From c11dcf2be334799c154422f66eba0ee4369713e4 Mon Sep 17 00:00:00 2001 From: "Schumacher, Jakob" Date: Mon, 23 Sep 2024 16:09:45 +0200 Subject: [PATCH] Case definitions added --- 3_Steps/step3.qmd | 56 ++++++- docs/1_Overview/01_overview_background.html | 4 +- docs/1_Overview/02_overview_steps.html | 6 +- docs/1_Overview/03_overview_types.html | 4 +- docs/1_Overview/04_overview_attributes.html | 12 +- docs/1_Overview/05_overview_evaluation.html | 2 +- .../2_Background/02_background_decisions.html | 6 +- .../03_background_definition.html | 2 +- .../04_background_othersurveillance.html | 2 +- .../05_background_objectives.html | 2 +- docs/2_Background/06_background_legal.html | 4 +- docs/3_Steps/step1.html | 2 +- docs/3_Steps/step2.html | 6 +- docs/3_Steps/step3.html | 145 +++++++++++++++++- docs/3_Steps/step4.html | 6 +- docs/3_Steps/step5.html | 2 +- docs/3_Steps/step6.html | 2 +- docs/3_Steps/step7.html | 2 +- docs/4_Types/02_type_case.html | 4 +- docs/4_Types/03_type_syndromic.html | 2 +- docs/4_Types/04_type_event.html | 2 +- docs/4_Types/05_type_wastewater.html | 2 +- docs/4_Types/06_type_mortality.html | 2 +- docs/4_Types/07_type_massgathering.html | 2 +- docs/4_Types/08_type_activevspassive.html | 2 +- docs/4_Types/09_type_sentinel.html | 2 +- docs/Infectious-disease-surveillance.epub | Bin 2562519 -> 3044259 bytes docs/Infectious-disease-surveillance.pdf | Bin 1507393 -> 1930949 bytes docs/img/steps_casedefinitions_avian.png | Bin 0 -> 153056 bytes ...eps_casedefinitions_caseclassification.png | Bin 0 -> 48479 bytes docs/img/steps_casedefinitions_qfever.png | Bin 0 -> 87791 bytes docs/img/steps_casedefinitions_zika.png | Bin 0 -> 200255 bytes docs/index.html | 2 +- docs/search.json | 61 +++++++- docs/sitemap.xml | 6 +- img/steps_casedefinitions_avian.png | Bin 0 -> 153056 bytes ...eps_casedefinitions_caseclassification.png | Bin 0 -> 48479 bytes img/steps_casedefinitions_qfever.png | Bin 0 -> 87791 bytes img/steps_casedefinitions_zika.png | Bin 0 -> 200255 bytes 39 files changed, 296 insertions(+), 56 deletions(-) create mode 100644 docs/img/steps_casedefinitions_avian.png create mode 100644 docs/img/steps_casedefinitions_caseclassification.png create mode 100644 docs/img/steps_casedefinitions_qfever.png create mode 100644 docs/img/steps_casedefinitions_zika.png create mode 100644 img/steps_casedefinitions_avian.png create mode 100644 img/steps_casedefinitions_caseclassification.png create mode 100644 img/steps_casedefinitions_qfever.png create mode 100644 img/steps_casedefinitions_zika.png diff --git a/3_Steps/step3.qmd b/3_Steps/step3.qmd index 22cc431..009d1b4 100644 --- a/3_Steps/step3.qmd +++ b/3_Steps/step3.qmd @@ -1,5 +1,57 @@ --- -title: "Step 3: Classification" +title: "Step 3: Case defintions" --- -Classification means categorizing the recorded events. Sometimes the word "collation" is used for this step. A person or software decides based on a definition how the event is included as a data point. Often, classification involves agreeing on what exactly counts as an event and what does not. This classification is often done using a so-called case definition. Classification is important because recorded events can be erroneous and should not be counted. Or there may not be enough information to decide whether a real event has occurred. Without classification, the events form an unclear collection with questionable significance. Classification is often a hidden part of the surveillance system or built into the system in a way that it is not recognized as such. For example, the application of case definitions in the reporting system is built into the reporting software. Even in seemingly trivial classifications, important definitions must be agreed upon: Does the death of a tourist with a foreign passport count as a death in the context of mortality surveillance? + +Classification means categorizing the recorded events. Sometimes the word "collation" is used for this step. A person or software decides based on a definition how the event is included as a value in the data. Often, classification involves agreeing on what exactly counts as an event and what does not. Classification is important because recorded events can be erroneous and should not be counted. Or there may not be enough information to decide whether a real event has occurred. Without classification, the events form an unclear collection with questionable significance. Classification is often a hidden part of the surveillance system or built into the system in a way that it is not recognized as such. For example, the application of case definitions in the reporting system is built into the reporting software. Even in seemingly trivial classifications, important definitions must be agreed upon: Does the death of a tourist with a foreign passport count as a death in the context of mortality surveillance? + +Classification is usually done with case definitions. + +## Definition of case definition +Case Definitions = A set of uniform criteria used to define a disease, health event or condition for public health surveillance (infectious and non-infectious diseases) + +## Rationale +- Case definitions are used by epidemiologists / public health authorities +- Case definitions ≠ no clinical definition, such as e.g. ICD-10 codes +- Enable public health officials to classify and count cases consistently across reporting jurisdictions (avoids comparing “apples to oranges’’) + +## Components of case definitions + +|Component|Explanation| +|---|---| +|Time|The timeframe in which a disease is looked at (in surveillance systems this is often missing)| +|Place|Where a disease is looked at. E.g. a region| +|Person|Who is looked at. It can be everybody in a certain region or it can be only a specific group in an outbreak session| +|Clinical|Include common and relevant signs and symptoms of the disease under surveillance Form either individually or in combination a clear or indicative picture of the disease| +|laboratory|Includes a list with methods used to confirm the pathogen Usually: One of the laboratory methods on the list is sufficient for confirmation of a disease| +|Epidemiological criteria|Are met when an epidemiological link is established Depending on: Incubation period of the disease Transmission Routes (person-to-person, contaminated food, …) Endemicity of the disease in the country | + +### Example for a clinical part of a case defintion +![Case definition for Q-Fever by the european center for disease control](../img/steps_casedefinitions_qfever.png) + +### Example for a laboratory part of a case defintion +![Case definition for avian flu by the european center for disease control](../img/steps_casedefinitions_avian.png) + +### Example for an epidemiological part of a case defintion +![Case definition for zika by the european center for disease control](../img/steps_casedefinitions_zika.png) + +## Categories for case definitions +There can be different categories for case definitions +- Only clinically confirmed case +- Clinically confirmed case with epidemiological link +- Clinically and laboratory confirmed case +- Laboratory confirmed with clinical criteria not met +- Laboratory confirmed with unknown clinical criteria + +## Case classification with the help of case definitions +![](../img/steps_casedefinitions_caseclassification.png) + +## Tips for developing case definitions +- Identify the objectives of the surveillance system +- Involve a multi-sectoral team (e.g. physicians, reference laboratories, epidemiologists,…) +- Balance between sensitivity and specificity when collecting / reporting +- Define important and frequently used terms (e.g. fever) +- Use a standardised format and structure for all case definitions +- Plan the implementation of the case definitions (e.g. communicate, train, evaluate) + + diff --git a/docs/1_Overview/01_overview_background.html b/docs/1_Overview/01_overview_background.html index dd1352d..c5b3513 100644 --- a/docs/1_Overview/01_overview_background.html +++ b/docs/1_Overview/01_overview_background.html @@ -235,7 +235,7 @@