Wild animals have been maintained in close association with humans since the dawn of human creation. Tremendous advances have been made in the care and management of wild animals, but some areas still need improvement. It is therefore important to identify the husbandry factors which minimize or maximize the occurrence of infectious or parasitic diseases. A universal influence on all animals is stress, and it is critical that managers, administrators, veterinarians and regulatory officials understand basic concepts and take steps to minimize stress in captive wild animal husbandry. To study the epizootiology of infectious and parasitic diseases, one must also understand the nidus concept of disease, which essentially holds that all animals evolved with a group of infectious and parasitic agents that have generally lived in harmony with their host. Now, with the movement of animals and agents throughout the world, explosive outbreaks of disease may occur unless the responsible persons know which species may be closely associated, and follow appropriate husbandry practices and appropriate quarantine procedures.