Natural disasters are not commonly associated with large outbreaks of epidemic diseases, with the possible exception of flooding. Once a population is displaced by a disaster, the risks of epidemic disease rise. Natural disasters may affect the epidemiology of endemic diseases or chronic diseases present in a community through reducing or changing the access a population has to health services. Preventing or limiting the public health impact of a disaster requires an effective disease surveillance system that is a critical early measure to establish in any emergency. Acting on surveillance data can not only prevent or limit epidemics from developing, but is also a means of evaluating the public health response to disasters.