Cities and the Health of the Public

11. Cities and Infectious Diseases: Controls and Challenges

209 11 Cities and Infectious Diseases Controls and Challenges David Vlahov and Emily Gibble Introduction The burden of infectious disease in the United States underwent a marked ­decrease in the 19th and 20th centuries, producing a dramatic reduction in population mortality . Although many of the infectious diseases that were a problem in the 19th century have been controlled, some remain endemic, others appear in more sporadic outbreaks or reappear, and novel infections emerge. City characteristics that influence patterns of infectious diseases include land area, infrastructure, popu­lation density, immigration patterns, rate of urbanization, and percentage of the population living in poverty. The conditions and determinants presented in the first two chapters of this book offer a framework for how these factors contribute to the burden of infectious disease within cities. On one level, disease is related to individual factors, such as lack of access to health care, substance use that can disinhibit risk behaviors , and the increased susceptibility that accompanies youngest and oldest age groups, through either immature or degrading immune systems. On another level, disease outcomes are affected by social and physical environments, such as the strength of informal networks of neighborhood communication and the integrity of physical infrastructure and services, including public transportation, which can be a link for transmission within cities. Health service delivery systems, including insurance coverage, are important, especially primary care and preventive services in areas of concentrated disadvantage. Public health interventions and the degree to which they contribute to infectious disease prevention and control are in turn influenced by municipal-level variables, such as city policies, the services and support that community organizations provide, and the markets that distribute basic goods and services, such as housing, food, and employment. These municipal 210 Part IV: Health Outcomes and Determinants factors affect funding for disease prevention and control, the public acceptance of control activities, and the daily living conditions of various urban populations. Finally, national and international trends influence or set the context for local decisions; for example, policies on transportation, immigration, or economic globalization enable or constrain cities in making decisions about health. Using this conceptual framework, this chapter explores how factors at each level—operating alone or interacting with other factors across levels—can create conditions in which urban populations or specific subpopulations within cities become vulnerable to infectious disease. Though this chapter focuses on contemporary characteristics of cities that make their populations vulnerable to infectious disease outbreaks, we begin by setting up the historical context of infectious disease —risk, outbreak, and control—in urban areas across the country. Cities and Infectious Diseases in U.S. History Throughout history, cities have been linked to infectious diseases—particularly in terms of epidemics and outbreaks. Thucydides reported on the Plague of Athens during the Peloponnesian War in 430 b.c., the cause of which continues to be debated .1 The Black Death, or bubonic plague, during the 15th and 16th centuries is thought to have reduced the population of London by two-thirds.2 Reports of these epidemics did not establish a connection between disease and cities, but they are the earliest evidence available to those attempting to explore and define such a connection. Disease Patterns and Risk Factors In the United States from colonial times through most of the 19th century, deadly outbreaks wreaked havoc in cities and towns.Chapter 7 explores this topic in detail .) During this period, cholera made its first appearance in New York City, and outbreaks of yellow fever occurred repeatedly in the port cities of New Orleans, Baltimore, Philadelphia, Boston, and New York City.3 Smallpox epidemics occurred in New York City throughout the 19th century (despite the availability of a vaccine, which remained unacceptable to much of the population),4 and Boston, Philadelphia, and Baltimore saw smallpox outbreaks as well. Typhus epidemics also threatened several U.S. cities.5 Though cholera, yellow fever, smallpox, and typhus generated fear because of their episodic and highly fatal occurrences, the major causes of urban mortality in the first half of the 19th century were endemic infectious diseases, including tuberculosis and pulmonary disorders (accounting for the largest numbers of deaths among adults), pneumonia, diphtheria, measles, whooping cough, and scarlet fever. Among infants and children, the most common cause of death was diarrheal disease. A variety of factors in 19th-century U.S. cities probably contributed to the predominance of infectious diseases. Water sources at the time included shallow wells, and sewage was untreated and commonly disposed of in unpaved streets with poor drainage...