Comparison of adult liver flukes from highland and lowland populations of Bolivian and Spanish sheep

A morphological study of adult liver flukes and eggs from sheep in a human fascioliasis endemic zone in the Northern Bolivian Altiplano showed that they belong to the species Fasciola hepatica. An exhaustive morphometric comparison with a F. hepatica population from Spanish sheep was made using image analysis and an allometric model: (y2m − y2)/y2 = c[(y1m − y1)/y1], where y1 = body surface or body length, y2 = one of the measurements analysed, y1m, y2m = maximum values towards which y1 and y2 respectively tend, and c, b = constants. Only slight allometric differences in worms were observed despite the geographic distance between both Spanish and Bolivian sheep populations and the very high altitude of the Bolivian Altiplano.