Sam, a 35-year old, married mother of two, is an elementary school

teacher at a private school in a suburban area. She recently complained of chest pains and an incessant cough, which resulted in her coughing up blood earlier today. Concerned, she has just entered the emergency room department at the city hospital. Diego is the ER nurse who processed Sam’s intake and took a sputum culture to be tested. Laboratory results confirm infection with tuberculosis. Concerned about Sam’s positive test result, Diego decided to re-interview Sam and determined that she recently returned from a mission trip to poverty stricken areas of Buenos Aires, Brazil.

I am not sure how to explain the significance of the “shrinking world” and how it may impact the field of epidemiology.