The Curious History of Rabbit Plague in Australia

Australia is an immense island, about twenty times larger than Spain, which, due to its condition as an isolated continent, offers new arrivals species great biological opportunities. But that I didn’t know Thomas Austin (1815-1871), an English colonist who, in 1859, imported two dozen rabbits wild in England and released them for sport hunting on his farm in Victoria.

The British could not imagine at that time what this “innocent action” would end. Its effect was devastating, in just three months the rabbits had spread over two thousand kilometres.

Austin was a very meticulous person and in his diary he recorded in detail his farming, hunting and ranching activities. Thanks to this diary, we can know that seven years after releasing the rabbits, he killed 14,253 rabbits, an average of 39 rabbits per day.

Having no natural predators on the continent, these first twelve pairs of rabbits multiplied in a very short time, becoming a real scourge endangering ecosystems.

One of the first steps taken by the Australian government to combat invasive species was to import natural predators that had not previously existed on the continent, in particular the red fox. However, these animals soon realized that it was easier to catch a koala than a rabbit, so these marsupials were on the verge of extinction.

1,700 km fence

In 1900, the authorities went further by raising a 1,700 kilometer fence to prevent the passage of rabbits to the western part of the island. A method that, unfortunately, also failed.

It is estimated that in the twenties of the last century there were already some 10 billion rabbits wild extended over the whole island.

Three decades later, the Australian government again changed the plague control strategy, replacing hunting with biological warfareby importing a disease that killed South American rabbits.

At the end of the 19th century, we discovered in Uruguay the mixomatosis, an infectious disease caused by a virus – myxoma – which affects rabbits and kills them. This disease is transmitted by the bite of insects that feed on blood, fleas and mosquitoes, that is, by blood-sucking vectors.

Death from myxomatosis is horrible, infected animals suffer from skin nodules in the area of ​​infection, swelling of the face and genitals, shortly after they stop eating and finally die about ten days after contracting the infection.

In 1950 this virus was successfully tested in parts of Australia and later it was used throughout the country. It is estimated that dozens of millions of rabbits died to myxomatosis. However, over time, the rabbits developed immunity against the pathogen, so the population rebounded.

Hemorrhagic virus, new solution

In 1995, researchers on Wardang Island (Australia) experimented with a virus that spread a haemorrhagic disease, a microorganism that killed up to 60% of Australia’s wild rabbit population. According to data published by scientists, it is a virus as contagious as human flu and as deadly as Ebola. In 2017, the government used a new variant – the RHDV1 K5 strain – a virus carrying a bleeding pathogen discovered in South Korea.

Nevertheless, the plague is not controlled and currently in some parts of Australia, such as Queensland, keeping or selling rabbits is considered a criminal practice punishable by six months in jail and a $44,000 fine.

ABOUT THE AUTHOR

Stone Choker

Internal doctor at El Escorial Hospital (Madrid) and author of several popular books.

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