In 1994, the Centers for Disease Control and Prevention (CDC) launched the first phase of a nationwide effort to protect the public from infectious diseases. This past fall, the CDC released an updated document titled “Preventing Emerging Infectious Diseases: A Strategy for the 21st Century,” which describes the CDC's plan to combat infectious diseases over the next five years (see table).
|A new variant of a fatal neurologic illness, Creutzfeldt-Jakob disease, in the United Kingdom, possibly transmitted by ingestion of beef from animals afflicted with “mad cow disease.”|
|A new and virulent strain of influenza in Hong Kong.|
|Staphylococcus aureus with reduced susceptibility to vancomycin in the United States and Japan.|
|A new strain of multidrug-resistant tuberculosis, now endemic in New York City and New York state.|
|Evidence that many infectious microbes cause or contribute to the development of some chronic diseases.|
|Discovery of many human genes that influence susceptibility to infection, severity of infection and responsiveness to vaccination or treatment.|
|Further discoveries about what appears to be a new type of transmissible agent, the prion, which appears to be responsible for certain neurologic diseases, including Creutzfeldt-Jakob disease.|
|Tools and technologies|
|Electronic communications linking public health institutions in most areas of the world.|
|Innovations in biotechnology that make it easier to identify and track microbes.|
|Changes in health care delivery|
|Increased participation in managed care plans in the United States, creating new opportunities and challenges for disease prevention, surveillance, control and research.|
|Shortened hospital stays for some conditions, making it necessary to develop ways to monitor patient outcomes that appear after the patient has left the hospital.|
|Growth of home health care, requiring new public health partnerships and new methods for assessing the impact of treatments and measuring the occurrence of health care-related infections in home health care settings.|
|Public and policy issues|
|Books, films and media reports about the dangers of emerging infectious diseases, resulting in increased public awareness.|
|Government reports and commitments, such as the 1997 National Food Safety Initiative.|
This plan represents the second phase of the effort launched by the CDC in 1994. It was developed in collaboration with experts and professional organizations throughout the United States and abroad. The CDC emphasizes that implementing this plan requires the support and collaborative efforts of these groups and many others in the public health and health care communities. An overview of the CDC plan was published in the September 11, 1998, issue of the recommendations and reports series of Morbidity and Mortality Weekly Report (MMWR). Parts of this report are taken from the overview.
Goals and Objectives
The CDC effort focuses on the following four goals: improving disease surveillance and response; supporting applied research to understand and combat emerging infectious disease threats; infrastructure and training; and prevention and control. The CDC believes that the four goals are interdependent.
Surveillance systems monitor emerging infectious pathogens and outbreaks of disease. A response is mounted when surveillance data indicate a change in the incidence or distribution of an infectious disease, or when a new or variant strain of a pathogen has become a health threat. Scientists are able to answer questions about the etiology, transmission, diagnosis, prevention and control of emerging infectious diseases. Research, surveillance and response all depend on the public health infrastructure that supports, trains and equips public health workers. Training scientists is an important component of the public health infrastructure.
All of these efforts, according to the CDC, are ultimately directed at implementing the fourth goal, which is prevention and control. In the CDC plan, prevention and control receive increased emphasis. The CDC will work with many partners to implement, support and evaluate disease prevention. As part of this effort, the CDC will conduct programs and will develop, evaluate and promote strategies that help health care professionals and other individuals change behaviors that facilitate disease transmission.
In addition to the four goals, the following nine program areas have been targeted by the CDC. The following descriptions of the program areas are excerpted from the MMWR overview:
Antimicrobial resistance. The emergence of drug resistance in bacteria, parasites, viruses and fungi is reversing advances of the past 50 years. As the 21st century approaches, many important drug choices for the treatment of common infections are becoming increasingly limited, expensive and, in some cases, nonexistent.
Foodborne and waterborne diseases. Changes in the ways that food is processed and distributed are causing more multistate outbreaks of foodborne infections. In addition, a new group of waterborne pathogens has emerged that is unaffected by routine disinfection methods.
Vector borne and zoonotic diseases. Many emerging or reemerging diseases are acquired from animals or are transmitted by arthropods. Environmental changes can affect the incidence of these diseases by altering the habitats of disease vectors.
Diseases transmitted through blood transfusions or blood products. Improvements in blood donor screening, serologic testing and transfusion practices have made the U.S. blood supply one of the safest in the world. However, because blood is a human tissue, it is a natural vehicle for transmitting infectious agents. Therefore, continued vigilance is needed to ensure the safety of the blood supply.
Chronic diseases caused by infectious agents. Several chronic diseases once attributed to lifestyle or environmental factors (e.g., some forms of cancer, heart disease and ulcers) might be caused or intensified by infectious agents. This new knowledge raises the possibility that certain chronic diseases might someday be treated with antimicrobial drugs or prevented by vaccines.
Vaccine development and use. Certain childhood diseases have been virtually eliminated in the United States through universal vaccination. However, additional vaccines are needed to prevent diseases that are a societal burden (e.g., human immunodeficiency virus infection, acquired immunodeficiency syndrome, dengue fever, hepatitis C and malaria).
Diseases of people with impaired host defenses. Persons whose normal host defenses against infection have been impaired by an illness or a medical treatment, or as a result of age are more likely to become ill with various infectious diseases. Infections that occur with increased frequency or severity in such persons are called opportunistic infections. Health care professionals and scientists must be ready to identify and investigate each new opportunistic infection as it appears and to learn how to diagnose, treat, control and prevent it.
Diseases of pregnant women and newborns. Certain asymptomatic infections in a pregnant woman can increase her infant's risk of prematurity, low birth weight, long-term disability or death. In addition, infections can be transmitted from mother to child during pregnancy, delivery or breast-feeding. Effective and accessible prenatal care is essential to the prevention of infection in pregnant women and newborn infants.
Diseases of travelers, immigrants and refugees. Persons who cross international boundaries (e.g., tourists, workers, immigrants and refugees) are at increased risk for contracting infectious diseases and can also disseminate diseases to new places. International air travel has increased substantially in recent years, and more travelers are visiting remote locations where they can be exposed to infectious agents that are uncommon in their native countries.
The CDC anticipates that achievement of the objectives described in the plan will improve understanding of infectious diseases and increase their detection, control and prevention. The goal is a stronger public health system that will be able to respond to known disease problems and address the emergence of new infection pathogens. The CDC believes that implementation of this plan will produce the following results:
A nationwide network for surveillance and response will ensure the prompt identification of emerging infectious diseases. State and local health departments will be prepared to provide the front-line public health response to infectious disease threats.
Intensive population-based surveillance and research programs in at least 10 areas of the United States will generate data to identify new threats to public health and help guide responses to emerging infectious diseases.
State health departments will rapidly detect and investigate outbreaks of foodborne illnesses by using sophisticated epidemiologic and laboratory techniques. Early detection will facilitate the rapid implementation of control measures and the prevention of illness and death.
Countries in all regions of the world will participate in a global system for surveillance and response that includes surveillance for infectious agents that are resistant to antimicrobial drugs. This effort will be undertaken in partnership with the World Health Organization and other organizations and agencies around the world.
Enhancement of the public health infrastructure will help prepare the United States to respond to bioterrorist incidents.
Improved diagnostic testing methods will be developed for new, reemerging and drug-resistant pathogens.
A better understanding of risk factors for the development of infection and disease will provide new opportunities for disease prevention.
New strategies will be designed to reduce insect vector populations and control animal populations that serve as reservoirs for human diseases.
Diagnostic and reference reagents will be available for use by public health laboratories. The CDC will have enhanced capacity to serve as the national reference center for diagnosis of infectious diseases and for drug-resistance testing.
The next generation of epidemiologists and laboratorians will be trained and prepared to respond to emerging infectious disease threats.
Implementation of prevention guidelines will result in decreased death and disability caused by nosocomial infections, opportunistic infections, antimicrobial resistance and infections in newborns.
Cooperative efforts among managed care organizations, health care facilities, state and local health departments, and the CDC will improve treatment and prevention of infectious diseases.
Deaths from vaccine-preventable diseases will be substantially reduced in the United States and abroad.
Community-based demonstration programs will help identify cost-effective approaches to addressing emerging infectious disease problems.