Fascioliasis in Cattle in the Human High Endemic Region of the Bolivian Northern Altiplano
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Research and Reviews ill Parasitology. 57 (2): 71-83 (1997) Published by A.P.E. © 1997 Asociaci6n de Parasit61ogos Espafioles (A.P.E.) Printed in Barcelona. Spain FASCIOLIASIS IN CATTLE IN THE HUMAN HIGH ENDEMIC REGION OF THE BOLIVIAN NORTHERN ALTIPLANO 1 2 2 2 2 1 P. BUCHON • , H. CUENCA , A.QUlTON , A.M. CAMACH0 & S. MAS-COMA I Departamento de Parasitologia, Facultad de Farmacia, Universidad de Valencia, Av. Vicenl Andres Estelles sin, 46100 Burjassot - Valencia, Spain 2Laboratorio 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 km 5, El A 110, Bolivia Received 29 October 1996; accepted 17 May 1997 REFERENCE:BUCHON(P.), CUE CA(H.), QUITO (A.), CAMACHO(A.M.) & MAS-COMA(S.), 1997.- Fascioliasis in cattle in the human high ende- mic region of the Bolivian orthern Altiplano. Research and Reviews in Parasitology, 57 (2): 71-83. ABSTRACT:Coprological surveys were carried out to study Fasciola hepatica infection in 5491 cattle from II zones and 107communities on the Bolivian Altiplano, where the highest prevalences and intensities in human subjects have been found. The research work had the aim of contribu- ting to the knowledge about the geographical distribution of the liver fluke and the epidemiological reservoir host role of bovines in the transmis- sion of the disease in this endemic area. According to the results obtained, the parasite is present throughout almost all the Northern Bolivian Alti- pIano, but it does not extend toward the Central Bolivian Altiplano, in the South.The total prevalence found in cattle of the Northern Bolivian Altiplano was 16,5%. The prevalences were irregularly distributed, varying considerably according to zones (7,8-34,0%) and communities (0,0- 66,6%). Bovines of less than I year appear to be only rarely infected (8, I%), whereas the prevalence increases markedly in animals aged 1-2years (35,I%) and is apparently maintained at a similar level in cattle aged more than 2 years (29,2%). Prevalences do not show marked monthly changes and community prevalence ranges are very wide within each month. It may be assumed that the contamination of the environment by eggs expelled by cattle is assured throughout the year. Egg output numbers do not vary considerably within a given community (usually between I and 30 eggs/4 g faeces) and in no case did the count reach 100. A few communities showed relatively high numbers in the upper range (up to 96 eggs/4 g faeces). It is concluded that in the orthern Bolivian Altiplano, cattle participate in the contamination of the environment with liver fluke eggs at a level si- milar to sheep. According to the prevalence and egg output results obtained, cattle may be considered, like sheep, a main reservoir host of fasciolia- sis in this Altiplanic endemic zone. At any rate, infection rates in Altiplanic bovines do not appear to be high enough to explain the high infection rates detected in human subjects of the Northern Bolivian Altiplano. KEYWORDS:Liver fluke, Fasciola hepatica, fascioliasis, cattle, coprological surveys, geographical distribution, prevalences, intensities, Northern Bolivian Altiplano. INTRODUCTION probably by Spanish colonizers (OVIEDO, BARGUES & MAS-COMA, J995a; BARGUES & MAS-COMA, 1997; BAR- The veterinary importance of fascioliasis caused by GUES et al., 1997; JABBOUR-ZAHAB et al., 1997). the cosmopolitan liver fluke species Fasciola hepatica In this fascioliasis endemic zone of the orthern Boli- (Linnaeus, 1758) (Trematoda: Fasciolidae) in livestock vian Altiplano, several studies have been undertaken to has long been well known (MALEK, 1980; BORAY, understand how the liver fluke is able to reach such 1982). Recently, it has been verified that it represents, transmission rates to human beings. Among these rese- moreover, a great human health problem (MAS-COMA & arch activities, investigations have been performed to as- BARGUES, 1997; MAS-COMA et al., 1998), with up to al- certain what role domestic and wild potential animal de- most seven thousand human cases diagnosed in the five finitive host species may play in the epidemiology of the continents (CHE & MOTT, 1990; ESTEBAN, BARGUES disease. Concerning domestic animals, several studies & MAS-COMA, 1998) and several world regions presen- on sheep, cattle and alpacas were carried out some time ting human endemic areas (MAS-COMA, BARGUES & Es- ago (UE 0 & MORALES, 1973; UENO et al., 1975; many TEBA, 1998). other reports, either unpublished or published in local In Bolivia, the region of the Northern Altiplano has pro- journals or diffusion booklets - see review by MAS- ved to be the zone in which the highest prevalences and COMA et al., 1995) to which a few recent ones must be intensities in human subjects have been found up to the added (BUCHON & MAS-COMA, 1995; HILLYER et al., present (HILLYER et al., 1992; MAS-COMA et al., 1995; 1996). A more recent paper by MAS-COMA et al. (1997) BJORLAND et al., 1995; ESTEBAN et al., 1997a, b; ANGLES has evaluated the epidemiological role played by domes- et al., 1997; STRAUSS et al., 1997). This endemic zone, tic animal species other than sheep and cattle, conclu- between Lake Titicaca and the valley of the city of La ding that only pigs and donkeys must be taken into ac- Paz, presents the peculiar characteristic of being at the count. Finally, FuE TES et al. (1997) analyzed the very high altitude of 3800-4200 m. Moreover, the inter- potential role of wild animal species present in the Alti- mediate molluscan host has recently proved to be the ba- planic endemic zone and concluded that small mammals sommatophoran species Lymnaea truncatula (Muller, (Lagomorpha and Rodentia) do not play a role in the 1774) (Lymnaeidae) imported long ago to Bolivia most transmission of the disease. 72 P. BUCHON et al. From the results of the above-mentioned studies, we lence, incidence and egg number in faeces throughout the different know now that sheep and cattle are the main reservoir months of the year. Another problem which could not be avoided is that, in given communities, sometimes a treatment of all animals had animal host species and that pigs and donkeys may be taken place more or less time (one or several months) before stool considered important secondary reservoir species in the samples were collected; there are communities in which treatments Northern Bolivian Altiplano. Concerning pigs and don- are regular and programmed, in others they are sometimes done irre- keys, both qualitative (prevalences) and quantitative (in- gularly (when animals appear to be affected or when the owner has tensities by counting liver fluke egg number in faeces) money to treat the herd), and in others not at all. studies have been carried out (MAS-COMA et al., 1997). Concerning sheep and cattle, however, research studies Stool sample preparation and study: In the Animal Health Labo- ratory of Kallutaca, from each stool sample a quantity of 4 g was up to the present refer only to prevalence surveys made sedimerued twice, first with 50 ml of detergent solution (I mill 000 by different coprological or serological methods in a few crrr') after filtration and second with 50 ml water, and stained with given Altiplanic localities (UENO et al., 1975; MAS- methyl green according to DENNIS, STONE & SWA SON (1954), be- COMA et al., 1995; BUCHON & MAS-COMA, 1995; HILL- fore examination under light microscope for F. hepatica eggs. YER et al., 1996). Qualitative analyses giving rise to prevalence results were made in In the Northern Bolivian Itiplano, there is a lack of all communities surveyed (Table I), but investigations on the rela- tionship of prevalences with age groups (Table 2) and quantitative analyses both on fluke burden aspects and on geographi- studies on egg output (Table 4) could only be performed in given cal distribution of the parasite among sheep and cattle communities. populations. The present research work aims to contri- bute to these two aspects concerning cattle. For geograp- hical distribution analyses, cattle are more appropriate than sheep because bovines are more resistant to reinfec- RESULTS tion and the parasites only survive up to 1 year in them, whereas sheep are relatively susceptible to reinfection Geographical distribution and the liver fluke life-span can be as long as 11 years in them (DAWES & HUGHES, 1964; DELEON & QUII\JONES, The geographical distribution of communities where 1981; SMITHERS, 1982; HAROUN & HILL YER, 1986). cattle herds are infected by F. hepatica is shown in Fig. Hence, cattle are more useful as information tools to as- I. All zones studied are inhabited by cattle infected by certain the geographical distribution of transmission the liver fluke, excepting the Patacarnaya zone, in the foci, as in the Bolivian Altiplano cattle transport from South. According to these results, the parasite is present one to another place is not common. throughout almost all the Northern Bolivian Altiplano, but it does not extend toward the Central Bolivian Alti- pIano. The presence of the digenean parasite in cattle in MATERIAL AND METHODS the so-called «Tiwanaku corridor» seems to be rare and to follow a patchy distribution, according to the results Animal samples: From 1991 to 1994, 5491 cattle (Holstein, obtained in communities of the Tiwanaku zone and Gua- Brown Swiss, native and crossbreeds) faecal samples from animals qui zone. aged 5 months to 12 years were collected from II zones of the Bo- livian AItiplano in the Departament of La Paz. These II zones were divided into 107 communities (Fig. I, Table I):A) orthern Prevalences Altiplano: a) Omasuyos province: zone of Belen-Achacachi (14 communities); b) Los Andes province: zones of Pucarani (11 com- F. hepatica infection prevalences according to com- munities), Huayrocondo (3), Kallutaca (6), Laja (3) and Tambillo munities and zones are shown in Table I.