yellow fever
Enable an agent to recognise yellow fever, assess evidence and disease progression, and identify appropriate clinical and public-health actions under applicable guidance.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an agent to recognise yellow fever, assess evidence and disease progression, and identify appropriate clinical and public-health actions under applicable guidance.
Yellow fever is an acute mosquito-borne infection caused by yellow fever virus, a flavivirus, that ranges from asymptomatic infection to severe disease with jaundice, haemorrhage, shock and multiorgan failure.
It can be Compare an occurrence's evidence with a named, versioned yellow fever case definition.; Identify missing specimens, timing information or confirmatory evidence needed for diagnostic review.; Track progression and flag observations meeting a cited escalation criterion.; Link suspected or confirmed occurrences to the applicable notification and investigation workflow.; Assess prevention needs against dated exposure information and vaccination guidance.; Compare population burden estimates while preserving their denominators and uncertainty..
Distinguishing features
Yellow fever is attributable to yellow fever virus transmitted by infected mosquitoes; fever or jaundice alone does not establish its identity. [WHO fact sheet](https://www.who.int/en/news-room/fact-sheets/detail/yellow-fever)
Clinical disease can be mild or severe; jaundice is not required to recognise every occurrence. [CDC clinical diagnosis](https://www.cdc.gov/yellow-fever/hcp/clinical-diagnosis/index.html)
Interpret laboratory evidence against specimen timing: a negative molecular test does not independently exclude yellow fever. [CDC clinical diagnosis](https://www.cdc.gov/yellow-fever/hcp/clinical-diagnosis/index.html)
Separate evidence of natural infection from vaccine-related antibody responses and cross-reactivity with other flaviviruses. [CDC clinical diagnosis](https://www.cdc.gov/yellow-fever/hcp/clinical-diagnosis/index.html)
Distinguish natural yellow fever from suspected vaccine-associated illness; recent vaccination requires explicit consideration when classifying evidence. [CDC 2019 surveillance definition](https://ndc.services.cdc.gov/case-definitions/yellow-fever-2019/)
Scope
+ Disease identity and versioned terminology mappings
+ Exposure to yellow fever virus and transmission context
+ Clinical manifestations, progression and severity
+ Diagnostic evidence and versioned case classification
+ Disease-specific prevention, response and population burden
- The patient's complete health record
- The healthcare encounter, admission or billing episode
- Full taxonomy and biology of the virus, mosquito vectors and animal hosts
- Vaccine product manufacture and general immunisation service operations
- Independent models of malaria, dengue, viral hepatitis and other differential diagnoses
Characteristics
- Disease identity mapping
- Registry id plus verified ICD-10, ICD-11 or SNOMED CT identifier, edition, jurisdiction and mapping relationship Prevents an unversioned code or approximate mapping from silently redefining yellow fever.
- Diagnostic assertion status
- Clinical assessment or surveillance classification, retaining the issuing authority's labels and criteria version Keeps clinical judgment distinct from reportable-case classification.
- Exposure context
- Location, dates, activities, mosquito exposure and linked local transmission evidence Makes exposure plausibility assessable without treating travel history as confirmation.
- Transmission cycle
- Sylvatic, intermediate, urban or undetermined; supporting evidence and geographic applicability required Connects an occurrence to the relevant transmission setting and response.
- Clinical phase
- Initial illness, apparent remission, severe recurrence, recovery or undetermined; dated observations Represents progression without assuming every occurrence follows the same sequence.
- Time from symptom onset to sampling
- Days, including uncertainty in onset date Supports interpretation of molecular and antibody testing.
- Laboratory evidence
- Specimen, collection date, assay, result, laboratory interpretation and confirmatory evidence Retains the evidence behind a diagnostic assertion.
- Organ dysfunction
- Bilirubin and creatinine in stated concentration units; transaminases in U/L; platelet count in stated count units; INR dimensionless; dated clinical observations Supports assessment of hepatic, renal and haemostatic involvement using trends and applicable reference ranges.
- Vaccination context
- Documented vaccination dates, product where known, evidence source and timing relative to illness Informs susceptibility assessment and interpretation of diagnostic evidence.
- Population burden estimate
- Cases, incidence, deaths or case-fatality proportion with population, period, denominator, ascertainment method and uncertainty Prevents reported cases, estimated infections and severe-case outcomes from being conflated.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 7 bundles · 13 layers · 21 findings · 40 questions.
Yellow fever identity Defines the disease and its relationships to classification systems and individual occurrences.
The missing registry definition must be supplied without confusing the disease with jaundice, the virus or a care encounter.
Defining cause and boundaries
Establishes what qualifies as yellow fever and which neighbouring concepts remain separate.
Causal disease definition
Record the authoritative disease definition and distinguish infection, symptomatic disease and vaccine-associated adverse events.
- Which authoritative definition establishes yellow fever virus as the cause of this disease? definition
- How should asymptomatic infection and suspected vaccine-associated illness relate to this disease concept? boundary
Terminology and occurrence links
Maintains versioned identifiers and separates the disease from assertions about an individual.
Versioned classification
Require verified terminology mappings and explicit links between disease occurrence, diagnostic assertion, patient and care episode.
- Which ICD-10, ICD-11 and SNOMED CT entries map to yellow fever, and in which releases and jurisdictions? provenance
- Does each mapped entry denote yellow fever generally or a narrower transmission subtype? boundary
- How will one suspected occurrence retain revised diagnoses across multiple encounters without being counted repeatedly? definition
Exposure and transmission Connects possible acquisition to time, place and transmission ecology.
Yellow fever assessment needs exposure context and distinctions between forest, intermediate and urban transmission.
Acquisition window
Records the interval and locations in which infection may have been acquired.
Dated exposure evidence
Capture travel or residence, relevant activities, onset timing and the provenance of local transmission information.
- Which locations and mosquito-exposure activities fall within the acquisition window supported by the selected reference? measurement
- Which dated surveillance source supports transmission at those locations during that interval? provenance
Transmission ecology
Distinguishes established transmission-cycle evidence from assumptions based on location.
Cycle attribution
Yellow fever involves mosquito transmission in forest, semi-domestic and domestic settings; cycle attribution needs local evidence. [WHO fact sheet](https://www.who.int/en/news-room/fact-sheets/detail/yellow-fever)
- What evidence supports a sylvatic, intermediate or urban cycle for this occurrence or cluster? provenance
- Which vector or nonhuman-primate observations are relevant, and which belong in linked ecological models? boundary
Diagnostic evidence Organises evidence needed to support, qualify or revise a yellow fever diagnosis.
Clinical overlap, testing windows and antibody interpretation make a simple positive-or-negative disease label inadequate.
Clinical and surveillance assessment
Separates clinical differential diagnosis from criteria used to count and report cases.
Case definition and differentials
Surveillance definitions serve a different purpose from individual clinical diagnosis. [CDC 2019 surveillance definition](https://ndc.services.cdc.gov/case-definitions/yellow-fever-2019/)
- Which issuing body, jurisdiction and revision govern the recorded yellow fever case classification? provenance
- What evidence distinguishes this presentation from malaria, dengue, leptospirosis, viral hepatitis or poisoning? boundary
- Which clinical assessment remains unresolved even if surveillance criteria are satisfied? definition
Specimen and assay interpretation
Preserves the context necessary to interpret virological and serological results.
Timing and serologic ambiguity
Retain specimen timing, vaccination history and possible flavivirus cross-reactivity alongside every laboratory interpretation.
- What specimen and assay were used, and how many days after symptom onset was the specimen collected? measurement
- Could vaccination or another flavivirus exposure explain the antibody finding, and what confirmatory evidence addresses that ambiguity? boundary
- What additional testing or expert interpretation does the applicable laboratory guidance require? action
Course, severity and outcome Represents the changing state of an individual yellow fever occurrence.
A single diagnosis cannot express early illness, apparent improvement, deterioration and recovery.
Illness timeline
Tracks observed progression without imposing an obligatory sequence.
Phase transitions
Some infections progress to recurrent fever with jaundice, bleeding or organ failure after initial symptoms subside. [WHO fact sheet](https://www.who.int/en/news-room/fact-sheets/detail/yellow-fever)
- When did symptoms begin, improve, recur or resolve, and how certain are those dates? measurement
- Which observed findings justify the assigned phase rather than merely assuming the usual course? definition
Organ dysfunction and resolution
Connects serial clinical evidence to severity, escalation and outcome assessment.
Severity and outcome evidence
Record organ involvement, measurement trends and dated outcomes using explicit assessment criteria.
- What dated observations establish hepatic injury, renal dysfunction, bleeding, shock or altered consciousness? measurement
- Which cited severity criteria or changes require urgent clinical escalation? action
- What evidence supports recovery, persistent impairment or death attributable to yellow fever? provenance
Prevention and response Connects yellow fever evidence to vaccination assessment, clinical care and public-health response.
Recognising the disease must support appropriate action while preserving clinical authority and jurisdictional requirements.
Vaccination and protection
Relates documented vaccination and exposure risk to applicable preventive guidance.
Individual prevention assessment
Keep vaccination evidence, eligibility assessment and travel-document requirements distinguishable.
- What documented vaccination history and individual precautions affect assessment under the applicable guidance? provenance
- Which vaccination review and mosquito-bite prevention actions follow from the dated exposure assessment? action
- Which requirements concern clinical protection and which concern a travel certificate? boundary
Clinical and public-health actions
Records response decisions, their triggers and responsible authorities.
Care and transmission response
Clinical management is primarily supportive; the model should link care decisions to current guidance and separately track transmission-control actions. [WHO fact sheet](https://www.who.int/en/news-room/fact-sheets/detail/yellow-fever)
- Which current clinical guideline governs supportive care, referral and treatment restrictions for this occurrence? provenance
- What notification, specimen referral and outbreak investigation actions are required locally, and who is responsible? action
- During what evidence-supported interval are measures to prevent mosquitoes from biting the infected person indicated? action
Population burden and surveillance Represents where yellow fever occurs, whom it affects and how confidently its burden is known.
Population estimates must preserve time, geography, ascertainment and denominators to support valid risk judgments.
Affected populations
Describes burden in explicitly bounded populations and periods.
Population-specific frequency
Require a population and year for every frequency estimate, distinguishing incidence, prevalence and outbreak totals.
- Which population, geographic boundary and year does the estimate describe? measurement
- Does it measure infections, symptomatic cases, severe cases or deaths, and what denominator makes it interpretable? definition
Ascertainment and outbreak context
Separates reported observations from modelled burden and official outbreak determinations.
Surveillance confidence
Retain reporting methods, uncertainty, revision dates and the authority behind outbreak status.
- Is this figure a surveillance count or a modelled estimate, and how are under-ascertainment and uncertainty handled? provenance
- Which authority established the outbreak status, using what criteria and reporting date? provenance
- What evidence links the occurrence to local acquisition, importation or an unresolved source? boundary
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This is a recall-based description; no sources were consulted. The intended sense is the infectious disease.
- The listed kinds are transmission cycles, not distinct viral species or formal clinical severity classes.
- Verify current WHO case-definition versions, laboratory interpretation criteria, coding revisions and country-specific vaccination rules before operational use; no prevalence estimate is supplied.
- Which of these check these first hold for the sense of yellow fever this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Sylvatic (jungle) yellow fever transmission
- Intermediate (savannah) yellow fever transmission
- Urban yellow fever transmission
- Which of these kinds and varieties hold for the sense of yellow fever this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- WHO ICD-10 - A95 - Yellow fever category; A95.0 denotes sylvatic yellow fever, A95.1 urban yellow fever and A95.9 yellow fever, unspecified. These classify the disease, not an individual patient or encounter.
- Which of these identifiers and schemes hold for the sense of yellow fever this model covers, and on what evidence? provenance
Standards and regulation
Recalled without web access and unsourced; every item is a lead to verify.
- WHO International Health Regulations (2005), including provisions concerning yellow fever vaccination and the International Certificate of Vaccination or Prophylaxis.
- WHO yellow fever surveillance standards and suspected, probable and confirmed case definitions.
- Which of these standards and regulation hold for the sense of yellow fever this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Public-health surveillance and outbreak investigation.
- Planning routine and outbreak-response vaccination.
- Travel vaccination assessment and certification.
- Laboratory investigation of compatible febrile or jaundice-associated illness.
- Mosquito surveillance and vector-control planning.
- Which of these real-world use hold for the sense of yellow fever this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Incubation period between infection and symptom onset - 3-6 - days
- Which of these typical measurements hold for the sense of yellow fever this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Severe infection can cause hepatic injury, jaundice, bleeding, renal failure, shock and death.
- A brief improvement after the initial febrile illness can precede a severe toxic phase.
- Early symptoms overlap with malaria, dengue, leptospirosis and viral hepatitis, creating diagnostic uncertainty.
- Flavivirus antibody cross-reactivity and previous vaccination can complicate interpretation of serological tests.
- The live attenuated vaccine can rarely cause serious adverse events and is unsuitable for some people.
- Which of these failure modes and hazards hold for the sense of yellow fever this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Endemic transmission occurs in tropical regions of sub-Saharan Africa and South America.
- Sylvatic transmission involves different mosquito genera: principally Haemagogus and Sabethes in the Americas and Aedes in Africa; urban transmission is associated with Aedes aegypti.
- The intermediate transmission cycle is characteristically described in Africa.
- Which of these regional variation hold for the sense of yellow fever this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Dengue - Caused by dengue viruses rather than yellow fever virus; overlapping symptoms require pathogen-specific testing for reliable distinction.
- Malaria - Caused by Plasmodium parasites rather than a virus; parasite detection distinguishes it from yellow fever.
- Viral hepatitis - A broader group of viral liver diseases; jaundice alone does not establish yellow fever, which requires compatible epidemiology and appropriate diagnostic evidence.
- Jaundice - A clinical sign of bilirubin accumulation, not a specific infectious disease; it may occur in severe yellow fever but is not required in every infection.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of yellow fever this model covers, and on what evidence? provenance
What the second pass must settle
- Does an existing Vercy world model already cover yellow fever and therefore require this registry entry to link to it?
- Which exact ICD-10, ICD-11 and SNOMED CT identifiers and releases should be adopted, including mappings for transmission subtypes?
- Which current WHO and jurisdiction-specific diagnostic and surveillance definitions should govern classification, including recent vaccination and asymptomatic infection?
- Which current laboratory algorithms and clinical escalation criteria are applicable in the intended deployment settings?
- Which population-and-year burden estimates are sufficiently supported, and how should surveillance counts, modelled infections and any prevalence measures be reconciled?