Answer:
Smallpox
Step-by-step explanation:
Yellow fever is to Napoleon's troops in Haiti as SMALLPOX is to native peoples of the Americas. This is a case of deadly diseases affecting a certain group of people.
Following the arrival of English colonists in Massachusetts in the year 1633, and their contact with the native Americans, the colonists infected Native Americans with smallpox which prove deadly, as it killed many of them.
Hence, in this case, the correct answer is SMALLPOX