Traders, travellers, priests, and pilgrims moved across vast distances carrying not only goods and ideas but also germs and diseases. The long-distance spread of disease-carrying germs can be traced back to the seventh century. For example, when Spanish conquerors reached America, they unknowingly carried smallpox germs, which wiped out entire indigenous communities that had no immunity against it.
Source: Chapter 3 – The Making of a Global World, Sections 1 and 1.3
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The examiner expects two points: (1) the general idea that trade/travel spread germs alongside goods, and (2) a specific example (smallpox in America is the strongest one from the chapter). Keep the example crisp. Mentioning the 7th-century reference shows textbook awareness. Avoid over-explaining — 2 marks = ~2 key points.