According to armalegos in" the viral super highway", how have diseases from far flung nations reached and infected americans who have not travelled outside the country?

This idea bases itself on the premise that everything is connected. One person picking up a pathogen and traveling half way around the world can then spread it to hundreds by innocent contact with every day items. Those hundreds spread it to hundreds more, and so on. Viruses and pathogens rely on this concept to spread and survive.