Water and Chicago's mortality transition, 1850-1925

Between 1850 and 1925, the crude death rate in the City of Chicago fell by 60 percent. We estimate that 30-50 percent of this reduction can be attributed water purification measures and the subsequent eradication of diarrheal diseases and typhoid fever and its sequella. Our findings are consistent with a proposition that early public-health scholars referred to as the Mills-Reincke phenomenon. According to advocates of the Mills-Reincke phenomenon, for every one death from typhoid fever that was prevented by water purification, there were three or more deaths from other causes (not usually considered waterborne) that were also prevented. At least part of this phenomenon appears to have driven by the fact that typhoid had a low case fatality rate but so weakened its survivors that they were vulnerable to later infections from tuberculosis and pneumonia. There is also evidence that typhoid survivors eventually developed kidney problems from which they later succumbed. These findings have implications for public health policies in developing countries.