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. 2016 Jan 27;9:29. doi: 10.1186/s13071-016-1311-1

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© Shuford et al. 2016

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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Fig. 3 — Number of publications by country. Unlabelled segments of the chart represent one study for the respective country. For publications involving multi-country studies, each country was counted towards the total