Correct Response: B. Cholera and typhoid (or typhoid fever) are both bacterial diseases that spread primarily through food or drinking water contaminated by the wastes of those who have the disease. Improvements in sanitation have nearly eradicated these diseases in the developed world. The ability to diagnose these diseases rapidly (A) was not a major factor in preventing their spread. Broad-spectrum antibiotics (C) were not used until the mid- to late twentieth century. Groundwater resources (D) such as wells were also frequently contaminated by poor sewage management practices and contributed to the spread of cholera and typhoid prior to improvements in sanitation.
