Studies in Giardia isolates have allowed to characterize the genetic diversity of the parasite, based on molecular markers such as the small subunit rRNA, glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi) and β-giardin (Ryan and Caccio, 2013), allowing to identify eight assemblages where A and B are related to infections in humans and animals and further subdivided into sub-assemblages: AI, AII, BIII, and BIV with no strict associations based on clinical presentation (Mayrhofer et al., 1995; Thompson, 2000). This evidence concerns the gene TPI1 and infection.