The author switches from prepping for the EM to a description of Tom's upcoming hunting trip and then to a description of the incubation period for the virus. Why does he employ this technique?

I think this all has to do with the relation between nature, man and science. Something of course went terribly wrong with the inception and spread of Ebola.THe biology is complex and humans are not prepared or ready for what nature can throw at us. Sometimes man, the hunter gatherer and manipulator of nature, is responsible for creating his own viral monsters.