This method of eradication is an option for most viral outbreaks in SPF barrier rodent rooms (i.e. rodents housed in microisolator cages). Because microisolator cages are individual biologic units, if appropriate technique is used, there should be minimal risk of viral spread from cage to cage. Eradication is directed at testing one or all mice in each cage and euthanizing any positive cages. This definition may change in unique circumstances.