epg, with a mean of 21,6 epg. According gent as described by CHERIUYOT & JORDAN (1990). The final sedi- to general estimations of the amount of stools defecated ment was placed in a 7 cm-diameter Petri dish and was examined by a pig per day (MORROS SARDA, 1967; GURTLER et under 30x magnification with a stereoscopic microscope. al., 1979), the total number of F. hepatica eggs shed with faeces by a pig per day in the Northern Bolivian AI- tiplano may be between 2000 and 195000. RESULTS Pigs are numerous in all zones of the endemic region, as they are usually part of the livestock of Aymara fami- Among the Aymara Indians there is the strong tradi- lies.According to their number, it appears to be the tion that each family sustains its own livestock, inclu- third domestic animal species in importance in the Nort- ding large mammals such as sheep, cattle, pigs, donkeys, hern Bolivian Altiplano, after sheep and cattle. In most horses, llamas or alpacas. Official data of the Ministry zones pigs run free and can usually be observed in or (MACA, 1988) refer to estimations of about 5350000 around fresh water bodies inhabited by Iymnaeid snails sheep, 500000 cattle, 350000 pigs, 1400000 llamas, and (Fig. 2 B). 150000 alpacas (no data on donkeys and horses could be found among official census reports) living in the whole Donkeys Bolivian Altiplano. In the endemic area, observations in the field concer- Stool samples of 65 donkeys were analysed: 35 don- ning domestic animal populations yielded data varying keys from the locality of Ancocagua; 2 from Tambillo; according to Aymara families and sometimes also accor- IQ from Lacaya Baja; 7 from Queroni; 2 from Huacu- ding to the different zones within the endemic region. llani; 2 from Chiripujo; 6 from Chojasihui; I from Ko- 42 S. MAS-COMA et af. rila. A total of 10 donkeys (15,4%) presented F. hepatica Horses appear to be very scarce in the Northern Boli- eggs in their faeces: 3 from Ancocagua; 3 from Lacaya vian Altiplano. Most of the few living in the endemic re- Baja; I from Huacullani; 3 from Chojasihui.The number gion are found in the «corridor of Batallas», sometimes of eggs per gram of faeces was from 3 to 101 epg, with a in pastures presenting water bodies inhabited by lymna- mean of 38,8 epg. According to general estimations of eids as in Chirapaca (Fig. 2 C). None could be seen in the amount of stools defecated by a donkey per day (de- the «corridor of Huacullani» despite the numerous visits duced from animal's weight from data of MORROS to this zone. SARDA, 1967 and GORTLERet al., 1979), the total number of liver fluke eggs expelled with faeces by a donkey Goats per day in the Northern Bolivian Altiplano may be around 9000-808000. The goat may not be considered a domestic animal Donkeys are relatively numerous in all zones of the species present in the Northern Bolivian Altiplano. Du- endemic region. A few donkeys are usually part of the li- ring the 6-year period of this study, only a very few go- vestock of Aymara families, although their numbers ats were seen throughout the whole endemic region: 4 vary in the different zones. In Ancocagua, for instance, specimens in the area of Batallas (Fig. 2 A) and about 10 they are very numerous. It appears to be the fourth do- in the zone between Oquetiti and Iquiaca. A stool sample mestic animal species in number in the Northern Boli- from I goat male from Batallas could be obtained and vian Altiplano, after sheep, cattle and pig. Donkeys are analysed. No F. hepatica eggs were found. frequently found in pastures besides water collections presenting lyrnnaeid snails (Fig. 2 D). Llamas Llamas can only very sporadically be observed in the Horses orthern Bolivian Altiplano.Besides the few specimens Faeces of only 4 horses could be analysed: I horse present in the garden of the Titicaca Hotel and the Tiwa- from the locality of Chijipata Alto and 3 from Chirapaca. naku ruins, both for mere touristic purposes, only a few All were negative in the coprological tests. individuals can regularly be found in the «corridor of Pe-

o. animals Prevalence Intensity (epg) Stools/day' o. liver fluke studied (%) range mean (kg) eggs/day"

Pigs 59 27,1 4-65 21.6 0,5-3 2000-195000

Donkeys 65 15,4 3- [01 38,8 9000-808000

Horses 4 0 15-23

Goats 0

Llamas 30 0

d Alpacas 22 59, Id 2-75d n.s." 4000-300000 29' 86,2' < I0->30' n.s." <20000-> 120000

Sheep 26 61,5 3-145 44,7 1-3 3000-435000 1345' 0-100 (43,6)'·g 4- [203,·h n.s. c 1-3 800-72[800

Cattier Kallutaca zone 569 0-50 (34,Ol 1-88; 5,9; 15-35 3750-770000 Laja zone 80 8,0-26,3 (17,W 1-31 ; 6.9; 15-35 3750-27 [250 Tambillo zone 351 4,0-45,2 (31.9)g 1-20; 5,2' 15-35 3750-175000 Pucarani zone 646 2.5-66,6 (7,8)g [-30; 4S 15-35 3750-262500 Huayrocondo zone 303 8,5-45,5 (14,8)g 1-49; 5.6; 15-35 3750-428750 Achacachi zone 1166 0-56,8 (23,8)g 1-96; 12,6; [5-35 3750-840000

Table 1.- Prevalences and intensities (egg output = eggs per gram = epg) of Fasciola hepatica infection in domestic animals in the orthern Bolivian Altiplano .• = general estimations of the amount of stools defecated by each domestic animal species per day, according to

MORROS SARDA (1967) and GORTLER et al. (1979); b = only approximate, deduced from animal's weight; '= estimations of the total number of F. hepatica eggs shed with faeces by each domestic animal species per day in the Bolivian Altiplano; d = after UE 0 et al. (1975); e = see review by MAS-COMA et al. (1995); r = after studies carried out by BucHO et al. (1997); g = prevalence range according to different communities in the zone (with prevalence mean in parenthesis); h = number of eggs per 5 g of faeces;; = number of eggs per 4 g of faeces; n.s. = not specified. Secondary reservoirs of fascioliasis in the Bolivian Altiplano 43 iias» (Fig. 2 F) and the «corridor of Huancarani-Jesus de concentrate in a trade fair specialized in this Andean ea- Machaca». However, the latter two corridors lie outside melid in the locality of Palcoco (Fig. 2 E). They come of the endemic region. At any rate, once a week llamas from zones outside of the endemic region, such as from

Fig. 2.- Large domestic mammal species present in the fascioliasis human endemic region in the Northern Bolivian Altiplano: A) a very few goats in the zone between Batallas and Huarina, with the Lake Titicaca in the background; B) pigs in a water collection inhabited by Iymnaeid snails near the locality of Pucarani; C) a horse in the transmission focus of Chirapaca; D) donkeys in the endemic zone of Lacaya Baja; E) weekly trade fair of llamas in the locality of Palcoco; F) llamas in the «corridor of Pefias»; G) an alpaca in the «corridor of Pefias»; H) sheep and cattle in familial livestock. 44 S. MAs-CoMAet al. the zone located north of the endemic region, at a higher in DE LEO& QUINONES,198 I). However, according to altitude on the way to the Eastern Andean Chain, or from general estimations of the amount of stools defecated by the Altiplanic zone located south of the endemic region, a cattle per day (MORROSSARDA, 1967; GURTLERet al., on the way to Oruro, where temperatures are colder 1979), it appears that their daily contribution to environ- owing to the absence of the climatic influence of Lake mental contamination with fluke eggs is similar to that Titicaca (LORI 1& LIBERMA , 1983). of sheep (Table I). A total of 30 llamas present in the Palcoco trade fair According to the results of the present study (see Ta- were surveyed. None showed liver fluke eggs in the ble I), it is evident that pigs and donkeys are able to de- stools. velop the role of potential reservoirs of fascioliasis in the Northern Bolivian Altiplano endemic zone. Their individual egg output (epg) capacities do not greatly differ Sheep from those detected in Altiplanic sheep and cattle. More- For comparison purposes, a total of 26 sheep were sur- over, their daily egg output (eggs/day) capacities are suf- veyed: 16 sheep from the locality of Batallas and 10 ficient to assure an important contamination of the envi- from Chijipata Alto. Stool samples from 16 sheep ronment. Owing to the smaller populations of pigs and (6 I,5%) presented F. hepatica eggs: 13 from Batallas donkeys compared to the more numerous and dense po- and 3 from Chijipata Alto. The number of eggs per gram pulations of sheep and cattle in the endemic region, pigs of faeces ranged between 3 and 145 epg, with a mean of and donkeys may be considered as secondary reservoir 44,7 epg. According to general estimations of the hosts in fascioliasis transmission. This means that, if la- amount of stools defecated by a sheep per day (MORROS boratory research work today under way demonstrates SARDA,1967; GURTLERet al., 1979), the total number of the viability of eggs expelled by Altiplanic pigs and don- F. hepatica eggs shed with faeces by a sheep per day in keys, these two domestic animal species must be inclu- the Northern Bolivian Altiplano may be between 3000 ded in the control measures (infection and transmission and 435000. Together with cattle, sheep are the most nu- prevention measures, treatment campaigns) to be applied merous domestic animals in all zones of the endemic re- in this endemic region. gion. Sheep usually constitute part of the livestock of Horses, goats and llamas may be discarded as contri- Aymara families (Fig. 2 H). butors to environmental contamination and fascioliasis transmission in the Northern Bolivian Altiplano, mainly because of the very scarce representatives of these three DISCUSSIO species in the endemic region. Concerning alpacas, besides a very few isolated indi- In sheep (Table I), the prevalence found of 6 1,5% viduals regularly found in the «corridor of Pefias» (Fig. agrees with the results of previous coprological surveys 2 G), outside of the fascioliasis transmission area, in the carried out by different authors, which vary from 0 to Northern Bolivian Altiplano endemic region alpacas are 100% in different localities of the Northern Bolivian Alti- only found on the farm of Belen, north of Achacachi. piano, with a mean of 71,6% when including only locali- Previous coprological studies on alpacas from Belen ties presenting the parasite and a mean of 43,6% when farm (UENO et al., 1975; MAS-COMA et al., 1995) re- also considering localities with prevalence 0% (see MAS- ported the following results: in one study 59,1 % of 22 COMAet al., 1995). Egg output data of a range of 3-145 alpacas were detected shedding F. hepatica eggs in sto- epg and a mean of 44,7 epg found in our study also co- ols, with averages of75, 16 and 2 eggs found in animals rrespond with similar results of 4- I203 eggs/5 g pre- with high (n = 7), moderate (n = 2) and low (n = 2) in- viously reported by other authors in the same Altiplanic fection, respectively; in another survey 25 alpacas endemic region (see review in MAS-COMAet al., 1995). among 29 studied showed eggs in their stools (86,2%), In the Bolivian Altiplano, cattle show F. hepatica in- of which 22 alpacas presented fewer than 10 eggs, 2 al- fection rates somewhat under those reported in sheep pacas showed between 10 and 30 eggs, and only I al- (Table I). In the same zones analysed in the present pa- paca presented more than 30 eggs.According to these per (Tambillo, Pucarani, Huayrocondo and Achacachi data, alpacas may be taken into account in the zone of zones) or in zones near to those here considered (Kallu- the Belen farm, but can be discarded in the remainder of taca and Laja zones), the prevalence of the different the endemic region. communities within the 6 zones taken into account ranges from 0 to 66,6% and the prevalence means of the same 6 zones range from 17,5 to 34,0% (data from Bu- ACKNOWLEDGEMENTS CHONet al., 1997). Egg output data concerning epg, with individual ranges from I to 96 eggs/4 g and mean ranges Study supported by a Project (Contract No. TS3-CT94-0294) of between 4,5 and 12,6 eggs/4 g (data from BUCHONetal., the STD Programme of the Commission of the European Commu- nities (DGXII: Science, Research and Development), Brussels. 1997), are also less than in Altiplanic sheep, although EU. by the Programme of Scientific Cooperation with Latin Ame- they may be considered normal when compared to other rica of the lnstituto de Cooperacion Iberoamericana of the Agencia world areas (see egg output after experimental infection Espafiola de Cooperacion Internacional (I.C.I.-A.E.C.I.), Madrid, Secondary reservoirs of fascioliasis in the Bolivian Altiplano 45 and by Project No. UE96-000 I of the Direcci6n General de Inves- laboratory and field diagnostic test for fluke ova in feces. tigaci6n Cientffica y Tecnica (DGICYT), Spanish Ministry of Journal of the American Veterinary Medical Association. 124: Education and Science, Madrid. 47-50. Or. J.G.Esteban and Or. M.V. Fuentes (Valencia. Spain) contri- ESTEBA(J.G.), FLORES(A.), AGUIRRE (C.). STRAUSS(W.), A - buted in technical aspects. Or. R. Fons and M. J.P. Clara of the La- GLES(R.) & MAS-COMA(S.), I 997a.- Presence of very high pre- boratoire Arago. Universite P. et M.Curie de Paris VI (Banyuls- valence and intensity of infection with Fasciola hepatica among sur-Mer, France) participated in the collection of Faeces samples Aymara children from the orthern Bolivian Altiplano. Acta from the animals. Or. Maribel Acosta of the Facultad de Veterina- Tropica, 66: I - I 4. ria.Universidad de C6rdoba (Cordoba, Spain) is acknowledged for ESTEBA(J.G.), FLORES(A.), ANGLES (R.), STRAUSS(W.).AGUI- information on aspects of domestic animal physiology. RRE(C.) & MAS-COMA(S.). I 997b.- A population-based copro- The authors want to acknowledge the facilities and collaboration logical study of human fascioliasis in a hyperendemic area of received from the following institutions and centers. as well as the Bolivian Altiplano. Tropical Medicine and International their respective representatives or directors: Direcci6n Nacional de Health. 2: 695-699. Relaciones Internacionales as well as the Direcci6n Nacional de ESTEBA(J.G.). AGUIRRE(C.), FLoREs (A.). STRAUSS(W.).AN- Epidemiologfa of the Ministerio de Previsi6n Social y Salud PU- GLES (R.) & MAS-COMA(S.), 1997c.- High Cryptosporidium blica (today become the Secretarfa Nacional de Salud of the new prevalences in healthy Aymara children from the Northern Boli- Ministerio de Desarrollo Humano) in La Paz; Cornite Regional de vian Altiplano. American Journal of Tropical Medicine and Hy- Zoonosis and Centro Piloto La Paz of the Unidad Sanitaria La Paz: giene. 58: SO-SS. Direcci6n Nacional de Producci6n Pecuaria and the Instituto Na- ESTEBAN(J.G.), AGUIRRE(C.), ANGLES (R.), ASH (L.R.) & MAS- cional de Biologfa Animal of Chasquiparnpa-Cota Cota both of the COMA(S.), 1997d.- Balantidiasis in Aymara children from the Ministerio de Asuntos Campesinos y Agropecuarios (M.A.C.A.) Northern Bolivian Altiplano. American Journal of Tropical Me- in La Paz; Granja de Mejoramiento Ganadero de Kallutaca related dicine and Hygiene: in press. to the Programa de Fomento Lechero of the Corporaci6n Regional FISEL (U.), 1989.- Huaraco: una comunidad campesina en el Alti- de Desarrollo de La Paz (CORDEPAZ); and Office of the Pan pIano Central de Bolivia. Observaciones sobre plantas, tierra y American Health Organization in La Paz. vida de la gente. Ecologia en Bolivia, 14: 35-72. GURTLER(H.), KETZ(H.A.), KOLB (E.),SCHRODER(L.) & SEIDEL (H.), 1979.- Las heces.In: Fisiologfa Veterinaria (E. Kolb REFERE CES edit.), Editorial Acribia.Zaragoza, p. 377. 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