Genetic characterization of Portuguese Fasciola hepatica isolates

Dissertation presented to obtain the Master Degree in Molecular, Genetics and Biomedicine

Part of the results discussed in this dissertation was presented in the following communications: R. Santos, M. Calado, J. Sampaio, C. Ferreira, A. Afonso and S. Belo. Contribution to the genetic characterization of Fasciola hepatica populations in Portugal. XXXVII Portuguese Genetic Conference, Lisbon, Portugal, May 28th-30th 2012 [poster communication] R. Santos, M. Calado, J. Sampaio, C. Ferreira, A. Afonso and S. Belo. Contribution to the genetic characterization of Fasciola hepatica populations in Portugal. Arquivos Portugueses das Ciências Biológicas. Tomo XXXVI (in press)

Fasciola hepatica is a parasitic trematode with debilitating and socio-economically devastating effects. At present near to 600 million animals and 2.4 million people in the entire world suffer from fascioliasis. Genetic characterization is of the utmost importance to an efficient epidemiologic control of helminth infections. In the present study we aimed to provide the first insights into the genetic variability of F. hepatica in Portugal. 47 isolates from different hosts (cattle and sheep) and geographical locations (Beja, Castelo Branco, Coimbra, Évora, Faro, Leiria, Lisboa, Portalegre, Santarém and Setúbal) were analyzed through Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR), Restriction Fragment Length Polymorphism (RFLP) and sequencing of NADH dehydrogenase subunit 1 (nad1) gene, cytochrome c oxidase subunit 1 (cox1) gene and Internal Transcribed Spacers (ITS) region. RAPD-PCR and RFLP patterns were similar for all the analyzed samples, despite their host and geographical origin. Nucleotide sequencing revealed low levels of genetic diversity within Portuguese isolates and no direct correlation was observed between haplotype and geographical location or host. Phylogenetic analysis revealed a high similarity within samples from Mediterranean countries, such as Portugal, Spain, Tunisia, Algeria and Egypt, possibly due to livestock import/export trade between these countries. Moreover, Portugal presents a low risk of fascioliasis drug-resistance.