Multilocus Genotyping of Human Giardia Isolates Suggests Limited Zoonotic Transmission and Association between Assemblage B and Flatulence in Children

Giardia intestinalis is a protozoan parasite found world-wide and it is a major cause of diarrhea in humans and other mammals. The genetic variability within G. intestinalis is high with eight distinct genotypes or assemblages (A-H). Here we performed sequence-based multilocus genotyping of around 200 human Giardia isolates. We found evidence of limited zoonotic transmission of certain A subtypes and an association between flatulence and assemblage B infection in children. This shows that it is important to investigate different assemblages and sub-assemblages of G. intestinalis in human infections in order to understand the clinical significance, zoonotic potential, sequence divergence, and transmission pathways of this parasite