Australian smallpox epidemic out of Africa
The arrival of smallpox in Australia, which devastated the Aboriginal populations of Sydney, could have been the result of a stopover by the First Fleet, says an Australian historian.
He says there are several theories as to how the disease arrived on Australian shores.
"The traditional assumption was that it must have arrived somehow from European contact," says Bennett.
But he says in the 20th century historians hypothesised that smallpox may have crossed the country, having arrived from Macassan fisherman who frequented northwest Australia.
"This theory has become the dominant theory of how smallpox may have arrived over the last 20 years."
But Bennett says it's difficult to find evidence to support it.
"Although we know the Aboriginal people across the country were connected, we have no evidence smallpox could have been transmitted."
Bennett says that the disease would have difficulty surviving in Australia's climate.
He says his theory, that smallpox was brought from Cape Town or Rio de Janeiro is supported by published works of British Marine Watkin Tench who wrote in the 1790's, that the surgeons had variolous matter on board the First Fleet.
"They would have brought it to inoculate children or to use if smallpox threatened, but the assumption shouldn't be that the virus was brought all the way from Britain," he says.
If surgeons did bring variolous matter, Bennett says it's more likely they picked it up on route in Rio de Janeiro or Cape Town because it could survive the shorter distance to Australia.
Bennett says that after arriving in Australia, the surgeons may have concluded they had no use for the vaccine.
"There's a strong possibility they would have been discarded," he says. "So in theory it's possible Aborigines could have been in contact with it."
Once the disease spread, close to half of the local Aboriginal population died. Those that survived fled taking the disease inland, says Bennet.
He says smallpox killed so many Aborigines that the balance of power was tipped heavily in favour of European settlers.
In 1804, cowpox, a mild disease present in cows, was brought to Australia and used as a vaccine against smallpox.
"We know several thousand people were vaccinated in Sydney and that would have probably included some Aborigines. It doesn't seem many Aborigines outside the settlements were ever vaccinated."