Giardia in Western Australian wildlife.

Giardia has been found in numerous species of mammalian wildlife but very little information is available on the species and strains/genotypes that occur naturally in mammals in the wild. Recently, a novel genotype of Giardia was described in Western Australia, in the Southern brown bandicoot, or quenda (Isoodon obesulus). In order to determine the host range, distribution and prevalence of this novel 'quenda' 'genotype of Giardia, a comprehensive survey of this marsupial and cohabiting mammalian species was undertaken throughout the mainland and some off-shore islands of Western Australia, including urban areas. The overall prevalence of Giardia in 351 wildlife samples was low, with only 4.8% (17) samples testing positive. Amongst the 51 quenda samples, 11.8% (6) were positive for the 'quenda' genotype, 5.9% (3) for assemblage C/D and 2% (1) for assemblages A and E. This study has demonstrated that Giardia is a remarkably rare parasite in native wildlife in Western Australia, raising questions about the ecology of Giardia infections in wildlife.