Research and Reviews ill Parasitology. 55 (2): 73-79 (1995) Published by A.P.E. © 1995 Asociaci6n de Parasit61ogos Espaiioles (A.P.E.) Printed in Barcelona. Spain HUMAN FASCIOLIASIS IN BOLIVIA: A GENERAL ANALYSIS AND ACRITICALREVIEW OF EXISTING DATA 2 S. MAS-COMA', R. ANGLES\ W. STRAUSS , J.G. ESTEBAN', J.A.OVIEDO' & P. BUCHONI.3 I Departamento de Parasitologia, Facultad de Farmacia, Universidad de Valencia, Av. Vicente Andres Estelles sin, 46100 Burjassot - Valencia, Spain 2Division de Parasitologia y Micologia, lnstituto Nacional de Laboratorios de Salud «Nestor Morales villazon» (INLASA), Secretaria Nacional de Salud, Ministerio de Desarrollo Humano, Pasaje Rafael Subieta No. 1889 (lado del Estado Mayor General), Miraflores, La Paz, Bolivia 3Laboratorio de Sanidad Animal de Kallutaca, Programa de Fomento Lechero, Corporacion Regional de Desarrollo de La Pa; (CORDEPAZ), Av. Juan Pablo 11, Crra. de El Alto kill 5, El Alto, Bolivia Received 15 November 1994; accepted 3 March 1995 REFERENCE:MAS-COMA(S.), ANGLES(R.), STRAUSS(W.), ESTEBAN(J.G.), OVIEDO(J.A.) & BUCHON(P.), 1995.- Human fascioliasis in Bolivia: a general analysis and a critical review of existing data. Research and Reviews in Parasitology, 55 (2): 73-93. SUMMARY:The large extent of human fascioliasis by the liver fluke species Fasciola hepatica has only been recognized in recent years. However, most of the literature dealing with human fascioliasis refers to more or less isolated cases, so that only a few real endemic regions of human fascio- liasis have been investigated up to the present. Bolivia does not even appear in recent reviews, because previous case reports were not published or published in local journals or diffusion booklets. Thus, published information is very scarce, despite the facts that the human endemic of fasciolia- sis in the Bolivian orthern Altiplano is well known to specialists and the zone has proved to have the highest human prevalences recorded. This paper aims to establish the real situation of knowledge on this human fascioliasis endemic by reviewing the existing literature on fascioliasis in the orthern Altiplano of Bolivia, composed mainly of unpublished documents and locally published reports. Most of these reports and studies were made by non-specialists and, consequently, the data furnished have not been appropriately reviewed and must therefore be considered in their true value, in many cases only at informative or suggestive level. This does not mean, however, that this large set of data is not very valuable. This re- view shows that there is useful information available on several important aspects, mainly coprological and immunological surveys on humans, sheep and cattle. Coprological and serological survey results include prevalences up to 72% and 100% in humans, up to 100% and 89% in sheep, and up to 100% and 60% in cattle of given localities, respectively. In humans, the existence of other parasitic diseases makes it difficult to establish clinical and pathological patterns, morbidity and mortality caused by fascioliasis. Bolivian official organisations recognize the important impact of both the human health problem and the veterinary economic and production losses due to fascioliasis in the Altiplano. Accordingly, national control programmes have already been established. But unfortunately the knowledge concerning essential aspects is largely insufficient. Concerning the li- ver fluke, there is no research work carried out on parasite species determination nor on its life cycle and transmission, a fact which is very impor- tant, taking into account that F. hepatica appears to be a parasite typical of very low altitude regions and sea level zones in other parts of the world. The Bolivian human endemic zone is located between Lake Titicaca and the valley of the city of La Paz, at an altitude of 3800-4100 m, although field research is needed to establish the real geographical extent of the human and livestock health problems. The few studies undertaken on the in- tennediate snail hosts suggest the presence of two different Iymnaeid species in the endemic area, Lymnaea viatrix and L. cubensis var., both with the capacity of transmitting the parasite. At any rate, both malacological and parasitological data need specialist confirmation, taking into conside- ration that these two species are typical American sea level region inhabitants. Studies on potential wild animal reservoirs, such as hares and mainly murid and herbivorous caviomorph rodents, possibly playing a role in parasite transmission, are needed. There is much information on human nu- tritional status, habits, ethnic customs and religious aspects of the Ayrnara inhabitants, which may be related to the disease. Careful studies on mi- lieu characteristcs, environmental and climatic conditions related to fascioliasis are lacking. KEY WORDS:Human fascioliasis, review, Northern Altiplano, Bolivia. CONTE TS Introduction. 74 The parasite .. 75 Species determination 75 Life cycle and transmission .. 75 The endemic zone. 76 The geographic distribution of Fasciola hepatica. 76 The milieu and environmental risk factors 77 Plants involved in transmission. 78 The human host. 78 Coprological and immunological surveys. 78 Clinical and pathological observations. 81 ational control programmes. 81 Association with other parasite species 82 Human contamination sources. 82 utritional status. 83 74 S. MAS-COMA et al. Human habits, ethnic customs and religious aspects . 83 Treatment 84 The molluscan intermediate host. 85 Species determination. 85 Geography, ecology and population dynamics. 85 Snail control measures.. 86 The domestic animal reservoirs . 86 CoprologicaJand immunological surveys .. 86 Sheep . 86 Cattle. 86 Alpacas 89 Economic and production losses due to fascioliasis. 89 National control programmes . 89 Treatment.. 89 The potential free living animal reservoirs. 90 Acknowledgements. 90 References.... 90 INTRODUCTION fascioliasis in the Northern Altiplano of Bolivia is exten- sive. This literature is, however, composed mainly of un- The recent review by CHEN & Morr (1990) has de- published papers of different types (reports to ministries; monstrated that human fascioliasis is more important internal reports of organisms; university theses; a few than was formerly believed, that human infection by papers presented to meetings; etc.). Moreover, most of Fasciola hepatica (Linnaeus, 1758)(Trematoda:Fascio- these reports and studies were made by non-specialists lidae) takes place in all continents and that in given and, consequently, the data furnished have not been ap- countries the number of cases is high. Thus, this disease propriately reviewed and must therefore be considered in has been largely underestimated, above all when taking many cases only at informative or suggestive level. This into account the number of cases in which infection is does not mean, however, that this large set of data is not not diagnosed, whether due to an asymptomatic or little- very valuable. That is why a complete review was under- symptomatic disease course or to an incorrect diagnosis taken to establish the real situation of knowledge before of the causes in symptomatic cases. Today, knowledge the beginning and during the first phases of the above- clearly suggests that if carefully researched, the extent mentioned research project. and prevalences all over the world would be markedly The aim of this paper is to present the results of this re- larger than what is shown in the review table made by view. Because of the unpublished nature of most of the CHE & Morr (1990). reports considered, most references cited at the end of However, most of the literature dealing with human this article will be unavailable for the reader. But the au- fascioliasis refers to more or less isolated cases (CHEN & thors of the present review consider that justice must be Morr, 1990), so that only a few real endemic regions of done to so many persons from different origins and pro- human fascioliasis have been investigated up to the pre- fessions who in one way or another have contributed to sent: Portugal (SAMPAIO SILVA in CHEN & Morr, the knowledge of fascioliasis in the endemic region of 1990), Iran (BAHAR et al., 1990; MASSOUD, 1990; POUR- the Bolivian Northern Altiplano, a zone which has pro- TAGHVA et al., 1990), Peru (STORK et al., 1973; KNo- ved to present the highest human prevalences by F. he- BLOCH, 1985; K OBLOCH et al., 1985; NAQUIRA, pers. patica infection, as already emphasized by HILL YER et comm.) and Bolivia. al. (1992). Bolivia does not even appear in CHEN & Mo'rr's Owing to the Bolivian administrative tradition of ma- world review (1990), because previous case reports were king numerous internal reports in official and public or- not published or published in local journals or diffusion ganisations and institutions, we cannot be sure that this booklets. Only one paper has appeared after 1990 in an review covers all studies carried out on human and ani- international journal (HILLYER et al., 1992). Thus pu- mal fascioliasis in the Bolivian Northern Altiplano.We blished information is very scarce, despite the fact that assume that there are most probably a very few other un- the human endemic of fascioliasis in Bolivia is well published papers which we were unable to find or obtain known to specialists, at least in the recent years. (e.g. ARAUJO, 1965; PA YNO, 1977; BOTELLO, MACH 1- In 1992, when starting a large multidisciplinary inter- CADO & PUCH, 1981). It must also be taken into account national project on human fascioliasis in the Bolivian that the results obtained in human and animal fasciolia- Northern Altiplano, a careful search for previously sis studies performed in recent years by the Bolivian co- known data on the question was initiated. During these authors of the present paper are actually being analysed last years it has been found that the existing literature on for future publications and consequently the contents of Human fascioliasis in Bolivia 7S the related unpublished internal reports made at the time tiplanic endemic zone in question has a mean altitude of of these surveys are not included in this review.