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Updated: Mar 27, 2026
A Multi-detection Assay for Malaria Transmitting Mosquitoes
Published on: February 28, 2015
Giardia duodenalis assemblage A: new genotype in non-human primates from the Brazilian Amazon region revealed by
Lisiane Lappe Dos Reis1,2,3, Lirna Salvioni Silva de Souza1, Maria Gabriela Rodrigues Antunes1
1Fundação Oswaldo Cruz-Fiocruz, Instituto Leônidas & Maria Deane, Laboratório de Diversidade Microbiana da Amazônia de Importância para a Saúde, Manaus, AM, Brasil.
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 G. duodenalis assemblage A in humans and animals in the State of Amazonas, Brazil.
Methods:
We performed parasitological analyses of faecal 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 genotype infecting two non-human primate (NHP) 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.
Main Conclusions:
These findings reveal a new, genetically distinct lineage within G. duodenalis assemblage A, likely representing a new sub-assemblage (AIV) associated with NHPs in the Amazon region, and reinforce the usefulness of high-resolution MLST for detecting fine-scale genetic diversity and potential zoonotic transmission pathways.
