Cyst morphology and sequence analysis of the small subunit rDNA and ef1α identifies a novel Giardia genotype in a quenda (Isoodon obesulus) from Western Australia

Abstract

Sequence analysis of the small subunit ribosomal DNA (SSU-rDNA) and elongation factor 1 alpha (ef1α) was performed on Giardia cysts isolated from faeces collected from a quenda (Isoodon obesulus) in the southwest of Western Australia. The SSU-rDNA and ef1α were sequenced in their entirety and correspondingly aligned with the published sequence information of other known species and genotypes of Giardia. Phylogenetic analysis of the SSU-rDNA and ef1α sequences identified the quenda isolate as a novel genotype of Giardia not previously reported. We believe that this quenda Giardia isolate constitutes a distinct species, which may be endemic within the Australian native fauna.

Zoonotic Potential and Molecular Epidemiology ofGiardiaSpecies and Giardiasis

“…One Giardia isolate from a southern brown bandicoot (Isoodon obesulus, commonly known as quenda) in Western Australia was reported to be a novel genotype based on a phylogenetic analysis of the SSU rRNA (GenBank accession number AY309064) and ef1␣ (accession number AY309065) gene sequences. Those authors believed that this isolate constituted a distinct species, because phylogenetic analysis shows it to be distinct from other recognized species such as G. microti, G. psittaci, G. ardeae, and G. muris (7). This new genotype was identified in another six quenda specimens in a recent study (262).…”

Giardia in Western Australian wildlife

“…In all cases the hosts of these species of Giardia are also 59 susceptible to zoonotic genotypes. More recently, a novel genotype of Giardia was 60 described in an Australian marsupial, a bandicoot known as the quenda (Isoodon 61 obesulus), and on the basis of genetic characteristics would appear to represent a distinct 62 species that may be endemic within Australian native fauna (Adams et al, 2004). 63…”

“…Genomic DNA was extracted using the 76 83 Presence of Giardia was tested both by the presence of cysts via microscopy following 84 zinc sulphate concentration and by amplification of the β-giardin and 18SrRNA genes, as 85 described below. 18S rRNA sequences were used to confirm the identity of the 'quenda' 86 genotype, by comparison with the sequence described by Adams et al (2004). 87…”

Molecular evidence for person-to-person transmission of a novel subtype in Giardia duodenalis assemblage B at the rehabilitation institution for developmentally disabled people

“…DNA was extracted and purified from the positive concentrates using the DNeasy Blood & Tissue Kit (QIAGEN GmbH, Hilden, Germany). The G. duodenalis isolates were genotyped and subtyped by multilocus homology searching and phylogenetic analyses of the following four loci: glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi), and β-giardin (bg) as variable loci, and elongation factor 1 alpha (ef1α) as a conserved locus (Homan et al 1998;Cacciò et al 2002;Sulaiman et al 2003;Adams et al 2004). The PCR products were purified using the QIAquick Gel Extraction or QIAquick PCR Purification Kit (QIAGEN GmbH, Hilden, Germany) and sequenced in both directions on an ABI 3130 automated sequencer (Applied Biosystems, Foster City, CA, USA).…”