{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.typhoid-fever","code":"thing-q83319","url":"https://ver.cy/models/thing/q83319/","name":"typhoid fever","alternateNames":[],"kind":"thing","status":"published","version":"0.1.0-research.1","language":"en","classifiers":{"family":"Thing Registry","category":"Activities and processes","entryKind":"thing","plane":"ACT","domain":["ACT.ACT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"Typhoid fever is a human-restricted systemic infection caused by Salmonella enterica subsp. enterica serovar Typhi, acquired by faecal-oral ingestion, that produces a prolonged febrile bacteraemic illness and, in a minority of survivors, chronic biliary carriage.","purpose":"Enable an AI agent to recognise suspected or confirmed typhoid fever, assess its course and transmission implications, and support evidence-based clinical and public-health decisions.","scope":{"in":["Attribution of an illness episode to Salmonella Typhi and explicit diagnostic uncertainty","Exposure history and the timing of fever and systemic illness","Diagnostic specimen interpretation and antimicrobial susceptibility evidence","Disease progression, complications and response to treatment","Recovery, recurrent illness, shedding and carriage follow-up","Episode-specific transmission precautions and public-health obligations"],"out":["Paratyphoid fever and other causes of undifferentiated fever","Nontyphoidal Salmonella gastroenteritis and invasive infections","Salmonella taxonomy, genome annotation and laboratory assay design","Antibiotic product specifications and general prescribing protocols","Vaccine products, immunisation programme design and sanitation infrastructure","Population-level outbreak management and the complete longitudinal patient record"],"boundaries":[]},"distinguishingFeatures":["Require Typhi-specific organism identification to distinguish confirmed typhoid from paratyphoid; their clinical presentations do not reliably separate them. [CDC Yellow Book](https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/typhoid-and-paratyphoid-fever.html)","Check the identified serovar before classifying Salmonella-associated diarrhoea or bloodstream infection as typhoid; a generic Salmonella result is insufficient. [CDC Yellow Book](https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/typhoid-and-paratyphoid-fever.html)","Distinguish compatible febrile illness from confirmed infection using microbiological evidence; neither a single negative blood culture nor a positive Widal test settles the diagnosis. [CDC clinical guidance](https://www.cdc.gov/typhoid-fever/hcp/clinical-guidance/index.html)","Separate acute illness from asymptomatic carriage by recording symptoms, specimen type and shedding duration; stool detection alone must not automatically create an acute episode. [CDC Yellow Book](https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/typhoid-and-paratyphoid-fever.html)"],"structure":{"bundles":[{"id":"typhi-attribution","name":"Typhi attribution","description":"Establish whether the episode is attributable to Salmonella Typhi and how certain that attribution is.","layers":[{"id":"disease-boundary","name":"Disease boundary","description":"Separate typhoid from neighbouring infections and distinguish clinical from surveillance labels.","findings":[{"id":"episode-classification","name":"Episode classification","description":"Record the evidence and named definition supporting the current typhoid classification.","questions":[{"text":"What definition establishes suspected, probable or confirmed typhoid in this clinical or surveillance context?","id":"episode-classification-q01","kind":"definition"},{"text":"What evidence separates this episode from paratyphoid, other Salmonella infections and competing febrile illnesses?","id":"episode-classification-q02","kind":"boundary"}]}]},{"id":"microbiological-evidence","name":"Microbiological evidence","description":"Interpret Typhi testing in relation to specimens, timing and treatment exposure.","findings":[{"id":"test-interpretability","name":"Test interpretability","description":"Blood culture is central to diagnosis; negative results and serology require explicit limitations. [CDC clinical guidance](https://www.cdc.gov/typhoid-fever/hcp/clinical-guidance/index.html)","questions":[{"text":"Which laboratory report identifies Typhi, using what specimen and method, collected when relative to onset and antibiotics?","id":"test-interpretability-q01","kind":"provenance"},{"text":"What unresolved sampling or test limitations require further diagnostic review before confirming or excluding typhoid?","id":"test-interpretability-q02","kind":"action"}]}]}]},{"id":"exposure-and-transmission","name":"Exposure and transmission","description":"Relate the episode to plausible acquisition routes and opportunities for onward transmission.","layers":[{"id":"acquisition-history","name":"Acquisition history","description":"Record dated exposures without assuming that travel or shared food proves acquisition.","findings":[{"id":"plausible-acquisition","name":"Plausible acquisition","description":"Typhoid commonly spreads through food or water contaminated by human faeces. [WHO typhoid fact sheet](https://www.who.int/news-room/fact-sheets/detail/typhoid)","questions":[{"text":"Which residence, travel, food, water or infected-contact exposures preceded onset, and on what dates?","id":"plausible-acquisition-q01","kind":"measurement"},{"text":"Which exposures are reported, independently corroborated or linked by an investigation?","id":"plausible-acquisition-q02","kind":"provenance"}]}]},{"id":"onward-exposure","name":"Onward exposure","description":"Identify activities and contacts relevant to transmission precautions.","findings":[{"id":"transmission-opportunities","name":"Transmission opportunities","description":"Record food preparation, sanitation conditions and relevant contacts alongside evidence of shedding.","questions":[{"text":"During which periods did the person prepare food for others or have contact circumstances relevant to faecal-oral transmission?","id":"transmission-opportunities-q01","kind":"measurement"},{"text":"Which precautions or contact assessments are indicated by the responsible public-health authority?","id":"transmission-opportunities-q02","kind":"action"}]}]}]},{"id":"illness-course-and-severity","name":"Illness course and severity","description":"Represent the typhoid episode over time and identify evidence of complications.","layers":[{"id":"febrile-course","name":"Febrile course","description":"Align symptoms and observations with onset, sampling and treatment.","findings":[{"id":"clinical-trajectory","name":"Clinical trajectory","description":"Track fever, gastrointestinal symptoms and functional change without requiring every typical symptom.","questions":[{"text":"When did fever and other symptoms begin, and how have measured temperature and clinical observations changed?","id":"clinical-trajectory-q01","kind":"measurement"},{"text":"Which observations support improvement, deterioration or reconsideration of the typhoid attribution?","id":"clinical-trajectory-q02","kind":"boundary"}]}]},{"id":"complication-assessment","name":"Complication assessment","description":"Distinguish suspected complications from confirmed findings and unperformed assessments.","findings":[{"id":"severe-disease-evidence","name":"Severe disease evidence","description":"Relevant serious complications include gastrointestinal bleeding, intestinal perforation and encephalopathy. [CDC clinical guidance](https://www.cdc.gov/typhoid-fever/hcp/clinical-guidance/index.html)","questions":[{"text":"What examination, laboratory or imaging evidence supports or argues against each suspected complication?","id":"severe-disease-evidence-q01","kind":"measurement"},{"text":"Which findings meet the applicable protocol's criteria for urgent referral, hospital assessment or specialist intervention?","id":"severe-disease-evidence-q02","kind":"action"}]}]}]},{"id":"resistance-and-treatment-response","name":"Resistance and treatment response","description":"Connect treatment decisions and observed response to microbiology and actual medication exposure.","layers":[{"id":"treatment-basis","name":"Treatment basis","description":"Separate empirical treatment rationale from isolate-directed decisions.","findings":[{"id":"susceptibility-informed-review","name":"Susceptibility-informed review","description":"Record susceptibility results and acquisition history used to inform treatment. [CDC clinical guidance](https://www.cdc.gov/typhoid-fever/hcp/clinical-guidance/index.html)","questions":[{"text":"Which isolate results, dated guidance and acquisition evidence support the clinician's treatment choice?","id":"susceptibility-informed-review-q01","kind":"provenance"},{"text":"Do new susceptibility results or patient-specific constraints require review of the current regimen?","id":"susceptibility-informed-review-q02","kind":"action"}]}]},{"id":"response-assessment","name":"Response assessment","description":"Evaluate clinical changes against treatment timing and delivery.","findings":[{"id":"response-and-nonresponse","name":"Response and nonresponse","description":"Record response criteria and reasons for reassessment without equating continuing fever alone with resistance.","questions":[{"text":"How have fever and overall condition changed relative to doses actually received and treatment interruptions?","id":"response-and-nonresponse-q01","kind":"measurement"},{"text":"When does the applicable protocol call for reassessment of resistance, inadequate exposure, a persistent focus or an alternative diagnosis?","id":"response-and-nonresponse-q02","kind":"action"}]}]}]},{"id":"recovery-carriage-and-clearance","name":"Recovery, carriage and clearance","description":"Separate clinical recovery, recurrent illness, bacterial shedding and permission to resume activities.","layers":[{"id":"episode-outcome","name":"Episode outcome","description":"Record recovery and preserve uncertainty about subsequent illness.","findings":[{"id":"recovery-and-recurrence","name":"Recovery and recurrence","description":"Link recurrent fever to the earlier episode without automatically assigning relapse or reinfection.","questions":[{"text":"What dated observations establish clinical recovery or another episode outcome?","id":"recovery-and-recurrence-q01","kind":"measurement"},{"text":"If illness recurs, what timing, exposure and microbiological evidence supports relapse, reinfection or an unrelated cause?","id":"recovery-and-recurrence-q02","kind":"boundary"}]}]},{"id":"carriage-and-public-health-disposition","name":"Carriage and public-health disposition","description":"Track shedding evidence and the authority responsible for clearance.","findings":[{"id":"shedding-status","name":"Shedding status","description":"People may continue shedding Typhi after symptoms resolve. [WHO typhoid fact sheet](https://www.who.int/news-room/fact-sheets/detail/typhoid)","questions":[{"text":"Which dated follow-up specimens establish detected shedding or negative results, and what remains untested?","id":"shedding-status-q01","kind":"measurement"},{"text":"Which duration and evidence criteria define chronic carriage in the adopted reference?","id":"shedding-status-q02","kind":"definition"}]},{"id":"notification-and-clearance","name":"Notification and clearance","description":"Record applicable reporting and return-to-activity requirements; follow-up clearance depends on local public-health guidance. [CDC Yellow Book](https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/typhoid-and-paratyphoid-fever.html)","questions":[{"text":"Which authority and dated rule govern notification, food-handling restrictions and return to work, school or childcare?","id":"notification-and-clearance-q01","kind":"provenance"},{"text":"What outstanding tests, reviews or documented decisions must be completed before restrictions can be lifted?","id":"notification-and-clearance-q02","kind":"action"}]}]}]},{"id":"evidence-and-external-alignment","name":"Evidence and external alignment","description":"What the world already says about this thing, gathered so the model can be checked against it.","layers":[{"id":"reported-evidence","name":"Reported evidence","description":"Findings from the breadth pass, kept separate from the structural claims.","findings":[{"id":"evidence-kinds","name":"Kinds and varieties","description":"Reported by the breadth pass; each item needs checking against its source before it becomes normative.","questions":[{"text":"Which of these kinds and varieties hold for the sense of typhoid fever this model covers, and on what evidence?","id":"evidence-kinds-q01","kind":"provenance"}]},{"id":"evidence-identifiers","name":"Identifiers and schemes","description":"Reported by the breadth pass; each item needs checking against its source before it becomes normative.","questions":[{"text":"Which of these identifiers and schemes hold for the sense of typhoid fever this model covers, and on what evidence?","id":"evidence-identifiers-q01","kind":"provenance"}]},{"id":"evidence-standards-and-regulation","name":"Standards and regulation","description":"Reported by the breadth pass; each item needs checking against its source before it becomes normative.","questions":[{"text":"Which of these standards and regulation hold for the sense of typhoid fever this model covers, and on what evidence?","id":"evidence-standards-and-regulation-q01","kind":"provenance"}]},{"id":"evidence-real-world-use","name":"Real-world use","description":"Reported by the breadth pass; each item needs checking against its source before it becomes normative.","questions":[{"text":"Which of these real-world use hold for the sense of typhoid fever this model covers, and on what evidence?","id":"evidence-real-world-use-q01","kind":"provenance"}]},{"id":"evidence-measurements","name":"Typical measurements","description":"Reported by the breadth pass; each item needs checking against its source before it becomes normative.","questions":[{"text":"Which of these typical measurements hold for the sense of typhoid fever this model covers, and on what evidence?","id":"evidence-measurements-q01","kind":"provenance"}]},{"id":"evidence-failure-modes-and-hazards","name":"Failure modes and hazards","description":"Reported by the breadth pass; each item needs checking against its source before it becomes normative.","questions":[{"text":"Which of these failure modes and hazards hold for the sense of typhoid fever this model covers, and on what evidence?","id":"evidence-failure-modes-and-hazards-q01","kind":"provenance"}]},{"id":"evidence-regional-variation","name":"Regional variation","description":"Reported by the breadth pass; each item needs checking against its source before it becomes normative.","questions":[{"text":"Which of these regional variation hold for the sense of typhoid fever this model covers, and on what evidence?","id":"evidence-regional-variation-q01","kind":"provenance"}]},{"id":"evidence-neighbours","name":"Neighbouring kinds and how to tell them apart","description":"Reported by the breadth pass; each item needs checking against its source before it becomes normative.","questions":[{"text":"Which of these neighbouring kinds and how to tell them apart hold for the sense of typhoid fever this model covers, and on what evidence?","id":"evidence-neighbours-q01","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Explain typhoid fever, its spread and its prevention from public health sources.","Relay official outbreak alerts and vaccination advice to travellers and residents.","Report suspected cases to the health authority where it is authorized to do so."],"mustNot":["Diagnose typhoid or prescribe antibiotics for a person.","Disclose a person's infection or carrier status without lawful basis.","Advise a person with suspected typhoid to handle food for others.","Blame communities or nationalities for outbreaks without evidence."],"requiresHuman":["Excluding a person from work or school on health grounds.","Declaring an outbreak in a community."]},"ethics":{"considerations":["Typhoid persists where clean water and sanitation are lacking; it is a disease of inequality.","Carriers have historically been stigmatised and confined; privacy and fairness matter."],"affectedParties":["Patients and carriers","Communities without safe water","Food handlers and their customers"]},"owners":{"steward":"Nobody owns the disease; public health authorities answer for its surveillance and control.","roles":[],"masterSystems":["Notifiable disease surveillance systems of public health authorities"]},"relations":[{"target":"Q1049711","type":"parent","note":"registry parent class"},{"target":"Q131345497","type":"parent","note":"registry parent class"},{"target":"Q18553247","type":"parent","note":"registry parent class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.typhoid-fever","Wikidata: Q83319 (https://www.wikidata.org/wiki/Q83319)"]},"properties":{"applicability":"not-applicable","items":["Diagnostic classification: Suspected, probable where defined, confirmed, excluded or unresolved; governing definition and date","Organism attribution: Typhi identified, Paratyphi identified, other Salmonella identified, unresolved Salmonella or no organism identified","Fever trajectory: Temperature in degrees Celsius with timestamps, measurement method and days since onset","Diagnostic evidence: Linked specimen, collection time, test method, laboratory report and preceding antibiotic exposure","Complication status: For each assessed complication: absent, suspected, confirmed, resolved or not assessed","Antimicrobial susceptibility: Per-agent laboratory interpretation with method, breakpoint standard, version and optional MIC in mg/L","Treatment exposure: Linked prescribed and administered regimens, start and stop times, interruptions and clinical rationale","Acquisition context: Dated travel, residence, food or water exposures, carrier contacts and outbreak links, each with confidence","Shedding and carriage: Unknown, shedding detected, follow-up negative, persistent carriage under evaluation or chronic carriage under a cited definition","Public-health clearance: Not assessed, requirements identified, restricted, awaiting clearance or cleared; authority and date"]},"recognition":{"applicability":"not-applicable","items":[]},"capabilities":{"applicability":"required","items":["Assemble a typhoid-specific evidence summary and identify missing confirmation evidence.","Flag observations requiring urgent clinical assessment under an applicable care protocol.","Surface isolate susceptibility and treatment-response evidence for clinician review.","Track recovery and flag recurrent illness for assessment of relapse, reinfection or another diagnosis.","Prepare an episode-specific notification and transmission-precaution checklist for authorised review.","Identify outstanding shedding assessments and jurisdiction-specific clearance requirements."]},"hazards":{"applicability":"required","items":["Untreated infection can cause intestinal perforation and death.","Drug-resistant strains limit treatment options.","Chronic carriers can spread infection through food and water for years."]},"interfaces":{"applicability":"required","items":["The World Health Organization's International Classification of Diseases, Tenth Revision, classifies typhoid fever under code A01.0."]},"context":{"applicability":"required","items":["Typhoid fever is encountered in clinical medicine, laboratory diagnosis, travel health and public health surveillance.","It is considered when evaluating compatible febrile illness in the context of exposure to contaminated food or water.","Confirmed cases and persistent carriage inform treatment, outbreak investigation and measures to prevent onward transmission."]}},"sources":[{"title":"Typhoid (fact sheet)","url":"https://www.who.int/news-room/fact-sheets/detail/typhoid","note":"Causal agent, faecal-oral transmission, clinical course, case-fatality with and without treatment, chronic carriage, and the role of vaccines and WASH."},{"title":"Typhoid vaccines: WHO position paper - March 2018. Weekly Epidemiological Record, 93(13):153-172. World Health Organization","url":"","note":"Vaccine products and schedules (including typhoid conjugate vaccine), burden in endemic regions, and public-health use of TCV."},{"title":"Typhoid and Paratyphoid Fever. CDC Yellow Book. Centers for Disease Control and Prevention","url":"","note":"Travel-associated disease, incubation range, diagnostic preference for culture, antimicrobial-resistance patterns including XDR S. Typhi from Pakistan, and traveller vaccination practice."},{"title":"ICD-10: A01.0 Typhoid fever. International Statistical Classification of Diseases and Related Health Problems, 10th Revision. World Health Organization","url":"","note":"The standard diagnostic code that names this disease in mortality, morbidity, and notifiable-disease systems."},{"title":"Wikidata item Q83319: typhoid fever","url":"https://www.wikidata.org/wiki/Q83319","note":"identity and sense of the item"},{"title":"Wikipedia: Typhoid fever","url":"https://en.wikipedia.org/wiki/Typhoid_fever","note":"general description of the item"}],"openQuestions":["Which clinical and surveillance case definitions should this model adopt across jurisdictions, especially where culture is unavailable?","Which validated diagnostic pathways and evidence thresholds should govern culture-negative illness after antibiotic exposure?","Which current regional resistance sources and care protocols should govern treatment-review triggers, including paediatric and pregnancy contexts?","What evidence is sufficient to distinguish relapse, reinfection and persistent infection when paired isolates are unavailable?","Which carriage definitions and jurisdiction-specific follow-up schedules govern clearance for food handlers, school attendance and childcare?"],"resources":{"spec":"/models/things/publications/thing-q83319/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q83319/spec.json"],"providers":["Codex","Grok"],"researchStatus":"unreviewed","generatedAt":"2026-09-07T10:30:31Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"not-applicable","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-07T10:10:33+00:00: completeness 1.00; sense: Wikidata description; 3 live sources; review by codex: pass","interaction.properties":"Plane ACT: no invented physical properties.","interaction.recognition":"Typhoid fever has no reliable visual identification because its possible visible signs are nonspecific and diagnosis requires clinical assessment and laboratory evidence."},"score":1.0}}