Smallpox in Australia

Smallpox was a variable yet often fatal viral infectious disease. Even with good nursing, it regularly killed around 30% of recognised cases. Though widespread in Europe and Asia, it was probably unknown in southern Australia when the first British colony began in 1788.

It never became widely established among the colonists, killing only about 100 of them over the next 100 years, and mostly in port-city outbreaks that were traced to visiting ships. Yet a smallpox outbreak in 1789 devastated the Aboriginal people near the Sydney colony, killing perhaps half of them, while sparing the British.

This imbalance leads some medical experts to argue that the main agent of death during major outbreaks of "smallpox" in 1789 and in 1829–1831 was in fact chickenpox. This is a disease to which the British were largely immune but which, in a virgin soil epidemic, can produce symptoms very similar to smallpox. Doctors began to distinguish smallpox more clearly from chickenpox in the early to mid-nineteenth century; and during the 1829–1831 outbreak there was vigorous debate among the colony’s surgeons as to which disease it was, with the chief surgeon favouring chickenpox.

However, most historians have called the 1789 and 1829–1831 diseases smallpox. Smallpox is commonly described as the main or one of the main diseases that reduced the Aboriginal peoples and left them unable to resist European settlement. Debate among modern medical and historical experts as to the identity of the deadly 1789 disease, how it reached Australia, and why it did not infect any of the British (though it killed two non-Europeans who were living inside the British colony) is ongoing.

European colonisation of Australia was accompanied by epidemic diseases to which the original inhabitants had little resistance. Colds, influenzas, tuberculosis (TB), and measles were major killers. Such diseases devastated Aboriginal populations, weakened their cultures, and often left them in no position to resist the newcomers. Within perhaps as little as six months of the arrival of the First Fleet, venereal disease was already a serious problem for local Aboriginal peoples; but the first disease to produce a major fall in the Aboriginal population around Sydney was the 1789 outbreak, some 16 months after the Fleet arrived, of what Governor Phillip and others referred to as "smallpox". Watkin Tench, a captain in the Marines, wrote that,

pustules, similar to those occasioned in the smallpox, were thickly spread on the bodies; but how a disease to which our former observations had led us to suppose them strangers could at once have introduced itself, and spread so widely, seemed inexplicable.

A full list of smallpox outbreaks in Australia falls into two main groups. Firstly, there were three widely-spaced "Aboriginal" epidemics which devastated Aboriginal populations but largely spared the colonists. Two of these outbreaks were recorded in New South Wales: in 1789 and in 1830. Later there was a long-running outbreak in the 1860s, which spread through much of Northern and Western Australia and down to the Great Australian Bight in the south. In the second group, there were six major ship-borne outbreaks in the nineteenth century, in 1857, 1868–1869, 1871, 1881–1882, 1884–1886, 1887 and 1893. These were successfully confined to port cities, and predominantly affected European colonists. Thereafter, further brushes with imported smallpox were relatively minor.

Although the electron microscope, which is capable of seeing and distinguishing viruses, did not begin to become available to doctors until the 1940s, there is little doubt that at least the second group of outbreaks were true smallpox. They had its typical death-rate of around one death per four recorded infections, and its relatively slow infection rate. They did not selectively kill Aboriginal persons, and there was no mystery as to their origin. In total this second group killed about one hundred people.