FoodCORE NOU Metrics
NOU metrics apply to Norovirus, other enteric disease pathogens, such as Cryptosporidium or Giardia, and outbreaks of unknown etiology. Collectively, these are referred to as the NOU metrics, for norovirus, other etiologies, and unknown etiologies. Other etiologies are enteric illnesses with determined etiology that are not Salmonella, Shiga toxin-producing Escherichia coli, Listeria, Shigella, Campylobacter, or norovirus. Unknown etiologies are enteric illness with no determined/identified etiology from case, product, or environmental testing to indicate the etiologic agent. This can be because no specimen or sample yielded an isolate or other positive result, and would also include investigations where no specimens or samples were collected.
The FoodCORE performance metrics are a list of measurable activities covering diverse aspects of outbreak response. These activities span from outbreak surveillance and detection through investigation, response, control, and prevention measures. Using the metrics, each center provides data about the burden, timeliness, and completeness of foodborne disease activities related to the key areas of activity. Data for all years of the FoodCORE program are available.
NOU Metrics
Laboratory-based Metrics
Rationale: The intent of these metrics is to evaluate the timeliness and completeness/availability of laboratory surveillance and subtyping data for norovirus, other etiology, and unknown etiology investigations. These metrics include all NOU investigations; they are not limited to foodborne or point-source, but include person-to-person NOU investigations as well. These metrics can be used to determine if there are gaps in the diagnostic specimen handling and testing processes. If gaps are identified, knowing the detailed circumstances around the gap will help develop targeted actions to address them specifically.
Note: These laboratory-based metrics are for laboratory testing conducted at the reporting public health laboratory. For laboratories that are not equipped to perform a certain type of testing (e.g., testing for certain viruses or parasites), the measures related to those tests would not be applicable since the completeness and timeliness of the testing would not be within the control of the reporting laboratory.
Investigation-based Metrics
Rationale: The intent of these metrics is to evaluate response activity related to investigations. These metrics can be used to determine if there are gaps in investigational activities. If gaps are identified, knowing the detailed circumstances around the gap will help develop targeted actions to address them specifically.
Outbreak-based Metrics
Rationale: The intent of these metrics is to evaluate outbreak reporting activity. These metrics can be used to determine if there are gaps in outbreak reporting. If gaps are identified, knowing the detailed circumstances around the gap will help develop targeted actions to address them specifically.
NOTE: 1Minimum reporting requirement for FoodCORE Centers
Definitions
Other Etiology: Enteric illness with determined etiology that is not Salmonella, Shiga toxin-producing Escherichia coli, Listeria, Shigella, Campylobacter, or norovirus.
Unknown Etiology: Enteric illness with no determined/identified etiology from any of the case, product, or environmental testing to indicate the etiologic agent. This can be because no specimen or sample yielded an isolate or other positive result, and would also include investigations where no specimens or samples were collected.
Foodborne or Point-source Investigation: Epidemiologic activity in response to cases where there is indication of non-person-to-person transmission of a similar enteric illness. This includes investigations where there are demographic or epidemiologic indications of a common, point-source of infection even without laboratory subtyping data to link cases.
Specimens: This will include all clinical specimens submitted to PHL.
Samples: This will include all non-clinical, samples (food, environmental, etc.) submitted to PHL.
Exposure assessment: To include an interview (of any format) that assesses exposures prior to onset of illness, via an open-ended exposure history, or via a list of potential exposures. The key factor to be considered an exposure history is an interview that goes beyond assessment of high-risk settings and prevention education to ascertain food consumption/preference, or other exposure data.
Analytic epidemiologic study: A systematic, statistical analysis against a comparison group or within a cohort to test a hypothesis
Suspect norovirus or other etiology outbreak: If there are not sufficient specimens or samples to classify an outbreak as a confirmed norovirus or other etiology, but the available data (testing, epidemiologic data such as signs, symptoms, and incubation period) indicate an etiologic agent, an investigation should still be classified under norovirus or other etiology, as appropriate, for metrics reporting.
Confirmed norovirus outbreak: Outbreak with two or more clinical specimens positive for norovirus by RT-PCR, EM, or EIA.
Confirmed other etiology outbreak: For most etiologic agents, CDC considers an outbreak to have a confirmed etiology if there are two or more lab-confirmed cases. However, in botulism, marine toxins, and other chemical outbreaks, the definition of a confirmed etiology is not as strict. Since botulism, marine toxins, and other chemical outbreaks have such distinct clinical symptoms, a physician’s diagnosis is often sufficient and laboratory confirmation is not necessary. Therefore, for such outbreaks, CDC would consider it a confirmed etiology outbreak if there is at least 1 probable case (based on clinical symptoms). (See also: Other Etiology definition above)
All measurements of time are in median days: Measurements will exclude weekend days. For laboratory time measurements, only isolates subtyped at the PHL should be included.
Vehicle/source Identified:
SUSPECT vehicle/source investigations: Investigations of infection where investigational and/or laboratory data indicate a likely vehicle/source of infection without confirmation: vehicle/source is a known risk factor, established errors in food preparation, or reported consumption by a high proportion of cluster-associated cases.
CONFIRMED vehicle/source investigations: Investigations of infection where the etiologic agent has either been identified from the vehicle/source, or the vehicle/source has been statistically implicated in an analytic study.
Control measure: to include interventions such as exclusion of an ill person(s) from high risk setting, remediation or closure of an establishment linked to illness, educational campaigns during daycare outbreaks, etc. To be considered a control measure, activities should extend beyond the routine educational component of an interview or exposure assessment.
Public health action: to include media, public messaging (web updates, press release, etc.), or regulatory action (recall, hold, etc.). To be considered a public health action, activities should extend beyond the routine investigation activities and reach at-risk individuals beyond identified cases. A public health action should be included in the metrics if the FoodCORE Center was directly involved in the action, or is aware that a public health action was taken during a multijurisdictional investigation. For example, if CDC produces public messaging during a multistate outbreak investigation that a FoodCORE Center is involved in, that investigation would be associated with a public health action for the purposes of the metrics.