Proposed taxonomic revision of Giardia duodenalis

Caroline Wielinga; Andrew Williams; Paul Monis; R C Andrew Thompson

doi:10.1016/j.meegid.2023.105430

Proposed taxonomic revision of Giardia duodenalis

Infect Genet Evol. 2023 Jul:111:105430. doi: 10.1016/j.meegid.2023.105430. Epub 2023 Mar 25.

Authors

Caroline Wielinga¹, Andrew Williams², Paul Monis³, R C Andrew Thompson⁴

Affiliations

¹ School of Veterinary and Health Sciences, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia. Electronic address: caroline.m.wielinga@gmail.com.
² School of Veterinary and Health Sciences, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia. Electronic address: Andrew.williams@murdoch.edu.au.
³ South Australian Water Corporation, Adelaide, South Australia 5000, Australia. Electronic address: Paul.Monis@sawater.com.au.
⁴ School of Veterinary and Health Sciences, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia. Electronic address: A.Thompson@murdoch.edu.au.

PMID: 36972861
DOI: 10.1016/j.meegid.2023.105430

Abstract

Giardia duodenalis, Giardia enterica, Giardia intestinalis and Giardia lamblia are the synonyms for a species complex of 8-11 phylogenetically distinct species of Giardia infecting a broad range of animals including humans. Retrospective alignment of 8409 gene sequences from 3 loci confirmed host associations of Assemblages and sub-Assemblages within this species complex and molecular species delimitation testing confirmed that the Assemblages and sub-Assemblages AI and AII should be recognised as distinct species. It is recommended to synonymise the Assemblages with historic species descriptions based on host associations and consider descriptions for new species where no corresponding description exists. Synonyms, Giardia duodenalis, Giardia intestinalis and Giardia enterica, to be removed from synonymy: synonymise "Giardia duodenalis-Assemblage AI" syn. n. to Giardia duodenalis (Davaine, 1875), Kofoid and Christansen, 1915, synonymise "Giardia duodenalis-Assemblage AII" syn. n. to Giardia intestinalis (Lambl, 1859; Blanchard, 1885), Alexeieff, 1914 and synonymise "Giardia duodenalis-Assemblage B" syn. n. to Giardia enterica (Grassi, 1881), Kofoid, 1920. Host specific Assemblages synonymised: synonymise canid-associated "Giardia duodenalis-Assemblage C" syn. n. to Giardia canisHegner, 1922; synonymise artiodactyl-associated "Giardia duodenalis-Assemblage E" syn. n. to Giardia bovisFantham, 1921; synonymise feline-associated "Giardia duodenalis-Assemblage F" syn. n. to Giardia catiDeschiens, 1925; and synonymise rodent-associated "Giardia duodenalis-Assemblage G" syn. n. to Giardia simoniLavier, 1924. New description for parasite type infecting specific host: canid-associated "Giardia duodenalis-Assemblage D" named Giardia lupus, sp. n. (LSID: urn:lsid:zoobank.org:act:1651A8CB-CBA8-40D9-AB59-D4AB11AC18A3). New proposed names and descriptions for consideration for parasite types infecting specific hosts: cervid-associated "Giardia duodenalis-sub-Assemblage AIII" for consideration "cervus" and Pinnipedia-associated "Giardia duodenalis-Assemblage H" for consideration "pinnipedis".

Keywords: Giardia; Host associations; Molecular species testing; Phylogeny; Taxonomy.

MeSH terms

Animals
Cats
Deer*
Feces / parasitology
Gastropoda*
Genotype
Giardia lamblia* / genetics
Giardiasis* / parasitology
Humans
Retrospective Studies