The Question and Answer section for The Hot Zone is a great resource to ask questions, find answers, and discuss the novel.
Preston is offering his own views of the origin and spread of the virus. Preston gives the reader context into his own life as well as his first hand view in tracing the virus.
Virus's like Ebola are airborne so any kind of contamination, including infected people visiting, can cause a catastrophe
I have not been able to find the quote you're referring to. Do you have a page number for this quote?