Giardiasis in urban and rural Amazonas, Brazil is driven by zoonotic and cosmopolitan A and B assemblages

BACKGROUND: Giardia duodenalis is a protozoan parasite that infects humans and other mammals and causes giardiasis worldwide. Giardia is genotyped into eight assemblages (A-H), with assemblages A and B considered zoonotic. OBJECTIVES: The aim of this study was to determine the assemblages of G. duodenalis from individuals living in rural and urban areas of the Amazonas State. METHODS: 103 human faecal specimens microscopically positive for the presence of Giardia obtained from four municipalities in Amazonas and four animal faecal specimens were genotyped based on the sequences of two genes, triosephosphate isomerase (TPI) and β-giardin (BG). FINDINGS: In humans, assemblage A was the most represented with the identification of sub-assemblages AI, AII and AIII based on BG and sub-assemblages AI and AII based on TPI. Similarly, there is a diversity of sub-assemblage B considering BG (B and BIII) and TPI (B, BIII and BIV). In addition, we characterised homogeneous and heterogeneous genotypes comprising assemblages/sub-assemblages A and B in individuals from urban and rural areas. Here, for the first time, it was genotyped Giardia that infects animals from the Brazilian Amazon region. We identified sub-assemblage AI in one Ateles paniscus and two Felis catus and sub-assemblage BIV in one Lagothrix cana. MAIN CONCLUSIONS: Therefore, humans and animals from the urban and rural Amazon share Giardia genotypes belonging to assemblages A and B, which are found in cosmopolitan regions around the world.