Rabbits clustered around a small pool of water.

By 1950 rabbit numbers in Australia reached 600 million.

The virus that stunned Australia's rabbits

The release of myxoma virus in 1950 led to a dramatic reduction of Australia’s rabbit population and recovered A$68 million to the wool and meat industries within two years.

  • 25 February 2011 | Updated 14 October 2011

Rabbits were introduced to Australia in 1859 by a wealthy Victorian grazier keen on the sport of hunting.

Hunters, however, could not keep up with extraordinary rate at which the animals multiplied and soon millions of rabbits were competing with Australia's livestock for feed and were damaging the environment.

Myxomatosis

The idea of using myxomatosis to control rabbits was first raised in 1919 by a Brazilian scientist but was rejected by the Australian Government. Fortunately, a prominent Melbourne paediatrician, Dame Jean Macnamara, persuaded the Australian government to undertake preliminary safety tests 14 years later.

CSIRO's predecessor, CSIR, conducted initial trials that ultimately resulted in the successful release of the virus in 1950.

It was the world's first successful biological control program of a mammalian pest, taming a scourge that had threatened Australian agriculture and environment.

From 600 million …

The initial release of myxoma virus led to a dramatic reduction of Australia’s rabbit population. The virus killed 99.8 per cent of rabbits that caught the infection, an unbelievable result, especially for landowners who had been battling rabbit outbreaks for decades.

Australia's wool and meat production recovered from the rabbit onslaught to the tune of A$68 million within two years.

The disease wiped out 99 per cent of infected rabbits in Australia in the 1950s.

Although myxomatosis dramatically reduced Australia's rabbit population from an estimated 600 million, some had no reason to celebrate.

Rabbits had supported generations of rural Australians. Exports of rabbit skins fell from about A$14 million in 1950-51 to A$4.5 million in 1954-55. Felt industry workers were also adversely affected.

Hype led to panic

The hype surrounding the project did, however, lead to the odd outbreak of panic fuelled by rumours and half-truths.

Shortly after myxomatosis was introduced, a human encephalitis epidemic began spreading through the Riverina region of NSW. In no time the public was pointing accusingly at CSIRO scientists and blaming the deadly new rabbit disease for the potentially fatal human brain disease.

In a remarkable demonstration designed to quell public anxiety, Professor Frank Fenner and two other top Australian scientists, Dr McFarlane Burnet and Dr Ian Clunies Ross, injected themselves with doses of myxomatosis. It did them no harm and the public's fears were allayed.

Long term impacts

By the late 1950s, resistance to the myxoma virus was starting to build up in Australia's rabbits. The virus became less effective and rabbit numbers increased, but never to pre-1950 levels.

The introduction of rabbit haemorraghic disease virus RHDV (also known as rabbit calicivirus) in 1995 again reduced rabbit numbers to very low levels, with greatest impact in arid zones and lesser impact in high rainfall areas.

RHDV is considered only the second successful control of a mammalian pest in the world.

Learn more about the work CSIRO does in Pest Management.