International > CAIP > Events > Summer 1998

Infectious Diseases and Public Health

by James Hughes
Center for Disease Control

Infectious diseases are the leading cause of death worldwide and the third leading cause of death in the United States. Nevertheless, considerable complacency has developed over the past 35 years in the United States and other developed countries regarding infectious diseases because of the availability of antibiotics and vaccines.

In 1992, an Institute of Medicine Committee co-chaired by Drs. Joshua Lederberg and Robert Shope issued a landmark report entitled Emerging Infections: Microbial Threats to Health in the United States which highlighted this complacency, emphasized the threats posed by microbial agents, identified the factors that contribute to disease emergence and re-emergence, and stressed the need to heighten vigilance and strengthen response capability. The report defined the issue as “new, re-emerging, or drug-resistant infections whose incidence in humans has increased within the past two decades or whose incidence threatens to increase in the near future.” The report identified six factors that contributed to disease emergence and re-emergence: changes in human demographics and behavior; advances in technology and industry; economic development and changes in land use patterns; dramatic increases in international travel and commerce, microbial adaptation and change (microbial evolution); and the breakdown of public health systems required to prevent and control infectious diseases at the local, state, national, and global levels.

The IOM Report was extremely timely. Within six months of its publication, clinicians, microbiologists, and public health officials in the U.S. were confronted with an interstate foodborne disease outbreak of hemorrhagic colitis and hemolytic uremic syndrome caused by E.coli 0157.H7 linked to undercooked hamburger served by a fast food restaurant chain; the largest waterborne disease outbreak in U.S. history which resulted in over 400,000 cases of cryptosporidiosis in Milwaukee, Wisconsin; and an outbreak of adult respiratory distress syndrome with a very high mortality rate caused by a previously unrecognized hantavirus in the Southwestern United States.

More recently, outbreaks of plague in India, Ebola hemorrhagic fever in Zaire and Gabon, leptospirosis in Nicaragua, Cyclospoera gastroenteritis in the United States and Canada, E. coli 0157:H7 hemorrhagic colitis in Japan and the United States, S. aureus infections caused by strains with diminished susceptibility to vancomycin in Japan and the United States, avian influenza (H5:N1) in Hong Kong, and Rift Valley fever in Kenya and Somalia have presented major challenges and reminded us that the world is a global village. Addressing the major challenges posed by these events require early recognition, rapid investigation, use of sophisticated laboratory techniques for diagnosis, and effective communication of results and development and implementation recommendations for prevention.

Because more than half of the recommendations in the IOM Report were directed at the Centers for Disease Control and Prevention (CDC), CDC developed a strategy for addressing emerging infections in consultation with outside experts in clinical infectious diseases, microbiology, and public health. The strategy contains four goals that focus on strengthening surveillance and response cavity, addressing applied research priorities, improving prevention and control strategies, and strengthening the public health infrastructure at the local, state, and federal levels.

Incremental implementation of this plan has begun, and an updated version will be published this September. Seven Emerging Infections Programs (EIPs) have been established through cooperative agreement awards with state health departments and partner organizations. These EIPs have core projects in common focused on invasive bacterial diseases and foodborne diseases. In addition, 30 smaller awards have been made to establish Epidemiology and Laboratory Capacity Cooperative agreements (ELCs). These funds are used in different ways in different locales, but each recipient health department is making an effort to strengthen infectious disease surveillance capacity and to improve laboratory capacity and the reporting and analysis of infectious diseases surveillance data Three new provider-based sentinel surveillance systems have been established in partnership with clinical groups. One network is based in emergency departments in academic medical centers (Emergency ID Network); the second, involving infectious disease clinicians, is in collaboration with the Infectious Diseases Society of America; and the third (GeoSentinel) involves collaboration with the International Society of Travel Medicine.

The President’s National Food Safety Initiative, entitled “Food Safety from Farm to Table,” was released in 1997. During the summer of 1997, the state public health laboratory in Colorado recognized a cluster of 15 cases of E. Coli 0157:H7 infections using molecular finger-printing techniques (pulse field gel electrophoresis) from widely scattered areas in the state. Rapid epidemiologic investigation implicated under-cooked ground beef from single company. This observation led to a recall that started modestly but expanded to 25 million pounds of ground beef ultimately being recalled and the plant closing. This outbreak illustrates the profound economic implications of emerging infectious disease outbreaks, and emphasizes the critical importance of public health laboratory capacity in outbreak detection and rapid public health action. The National Molecular Subtyping Network, known as PulseNet, was recently announced by Vice President Gore. PulseNet is a partnership among CDC, FDA, USDA, and state public health laboratories designed to facilitate early detection of local, regional, and national foodborne disease outbreaks through timely application of molecular fingerprinting techniques.

Drug resistance is a very important national and global emerging problem and a serious public health threat in both health care and community settings. Strains of Staphylococcus aureus with diminished susceptibility to vancomycin were reported initially from Japan last summer; within just a few weeks of that report, cases were recognized in the United States in Michigan and New Jersey. Control of drug resistance is a major challenge requiring a multifaceted approach. Strong partnerships between clinicians, microbiologists and public health officials are critical to addressing this problem. However, John Burke nicely summarized a critically important part of the problem: “Despite the multi-factorial nature of antibiotic resistance, the central issue remains quite simple, the more you use it, the faster you lose it.” Judicious antimicrobial use is clearly an important component of an overall strategy to control this problem. We must continue to educate health care professionals about the importance of judicious use of these valuable resources. We must also educate the public regarding the need to conserve these valuable pharmaceutical resources by using them only as indicated.

The Working Group on Emerging and Re-emerging Infectious Diseases of the Committee on International Science, Engineering and Technology (CISET) formulated recommendations for federal agencies to collaborate with each other and the private sector to address these global threats. This report served as the basis for the Presidential Decision Directive on emerging infections issued by President Clinton in 1996. Implementation will require effective partnerships with other federal, state, and local public health agencies, clinicians and clinical microbiologists, academic institutions, industry, the World Health Organization, and other international organizations and agencies. The importance of addressing this issue was emphasized by the Group of Eight at the Denver Summit last year.

What does the future hold? Although difficult to predict, we can be fairly certain we will have more problems with antimicrobial resistance. One day the next pandemic of influenza will occur. We are likely to continue to experience, national and international foodborne disease outbreaks. We are going to appreciate more and more the important role that microbes have in chronic diseases. Finally, we know we are going to have to continue to confront the unexpected. We could not have predicted the emergence of AIDS. I do not think we could have predicted the occurrence of hantavirus pulmonary syndrome. Recent experience also emphasizes the need to be prepared for the threat of bioterrorism.

Infectious diseases are important, evolving, complex national and global public health problems. Their prevention and control require application of sophisticated epidemiologic, molecular biologic, statistical, and behavioral approaches and technologies. An integrated approach involving epidemiologic, laboratory, and behavioral sciences is critical to the prevention and control and infectious diseases. Policy makers and the public are also important partners in addressing these threats.

1998 Summer Meeting Papers

Education and Capacity Building
Shirley Malcom

Sustainable Development and the Environment
Walter Reid

Infectious Diseases and Public Health
James Hughes

ICSU Capacity Building Program
Molly Teas

Status and Trends in World Science
Maurizio Iaccarino