Special Issue

Life expectancy in the United States from 1900 to the present (Figure 1) shows an overall steady rise, reflecting improved health conditions in general, the result of advances in medical science, hygiene, personal care, health technolo-gies, and public health administrations. The rise decelerates asymptotically to a near plateau from the 1950s to the 1970s, reflecting an epidemic of coronary disease, which we do not yet fully understand. Improvements in medical care, attention to life style, or indiscriminate use of aspirin may all be responsible for the subsequent decrease in deaths from coronary disease. Up to the 1940s, the rising curve is jagged, reflecting sporadic infectious disease outbreaks, especially the Spanish influenza outbreak of 1918. Whether the life expectancy curve continues to rise smoothly or whether it has some jagged declines depends on what we do about transmission of infectious disease, including foodborne disease. When plotted another way (Figure 2), both the absolute number of deaths from infectious disease and the proportion of total deaths attributable to infectious disease also show steady amelioration from 1900 almost to the present. The 1918 Spanish influenza pandemic may be a prototype for future emerging infections