What are three ways preston makes the reader feel fear through atmosphere? (setting, etc.)

The power of nature is a recurring theme in Preston's descriptions of the various outbreaks of Marburg and Ebola. While human beings may consider themselves to be "master of the earth", Preston argues that nature has the ultimate power, even to the point of determining the course of human evolution. While scientists such as Nancy Jaax and Gene Johnson can strive to understand filoviruses, all humans are ultimately at the mercy of the natural order.Despite whatever heroic steps people take to contain the virus, nature has the ultimate trump card. It is this fear of man's mercy to nature, whether induced by man or not, that haunts this story.