In the 19th century, European settlers brought rabbits to Australia, where they quickly multiplied because there were no natural predators to control their population. This led to serious environmental and agricultural problems, as rabbits destroyed crops and native vegetation. To address the issue, Australian authorities decided on a bold solution in 1950: they released a virus called myxomatosis, which originally came from South America. This virus was extremely deadly, killing nearly all infected rabbits, which led to a sharp decline in their numbers and helped restore agricultural production. However, the virus's impact didn't last. Some rabbits survived the initial outbreak, and these survivors had genetic traits that made them more resistant to the virus. Over time, these resistant traits were passed on to their offspring, leading to the emergence of rabbit populations that were much less affected by the virus. At the same time, the virus itself evolved. Less deadly versions of the virus began to spread, as these variants allowed rabbits to live longer and spread the virus more effectively. This kind of evolutionary competition between the virus and its host wasn't unique to Australia. Myxomatosis was also introduced to France in 1952, where it spread in a more aggressive form. In both Europe and Australia, scientists observed similar patterns: the virus became less deadly over time, and rabbits developed stronger resistance. Even though the initial conditions and ways the virus spread were different, the evolutionary outcomes were surprisingly similar. To better understand this process, an international team of researchers compared the genetic makeup of rabbits from Australia, France, and the United Kingdom before and after the virus outbreak. They found that the same genetic changes occurred in all three regions, particularly in genes related to the immune system and how the virus replicates inside the body. This suggests that the way rabbits evolved to resist the virus was not random, but a common response to the same threat. Despite these findings, scientists still don’t have recent data on how resistant rabbits are to myxomatosis today. It has been nearly thirty years since the last study on this topic, even though new, deadly diseases have emerged that affect rabbits worldwide. Researchers stress the importance of continuing to study this relationship to understand how effective the virus is now and how both the virus and rabbits are continuing to evolve together.