Which statement best describes malaria trends with respect to DDT?

Which statement best describes malaria trends with respect to DDT?

• A. Increased cases
• B. No effect
• C. Dramatically decreased cases
• D. Eliminated all cases

Answer: (C)

DDT reduced malaria mainly by killing the mosquitoes that transmit it, especially when used in indoor residual spraying. When these vector populations dropped, malaria transmission fell sharply, leading to dramatic decreases in malaria cases in many regions during the mid-20th century. This is the most accurate description of the overall trend. It’s important to remember that the reduction wasn’t universal or permanent—resistance, environmental concerns, and changes in control programs meant malaria did not stay eliminated everywhere, and in some areas cases later rose again. So the best description is that malaria cases dramatically decreased with the widespread use of DDT.

DDT reduced malaria mainly by killing the mosquitoes that transmit it, especially when used in indoor residual spraying. When these vector populations dropped, malaria transmission fell sharply, leading to dramatic decreases in malaria cases in many regions during the mid-20th century. This is the most accurate description of the overall trend. It’s important to remember that the reduction wasn’t universal or permanent—resistance, environmental concerns, and changes in control programs meant malaria did not stay eliminated everywhere, and in some areas cases later rose again. So the best description is that malaria cases dramatically decreased with the widespread use of DDT.