European rabbits introduced to Australia and their management through myxomatosis and calicivirus raise significant welfare questions about biological control methods.
Biological control of rabbits using myxomatosis has caused enormous welfare harm through prolonged illness and death in hundreds of millions of individual animals. While ecological damage from introduced rabbits is severe, the welfare cost of this control method is also severe. Faster-killing calicivirus strains represent some welfare improvement. The scale of individual suffering in biological control programs deserves serious ethical consideration alongside conservation goals.