Identification of Giardia species and Giardia duodenalis assemblages by sequence analysis of the 5.8S rDNA gene and internal transcribed spacers

PCR assays have been developed mainly to assist investigations into the epidemiology of Giardia duodenal's, the only species in the Giardia genus having zoonotic potential However, a reliable identification of all species is of practical importance, particularly when water samples and samples from wild animals are investigated The rum of the present work yeas to genotype Giardia species and G duodenalils assemblages using as a target the region spanning the 5 8S gene and the 2 flanking internal transcribed spacers (ITS1 and ITS2) of the ribosomal gene Primers were designed to match strongly conserved legions in the 3' end of the small subunit and in the 5' end of the large subunit ribosomal genes The corresponding region (about 310 bp) was amplified from 49 iso kites of both human and animal origin, representing all (3 duodenalis assemblages as well as G muris and G microti Sequence comparison and phylogenetic analysis showed that C ardeae, C muris, G mucroti as well as the 7 G duodenalis assemblages can be easily distinguished Since the major subgroups within the zoonotic assemblages A and B can be identified by sequence analysis, this assay is also informative for molecular epidemiological studies.