A spatial analysis of risk factors for sarcocystosis in South Australian sheep flocks, 2007-2017

Abstract

Event Abstract Back to Event A spatial analysis of risk factors for sarcocystosis in South Australian sheep flocks, 2007-2017 Patrick L. Taggart1, Mark Stevenson2*, Simon Firestone2, Milton McAllister1 and Charle Caraguel1 1 School of Animal and Veterinary Sciences, Faculty of Sciences, University of Adelaide, Australia 2 Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Australia Cat-borne parasites and their associated diseases have substantial impacts on human, livestock, and wildlife health worldwide. Despite this, large and detailed data sets that allow researchers to study broad-scale trends in the ecology of cat-borne diseases are either difficult to obtain or non-existent. In sheep (Ovis aries), one cat-borne parasite that is easily detected at slaughter is macroscopic sarcocystosis. This was an analysis of factors influencing the geographic distribution of sarcocystosis among sheep farms in South Australia. Data were obtained from two slaughterhouses which processed 3,865,608 sheep from 4,204 farms across 385,468 km2 of South Australia’s land mass for the period 2007 to 2017. A Poisson point process model was developed to quantify environmental characteristics associated with higher densities of sarcocystosis-positive farms. Sarcocystosis-positive farms were concentrated on Kangaroo Island (located a short distance from the South Australian mainland) and the density of sarcocystosis-positive farms increased in areas with acid soils and soils with relatively high clay content. Unit increases in soil pH decreased the intensity of sarcocystosis-positive farms by a factor of 0.86 (95% CI 0.78 to 0.95). Where soil clay content was ≥16.5% sarcocystosis-positive farm density was increased by a factor of 1.45 (95% CI 1.10 to 1.92) compared with farms in areas where soil clay content was <14.5%. The density of sarcocystosis-positive farms on Kangaroo Island was 15.2 (95% CI 8.04 to 28.9) times greater than the density of sarcocystosis-positive farms located in the Adelaide Hills/Fleurieu Peninsula. Our analyses show a marked heterogeneous distribution of macroscopic ovine sarcocystosis across South Australia with a clear hotspot on Kangaroo Island. Since the density of feral cats on Kangaroo Island is relatively high we hypothesize that region in this analysis was confounded by, and acted as a proxy for, cat density. Whilst management of soil pH and/or soil clay content provide some opportunity to reduce the risk of sarcocystosis in South Australian sheep, we propose that control of feral cat populations is the most feasible and sustainable approach to sarcocystosis control. Acknowledgements Primary Industries and Regions, South Australia Biosecurity, Elise Matthews, Celia Dickason, Adrian Baddeley, Rolf Turner, and Tilman Davies. References Taggart, P., Stevenson, M., Firestone, S., McAllister, M., Caraguel, C., 2019. Spatial analysis of a cat-borne disease reveals that soil ph and clay content are risk factors for sarcocystosis in sheep. Frontiers in Veterinary Science. DOI: 10.3389/fvets.2019.00127. Keywords: Poisson point process modelling, Feral cats, surveillance, Spatial Epidemiology, Sarcocystosis Conference: GeoVet 2019. Novel spatio-temporal approaches in the era of Big Data, Davis, United States, 8 Oct - 10 Oct, 2019. Presentation Type: Regular oral presentation Topic: Spatial methods for environmental & exposure epidemiology and climate change Citation: Taggart PL, Stevenson M, Firestone S, McAllister M and Caraguel C (2019). A spatial analysis of risk factors for sarcocystosis in South Australian sheep flocks, 2007-2017. Front. Vet. Sci. Conference Abstract: GeoVet 2019. Novel spatio-temporal approaches in the era of Big Data. doi: 10.3389/conf.fvets.2019.05.00060 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 01 Jun 2019; Published Online: 27 Sep 2019. * Correspondence: Prof. Mark Stevenson, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, VIC 3010, Australia, mark.stevenson1@unimelb.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Patrick L Taggart Mark Stevenson Simon Firestone Milton McAllister Charle Caraguel Google Patrick L Taggart Mark Stevenson Simon Firestone Milton McAllister Charle Caraguel Google Scholar Patrick L Taggart Mark Stevenson Simon Firestone Milton McAllister Charle Caraguel PubMed Patrick L Taggart Mark Stevenson Simon Firestone Milton McAllister Charle Caraguel Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.