Gassed mice at a wheat stack during a mouse plague. The House mouse (Mus musculus) is second only to humans in the extent of its global distribution. Over most of Australia, unlike Europe, it is virtually the only rodent found in cultivated fields and periodically they reach plague proportions. The cause of the plagues can vary from region to region but usually relate to rainfall patterns.

Grain-growers suffer significant crop loss and damage to stored grain, intensive livestock farmers can experience reduced production levels, and electrical equipment can be destroyed. There is also the health risk to humans.