The virus, myxoma, was transmitted from rabbit to rabbit by mosquitos and rabbit fleas. Over the next three years rabbits died of myxomatosis by the millions, grass grew back on the pastures, and sheep farming began to flourish again. There was a sudden upset in the balance of nature. The Myxoma virus had been successfully introduced into European rabbits too and, especially in England, with a scarcity of rabbits, foxes began eating poultry, rats and mice. Scientists believe that, as populations of rabbits with resistance to Myxoma increase, there will be rabbit plague problems again.
Locusts periodically cause natural disasters in several parts of the world.
When the locust population density is low the locusts behave as individuals. However, when the population density increases locusts form highly mobile swarms. The change from solitary to gregarious is generally accompanied by changes in body shape and colour. In Australia locust plagues occur when widespread inland areas receive good rainfall in successive seasons. High rainfall stimulates the growth of grass which creates an ideal habitat for locust breeding.