Statement by
Joseph M. Henderson, M.P.A., Director
Office of Terrorism Preparedness and Emergency Response Centers for Disease Control and Prevention, U.S. Department of Health and Human Services

CDC's Disease Surveillance Systems Efforts
before the
Subcommittee on Emergency Preparedness and Response, Select Committee on Homeland Security, United States House of Representatives

September 24, 2003

Good morning, Mr. Chairman and Members of the Subcommittee. I am Joseph M. Henderson, Director of the Office of Terrorism Preparedness and Emergency Response at the Centers for Disease Control and Prevention (CDC). As the nation's disease prevention and control agency, CDC, working with state and local public health agencies is charged with detecting and responding to illnesses, both man-made and naturally occurring. This task is an integral part of CDC's overall mission to monitor and protect the health of the U.S. population.

Thank you for the opportunity to discuss how disease surveillance systems can prepare the nation for potential terrorist threats. "Disease surveillance systems" or disease detection systems, address one important aspect of our nation's overall public health preparedness. CDC, working with our federal, state, and local partners is working to build systems that can: (1) rapidly detect an event in our communities; (2) mobilize the appropriate response to contain the event, and (3) ensure affected communities return to a sense of normalcy. These are what we refer to as our foundations of public health readiness. My testimony will focus on rapid detection of an event, which is the topic of discussion for this sub-committee today.

National disease detection can best be described as the ongoing collection, analysis and dissemination of public health data related to illness and injury. These ongoing data collection and analysis activities enable public health officials to detect disease early, thus resulting in faster intervention to control and contain the consequences created by the causative agents. Without these early detection systems, the consequences of outbreaks of infectious disease and human exposures to agents such as chemicals and radiation would take a much greater toll by way of increased illness, injury, and in some cases death. Recent events, such as the SARS and Monkeypox outbreaks, have underscored the essential role early detection systems play in mobilizing rapid response. Detection of a disease almost always occurs at the local level where health care professionals encounter patients seeking medical assessment or treatment. A clinician's ability to quickly recognize and identify symptoms of unusual illnesses on the frontline has been critical to the CDC's ability to recognize unfolding disease events and implement containment measures to prevent further spread of disease, thus mitigating further harm to the public. Today, I will address three critical components of our disease detection systems: (1) Current state of national disease detection systems; (2) the Public Health Information Network PHIN; and (3) global disease surveillance.

Current State of National Disease Detection Systems

One key to successful defense against any threat to the nation's public health, whether naturally occurring or deliberately caused, continues to be accurate, early recognition of the problem.

Awareness and diagnosis of a condition by a clinician or laboratory is a key element of our current disease detection systems. Clinicians and laboratories report diseases to state and local health departments, which in turn share information with CDC. CDC works with its public health partners to define conditions that should be reported nationally. Health departments share these definitions and guidelines with health care providers, infection control practitioners, emergency department physicians, laboratorians, and other members of the health care system to ensure accurate and timely reporting.

Many local reporters of disease incidence still report to public health authorities on paper via facsimile. If a case of illness is particularly unusual or severe (such as a case of anthrax), the local health care worker may call the local health department immediately to report the case. Current reporting systems are largely paper-based and burdensome to both providers and health departments, often resulting in reports which are neither complete nor timely. In addition to initial detection, these detection and reporting systems play a pivotal role in the detection of subsequent cases and help support the management of the event once a response/investigation are initiated. Such information is vital to coordinating response decisions, which ultimately lead to the containment of an outbreak.

A comprehensive surveillance system requires a strong foundation at all levels of local, state, and federal public health agencies. CDC has been working with state and local health agencies for many years to build the public health infrastructure to improve disease detection and reporting systems. Since September 11, 2001, the Administration has budgeted for and the Congress has appropriated over $2 billion to develop and sustain state and local public health readiness, specifically to enhance capacities to detect, respond, contain and recover from biological, chemical, and radiological acts of terrorism. States estimate that they are spending significant portions of this funding in both FY02 and FY03, to: 1) enhance epidemiological and surveillance capacity and 2) develop and leverage information technology and systems to support various public health functions.

Some examples of how states used their funding in these areas include:

  • Michigan has begun implementation of a secure web-based disease surveillance system to improve the timeliness and accuracy of disease reporting.

  • Missouri has implemented a new hospital tracking system to detect possible outbreaks by monitoring the number of patient admissions and ambulance diversions at hospitals. This system provides a way for hospitals to obtain instant messages and alerts.

  • Virginia, Maryland, Washington DC, and Pennsylvania are all developing early warning systems based on symptom data from emergency departments to detect unusual patterns of illness and automatically alert hospitals and public health agencies when the incidence of disease exceeds a critical threshold. Use of such early warning systems might enable the earliest possible response and intervention before an outbreak or epidemic spreads.

Other related activities useful for early detection of emerging infections or other critical biological agents include CDC's Emerging Infections Programs (EIP). Through the EIP, state and local health departments receive funds to conduct population-based surveillance that goes beyond their routine function to develop "next generation" surveillance science, and often involves partnerships among public health agencies and academic medical centers. In addition, CDC has established networks of clinicians that serve as "early warning systems" for public health by providing information about unusual cases encountered in the clinical practices. As noted earlier, these relationships, particularly between health care providers and local health departments, are the foundation on which disease detection systems operate.

Public Health Information Network

For many years CDC has made significant achievements in building or enabling state and local health agencies to build information systems that support the practice of public health. However, many of these systems operate in isolation, not capitalizing on the potential for a cross-fertilization of data exchange. A crosscutting and unifying framework is needed to better integrate these data streams for early detection of public health issues and emergencies. The Public Health Information Network (PHIN) provides this framework. Through defined data, vocabulary standards and strong collaborative relationships, the PHIN will enable consistent collection and exchange of response, health, and disease tracking data among public health partners. Ensuring the security of this information is critical as is the ability of the network to work reliably in times of national crisis. PHIN encompasses four key components: (1) detection and monitoring; (2) analysis and interpretation; (3) information dissemination and knowledge management; and (4) public health response. Each of these components is briefly described below.

Public health information systems must support functions that include:

  • Early event detection - BioSense is being developed to support early event detection activities associated with a possible Bioterrorism threat. Regional health data will be sent to authorized health officials detailing health trends that could be related to a possible Bioterrorism attack.

  • Routine public health surveillance - NEDSS supports routine surveillance activities associated with the rapid reporting of disease trends to control outbreaks. The NEDSS platform allows states to enter, update and electronically transmit demographic and notifiable disease data.

  • Secure communications among public health partners - Epi-X technology allows for the secure exchange of communications between participating public health partners via the web by providing up-to-the-minute information, reports, alerts, and discussions about terrorist events, toxic exposures, disease outbreaks, and other public health events.

  • Management and dissemination of information and knowledge - HAN's architecture upgraded the capacity of state and local health agencies to communicate different health threats such as emerging infectious and chronic diseases, environmental hazards, as well as Bioterrorism related threats.

  • Other functions include - Analysis and interpretation of relevant public health data and public health response systems.

PHIN will provide the framework for these functions to serve as part of an integrated and interoperable network critical in establishing a more effective public health system.

Detection and Monitoring

The CDC is in the proof-of-concept stage of BioSense a proposal in development to enhance early event detection for public health emergencies such as bioterrorism. BioSense is proposed to enhance the nation's capabilities to rapidly detect and quantify public health emergencies by enabling rapid access to, and analysis of, diagnostic and pre-diagnostic health data. BioSense could establish the capability for rapid, around-the-clock electronic transmission of data to local, state and federal public health agencies from national, regional and local health data sources such as clinical laboratories, hospital systems, health plans, DoD and VA medical treatment facilities, and pharmacy chains. Many of the pre-diagnostic data sources need to be rigorously evaluated to determine which are most effective, but importantly, the initiative is based on the use of existing data and will not add to the reporting burden of clinical care or other healthcare professionals. BioSense data would not include patient names or personal identifiers, but may allow for the identification of early signs of a possible bioterrorist attack and facilitate appropriate public health investigation and follow-up by public health authorities. As proposed, BioSense will provide public health professionals a daily picture of normal diagnostic and therapeutic activities, provide indications of abnormal activities and also provide a way to rapidly investigate events to discern true concerns from false alarms.

Some early detection activities are currently occurring in local jurisdictions. BioWatch, which is a locally managed activity, is one source of data supporting BioSense. BioWatch involves the deployment of environmental air samplers in key locations throughout a city. Filters from these air samples are routinely gathered and analyzed by public health laboratories to determine if a potential release of a biological agent has occurred. Currently, many metropolitan areas within the United States participate in this project which is led by the Department of Homeland Security with support from CDC and our state and local public health partners.

CDC has initiated the development of the National Electronic Disease Surveillance System (NEDSS) which is a part of PHIN. The ultimate goal of NEDSS is the electronic, real-time reporting of information for public health action. NEDSS will include direct electronic linkages with the health care system allowing medical information, such as diagnostic tests, to be shared electronically with public health officials as soon as a clinical laboratory receives a specimen or makes a diagnosis of a condition of public health importance.

NEDSS integrates the numerous existing disease detection and monitoring systems using a standards-based approach with standards for data, information architecture, security, and information technology. This adherence to standards will ensure that data be entered once at the point of patient care, without a need for re-entry of data at each level of reporting. Use of standards is critical in ensuring that public health practices use technology more effectively and collaboratively. The NEDSS strategy provides for state implementation of the CDC-developed version of NEDSS or state systems compatible with NEDSS. Some states are building their own NEDSS compatible systems. Two states have fully implemented the CDC NEDSS system and thirty other states have requested installation of the CDC-developed system.

As NEDSS progresses, we need to ensure that the data standards we use are compatible with those used in the health care delivery system. This will ensure ease of adaptation to future advancements in the field and ease of use for all levels of the clinical and public health systems. Moreover, NEDSS is fully consistent with Secretary Thompson's recently announced Consolidated Health Informatics (CHI) standards. These are health data interoperability standards established under one of the Administration's electronic government projects covering the federal health care enterprise. In addition, a standard information and security architecture will enable public health partners to share data while ensuring patients' privacy. The reliance on industry standards for information technology ensures the ability to interface with multiple commercial products to meet the needs of the public health community, including state-of-the-art analytic tools and geographic information system capacity.

Analysis and Interpretation

CDC depends on its scientific and epidemiological expertise to interpret the volume of data received to ensure accurate conclusions are developed and disseminated to our public health colleagues in a timely manner to impact public health decisions. As we develop more integrated systems and open new channels of data and information, more powerful tools and systems will be needed to rapidly and accurately perform this critical public health task. CDC's concept of this effort is a Bio-Intelligence center or BIC. The center would provide a centralized approach to analyzing and interpreting data and information and will assure appropriate communication channels are established to provide this information and analysis back to state and local health officials. In FY2004, CDC will continue to develop and investigate this concept.

Information Dissemination and Knowledge Management

Since September 11, 2001, the anthrax attacks, and more recently the SARS and Monkeypox outbreaks, the general public, the first responder community, laboratory professionals, and our state and local partners have become more and more reliant upon the CDC website (www.cdc.gov) for critical public health information and knowledge resources. CDC will continue to refine this national resource as we improve our ability to provide information across the web.

Within this particular component of the PHIN is CDC's health alerting capability (formerly referred to as the Health Alert Network). Through this program all fifty states, four large cities and eight territories are receiving funding and technical assistance from CDC to strengthen core infrastructure for information access, communications, and training at the community level. This effort has built the foundation nationwide for: 1) continuous, high-speed Internet connectivity to support rapid information access; 2) broadcast capacity to support emergency communication; and 3) distance-learning infrastructure to support just-in-time training.

On September 11, 2001, CDC issued the first Health Alert Network message advising state and local health agencies of the need to enhance their disease detection systems to look for any unusual signs or symptoms related to a bioterrorist event. Since 9/11, CDC has issued over one-hundred fifty health alerts and advisories reaching 1.5 million health care professionals, as well as other first responder communities, on topics such as bioterrorism, West Nile virus, SARS, patient safety, and smallpox vaccination. Over 95% of our nation's public health agencies have the capability to receive and/or further distribute critical health alerts to their community stakeholders. The ability to access the web has allowed state and local health departments to utilize CDC's web based resources including CDC's secure communication system, Epi-X.

Epi-X (the Epidemic Information Exchange) is CDC's secure web-based communications system for public health professionals. This network provides secure communication of preliminary information regarding new health threats to a limited audience of authorized public health officials. Epi-X was created to provide a single source of up-to-the-minute alerts, reports, discussions, and comments contributed by their peers, and it is moderated by medical epidemiologists at CDC. Its primary goal is to inform health officials about important public health events, help them respond to public health emergencies, and to encourage exchange of information. Through Epi-X, health officials at CDC, other federal agencies, state and local health departments, poison control centers, and the military share preliminary health surveillance information quickly and securely. Users are notified immediately of breaking health events as they occur. Currently, Epi-X has approximately 1800 users nationwide. Since its inception in December 2000, health officials have posted approximately 1500 reports of disease outbreaks. Epi-X highlights include local and national responses to terrorism, responses to emerging diseases such as severe acute respiratory syndrome (SARS) and monkeypox, West Nile virus surveillance, influenza surveillance, foodborne outbreaks and food recalls that affected residents in multiple states, and investigations of travelers with contagious illnesses.

Public Health Response

Since the majority of the data management needs come after disease is detected, CDC through PHIN is investing in information systems to support our public health response teams, our Director's Emergency Operations Center in Atlanta and to assist state and local health agencies in tracking and managing vital public health information before, during, and after an event has occurred. These systems have been used to support the SARS outbreak, special events such as the 2002 Winter Olympics in Salt Lake City, and other events that could potentially be targets of a terrorist attack.

Global Disease Surveillance

The emergence of SARS, a previously unrecognized infectious disease outbreak, has provided a strong reminder of threats posed by emerging infectious diseases. In March 2003, the Institute of Medicine (IOM) published Microbial Threats to Health: Emergence, Detection, and Response, a report describing the spectrum of microbial threats to national and global health, factors affecting their emergence or resurgence, and measures needed to address them effectively. Although much progress has been made, especially in the areas of strengthened surveillance and laboratory capacity, CDC is taking steps to make further improvements both domestically and internationally.

CDC is intensifying its efforts to work with the World Health Organization (WHO) and other partners to create a comprehensive global network that detects and controls outbreaks before they grow into worldwide pandemics. Currently, there are Field Epidemiology Training Programs (FETP's) in thirty countries throughout the world that support disease detection activities and provide an essential link in global surveillance. The FETP program is modeled after CDC's Epidemic Intelligence Service (EIS) training program which focuses on training public health practitioners in epidemiology and surveillance and their application as a means to detect and control outbreaks and to implement interventions to prevent the further spread of disease. Additionally, there is a concerted effort to develop and expand regional disease surveillance networks that include less developed nations as members.

CDC has also created two International Emerging Infections Programs (IEIPs)--one in Thailand (established in 2001) and one in Kenya (scheduled to open in 2003)--that are modeled on the domestic EIP Programs described earlier which have been so successful in the United States. The IEIPs will help to foster the next generation of international public health leaders while providing high quality disease surveillance data and rapid response capacity for new and emerging diseases.


CDC is committed to working with federal, state and local partners to protect the nation's health. Our best public health strategy against disease is the development, organization, and enhancement of public health disease detection systems, tools, and the people needed to wield them. The astute clinician remains the critical link in disease detection and reporting. The first case of West Nile in 1999, and the first case of anthrax reported in early October 2001, were identified by astute clinicians. Training and education of these front-line health protectors remains a high priority for CDC and will continue to be a priority as we strive to improve all components of the nation's disease detection systems.

While we have made substantial progress towards enhancing the nation's capability to rapidly detect disease within our communities, improving our response and containment strategies, and developing plans to recover from tragic events, much remains to be done. CDC is very grateful for the congressional support received to date and looks forward to working with the Members of Congress, especially this committee as we strive to protect the public's health from terrorism and other public health emergencies.

Thank you very much for your attention. I will be happy to answer any questions you may have.

Last Revised: September 25, 2003