Introduction: Infectious diseases

In any discussion of the great challenges facing humanity in addressing global environmental problems, a small number of topics automatically rise to the top: climate change, the loss of biodiversity, and the sustainability of the services ecosystems provide us. But no threats to human welfare are more urgent than those posed by infectious diseases; we suffer already the devastating consequences of the emergence of new diseases such as HIV, the reemergence of old ones such as tuberculosis, and simply the increasing toll of endemic diseases such as malaria. Non-human animals play fundamental roles in the spread of many of these diseases – as reservoirs, as vectors, and as cauldrons for the creation of new types. Land-use practices and environmental management both affect the persistence and spread of endemic diseases, such as malaria. Furthermore, as animal populations increase their ranges, due to climate change and human-facilitated alien introductions, the potential for disease spread also increases. These factors, together with the increasing mobility of the human population, conspire to make these environmental problems of great and immediate concern.