Outbreak: detection and investigation.

With the increased movement of rodents between institutions of various pathogen status, the risk of introducing unwanted agents into a facility is high. This situation is in direct conflict with the increasing demand for "clean" rodents for use in biomedical research. If an institution is to have any hope of attaining specific-pathogen-free status, a rational surveillance program should be in place, along with a plan of action to be undertaken when an unwanted agent is detected in the facility. This review summarizes the factors that should be considered when designing a rodent health-surveillance program and outlines a general approach to be taken when rodents in a facility become infected with an undesirable agent.