Communicable diseases such as smallpox and leprosy existed even before the birth of Christ. Plague raged intermittently throughout Europe and China during the thirteenth and fourteenth centuries, decimating the population. In the fourteenth century, physicians first formulated a theory to explain the communicable disease process. Although it was not completely accurate, this and subsequent trial-and-error efforts helped physicians develop sound principles for communicable disease control (Box 8-1). Today, quarantine, sanitary precautions, and travel restrictions remain methods of communicable disease control.

As the relationship between disease-producing microorganisms and factors that are beneficial to their growth became more apparent, control measures became more specific. Sanitary regulation of the environment and isolation of infected individuals became accepted strategies. These control measures were widely enforced. Streets were cleaned, the throwing of garbage into rivers and streets was discouraged, standing water was drained, and infected individuals were isolated. In America, quarantine laws became acceptable in the mid-1800s.

Communicable disease control at the federal level was almost nonexistent until the 1800s. In 1872, the Marine Hospital Service, the forerunner of the Public Health Service, was founded by an act of Congress. At approximately the same time, the American Public Health Association was established. The American Public Health Association provided a forum for physicians and other public health workers to set standards of care. In 1878 the Quarantine Act was passed, granting the federal government the power to impose quarantine. In 1912, the Marine Hospital Service officially became the Public Health Service (PHS), and states were held responsible for reporting statistics to the federal government via the PHS (Miller, 2002; Mullan, 1989).

Federal support for research assistance in communicable disease control led to several important actions. In 1930, the Ransdell Act established the National Institutes of Health (NIH), which continues to be the major source of research for the PHS. In 1946, the Communicable Disease Center, currently known as the Centers for Disease Control and Prevention (CDC), was established. The CDC’s original mandate was control of infectious diseases. Over the years, however, the scope of the CDC has expanded to include noninfectious diseases and environmental issues. The CDC is responsible for collecting morbidity and mortality statistics on reportable infectious diseases.

The 1970s were a decade of health reform and legislation. The needs of migrant workers were supported, and vaccines were made available to the poor. Funding for the NIH was increased, and a national effort began to decrease the incidence of cancer, heart attacks, and strokes. In the 1980s the important role of the PHS was underscored by the advent of HIV infection. The need for HIV infection prevention and education efforts, the issue of confidential or anonymous testing and counseling, the need for contact tracing and notification, and the care of infected individuals in hospitals and in the community have served to emphasize the need for a public health response to communicable diseases.

Today public health officials face many challenges, including the need for a quick response to a bioterrorism attack (see Chapter 22); the potential for rapid spread of infectious diseases due to the ease of travel between countries; and the rise of new and drug-resistant diseases. The public health community must meet these challenges in spite of limited funding for public health programs.

Vaccine development and immunization programs eliminated smallpox and have dramatically decreased the incidence of childhood diseases such as measles, mumps, pertussis, polio, and rubella. In 1977 a national campaign, the Childhood Immunization Initiative, resulted in massive immunizations of young children. Unfortunately, a reduced emphasis on public health at the national level, with corresponding funding cuts, diminished the impact of this early immunization effort (Jekel et al., 2007). When the public becomes complacent, some diseases resurface or new ones emerge to affect the health of populations.

One trend of special concern to public health practitioners is the increase in drug-resistant strains of organisms that cause communicable diseases. After years of successful treatment, cases of gonorrhea, TB, pneumonia, and syphilis are on the rise. These increases are the result of less success with standard antibiotic therapies. Examples of drug-resistant organisms are the following:

Drug-resistant communicable diseases are a special concern not only because they are more complicated to treat but also because the delay in control increases the risk of infection for every person, including health care workers. Community health nurses must be alert to screen high-risk groups (Box 8-2), be aware of current treatments, and be able to identify the signs of drug-resistant infection in clients. In addition, community health professionals must take an active role in educating practitioners and the public alike concerning the prudent use of antimicrobial drugs to reduce the emergence of drug-resistant strains.

Nearly one third of the world’s population is infected with TB. It is a leading infectious cause of death worldwide, causing more than 2 million deaths each year (CDC, 2011f). Persons infected with the TB organism but without overt disease are asymptomatic and are not contagious to others. If infection progresses to TB disease, individuals will have symptoms and become contagious. A person who has a compromised immune system, practices poor nutrition, lives in poverty, or has other diseases is at greater risk of progressing from TB infection to TB disease (see Chapter 21). People who live in or emigrate from countries in which TB is indigenous are at greater risk of having been infected (see Chapter 5). Without prophylactic treatment for the infection, individuals have a 5% to 10% chance of progressing to disease (CDC, 2008a). HIV-infected individuals are at special risk. The number of persons with the dual diagnosis of HIV and TB has increased dramatically, with approximately 10% of all TB cases also having HIV (CDC, 2008a).

The risk of acquiring TB infection or disease is relatively low in the United States. Immigrants from countries in which TB is indigenous are at greater risk because they are more likely to have been exposed and infected in their country of origin (CDC, 2011f). Although the total number of TB cases has declined, the incidence among foreign-born persons as a percentage of total cases has increased (Figure 8-1). The TB case rate among foreign-born persons in the United States is eleven times greater than U.S.-born persons (CDC, 2010d). Today, public health agencies have renewed efforts to identify and treat foreign-born individuals. Closing the gap between TB rates among foreign-born and native-born Americans is a national health objective and a goal of the CDC.