{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,20]],"date-time":"2026-03-20T14:02:25Z","timestamp":1774015345421,"version":"3.50.1"},"reference-count":36,"publisher":"FapUNIFESP (SciELO)","license":[{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"am","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004916","name":"FAPEAM","doi-asserted-by":"crossref","award":["002\/2021"],"award-info":[{"award-number":["002\/2021"]}],"id":[{"id":"10.13039\/501100004916","id-type":"DOI","asserted-by":"crossref"}]},{"name":"PROEP-LABS\/ILMD Fiocruz Amaz\u00f4nia","award":["002\/2021"],"award-info":[{"award-number":["002\/2021"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Mem. Inst. Oswaldo Cruz"],"abstract":"<jats:p>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.<\/jats:p>","DOI":"10.1590\/0074-02760250234","type":"journal-article","created":{"date-parts":[[2026,3,20]],"date-time":"2026-03-20T11:50:20Z","timestamp":1774007420000},"source":"Crossref","is-referenced-by-count":0,"title":["Giardia duodenalis assemblage A: new genotype in non-human primates from the Brazilian Amazon region revealed by high-resolution MLST"],"prefix":"10.1590","volume":"121","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7968-3718","authenticated-orcid":false,"given":"Lisiane Lappe","family":"dos Reis","sequence":"first","affiliation":[{"name":"Funda\u00e7\u00e3o Oswaldo Cruz-Fiocruz,  Brasil; Funda\u00e7\u00e3o Oswaldo Cruz-Fiocruz,  Brasil; Funda\u00e7\u00e3o Oswaldo Cruz-Fiocruz,  Brasil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lirna Salvioni Silva","family":"de Souza","sequence":"additional","affiliation":[{"name":"Funda\u00e7\u00e3o Oswaldo Cruz-Fiocruz,  Brasil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maria Gabriela Rodrigues","family":"Antunes","sequence":"additional","affiliation":[{"name":"Funda\u00e7\u00e3o Oswaldo Cruz-Fiocruz,  Brasil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alessandra Ferreira Dales","family":"Nava","sequence":"additional","affiliation":[{"name":"Funda\u00e7\u00e3o Oswaldo Cruz-Fiocruz,  Brasil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ana Carolina Paulo","family":"Vicente","sequence":"additional","affiliation":[{"name":"Funda\u00e7\u00e3o Oswaldo Cruz-Fiocruz,  Brasil"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"530","published-online":{"date-parts":[[2026]]},"reference":[{"key":"ref1","doi-asserted-by":"crossref","first-page":"335","DOI":"10.1016\/j.meegid.2017.12.001","article-title":"Host specificity in the Giardia duodenalis species complex","volume":"66","author":"Cacci\u00f2 SM","year":"2018","journal-title":"Infect Genet Evol"},{"issue":"13","key":"ref2","doi-asserted-by":"crossref","first-page":"1356","DOI":"10.1001\/jama.2020.10289","article-title":"Giardiasis","volume":"325","author":"Desai AN","year":"2021","journal-title":"JAMA"},{"issue":"12","key":"ref3","doi-asserted-by":"crossref","first-page":"2498","DOI":"10.1093\/gbe\/evt197","article-title":"Genome sequencing of Giardia lamblia genotypes A2 and B isolates (DH and GS) and comparative analysis with the genomes of genotypes A1 and E (WB and pig)","volume":"5","author":"Adam RD","year":"2013","journal-title":"Genome Biol 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