Ecology and epidemiology of zoonotic pathogens.

The possibility that a perplexing febrile illness may represent a zoonotic infection should be explored. The history should include where the person has been, what he or she has done, what has been eaten and drunk, what contacts have occurred with vertebrates or arthropods in wild or domestic venues, and whether there has been exposure to unusual animal products. The preceding discussion emphasized, via some examples, mechanisms of spread as well as the physical and biologic conditions that enhance the probability of an encounter with a pathogen. From clues in the history and physical examination the appropriate diagnostic and therapeutic decisions can be made. These decisions may be life saving for the patient, and perhaps protect care providers and family from acquiring the same disease. Many of the infections mentioned in this article will be amplified in subsequent articles, which will deal with diseases encountered primarily in the United States.