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The prevalence of Cryptosporidium and Giardia in Western Australian freshwater and marine fish species, and Australian cultured fingerlings

Reid, Anna (2008) The prevalence of Cryptosporidium and Giardia in Western Australian freshwater and marine fish species, and Australian cultured fingerlings. Honours thesis, Murdoch University.

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Abstract

This study aimed to examine the prevalence of protozoan parasites, Giardia and Cryptosporidium in fish hosts. Three different subgroups of fish: cultured species, wild freshwater species and wild marine/estuarine species were all screened for Cryptosporidium and Giardia by PCR amplification at the small subunit (SSU) rRNA locus. With all positives sequenced at second locus, actin for Cryptosporidium and gdh for Giardia.

Two hundred and twenty seven fingerlings (juvenile fishes) were collected from commercial aquaculture hatcheries within Australia, with 8 different fish species represented. From the Canning/Swan River and Blackwood River systems in Western Australia sampling of freshwater fish produced 227 samples, again 8 different fish species were sampled. Five species of marine fish were obtained from commercial fishers, in total 255 fish were collected.

A low prevalence of both parasites was recorded in fish hosts, 0.8% (6/709) for Cryptosporidium and 3.8% (27/709) for Giardia. This study provides the first recording of Giardia species, G. duodenalis assemblage A, B and E, Giardia microti, C. parvum, C. bovis and the pig genotype II in piscine hosts and identify a genetically distinct genotype of Cryptosporidium in Mugil cephalus, which is distinct from all currently acknowledged species of Cryptosporidium. This study provides initial investigation into the prevalence and geographical distribution of these parasites within fish. The presence of zoonotic species of both parasites draws attention to the public health importance of investigating parasites within piscine host species.

Item Type: Thesis (Honours)
Murdoch Affiliation: School of Veterinary and Biomedical Sciences
Notes: Note to the author: If you would like to make your thesis openly available on Murdoch University Library's Research Repository, please contact: repository@murdoch.edu.au. Thank you.
Supervisor(s): Ryan, Una and Lymbery, Alan
URI: http://researchrepository.murdoch.edu.au/id/eprint/53068
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