Environmental changes induced by the activities of the increasing human population are likely, through effects on both hosts and infectious agents, to alter the patterns of incidence of diseases of wildlife. These changes may affect the conservation status or welfare of some populations. There is a need for investigations into causes of wildlife mortality incidents and for assembling information on these to assist in guiding responses to incidents in the future. Increasingly, interventions are made for the conservation or welfare of free-living wild animals and veterinary involvement in these ventures is important.