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Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats

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This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

A multi-modal approach to enhance Toxoplasma gondii detection in the Australian landscape

Amanda Breidahl 0000-0002-5947-3393, Michael Lynch, Duncan Sutherland, Rebecca Traub, Jasmin Hufschmid

Abstract

Context: The disease toxoplasmosis, caused by infection with the intra-cellular protozoan parasite Toxoplasma gondii, is a potential threat to the conservation of some endothermic vertebrates. Toxoplasmosis has been reported to cause disease and acute death in many marsupials, including endangered bandicoots. Methods are required to quantify the environmental contamination with T. gondii and hence assess the relative threat it poses to resident species. A multi-modal approach to assess an environment for the presence of pathogens increases the likelihood of a more accurate estimate of the level of contamination and inferred risk of infection to target species. Aim: This project aimed to use a multi-modal approach to estimate the environmental contamination with T. gondii across two separate landscapes with differing cat populations in the northern hinterland of Western Port, Victoria, Australia. Methods: Four parameters were used: the presence of IgG antibodies to T. gondii in free-ranging southern brown bandicoots (Isoodon obesulus) using the modified agglutination test (MAT); the presence of T. gondii DNA in the tissues of free-ranging rabbits (Oryctolagus cuniculus) and mice (Mus musculus) by real-time PCR; and the presence of T. gondii oocysts in the soil using filtration methods and real-time PCR. Key results: Toxoplasma gondii was not identified in any of the soil samples (n=594), southern brown bandicoots (n=24) or mice (n=267). Only one rabbit tested positive for T. gondii (n=118). Conclusions: The tests across soils and three different mammalian species all delivered similar results, leading to the conclusion that the landscapes measured had relatively low T. gondii contamination at the time of assessment. Implications: This Australian study is the first to show that the use of pathogen detection in target and two sentinel species, combined with soil analysis, may be a useful approach to assess the environmental risk of T. gondii infection in endangered and vulnerable species. Further research is recommended across sites with a gradient of T. gondii contamination and into the use of other sentinel species. Further refining of techniques for direct soil analysis in Australian conditions is recommended.

WR23091  Accepted 21 January 2025

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