The Northern Bolivian Altiplano: a region highly endemic for human fascioliasis

Abstract

SummaryThe worldwide importance of human infection by Fasciola hepatica has been recognized in recent years. The endemic region between Lake Titicaca and the valley of La Paz, Bolivia, at 3800-4100 m altitude, presents the highest prevalences and intensities recorded. Large geographical studies involving Lymnaea truncatula snails (malacological, physico-chemical, and botanic studies of 59, 28 and 30 water bodies, respectively, inhabited by lymnaeids; environmental mean temperature studies covering a 40-year period), livestock (5491 cattle) and human coprological surveys (2723 subjects, 2521 of whom were school children) were conducted during 1991-97 to establish the boundaries and distributional characteristics of this endemic Northern Altiplano region. The endemic area covers part of the Los Andes, Ingavi, Omasuyos and Murillo provinces of the La Paz Department. The human endemic zone is stable, isolated and apparently fixed in its present outline, the boundaries being marked by geographical, climatic and soil-water chemical characteristics. The parasite distribution is irregular in the endemic area, the transmission foci being patchily distributed and linked to the presence of appropriate water bodies. Prevalences in school children are related to snail population distribution and extent. Altiplanic lymnaeids mainly inhabit permanent water bodies, which enables parasite transmission during the whole year. A confluence of several factors mitigates the negative effects of the high altitude.

Fasciola hepatica and Paramphistomum daubneyi: changes in prevalences of natural infections in cattle and in Lymnaea truncatula from central France over the past 12 years

“…In a review by Torgerson and Claxton [23], these prevalences ranged from 0.95% up to 94% between 1989 and 1995. In more recent studies, similar variations could be noted, with prevalences ranging from 1.3% in Venezuela [8] (out of 763 065 cattle slaughtered) up to 51.2% in Ethiopia [24] (out of 4 730 cattle) or 100% in Bolivia [15] (out of 5 191 cattle). In France, the most important set of results concerns the Limousin region, with a global prevalence of 13.0% [14] out of 51 555 cattle examined.…”

Epidemiological studies onFasciola hepaticain Gafsa oases (South West of Tunisia)

“…The infection rate of ovine was lower in Algeria (6.4 % in Constantine and 23 % in Jijel) (Mekroud et al, 2004);7.3 % in Iran (Moghaddam et al, 2004). But the rate was more important in cows in Bolivia (100 %) (Mas-Coma et al, 1999) and in Ethiopia (51.2 %) (Yilma & Mesfin, 2000). Usually sheep and cattle are preferential hosts; goats are a less receiver and less parasitized.…”

Zoonotic helminth infections with particular emphasis on fasciolosis and other trematodiases

“…The main types of aquatic plants are 'berro berro' (watercress), 'algas' (algae), kjosco and totora (Mas-Coma et al 1999a. Drinking untreated water may be a source of infection due to the presence of free-floating metacercarial cysts.…”