Novel lineages of Giardia intestinalis identified by genetic analysis of organisms isolated from dogs in Australia.

Simple item page
dc.contributor.authorMonis, P.
dc.contributor.authorAndrews, R.
dc.contributor.authorMayrhofer, G.
dc.contributor.authorMackrill, J.
dc.contributor.authorKulda, J.
dc.contributor.authorIsaac-Renton, J.
dc.contributor.authorEy, P.
dc.date.issued1998
dc.descriptionCopyright © 1998 Cambridge University Press Research Article
dc.description.abstractInfection of suckling mice with Giardia trophozoites recovered from the intestines of 11 dogs autopsied in Central and Southern Australia in each case produced an established isolate. In contrast, only 1 isolate was obtained by inoculation of faecal cysts. The organisms grew poorly in comparison with isolates from humans or non-canine animal hosts. Light microscopy revealed that the trophozoites had median bodies with the `claw hammer' appearance typical of G. intestinalis (syn. G. duodenalis, G. lamblia) but that they differed in shape and nuclear morphology from axenic isolates of human or canine origin. Allozymic analysis of electrophoretic data representing 26 loci and phylogenetic analysis of nucleotide sequences obtained from DNA ampli®ed from the glutamate dehydrogenase locus showed that the 11 isolates examined from Australian dogs were genetically distinct from all isolates of G. intestinalis that have been established previously from humans and animals, and also from G. muris. Both analytical methods placed 10 of the Australian canine isolates into a unique genetic lineage (designated Assemblage C) and the eleventh into a deep-rooted second branch (designated Assemblage D), each well separated from the 2 lineages (Assemblages A and B) of G. intestinalis that encompass all the genotypes known to infect humans. In contrast, 4 axenic isolates derived from dogs in Canada and Europe (the only other isolates to have been established from dogs) have genotypes characteristic of genetic Assemblages A or B. The ®ndings indicate that the novel Giardia identi®ed in these rural Australian dogs have a restricted host range, possibly con®ned to canine species. The poor success rate in establishing Giardia from dogs in vitro suggests, further, that similar genotypes may predominate as canine parasites world-wide. The absence of such organisms among isolates of Giardia that have been established from humans by propagation in suckling mice indicates that they are unlikely to infect humans. However, infection of humans by those dog-derived genotypes that grow in vitro cannot be excluded.
dc.description.statementofresponsibilityP. T. Monis, R. H. Andrews, G. Mayrhofer, J. Mackrill, J. Kulda, J. L. Isaac-Renton and P. L. Ey
dc.identifier.citationParasitology, 1998; 116(1):7-19
dc.identifier.doi10.1017/S0031182097002011
dc.identifier.issn0031-1820
dc.identifier.issn1469-8161
dc.identifier.urihttp://hdl.handle.net/2440/11673
dc.language.isoen
dc.publisherCambridge University Press (CUP)
dc.source.urihttps://doi.org/10.1017/s0031182097002011
dc.subjectDogs
dc.subjectGiardia
dc.subjectprotozoa
dc.subjectnucleotide sequences
dc.subjectphylogenetics
dc.subjectsystematics
dc.titleNovel lineages of Giardia intestinalis identified by genetic analysis of organisms isolated from dogs in Australia.
dc.typeJournal article
pubs.publication-statusPublished

Files

Collections

Microbiology and Immunology publications