Giardia duodenalis assemblage A: new genotype in non-human primates from the Brazilian Amazon region revealed by High-Resolution MLST

Abstract

BACKGROUND Giardia duodenalis is an intestinal protozoan parasite that infects a wide range of vertebrate hosts, including humans, and is the etiological agent of giardiasis. Within this species, assemblage A is further subdivided into three sub-assemblages: AI, AII, and AIII. OBJECTIVES To apply the high-resolution multilocus sequence typing (MLST) to perform molecular epidemiology of Giardia duodenalis assemblage A in humans and animals in the state of Amazonas, Brazil. METHODS We performed parasitological analyses of fecal samples from animals and collected Giardia-positive samples from humans in the state of Amazonas, Brazil. Giardia genotyping was carried out using an MLST scheme based on six genes (CID1, NEK15411, DIS3, HCMP22547, HCMP6372, RHP26), as well as the three conventional loci (tpi, bg and gdh), followed by phylogenetic analysis. FINDINGS Using an extended MLST scheme for assemblage A, we identified a new geno-type infecting two non-human primate species from the Amazon region. Additionally, Giardia from sub-assemblage AII infecting humans in this region shows a close phylogenetic relationship with isolates from other countries. Furthermore, a sub-assemblage AI isolate from an anteater (Tamandua tetradactyla) belongs to a lineage infecting diverse animals and humans, highlighting its zoonotic and cosmopolitan nature.