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| Agenda Item 2 | Conference Room Document 75 |
second fao/who global forum of food safety regulators
Bangkok, Thailand, 12-14 October 2004
(Prepared by the United States of America)
Public health surveillance is the systematic collection of reports on specific categories of illness from health care providers and diagnostic facilities. Surveillance is the keystone of much public health and prevention activity. Surveillance drives the cycle of public health prevention. When surveillance identifies a problem, such as an outbreak of illness or an increase in incidence of a specific type of infection, a detailed epidemiological investigation is conducted to identify the nature and source of the problem, and to guide potential control measures. Applied targeted research may be stimulated by the findings of the investigation, which identify better prevention strategies. When a prevention strategy is implemented, it is surveillance that shows whether it is working, and the disease entity returns to baseline, or even better, drops to a new lower baseline.
The Centers for Disease Control and Prevention within the Department of Health and Human Services (HHS/CDC) is the lead Federal agency for conducting national disease surveillance in the United States, in collaboration with state and local health departments. HHS/CDC surveillance for foodborne disease is conducted by the respective program areas that deal with those infections and chemical poisonings, including the Division of Viral and Rickettsial Diseases for norovirus, the Division of Hepatitis for Hepatitis A, and the Division of Parasitic Diseases for parasitic infections.
HHS/CDC maintains routine national surveillance for individual cases of foodborne infections that depend on regular reporting from state public health departments. These nationally notifiable disease reporting systems collect limited standard information, but help to track trends in those infections and to alert local, state and national health authorities to potential outbreaks. These surveillance systems are voluntary and depend upon resources committed to public health at State and local health departments for their operation, as well as resources at HHS/CDC to continue and improve them. They are a warning system for outbreaks that are intentional as well as unintentional or natural.
In addition, HHS/CDC maintains a reporting system for foodborne outbreaks that are investigated and reported by local and state health departments. This is a web-based reporting system called the Electronic Foodborne Outbreak Reporting System (EFORS). EFORS collects more than 1200 reports of outbreaks each year. Reported information includes the size and impact of the outbreak, the pathogen that caused the outbreak, if determined, the food associated with the outbreak, and the nature of the information used to implicate the food, and other related observations. See www.cdc.gov/foodborneoutbreaks/.
HHS/CDC’s PulseNet employs new methods for molecular “fingerprinting” of foodborne pathogens to increase the sensitivity and timeliness of public health surveillance to detect outbreaks which are diffuse and spread over many jurisdictions. PulseNet includes HHS/CDC, 50 state and some large city public health laboratories, the U.S. Department of Agriculture Food Safety and Inspection Service (FSIS), and FDA laboratories. These laboratories are all trained and equipped to determine the “fingerprint” strains of E. coli O157, Listeria monocytogenes, Salmonella, Shigella, and other bacteria that may be foodborne. These laboratories can compare the “fingerprints” strains with what other states are seeing and with what is in the national database at HHS/CDC via the World Wide Web. The appearance of the same “fingerprint” strain in several locations at the same time can help identification and investigation of outbreaks more rapidly. PulseNet also includes an electronic information exchange that links the participating laboratories for rapid communication, troubleshooting and sharing of "fingerprint" patterns, when a cluster of related infections is suspected. By identifying clusters of infections with the same molecular fingerprint pattern, PulseNet can provide early warning of a potential outbreak, even if the cases are scattered across several states. PulseNet is now being integrated into the routine surveillance of a growing list of foodborne infections, including E. coli O157:H7, Listeria monocytogenes, and common types of Salmonella. See www.cdc.gov/pulsenet
The HHS/CDC also maintains the Foodborne Diseases Active Surveillance Network (FoodNet), the principal foodborne disease component of HHS/CDC’s Emerging Infections Program (EIP). FoodNet was established in 1996. It is a collaborative activity of HHS/CDC, HHS/FDA, FSIS, and ten EIP sites, (California, Colorado, Connecticut, Georgia, New York, Maryland, Minnesota, Oregon, Tennessee, and New Mexico). Through this active surveillance system, these sites actively seek out information on foodborne illnesses identified by clinical laboratories, collect more detailed information from patients about their illnesses, and conduct investigations to determine which foods are linked to specific pathogens. FoodNet is the best source of reliable incidence data on infections with bacteria and parasites where routine national surveillance is incomplete and trends in the number of infections of a particular pathogen occurring in a population over time. See www.cdc.gov/foodnet
Several mechanisms exist for prompt communication among federal, state and local food safety agencies, foreign governments, and the private sector. For example, HHS/CDC’s Foodborne and Diarrheal Diseases Branch maintains an email communication network that links epidemiologists from 50 states, the District of Columbia, Canada, and other HHS/CDC Divisions, to facilitate investigations. Reports of foodborne outbreaks and food safety issues may also be posted on Epi-X, a web-based public health communication network maintained by HHS/CDC. HHS/CDC, HHS/FDA, and FSIS have exchanged liaison officers to facilitate rapid communication and coordination.
Surveillance for foodborne diseases and outbreaks of foodborne diseases is the keystone of efforts to control and prevent foodborne diseases. Foodborne disease surveillance at the national level requires a multi-faceted approach that involves public health agencies at the federal, state and local levels. Public health foodborne disease surveillance is critical to early detection of a contamination event, whether it be due to unintentional or intentional causes. Furthermore, it requires a well-coordinated strategy that incorporates new laboratory techniques like molecular “fingerprinting” as well as novel surveillance and communication networks among all agencies involved in food safety. When surveillance identifies a cluster of cases that may be related, prompt public health investigation is critical to control ongoing hazards, and to identify the control points that would prevent future similar outbreaks.