Foodborne Illness Surveillance, Response, and Data Systems
Many surveillance systems are used in the United States to provide information about the occurrence of foodborne disease. Most of CDC’s surveillance systems rely on data from state and local health agencies. Some focus on specific pathogens likely to be transmitted through food and have been used extensively for decades. More recently, new surveillance methods have emerged which improve the quality, quantity, and timeliness of data (e.g., sentinel surveillance systems and national laboratory networks).
Each surveillance system plays a role in detecting and preventing foodborne disease and outbreaks. CDC provides leadership for the following surveillance systems:
Foodborne Disease Active Surveillance Network (FoodNet)
Reports trends in foodborne infections and tracks the impact of food safety policies nationally
Foodborne Diseases Active Surveillance Network, referred to as FoodNet, is the principal foodborne disease component of CDC's Emerging Infections Program. It is a sentinel1 surveillance system that collects information from sites in 10 states—covering 15% of the US population, or 46 million Americans—about diseases that are caused by any of seven bacteria and two parasites2 commonly transmitted through food. The system has been in operation since 1995. Investigators actively seek out laboratory confirmed cases of illness in an attempt to detect every person in the 10 sites who went to a doctor's office, had a sample tested, and was diagnosed with one of these infections. With the information on epidemiology, incidence, and trends of foodborne diseases in the US, public health officials can conduct analyses and epidemiological studies. FoodNet is a collaborative program among CDC, the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS), the Food and Drug Administration (FDA), and state health departments in Connecticut, Georgia, Maryland, Minnesota, New Mexico, Oregon, Tennessee, and selected counties in California, Colorado, and New York.
National Antimicrobial Resistance Monitoring System—enteric bacteria (NARMS)
Enhances collaboration among public health and agricultural agencies to detect, respond, and prevent antimicrobial resistance among foodborne bacteria
The National Antimicrobial Resistance Monitoring System, referred to as NARMS, conducts surveillance for antimicrobial resistance among foodborne bacteria. It has been monitored jointly by CDC, the Center for Veterinary Medicine in the Food and Drug Administration, and USDA since 1996. CDC is in charge of samples isolated from humans. Annual reports from all three agencies are published and can be found online (FDA, USDA). .
- Surveillance Reports: NARMS Annual Reports
National Electronic Norovirus Outbreak Network (CaliciNet)
Rapidly links clusters of illness and identifies emerging norovirus strains
The National Electronic Norovirus Outbreak Network, or CaliciNet, rapidly links norovirus clusters to outbreaks with a common food source, as identifying emerging norovirus strains. The network allows public health agencies to determine which samples are part of the same outbreak. CaliciNet went live in March 2009 and currently has 25 states certified for participation, reporting norviruses that are spread either through food or person to person, important given that norovirus causes the majority of foodborne illness in the United States. CaliciNet is linked to the National Outbreak Reporting System (NORS).
National Molecular Subtyping Network for Foodborne Disease Surveillance (PulseNet)
Connects cases of illness nationwide to quickly identify outbreaks, including many that would otherwise go undetected
The National Molecular Subtyping Network for Foodborne Disease Surveillance, or PulseNet, connects cases to potential outbreaks, especially across states. PulseNet has revolutionized the detection and investigation of foodborne disease outbreaks, especially those occurring in multiple sites across the country which, before PulseNet, often went undetected or were detected only after they grew very large. Analysis is done through subtyping and categorization of foodborne bacterial pathogens though a standardized process of pulsed-field gel electrophoresis (PFGE)3. PulseNet is a national network of local, state, territorial, agricultural, and federal laboratories—in all 50 states and 82 countries—coordinated by CDC and the Association of Public Health Laboratories (APHL) since 1996. PulseNet allows investigators from participating sites to upload PFGE patterns to an electronic database and compare them with patterns of other pathogens isolated from humans, animals, and foods to identify matches and possible linkages between pathogens (e.g., outbreaks).
National Surveillance for Enteric Disease
Provides a national picture of the occurrence of infections and their impact on human health
CDC collects and analyzes data from all states on infections due to enteric bacterial pathogens including species of Listeria, Salmonella (including Salmonella serotypes Typhi and Paratyphi), Shigella, and Vibrio (including V. cholerae), and Shiga toxin-producing Escherichia coli (STEC), and case reports of botulism which are nationally notifiable in order to track and improve understanding of the human health impact of these infections in particular populations. This information provides a national picture of the occurrence of these infections. Infections caused by species of Campylobacter are not nationally notifiable, but many states voluntarily submit data on Campylobacter infections to CDC. Information is gathered from both "case-based" and "laboratory-based" surveillance systems.
"Case-based" surveillance relies on the collection of reports of cases of illness. These case reports include information such as the symptoms of illness, when those symptoms started, demographic information about the ill person (age, sex, state of residence), and key risk factor information (e.g., travel, activities, foods consumed) for the specific infection. CDC conducts case-based surveillance for botulism, cholera and other Vibrio illnesses (including V. parahaemolyticus and V. vulnificus infections), Listeria infections, and Typhoid and Paratyphoid infections by collecting case report forms for each person who is diagnosed with a case of one of these illnesses. These data are reported to CDC by state and territorial public health departments.
"Laboratory-based" surveillance relies on the collection of information about bacteria that have been identified by laboratory testing of ill persons. Bacteria are isolated and identified from patient specimens by clinical laboratories, and the isolates are then submitted to state public health laboratories for further characterization or reported to them. CDC conducts laboratory-based surveillance for infections caused by Salmonella, Shigella, Shiga toxin-producing Escherichia coli (STEC), and Campylobacter, using reports from state and territorial public health laboratories.
- Surveillance Reports:
Foodborne Disease Outbreak Surveillance System (FDOSS)
Captures outbreak data on agents, foods, and settings responsible for illness
CDC collects reports of foodborne outbreaks due to enteric bacterial, viral, parasitic, and chemical agents. State, local, and territorial public health agencies report these outbreaks to the Foodborne Disease Outbreak Surveillance System through the National Outbreak Reporting System (NORS). The CDC surveillance team conducts analyses of these data to improve understanding of the human health impact of foodborne outbreaks and the pathogens, foods, settings, and contributing factors (for example, food not kept at the right temperature) involved in these outbreak, which can identify microbes and their associated foods. Though this system has existed since 1973, starting in 2009, the system has also included modules for reporting enteric disease outbreaks transmitted through water, person-to-person contact, or direct contact with animals. The data transmission tool that preceded NORS was called the electronic Foodborne Outbreak Reporting System (eFORS) from 1998-2008.
For data on foodborne outbreaks, the Foodborne Outbreak Online Database (FOOD) can be searched. Foodborne Outbreak Online Database (FOOD) is an annual listing of foodborne disease outbreaks in the United States (1998–2009) which has been designed to allow the public direct access to information on foodborne outbreaks reported to CDC. Most outbreaks are reported to the system by the state, local, territorial, or tribal health department that conducted the outbreak investigation. Outbreak reporting is voluntary. Multistate outbreaks are generally reported by CDC. For more information, see FOOD Tool Questions and Answers.
- Surveillance Reports: Annual Reports of Surveillance for Foodborne Disease Outbreaks
Environmental Health Specialists Network (EHS-Net):
Contributing factor surveillance
Links environmental health specialists to epidemiologists and laboratorians to identify and prevent environmental factors contributing to illnesses and outbreaks
“Good surveillance does not necessarily ensure the making of the right decisions, but it reduces the chances of wrong ones.”
Dr. Alexander D. Langmuir, 1963
Founder of the Epidemic Intelligence Service
In the Environmental Health Specialists Network, or EHS-Net, investigators from state and local public health agencies gather information about contributing factors in foodborne outbreaks through environmental assessments conducted by food control officials and report the results to CDC. Contributing factors cannot be identified through general inspections of operating procedures or sanitary conditions, such as those used for licensing or routine inspection of a restaurant, but require a systematic description of what happened and how events most likely unfolded in an outbreak. EHS-Net was established in 2000 to address the environmental causes of foodborne disease. Participants include environmental health specialists and epidemiologists from nine states, the US Food and Drug Administration (FDA), the Food Safety Inspection Service in the US Department of Agriculture (FSIS/USDA), and CDC. CDC has developed through EHS-Net an electronic reporting system for contributing factors and other root causes of foodborne outbreaks. In 2012, this EHS-Net activity will be launched nationally through the Conference for Food Protection as the National Voluntary Environmental Assessment Information System (NVEAIS) and participation will be open to any food regulatory program in the United States.
- Publications and presentations of EHS-Net studies
- Periodic reports from the NVEAIS system will be posted and made available through appropriate publications.
DPDx: Laboratory Identification of Parasites of Public Health Concern
Strengthens diagnosis of parasitic diseases in the US and around the world through interactive technology and distance-based education
DPDx offers many services including diagnostic assistance (through telediagnosis, laboratory inquiries, and technology transfer) and training (via an interactive website, monthly case studies, workshops, and CD-ROM tools).
- Surveillance Reports:
National Notifiable Diseases Surveillance System (NNDSS)
Tracks notifiable infectious diseases across the US
The National Notifiable Disease Surveillance System, or NNDSS, tracks contagious diseases that laboratory professionals and doctors are required to report to the state or territorial public health agency. These agencies voluntarily submit the information to NNDSS, which CDC oversees. The general system has been in existence since 1878. Notifiable disease surveillance is "passive" (i.e., the investigator at CDC waits for disease reports from those required to report) and is susceptible to underreporting. Foodborne diseases that are reportable include botulism, cholera, hemolytic uremic syndrome (HUS), listeriosis (Listeria), salmonellosis (Salmonella), Shiga Toxin-producing Escherichia coli (STEC) infections, shigellosis (Shigella), and vibriosis.
- Nationally notifiable diseases and conditions and current case definitions for 2012 [PDF - 148 pages]
- Annual Summaries 1993-2010
- Weekly Summaries of State/Territory Counts