Yes it can be spread. Through the air and from one person to another
I think that the element of the story that is least related tot he author's biographical story is the C. SMELL OF MILDEW IN A VIETNAMESE VILLAGE.
Tim O'brien wrote the story using his personal experiences. He was sent to Vietnam in his tour of duty. He's familiar with the geography of the Vietnamese coastline, he vividly describes the climate and landscape, and he feels the fear that the soldier felt during wartime.
Answer:
In lines 97-98 there is a simile "the notch is just like the pipe of a great pair of bellows" the notch is like the instruments to increase the draft of a fire