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La fascioliasis es una importante enfermedad causada por dos especies de trematodos, Fasciola hepatica y Fasciola gigantica, que incluye un amplio espectro de especies hospedadoras definitivas tanto domésticas como silvestres. En el presente trabajo, como primer paso, se realizó una revisión bibliográfica exhaustiva de todos los casos humanos de fascioliasis en México, reportados tanto en la literatura mexicana, como casos de pacientes mexicanos diagnosticados en Canadá y USA. El estudio fenético y genético se realizó con adultos del parásito, obtenidos de bovinos del matadero de la Ciudad de Toluca, Estado de México, México, zona de endemia humana. Para el estudio fenético comparativo se usaron parásitos adultos de especies standard provenientes de Bóvidos de los siguientes lugares geográficos: a) F. gigantica: Bobo Dioulasso, Burkina Faso (África); F. hepatica: Córcega, Francia (Europa); Valencia, España (Europa): Altiplano Norte Boliviano (América): Se realizó un análisis morfométrico exhaustivo usando un Sistema de Análisis de Imágenes Digitales (CIAS). El análisis genético se efectuó utilizando marcadores genéticos ribosomales (ITS-1, 5.8S, ITS-2). Los resultados de este estudio demuestran la única presencia de F. hepatica, en todas las poblaciones estudiadas de México, no detectándose la presencia de F. gigantica ni de formas intermedias.Fascioliasis is a plantborne and zoonotic parasitic disease caused by fasciolid liver flukes. Fasciola
hepatica is the only fasciolid species described in the Americas, mainly transmitted by lymnaeid
snail vectors of the Galba/Fossaria group. Human fascioliasis endemic areas are mainly located in
high altitude areas of South America but also North America. Given the necessity to characterize
the F. hepatica populations involved, the phenotypic features of fasciolid adults infecting cattle
present in fascioliasis endemic areas such as in State of Mexico (Mexico) (valley transmission
pattern) were analysed and compared with material from the Northern Bolivian Altiplano (altiplanic
transmission pattern). In Mexico, parasites were obtained from the Toluca Valley, located in the
central area of the State of Mexico, at a mean altitude of 2,600 m. Numerous permanent water
bodies are situated in the area, continuously receiving thaw water from Nevado de Toluca o
Xinantécatl volcano (4,200 m altitude) through community supply channels, an epidemiological
scenario similar to that previously described in the hyperendemic areas of Andean countries. A
computer image analysis system (CIAS) was applied on the basis of standardized measurements.
The aforementioned F. hepatica highland populations from Mexico and Bolivia were compared to
standard lowland natural populations of European origin (Spain and France) and also to a
population of F. gigantica of African origin (Burkina Faso). Liver-fluke size was studied by
principal component analysis (PCA). Thus, for the first time, a comparative phenotypic study of the
adults of F. hepatica from cattle in Mexico has been carried out. Results are analyzed in terms of
permanent/seasonal transmission characteristics. The present work validates the utility of the
phenotypic characterization of fasciolid adults in multidisciplinary studies.
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