Why were incidents of typhoid fever reduce by 70 percent in the early years of the twentieth century?

Question

Quizplus · Accepted Answer

The early years of the twentieth century saw significant improvements in public sanitation, including the installation of sewer systems and the development of water treatment facilities. These advancements greatly reduced the incidence of waterborne diseases like typhoid fever. While transportation networks and immigration policies may have indirectly played a role, they were not the primary drivers behind the significant reduction in typhoid fever cases. Similarly, while vaccines were certainly developed for typhoid fever, they were not widely available or effective until later in the century.

Why Were Incidents of Typhoid Fever Reduce by 70 Percent