engleski

Insights into the molecular detection of Giardia duodenalis: implications for epidemiology

Giardia duodenalis is a widespread parasite of mammalian species, including humans. Due to its invariant morphology, investigation on aspects such as host specificity and transmission patterns requires a direct genetic characterization of cysts/trophozoites from host samples. A number of molecular assays have been developed to target fragments of the small subunit ribosomal RNA, the  -giardin, the glutamate dehydrogenase, the elongation factor 1-alpha, and the triose phosphate isomerase genes. Recently, molecular epidemiologic approaches have been complicated by the recognition of intra-isolate sequence heterogeneity (i.e., “ mixed templates” ) that affects subtype identification, and of “ assemblage swapping” , that affects assignment of isolates to specific G. duodenalis assemblages. This raises doubts on the way genotyping data have been interpreted so far, and indicates the need to understand the mechanisms that are responsible for these unexpected findings. Here, we critically review those different mechanisms, and discuss some possible experimental strategies that can be used in future studies.

Giardia duodenalis, molecular typing, epidemiology

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