Stochastic models indicate rapid smallpox spread and mass mortality of Indigenous Australians after colonial exposure

Stochastic models indicate rapid smallpox spread and mass mortality of Indigenous Australians after colonial exposure | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Stochastic models indicate rapid smallpox spread and mass mortality of Indigenous Australians after colonial exposure Matthew Nitschke, Alan Williams, Shane Ingrey, Billy Griffiths, and 11 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5683492/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract The impact of smallpox (variola) on Aboriginal communities in Australia beginning in 1789 was catastrophic and continues to cause intergenerational trauma. Historically biased perspectives and contemporary misinformation of the disease’s introduction and spread impede modern-day truth-telling and subsequent reconciliation and national healing. Understanding whether the disease entered and spread from pre-colonial Makassan (Indonesian) trade along the northern coast, or from the First Fleet’s arrival in south-eastern Australia in 1788, is necessary to estimate demographic impact. We developed stochastic, multi-patch epidemiological models supported by systematic evaluation of historical observations to test hypotheses regarding possible disease entry points, spread rate, and demographic impacts. Our models suggest that entry of the disease was in south-eastern Australia. No successful simulations reached Sydney from a northern entry, even under ideal conditions and with higher-than-probable infection rates. Our model predicts time from initial entry of the disease to its extinction took between 1,200 and 1,400 days (< 4 years). Due to a high mortality rate, it appears to have been limited to the south-eastern coastal margins of Australia and along major intersecting river systems such as the Murray and Lachlan Rivers. There is no evidence that the 1789 epidemic was Australia-wide. Assuming a 60% lethality based on global data, the loss of 40,000–240,000 people would have occurred in these regions in < 4 years. While catastrophic to traditional Indigenous lifeways in the southeast, the disease also provided the catalyst for population decline and marginalisation of Indigenous people in the face of expanding European populations. It seems unlikely that other parts of Australia were affected by the initial epidemic, and we recommend revisiting previous assumptions of the subsequent impacts to Indigenous societies by other diseases and frontier violence. While there is evidence for the presence of variola matter in early colonial Sydney, we cannot yet confirm that the disease was spread deliberately. We warn readers that the content of this study is confronting and possibly distressing. Humanities/History Health sciences/Diseases/Infectious diseases Social science/Anthropology/Biological anthropology Biological sciences/Systems biology/Numerical simulations Biological sciences/Systems biology/Stochastic modelling epidemics smallpox multi-patch model demographic collapse First Fleet Full Text Additional Declarations There is NO Competing Interest. Supplementary Files NitschkeetalSupplement.pdf Stochastic models indicate rapid smallpox spread and mass mortality of Indigenous Australians after colonial exposure--Supplementary Material Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5683492","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":403148982,"identity":"f94f8a7b-0fd1-4d0c-bb29-fb4312572f18","order_by":0,"name":"Matthew 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