A new study has used computer modeling to provide one of the clearest pictures yet of the devastating smallpox epidemic that struck Indigenous Australians soon after the arrival of the First Fleet in 1788.
The research suggests that the disease likely began in the Sydney area and may have killed between 40,000 and 220,000 Aboriginal people across southeastern Australia.
The study, published in Nature Human Behaviour, was led by researchers from Flinders University and the ARC Centre of Excellence for Indigenous and Environmental Histories and Futures, working closely with the Gujaga Foundation of the Dharawal Nation.
The research combines historical records with computer models to better understand how the deadly disease spread and how it changed the lives of First Nations communities.
Smallpox is a highly contagious viral disease that causes fever, severe illness, painful skin sores, permanent scarring, and often death. Before vaccines became available, it was one of the world’s deadliest diseases.
Indigenous Australians had no previous exposure to smallpox, leaving them especially vulnerable when it first appeared after European settlement.
For many years, historians have debated where the 1789 outbreak came from. Some argued it arrived with the British First Fleet, while others suggested it was brought by Makassan sailors from Southeast Asia who visited northern Australia before British settlement.
To answer this question, the researchers built detailed computer models that recreated how people traveled across Australia at the time. They considered walking routes, rivers, coastlines, trade networks, and the amount of time infected people could realistically travel before becoming too sick.
The models showed that if smallpox had entered through northern Australia, it was extremely unlikely to have reached Sydney in the time recorded by historical accounts.
Instead, the findings strongly support the idea that the epidemic began in Sydney after the arrival of the First Fleet. According to the researchers, the disease then spread rapidly through Aboriginal communities along the southeastern coastline and major river systems such as the Murray and Lachlan rivers. However, the study also found that the first epidemic probably did not spread across the entire Australian continent.
Based on their modeling, the researchers estimate that if about 60% of infected people died—a death rate consistent with populations that had never encountered smallpox before—the epidemic may have claimed between 40,000 and 220,000 lives in southeastern Australia alone.
The researchers say the effects went far beyond the tragic loss of life. Entire families were devastated, and many Elders, who carried important cultural knowledge, language, and traditions, died during the outbreak. Children and pregnant women were also especially vulnerable. As communities struggled to recover, many survivors were left too sick or weakened to care for their lands, pass on traditional knowledge, or resist the growing pressures of colonization.
Even so, the study also highlights the resilience of Aboriginal communities. Historical observations from the First Fleet recorded Aboriginal people returning to Sydney Harbour only weeks after the outbreak, continuing to fish, hunt, live on Country, and maintain their cultural traditions. Despite enormous disruption, communities regrouped and continued practicing their language, culture, and knowledge for generations.
Researchers from the Dharawal Nation emphasize that this history is still remembered within their communities. While many people believe the epidemic completely wiped out Sydney’s Aboriginal population, descendants survived and maintained their connection to Country despite later forced removals and other hardships.
The researchers stress that their computer modeling is intended to work alongside Aboriginal knowledge and oral history, not replace it. They also note that while the study clarifies the likely origin and spread of the first smallpox epidemic, more research is needed to understand the impact of later disease outbreaks and frontier violence on Indigenous communities across Australia.
The authors hope the findings will encourage a deeper understanding of one of the most devastating events in Australia’s history. They believe acknowledging this shared past is an important step toward healing and recognizing the lasting strength and survival of First Nations peoples despite the enormous challenges they faced.
