Researchers, research technicians, graduate students, and animal care staff all have a role to play in minimizing the impact of disease in an animal facility. Important elements in health monitoring are the identification of sick animals and the implementation of procedures for dealing with the animals. Animals may be ill because of something unrelated to the experimental protocol. It is important that sick animals are promptly reported to the veterinary staff for diagnosis. It may be appropriate to isolate the animal during the diagnostic period or it may be necessary to euthanize it to secure a definitive diagnosis.