Impact study: the spread of imported disease in Australia and New Zealand

Sophia (Year 13) looks at how European colonialism spread disease to Australia and New Zealand.

Although the tragedies brought by actions of colonisers such as slavery, wars and other abysmal treatment of native populations caused many deaths, one of the biggest killers of this action was the introduction of new diseases to which natives had no immunity due to their previous isolation from the European invaders.

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Between 1200 and 1500 Europe itself was suffering several pandemics due to the growth of unsanitary cities, creating the perfect environment for infection, and also increasing contact with the Old World, such as through Mongol and Turkish invasions, which exposed Europe to major disease outbreaks. For example, between 1346-51, the Black Death killed off about a third of Europe’s population. As relatively disease-hardened populations in Europe emerged from this, although local epidemics emerged after 1500, none were really as bad as the years before it, rather such epidemics after this date were in colonised nations. Here I will focus on the colonisation of Australia and New Zealand, with different native peoples (the Aborigines and the Maoris) and with different effects of diseases.

New Zealand

Imported diseases began to impact many Maori from the 1790s. These diseases were those such as viral dysentery, influenza, whooping cough, measles, typhoid, venereal diseases, and the various forms of tuberculosis. Missionaries and observers reported massive death rates and plummeting birth rates. However, unlike the Americas and Australia, there is a big chance that the deaths as a result of foreign disease are widely exaggerated.

Rather, such exaggeration labelled the Maori as a dying race (a view which persisted to 1930), which helped to project the British Empire into New Zealand in 1840. One of the reasons for which the effect of disease was probably the smallest was simply the distance from Europe to New Zealand; it was a natural quarantine. The trip took 4 months or more, meaning that the sick either died or recovered; either way they were often no longer infectious on arrival. Therefore, the most pernicious European diseases – malaria, bubonic plague, smallpox, yellow fever, typhus and cholera – did not manage to transfer to New Zealand.

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Another factor which fostered the gross magnification of the demise of the Maori was the comparison in birth rates; missionary families were extremely large – the fourteen couples who went to New Zealand before 1833 had 114 children. Therefore, it was easy to amplify the decline in Maori birth rates into something far more serious than it was. The population of Maori on contact with the Europeans are very unreliable and, in most cases, wild guesses, and also allow for the misjudgement of the effect of the disease. For example, one estimate for 1769 based upon archaeological science gives an estimated pre-contact birth rate of 37 per thousand per year, and a death rate of 39[1], obviously impossible given that it leaves the Maori population in the minus-thousands. However, more moderate calculations suggest an average decline of 0.3% per year between 1769 and 1858[2]. Therefore, although the Maori population somewhat suffered as a result of these diseases, there is a tendency to exaggerate this, to portray them as ‘weaker’ peoples, and a dying race, allowing for easier colonisation.


Although Australia was initially discovered by the Dutch, it was a fleet of British ships which arrived at Botany Bay in January 1788 to establish a penal colony[3].  European disease spread to areas of Australia, even before Europeans had reached those parts. For example, there was a smallpox epidemic near Sydney in 1789, wiping out around half of the Aborigines there.[4] 

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Some historians claim that this was acquired through contact with Indonesian fishermen in the far north, which then spread, and others argue that it is likely that the outbreak was a deliberate act by British marines when they ran out of ammunition and needed to expand their settlement. Indeed, unfortunately colonial thinking at the time placed Europeans as the ‘superior race’; a book written by William Westgarth in 1864 on the colony of Victoria included: ‘the case of the Aborigines of Victoria confirms…it would seem almost an immutable law of nature that such inferior dark races should disappear’. Therefore, as with New Zealand, description of the natives as a ‘dying race’ was an important tool for colonisation, meaning purposeful introduction and spread of some diseases is not too hard to believe.

Smallpox spread between Aboriginal communities, reappearing in 1829-30; according to one record killing 40-60% of the Aboriginal population.[5]  In addition, during the mid-late 19th century, many Aborigines in southern Australia were forced to move to reserves; the nature of many of these institutions enabled disease to spread quickly and many even began to close down as their populations fell.


Although one must be wary of statistics about native mortality rates in both countries, given the European tendency to exacerbate the decline in native populations, it is fair to say that the decline in Aboriginal populations was much higher than that of the Maori in New Zealand, although wars also massively contributed to this.

While roughly 16.5% of the New Zealand population is Maori, only 3.3% of Australians are aboriginal, and it is safe to say that disease influenced this to some extent. So why was there such a difference between the effects of diseases in these countries, seemingly close together and both colonised by the British? A very large reason was smallpox; this was by far the biggest killer in Australia, but never reached New Zealand. The nature of the existing native communities was also important; there were 200-300 different Aboriginal nations in Australia, all with different languages, but the Maori were far more united, and often seen to be a more ‘advanced’ society, and therefore were never forcibly placed into reserves; which is where a lot of the spread of disease took place.

In addition, events in New Zealand occurred much later than Australia, after slavery had been outlawed, meaning there was a slightly more humanitarian approach, and there is less evidence to suggest purposeful extermination of the Maori. This is not to discount any injustices suffered by the Maori; indeed, many did die from European disease, and in both cases the native populations were treated appallingly and were alienated from their land.

The influence of European disease was overwhelmingly more powerful in Australia. However, one must approach statistics about the effect of disease on native peoples with caution, as Europeans tended to exaggerate this area to portray such peoples as ‘dying races’, a device often used to support colonisation.


Ian Pool, Te Iwi Maori (New Zealand: Oxford University Press), 1991

James Belich, Making Peoples (New Zealand: Penguin Books), 1996

John H. Chambers, A Traveller’s History of New Zealand and the South Pacific Islands (Great Britain: Phoenix in association with the Windrush Press), 2003

[1] cited in Ian Pool, Te Iwi Maori (New Zealand: Oxford University Press), 1991, 35

[2] Ibid, 56

[3] wikipedia cites Lewis, Balderstone and Bowan (2006), 25

[4] Judy Campbell, Invisible Invaders: Smallpox and other Diseases in Aboriginal Australia 1780-1880 (Australia: Melbourne University Press), 2002, 55

[5] wikipedia cites Richard Broome, Arriving (1984), 27