INVESTIGADORES
KAMENETZKY Laura
congresos y reuniones científicas
Título:
Molecular epidemiology of Hydatid Disease
Autor/es:
KAMENETZKY, L.
Lugar:
Argentina
Reunión:
Conferencia; IX Congreso Argentino de Protozoología y Enfermedades Parasitarias; 2011
Resumen:
Genomic projects and amplification of DNA fragments by polymerase chain reaction (PCR) has greatly acelerated epidemiology studies on parasites. Mitochondrial DNA (mtDNA) is always a major target to differentiate closely related taxa because of its rapid evolution. Molecular analyses using the mtDNA sequences of genes for cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) could identify 5 species: E. multilocularis, E. vogeli, E.oligarthrus, E. shiquicus and E. granulosus including its genotypes (G1–G10). Recently, taxonomic revisions based on complete mitochondrial genomes were made and the species E. granulosus has been split into E. granulosus s. s. (genotypes G1–G3), Echinococcus equinus (G4), Echinococcus ortleppi (G5) and Echinococcus canadensis (G6–G7-G8). For G9 and G10 genotypes more analysis are required to certainly classify them. In Argentina and neighboring countries three species of Echinococcus,E. granulosus s.s., E. canadensis and E. ortleppi were found in humans and livestock, (Rosenzvit et al., 1999; Kamenetzky et al., 2002). Unlike the situation found in other regions, where the common E. granulosus s.s is the major source of human contamination, the E. canadiensis produced a significant number of human infections. Based on cox1 single nucleotide polymorphisms only a particular genotype (G6) was found in humans. In order to identify the natural intermediate host, other than sheep or cow, that could be the reservoir of this human infective genotype, cysts from pigs, goats and alpacas were cox1 sequenced. We found the E. canadiensis G6 genotype in fertile hydatid cysts from goats and alpacas suggesting that both species could act as natural reservoirs. We previously determined that both species have a differential genomic structure and antigen expression profile (Rosenzvit et al., 2001; Kamenetzky et al., 2005, Muzulin et al., 2008). In order to get further insight into the molecular mechanisms that differentiate the infection of both Echinococcus species we studied protoscoleces behaviour in murine hosts. Our results suggest that, unlike E. granulosus s. s. (G1 genotype), E. canadiensis (G7 genotype) is unable to establish a regular infection in this experimental model (figure). The differences in secondary hydatid cyst development in murine hosts do not necessarily indicate similar differences in natural intermediate hosts (or man), but we regard the comparison of E. granulosus s.s  and E. canadiensis development in mice as a good approach to study which factors from the host, the parasite or both, generate the right scenario for a successful establishment. These ?ndings may have important consequences for human health and the control of hydatid disease