Final answer:
The final paragraph explains the CDC's involvement in cases throughout the world, not just in the United States.
Step-by-step explanation:
The final paragraph about the CDC connects to the main case study by explaining how the CDC is involved in many cases in many countries. It mentions how the CDC has been active in responding to infectious diseases like smallpox, polio, tuberculosis, AIDS, and SARS globally, not just in the United States.