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Testimony on Global Health: the United States Response to Infectious Diseases by Stephen Blount, M.D., M.P.H.
Associate Director for Global Health
Centers for Disease Control and Prevention U.S. Department of Health and Human Services

Before the Senate Committee on Labor and Human Resources , Subcommittee on Public Health and Safety
March 3, 1998

Good morning. I want to thank you, Senator Frist, and the Subcommittee for your invitation to testify at this critical hearing on global health and the U.S. response to infectious diseases. My name is Stephen Blount. I am the Associate Director for Global Health at the Centers for Disease Control and Prevention (CDC), a physician and epidemiologist.

We appreciate this opportunity to present CDC's perspective on the pressing need for infrastructure to maintain surveillance and respond to outbreaks of infectious diseases and on the need for collaborative efforts in prevention, monitoring, and controlling infectious diseases worldwide. My testimony will review CDC's accomplishments in global disease control activities and our future plans to protect the U.S. and work with WHO and others to enhance global response capabilities against infectious disease threats.

CDC has a proud history of working with other U.S. agencies, international organizations, and individual nations, to promote health and prevent disease. CDC provided leadership, in partnership with United States Agency for International Development (USAID) and the World Health Organization (WHO), in the historic efforts leading to the global eradication of smallpox in 1977. Over the past 20 years we have worked closely with these organizations and others to apply the lessons of smallpox eradication toward the goals of global elimination of polio and guinea worm and hemispheric elimination of measles, both by the year 2000. Throughout those 20 years we have also worked with a variety of partners to strengthen the global capacity necessary to address infectious disease threats in developing countries.

Growing concern about the global threat of emerging infectious diseases was described in a 1992 policy report issued by a committee of the Institute of Medicine (IOM) of the National Academy of Sciences co-chaired by Robert Shope, a distinguished virologist, and Nobel Laureate Joshua Lederberg. The report emphasized that addressing this threat would require a global strategy, and it challenged the U.S. government to take action. CDC answered that challenge in 1994 by launching a national effort to revitalize the U.S. capacity to protect the public from infectious diseases. This effort was described in Addressing Emerging Infectious Disease Threats: A Prevention Strategy for the United States, copies of which are here.

Before I review with you some of CDC's accomplishments and activities in the area of global health, I first want to emphasize that infectious diseases honor no national boundaries. The deadliest infectious diseases can emerge from the markets of Hong Kong or the rainforests of Africa and are only a plane ride away from any major city in the world. Infectious microbes have proven that they can easily travel across borders with their human or animal hosts.

Controlling disease outbreaks in other countries is a necessity, not only for humanitarian reasons, but also to prevent those diseases from spreading globally, including to the U.S. Moreover, U.S. support for disease investigations in other countries provides U.S. scientists with opportunities to learn about new pathogens -- like the new strain of influenza virus in Hong Kong or the deadly Ebola virus -- and to discover how best to control, prevent, and treat them--before they reach our shores. All of these efforts are beneficial both to U.S. citizens and to the global community.

Thus, it is no longer possible to protect the health of U.S. citizens without addressing infectious disease problems that are occurring elsewhere in the world. As stated in the 1996 Presidential Decision Directive on Emerging Infectious Diseases, the U.S. is committed to working with international partners to promote an inclusive, global network for surveillance and response to infectious diseases. CDC has a major role to play in this important endeavor.

I want to take this opportunity to describe some of CDC's accomplishments in five broad areas related to the global problem of emerging diseases: surveillance, outbreak response, building global capacity, disease eradication, and applied research. I will also indicate our future plans.

Disease Surveillance

In order to protect ourselves, we must be able to identify infectious disease threats, and disease surveillance is our major tool. Like the United States, many countries are trying to improve their national capacities for disease surveillance and response. It is especially important that disease surveillance be enhanced in developing nations, where emerging diseases may go undetected for long periods of time. CDC is working with partners throughout the world to further this aim, helping to enhance both human and technical resources.

A fundamental component to building global capacity is to strengthen existing institutions in this country. For example, CDC has helped enhance surveillance and response capabilities at 30 U.S.-based WHO Collaborating Centres, which help diagnose diseases and control outbreaks around the world. A new WHO Collaborating Centre on Control of Epidemic Meningitis, established at CDC in 1996, provided the technical lead in an international effort to respond to a meningitis outbreak in Sub-Saharan Africa during the winter of 1996-97.

I'd also like to mention CDC's work in regard to surveillance and response to a few specific diseases, including influenza -- a disease that has recently been on our minds and in the news. Over the past year, CDC has augmented its international influenza network by increasing the number of surveillance sites in China from 6 to 12, and by training laboratorians from 14 countries in Latin America and the Caribbean. It has also provided resources for enhanced influenza surveillance in Russia. In addition, CDC has worked with the Pan American Health Organization to provide training in the diagnosis of influenza and dengue hemorrhagic fever to support active surveillance for these diseases in the Americas. CDC has played a major role in the development and distribution of reagents through the WHO network for diagnosis and surveillance of the new strain of influenza identified in Hong Kong. In conjunction with WHO, CDC has also provided leadership in the development of a protocol for enhanced surveillance for this new strain.

Outbreak Response

One of our most effective weapons against emerging and re-emerging diseases is an effective international disease surveillance system backed up by the capacity to investigate and control outbreaks of a variety of health problems in a timely manner. CDC continues to assist WHO and foreign governments in responding to outbreaks of diseases that have high fatality rates or the potential for international spread, such as the outbreak of a new and virulent strain of avian flu in Hong Kong last fall and current investigations of Rift Valley Fever in Kenya and leptospirosis in Peru and Ecuador. CDC's assistance may also be requested when the cause of an outbreak is unknown, or when it involves a highly dangerous microbe that must be handled under the most stringent biocontainment conditions -- like Ebola virus.

In August 1991, the first outbreak of cholera associated with an imported commercial food product occurred in this country among persons attending a private picnic. An epidemiologic investigation by CDC showed infection was associated with consumption of coconut milk imported from Thailand. Working with the CDC and the Maryland Department of Health, the CDC-sponsored Thai Field Epidemiology Training Program conducted an on-site investigation of the production facility of the implicated coconut milk in Thailand. This investigation showed several sanitary violations, suggesting that contamination had occurred during production. This outbreak shows the linkage between domestic and international public health problems and how CDC is working in partnership with other countries to build investigative capabilities.

Capacity-building

As evident from the above example, one of CDC's priority activities is, in partnership with USAID, building the capacity in other countries to identify and respond to infectious diseases by strengthening the human and technical infrastructure. Over the past 50 years, CDC has contributed to the international supply of highly skilled public health practitioners through several programs. Perhaps the best known of these programs is the Field Epidemic Training Program (FETP). This is a 2-year training program that is modeled on CDC's domestic Epidemiologic Intelligence Service (EIS). To date, CDC has sponsored FETPs in 17 countries. These programs are designed for health professionals in entry- or mid-level positions and are intended to assist in building capacity in the areas of applied epidemiology and enhanced public health practice. In addition, CDC has worked with the Rockefeller Foundation to establish Public Health Schools Without Walls (PHSWOW) programs in a number of other countries; these programs also provide long-term training in both the principles and practice of public health science. This innovative 2-year course of study in PHSWOW combines the strengths of CDC's field training-through-service approach and the more traditional academic training provided by schools of public health. In their individual countries the staff and trainees of FETP and PHSWOW have already substantially improved both their national surveillance systems and their responses to public health threats. CDC is actively working with WHO, the FETPs, and the PHSWOWs in 15 countries to establish a network for global surveillance, outbreak investigation, and training.

Other critical efforts to build capacity focus on strengthening laboratories to rapidly identify new diseases and building health information and communication systems in order to collect and disseminate information. CDC has an ongoing training program to transfer safe and simple laboratory methods to developing countries and has developed innovative and low cost computer-based tools to rapidly share information. The Epi Info program developed by CDC is now the global standard for the collection and analysis of epidemiologic data.

Disease Eradication

I mentioned earlier CDC's leadership role in the global prevention of vaccine-preventable diseases, beginning with the historic effort that culminated in the eradication of smallpox in 1977. In addition to the unprecedented humanitarian benefits, the financial benefits were substantial. U.S. participation turned out to be a remarkably good economic investment. A total of $32 million was spent by the U.S. over a 10-year period for the global campaign. This entire sum has been recouped by the U.S., in 1968 dollars, every 2 1/2 months since 1971. This is the amount saved because we have been able to halt routine smallpox vaccination, eliminating the complications of smallpox, reducing foreign quarantine needs and eliminating requirements for vaccination on entry to the country.

In 1988, the World Health Assembly resolved to eradicate polio by the year 2000. Extraordinary progress continues to occur, including a 90% decrease in reported polio cases since 1988, suggesting that the current strategies are effective and that achievement of the objective by the year 2000 is feasible. However, acceleration and intensification of polio eradication activities will be required, particularly in war-torn countries.

Collaboration among Rotary International, UNICEF, WHO, USAID, Japan, the Task Force for Child Survival and Development, other international agencies, and CDC continues to strengthen. This collaboration is unique among public health initiatives for the unprecedented level of collaboration, the scale of private sector contributions, and the amount of funds raised. It is estimated that Rotary International alone will have contributed $400 million (U.S. dollars) by 2005. The underserved areas of developing countries that present the greatest challenges for disease eradication are often the same areas where surveillance and response to emerging diseases are most difficult. Therefore, infrastructure developed for disease eradication programs is an extremely important byproduct of disease eradication campaigns. Eradication programs provide tremendous training opportunities for epidemiologists, public health advisors, laboratorians, and village health workers. Furthermore, as diseases are conquered, the resources used to address them can be applied to new threats.

Applied Research

Over the past 50 years, CDC has established an outstanding tradition in the conduct of public health research, with major benefits for the American people and other countries. Through its applied research, CDC has helped to identify infectious disease agents, develop new diagnostic tools, identify population groups at high risk, and evaluate the effectiveness of disease control interventions. Our focus is on rapidly sharing research findings with other public health workers in the field.

One of the areas in which CDC continues to make major research contributions is in the field of HIV/AIDS. Worldwide, it is estimated that more than 1 million children have been infected with HIV through mother-to-infant (perinatal) transmission. WHO projects that without an effective and feasible preventive therapy, during this decade alone, 5-10 million children will become infected with HIV through perinatal transmission, the vast majority in the developing world.

Since 1995, CDC has worked closely with public health authorities abroad to design and evaluate a preventive therapy feasible to implement in developing nations. On February 18, 1998, CDC was pleased to release preliminary findings from one of these collaborative clinical trials that demonstrated that a short course of AZT therapy given late in pregnancy and during delivery reduced the rate of HIV transmission of infants to infected mothers by 50% and is safe to use in the developing world. The international community now faces the challenges of making this prevention opportunity a reality for HIV-infected woman worldwide. The remarkable news is that we begin with the first conclusive evidence that simpler, practical therapies can make a difference.

Another area in which CDC's global health research activities have helped improve the health of American citizens involves tuberculosis. In 1996, 37% of all new TB cases in the U.S. were among foreign-born persons, representing a large increase from the 22% who were foreign-born in 1986, when CDC first began collecting data on place of birth of its TB cases. Two-thirds of the cases are from just seven countries: Mexico accounts for nearly a quarter of the cases, with the Philippines and Vietnam accounting for an additional 14% and 11% respectively; India, China, Korea, and Haiti each account for an additional 3-5%. In Mexico, a study done in collaboration with local authorities revealed that most TB cases among foreign born patients living in the U.S. occur among longtime U.S. residents and that frequent travel to Mexico is a risk factor. Intervention strategies focused on this group of patients are now being developed.

Finally, CDC research has played a major role in better understanding hepatitis C infection, which affects 170 million persons worldwide. CDC investigators helped to identify the hepatitis C virus and demonstrate that chronic infection with that virus is a cause of death and serious liver disease. These researchers also developed the diagnostic test for the virus. We can apply these same skills to identify new diseases of global importance.

Future Plans

To fill gaps in the global capacity to address emerging diseases, as resources become available, CDC proposes to intensify its efforts in several areas. These include preventing antimicrobial resistance, ensuring the worldwide availability of diagnostic tests, improving preparedness for outbreak responses on a regional basis, improving disaster preparedness, and addressing environmental health conditions that give rise to some of these emerging diseases.

CDC is in the process of updating its emerging infections plan, taking into account the new discoveries and challenges of the past 4 years, and building on the experience, success, and knowledge gained from implementing the 1994 plan.

Controlling the global emergence and spread of drug-resistant pathogens remains a major focus for CDC and its partners. The urgency of this problem was underscored by 1997 reports from physicians in Japan and the U.S. that some strains of Staphylococcus aureus, a common bacteria that can cause serious illness, are developing resistance to vancomycin, which is the only antibiotic that remains effective against them. CDC is currently working with WHO, the US-EU Task Force on Communicable Diseases, and many other partners to establish systematic antimicrobial resistance monitoring throughout the world.

CDC's 1994 plan recognized the need to review the procedures for the detection and containment of infectious diseases imported into the United States. CDC has begun to implement a plan to improve detection and control at U.S. ports of entry, to improve management of diseases in refugee and migrant groups that enter the U.S., and to improve communication of health information related to international travel.

In addition, CDC has helped create a Sentinel Network of Travel Medicine Clinics, called GeoSentinel, has been formed to monitor diseases in travelers, [including schistosomiasis, dengue, hepatitis, and persistent fever of unknown origin.] GeoSentinel involves 15 travel medicine clinics in the United States, plus 7 more in other countries (2 in Australia, 1 each in Germany, New Zealand, Canada, Nepal, and Switzerland). The data are analyzed by CDC and used to develop travel advisories and recommendations for health care providers. In the future, GeoSentinel may help track the spread of diseases from place to place when outbreaks occur.