In the western hemisphere, where do about 90% of malaria cases occur?

• A. The Caribbean
• B. The Andes
• C. The Amazon region
• D. The Patagonian region

Answer: (C)

Malaria thrives where warm temperatures, high humidity, and standing water create ideal breeding grounds for Anopheles mosquitoes and year‑round transmission. The Amazon region provides this perfect tropical rainforest environment, with vast areas of dense vegetation, abundant water sources, and climate that supports mosquitoes most of the year. Because of these conditions, transmission remains high, making this area the main hotspot for malaria in the western hemisphere and accounting for about 90% of cases. Regions like the Caribbean have some transmission but far fewer cases, the Andes are cooler and at higher altitudes which limits mosquito activity, and Patagonia is too temperate and dry for sustained malaria transmission.