The stress of the weaning process and the immune system transition can leave the nursery pig vulnerable to disease challenges. In order to control disease challenges in the nursery the type of pathogen, the clinical symptoms, the severity of the disease, the herd health status, and long-term impacts should all be understood. Intervention strategies can help reduce the impact, and can involve antimicrobial therapies, vaccination, and good production practises for standard challenges. For more serious or external disease threats, depopulation and repopulation can be used, or herd closure.