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Molecular typing of Giardia duodenalis in humans in Queensland – first report of Assemblage E

Zahedi, A.ORCID: 0000-0002-0165-3797, Field, D. and Ryan, U.ORCID: 0000-0003-2710-9324 (2017) Molecular typing of Giardia duodenalis in humans in Queensland – first report of Assemblage E. Parasitology, 144 (9). pp. 1154-1161.

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Little is known about the genetic diversity of the protozoan parasite, Giardia duodenalis, infecting humans in Queensland, Australia. The present study typed 88 microscopically Giardia-positive isolates using assemblage-specific primers at the triose phosphate isomerase (tpi) gene and sequenced a subset of isolates at the glutamate dehydrogenase (gdh) gene (n = 30) and tpi locus (n = 27). Using the tpi-assemblage specific primers, G. duodenalis assemblage A and assemblage B were detected in 50% (44/88) and 38·6% (34/88) of samples, respectively. Mixed infections with assemblages A and B were identified in 4·5% (4/88) and assemblage E was identified in 6·8% (6/88) of samples. Sequence analysis at the gdh and tpi loci also confirmed the presence of assemblage E in these isolates. Cyst numbers per gram of feces (g−1) were determined using quantitative polymerase chain reaction and of the isolates that were typed as assemblage E, cyst numbers ranged 13·8–68·3 × 106 cysts g−1. This is the first report of assemblage E in humans in Australia, indicating that in certain settings, this assemblage may be zoonotic

Item Type: Journal Article
Murdoch Affiliation: School of Veterinary and Life Sciences
Publisher: Cambridge University Press
Copyright: © Cambridge University Press 2017
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