Pest control can sometimes get out of hand. In 1995, Australia was testing the deadly calicivirus for controlling rabbits on an island. Somehow the virus escaped and spread across the entire country.
New Zealand, which also has a serious rabbit problem, decided not to introduce the virus. But a group of farmers took it upon themselves to smuggle the virus into the country in 1997, where it still circulates today.
Now New Zealand is considering using genetic “extinction” drives to tackle invaders such as rats, possums