Modern public health
With the onset of the epidemiological transition and as the prevalence of infectious diseases decreased through the 20th century, public health began to put more focus on chronic diseases such as cancer and heart disease. Previous efforts in many developed countries had already led to dramatic reductions in the infant mortality rate using preventative methods. For instance in the United States, public health worker Dr. Sara Josephine Baker established many programs to help the poor in New York City keep their infants healthy, leading teams of nurses into the crowded neighborhoods of Hell’s Kitchen and teaching mothers how to dress, feed, and bathe their babies.
During the 20th century and early in the next, the dramatic increase in average life span is widely credited to public health achievements, such as vaccination programs and control of many infectious diseases including polio, diphtheria, yellow fever and smallpox; effective health and safety policies such as road traffic safety and occupational safety; improved family planning; tobacco control measures; and programs designed to decrease non-communicable diseases by acting on known risk factors such as a person’s background, lifestyle and environment. One of the major sources of the increase in average life span in the early 20th century was the decline in the “urban penalty” brought on by improvements in sanitation. These improvements included chlorination of drinking water, filtration and sewage treatment which led to the decline in deaths caused by infectious waterborne diseases such as cholera and intestinal diseases. In Cutler and Miller’s, “The Role of Public Health Improvements in Health Advances”, they display evidence of the decline in typhoid fever deaths in Chicago, Baltimore, Cincinnati, and Cleveland after these American cities adopted chlorination, filtration, or a sewage improvement.
Meanwhile, large parts of the developing world remained plagued by largely preventable/treatable infectious diseases and poor maternal and child health outcomes, exacerbated by malnutrition and poverty. The WHO reports that a lack of exclusive breastfeeding during the first six months of life contributes to over a million avoidable child deaths each year. Intermittent preventive therapy aimed at treating and preventing malaria episodes among pregnant women and young children is one public health measure in endemic countries.
Front-page headlines continue to present society with public health issues on a daily basis: emerging infectious diseases such as SARS, rapidly making its way from China (see Public health in China) to Canada, the United States and other geographically distant countries; reducing inequities in health care access through publicly funded health insurance programs; the HIV/AIDS pandemic and its spread from certain high-risk groups to the general population in many countries, such as in South Africa; the increase of childhood obesity and the concomitant increase in type II diabetes among children; the social, economic and health impacts of adolescent pregnancy; and the ongoing public health challenges related to natural disasters such as the 2004 Indian Ocean tsunami, 2005′s Hurricane Katrina in the United States and the 2010 Haiti earthquake.