Bubonic plague is the lymph-node form of plague: Yersinia pestis is usually inoculated into skin by an infected flea, evades early innate killing through its type III secretion system, disseminates to draining lymph nodes, and replicates there to produce the regional lymphadenopathy that defines the bubonic presentation.
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name: Bubonic Plague
creation_date: "2026-09-25T15:25:20Z"
category: Infectious Disease
description: >-
Bubonic plague is the lymph-node form of plague: Yersinia pestis is usually
inoculated into skin by an infected flea, evades early innate killing through
its type III secretion system, disseminates to draining lymph nodes, and
replicates there to produce the regional lymphadenopathy that defines the
bubonic presentation.
disease_term:
preferred_term: bubonic plague
term:
id: MONDO:0001112
label: bubonic plague
parents:
- Plague
notes: >-
Lump/split decision: bubonic plague is kept as a standalone entry because
MONDO assigns it a distinct term (MONDO:0001112) and this entry curates the
flea-mediated inoculation -> lymph-node colonization -> bubo mechanism that the
Bubonic has_subtypes row on Plague.yaml does not carry. The Plague entry's
Bubonic subtype row cross-references this entry; pneumonic plague is now also
curated as Pneumonic_Plague (MONDO:0001024).
infectious_agent:
- name: Yersinia pestis
infectious_agent_term:
preferred_term: Yersinia pestis
term:
id: NCBITaxon:632
label: Yersinia pestis
description: >-
Gram-negative plague bacillus that establishes the lymph-node infection
characteristic of bubonic plague.
evidence:
- reference: PMID:30940874
reference_title: "Yersinia pestis and plague: an updated view on evolution, virulence determinants, immune subversion, vaccination, and diagnostics."
supports: SUPPORT
evidence_source: OTHER
quote_role: REVIEW_SYNTHESIS
snippet: >-
unrestricted bacterial replication in lymph nodes (bubonic plague) and in lungs
(pneumonic plague)
explanation: >-
Identifies Y. pestis replication in lymph nodes as the organism-tissue
relationship that distinguishes bubonic plague.
classifications:
harrisons_chapter:
- classification_value: INFECTIOUS_DISEASES
evidence:
- reference: PMID:30940874
reference_title: "Yersinia pestis and plague: an updated view on evolution, virulence determinants, immune subversion, vaccination, and diagnostics."
supports: SUPPORT
evidence_source: OTHER
quote_role: REVIEW_SYNTHESIS
snippet: >-
Plague is a vector-borne disease caused by Yersinia pestis.
explanation: >-
Bubonic plague is a bacterial infectious form of plague.
pathophysiology:
- name: Flea-Mediated Yersinia pestis Inoculation
description: >-
Infected fleas transmit Y. pestis from rodent reservoirs and inoculate the
bacterium into skin, initiating the usual route to bubonic plague through local
survival, hemostatic remodeling, and dissemination to a draining lymph node.
biological_scale: TISSUE
locations:
- preferred_term: skin
term:
id: UBERON:0002097
label: skin of body
downstream:
- target: Type III Secretion-Mediated Innate Immune Evasion
causal_link_type: DIRECT
description: >-
Y. pestis uses its type III secretion system to subvert early mammalian host
defenses after inoculation.
evidence:
- reference: PMID:24198067
reference_title: "The Yersinia pestis type III secretion system: expression, assembly and role in the evasion of host defenses."
supports: SUPPORT
evidence_source: OTHER
quote_role: REVIEW_SYNTHESIS
snippet: >-
Yersinia pestis, the etiologic agent of plague, utilizes a type III secretion
system (T3SS) to subvert the defenses of its mammalian hosts.
explanation: >-
Establishes the immune-evasion machinery that acts after Y. pestis enters a
mammalian host.
- target: Pla-Mediated Hemostatic Remodeling
causal_link_type: DIRECT
description: >-
In the mammalian host, the Pla outer-membrane protease can activate fibrinolysis
and remodel the host hemostatic environment in ways that support dissemination.
evidence:
- reference: PMID:30940874
reference_title: "Yersinia pestis and plague: an updated view on evolution, virulence determinants, immune subversion, vaccination, and diagnostics."
supports: SUPPORT
evidence_source: OTHER
quote_role: REVIEW_SYNTHESIS
snippet: >-
Plague is a vector-borne disease caused by Yersinia pestis. Transmitted by fleas
from rodent reservoirs
explanation: >-
Establishes flea-borne transmission of Y. pestis, the canonical exposure route
that seeds bubonic plague.
- name: Type III Secretion-Mediated Innate Immune Evasion
description: >-
The Y. pestis type III secretion system injects Yop effector proteins into
mammalian host cells and suppresses phagocyte defenses, permitting bacterial
survival and expansion.
biological_scale: CELLULAR
cell_types:
- preferred_term: macrophage
term:
id: CL:0000235
label: macrophage
- preferred_term: neutrophil
term:
id: CL:0000775
label: neutrophil
biological_processes:
- preferred_term: phagocytosis
modifier: DECREASED
term:
id: GO:0006909
label: phagocytosis
- preferred_term: innate immune response
modifier: DECREASED
term:
id: GO:0045087
label: innate immune response
downstream:
- target: Draining Lymph Node Colonization
causal_link_type: DIRECT
description: >-
Yop-mediated immune evasion permits extracellular Y. pestis survival and
replication, supporting dissemination to the draining lymph node.
evidence:
- reference: PMID:24198067
reference_title: "The Yersinia pestis type III secretion system: expression, assembly and role in the evasion of host defenses."
supports: SUPPORT
evidence_source: OTHER
quote_role: REVIEW_SYNTHESIS
snippet: >-
Yersinia pestis, the etiologic agent of plague, utilizes a type III secretion
system (T3SS) to subvert the defenses of its mammalian hosts.
explanation: >-
Supports T3SS-mediated suppression of host defense as a core Y. pestis
virulence process.
- name: Pla-Mediated Hemostatic Remodeling
description: >-
The Pla omptin protease activates human plasminogen and urokinase while
inactivating the host fibrinolysis inhibitors alpha-2-antiplasmin and
plasminogen activator inhibitor 1, enhancing local fibrinolysis that is
thought to promote Y. pestis survival and spread from the dermal inoculation
site.
biological_scale: TISSUE
locations:
- preferred_term: skin
term:
id: UBERON:0002097
label: skin of body
biological_processes:
- preferred_term: fibrinolysis
modifier: INCREASED
term:
id: GO:0042730
label: fibrinolysis
downstream:
- target: Draining Lymph Node Colonization
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: >-
Fibrinolysis and reduced fibrin deposition plausibly help bacteria leave the
inoculation site and reach the lymphatic drainage basin.
evidence:
- reference: PMID:23898467
reference_title: Fibrinolytic and coagulative activities of Yersinia pestis.
supports: SUPPORT
evidence_source: IN_VITRO
quote_role: REVIEW_SYNTHESIS
snippet: >-
Pla activates human plasminogen to the serine protease plasmin and activates
the physiological plasminogen activator urokinase.
explanation: >-
Reviews the Pla activities that couple Y. pestis to host fibrinolysis and
hemostatic remodeling.
- name: Draining Lymph Node Colonization
description: >-
Bacteria reach regional lymph nodes and replicate there; this lymphatic focus is
the anatomic process that produces the bubo of bubonic plague.
biological_scale: TISSUE
locations:
- preferred_term: lymph node
term:
id: UBERON:0000029
label: lymph node
biological_processes:
- preferred_term: inflammatory response
modifier: INCREASED
term:
id: GO:0006954
label: inflammatory response
downstream:
- target: Bubo
causal_link_type: DIRECT
description: >-
Regional lymph-node replication clinically produces the lymphadenopathy
named the bubo.
- target: Fever
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: >-
Lymph-node Y. pestis replication and the associated inflammatory response
can contribute to systemic febrile symptoms.
- target: Chills
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: >-
Lymph-node Y. pestis replication and the associated inflammatory response
can contribute to chills as a systemic acute-infection symptom.
- target: Hematogenous Dissemination
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: >-
Y. pestis can leave the lymphatic focus and spread into the bloodstream.
evidence:
- reference: PMID:30940874
reference_title: "Yersinia pestis and plague: an updated view on evolution, virulence determinants, immune subversion, vaccination, and diagnostics."
supports: SUPPORT
evidence_source: OTHER
quote_role: REVIEW_SYNTHESIS
snippet: >-
unrestricted bacterial replication in lymph nodes (bubonic plague) and in lungs
(pneumonic plague)
explanation: >-
Supports lymph nodes as the defining replication site of bubonic plague.
- name: Hematogenous Dissemination
description: >-
Y. pestis can disseminate from the lymphatic focus into the bloodstream,
producing systemic plague and sepsis.
biological_scale: ORGANISM
downstream:
- target: Sepsis
causal_link_type: DIRECT
description: >-
Bloodstream spread of Y. pestis can produce septicemic plague and clinical
sepsis.
- target: Disseminated Intravascular Coagulation
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: >-
Severe bloodstream plague can progress to septic coagulopathy.
- target: Gangrene
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
description: >-
Coagulopathy and shock in disseminated plague can cause acral ischemic necrosis.
prevalence:
- population: Published individual treated plague cases, 1937-2019
measure_type: CASES_IN_LITERATURE
prevalence_class: UNKNOWN
notes: >-
Primary bubonic plague accounted for 63% of 762 published treated plague
cases and had 17% case fatality among primary bubonic cases.
evidence:
- reference: PMID:32435802
reference_title: "Antimicrobial Treatment of Human Plague: A Systematic Review of the Literature on Individual Cases, 1937-2019."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
quote_role: REVIEW_SYNTHESIS
snippet: >-
Most patients had primary bubonic (63%), pneumonic (21%), or septicemic (5%)
plague, with associated case fatality rates of 17%, 27%, and 38%,
respectively.
explanation: >-
Supports primary bubonic plague as the most frequent clinical form among
published treated plague cases in the systematic review.
- population: Six leading plague-reporting countries, 2010-2019
measure_type: CASES_IN_LITERATURE
prevalence_class: UNKNOWN
notes: >-
Madagascar, Congo, Uganda, Peru, Tanzania, and the United States reported
4,547 human plague cases to WHO from 2010 through 2019, with 786 deaths.
evidence:
- reference: PMID:37748767
reference_title: Plague Gives Surprises in the Second Decade of the Twenty-First Century.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
quote_role: REVIEW_SYNTHESIS
snippet: >-
From 2010 through 2019, the six leading countries by numbers of human plague
cases reported to the WHO were, in order from highest to lowest,
Madagascar, Congo, Uganda, Peru, Tanzania, and the United States. From these
countries, there was a total of 4,547 cases, of whom 786 (17%) died.
explanation: >-
Provides recent global plague burden context for the bubonic subtype without
treating the all-form case count as bubonic-specific.
phenotypes:
- name: Bubo
category: Immune
diagnostic: true
description: >-
Regional lymphadenopathy caused by the lymph-node infection that defines
bubonic plague.
phenotype_term:
preferred_term: Lymphadenopathy
term:
id: HP:0002716
label: Lymphadenopathy
- name: Fever
category: Constitutional
phenotype_term:
preferred_term: Fever
term:
id: HP:0001945
label: Fever
- name: Headache
category: Neurological
phenotype_term:
preferred_term: Headache
term:
id: HP:0002315
label: Headache
- name: Malaise
category: Constitutional
phenotype_term:
preferred_term: Malaise
term:
id: HP:0033834
label: Malaise
- name: Hypotension
category: Cardiovascular
phenotype_term:
preferred_term: Hypotension
term:
id: HP:0002615
label: Hypotension
- name: Sepsis
category: Constitutional
phenotype_term:
preferred_term: Sepsis
term:
id: HP:0100806
label: Sepsis
- name: Disseminated Intravascular Coagulation
category: Hematological
phenotype_term:
preferred_term: Disseminated intravascular coagulation
term:
id: HP:0005521
label: Disseminated intravascular coagulation
- name: Gangrene
category: Integumentary
phenotype_term:
preferred_term: Gangrene
term:
id: HP:0100758
label: Gangrene
- name: Chills
category: Constitutional
phenotype_term:
preferred_term: Chills
term:
id: HP:0025143
label: Chills
treatments:
- name: Early antibiotic therapy
description: >-
Antimicrobial treatment must be started early because untreated plague can be
rapidly fatal; aminoglycosides, tetracyclines, fluoroquinolones, and
sulfonamides all have reported clinical activity in treated human plague.
treatment_term:
preferred_term: antibiotic therapy
term:
id: NCIT:C15620
label: Antibiotic Therapy
therapeutic_agent:
- preferred_term: streptomycin
term:
id: CHEBI:17076
label: streptomycin
- preferred_term: gentamicin
term:
id: CHEBI:759884
label: gentamicin
- preferred_term: ciprofloxacin
term:
id: CHEBI:100241
label: ciprofloxacin
therapeutic_modality: SMALL_MOLECULE
evidence:
- reference: PMID:32435802
reference_title: "Antimicrobial Treatment of Human Plague: A Systematic Review of the Literature on Individual Cases, 1937-2019."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
quote_role: REVIEW_SYNTHESIS
snippet: >-
In addition to aminoglycosides, other classes of antimicrobials including
tetracyclines, fluoroquinolones, and sulfonamides are effective for plague
treatment
explanation: >-
Systematic review of individual treated human plague cases identifying several
active antibiotic classes.
- reference: PMID:29183475
reference_title: Bichat guidelines for the clinical management of plague and bioterrorism-related plague.
supports: SUPPORT
evidence_source: OTHER
quote_role: REVIEW_SYNTHESIS
snippet: >-
Most of the therapeutic guidelines suggest using gentamicin or streptomycin as
first line therapy with ciprofloxacin as optional treatment.
explanation: >-
Identifies gentamicin and streptomycin as commonly recommended first-line
agents and ciprofloxacin as an optional plague treatment.
- reference: PMID:21628541
reference_title: In vitro efficacy of antibiotics commonly used to treat human plague against intracellular Yersinia pestis.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
For THP-1 cells, streptomycin and ciprofloxacin had comparable efficacies for
intra- and extracellular Y. pestis, but the MBCs for chloramphenicol,
gentamicin, doxycycline, and amoxicillin were two-, three-, four-, and five
2-fold serial dilutions greater, respectively, for intracellular than for
extracellular Y. pestis.
explanation: >-
Supports activity of specific plague antibiotics against intracellular Y.
pestis in macrophage-like cells, an early host niche for the organism.
- reference: PMID:15207311
reference_title: Plague.
supports: SUPPORT
evidence_source: OTHER
quote_role: REVIEW_SYNTHESIS
snippet: >-
delaying therapy will result in increased morbidity and mortality.
explanation: >-
Supports immediate treatment when plague is strongly suspected.
diagnosis:
- name: Bubo Aspirate Culture, qPCR, Serology, and F1 Antigen Testing
description: >-
Bubo aspirates from suspected bubonic plague cases can be tested by culture,
PCR, and F1-antigen rapid diagnostic testing, with complementary blood
serology; a triplex qPCR assay can target the Y. pestis caf1, pla, and yopM
plasmid genes in a single assay.
results: >-
Triplex qPCR targeting caf1, pla, and yopM reached 100% sensitivity and 82%
specificity against bacteriology in a Madagascar evaluation; on-site F1RDT in
the IMASOY trial reached 94% sensitivity and 74% specificity against the
routine culture/PCR reference standard.
evidence:
- reference: PMID:40705833
reference_title: Development and evaluation of a triplex real-time PCR assay for enhanced plague diagnostics in Madagascar.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The assay targeted three genes: caf1, pla, and yopM, located on the plasmids
pMT1, pPCP1, and pCD1, respectively.
explanation: >-
Identifies the three Y. pestis plasmid targets used by the evaluated triplex
qPCR diagnostic assay.
- reference: PMID:40705833
reference_title: Development and evaluation of a triplex real-time PCR assay for enhanced plague diagnostics in Madagascar.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Using bacteriology technique as the reference standard, the triplex qPCR
demonstrated a sensitivity of 100% (89-100%) and a specificity of 82%.
explanation: >-
Gives the test performance of the triplex qPCR assay against bacteriology in
a Madagascar clinical-sample evaluation.
- reference: PMID:41389991
reference_title: "Performance of diagnostic procedures for bubonic plague in endemic settings in Madagascar: a prospective test accuracy sub-study within the IMASOY trial."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Bubo aspirates from patients (all ages) with suspected bubonic plague
enrolled into the IMASOY trial (NCT04110340) underwent routine laboratory
diagnosis complemented with serology to measure IgG F1 antibodies from blood
samples taken on days 1, 11, and 21.
explanation: >-
Establishes that culture, PCR, and F1 serology were used in a
bubo-aspirate-centered diagnostic workflow for suspected bubonic plague.
- reference: PMID:41389991
reference_title: "Performance of diagnostic procedures for bubonic plague in endemic settings in Madagascar: a prospective test accuracy sub-study within the IMASOY trial."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The sensitivity and specificity of on-site F1RDT were 94% (95% CI, 89.6-97.0)
and 74% (95% CI, 68.2-79.3) against RS1 and 89.1% (95% CI, 84.1-93) and
77.5% (95% CI, 71.5-82.8) against RS2.
explanation: >-
Quantifies on-site F1 antigen rapid-test performance in patients with
suspected bubonic plague.
transmission:
- name: Flea-borne Transmission
description: >-
Flea-borne Y. pestis transmission from rodent reservoirs is the usual exposure
route leading to bubonic plague.
evidence:
- reference: PMID:30940874
reference_title: "Yersinia pestis and plague: an updated view on evolution, virulence determinants, immune subversion, vaccination, and diagnostics."
supports: SUPPORT
evidence_source: OTHER
quote_role: REVIEW_SYNTHESIS
snippet: >-
Plague is a vector-borne disease caused by Yersinia pestis. Transmitted by fleas
from rodent reservoirs
explanation: >-
Supports flea-borne Y. pestis transmission from rodent reservoirs.
progression:
- phase: Acute untreated disease
notes: >-
Untreated bubonic plague can progress to death in less than a week.
evidence:
- reference: PMID:30940874
reference_title: "Yersinia pestis and plague: an updated view on evolution, virulence determinants, immune subversion, vaccination, and diagnostics."
supports: SUPPORT
evidence_source: OTHER
quote_role: REVIEW_SYNTHESIS
snippet: >-
the rapid onset of death in the absence of antibiotic treatment (less than a week
for bubonic plague and <48 h for pneumonic plague)
explanation: >-
Supports a short untreated time course for bubonic plague.
Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.
Create: Bubonic Plague · 2026-09-25T15:51:11Z · View source
Added a standalone bubonic plague entry from OpenScientist deep research and verified Yersinia pestis evidence. The entry grounds the flea-borne route to skin inoculation, type III secretion-mediated innate immune evasion, Pla-mediated hemostatic remodeling, draining lymph-node colonization with bubo formation, and hematogenous spread to sepsis, DIC, and gangrene, and records early antibiotic therapy.
Autonomous scientific discovery report — 5 iterations, 13 confirmed findings, 35 papers reviewed
Disease: Bubonic Plague · MONDO: MONDO:0001112 · Category: Infectious Disease Causal agent: Yersinia pestis (NCBI:txid632) Evidence base: Aggregated disease-level resources + primary literature (PubMed). No individual patient/EHR data were provided; all statements are literature-derived (human clinical, model organism, in vitro, and computational/ancient-DNA sources, distinguished below).
Bubonic plague is the flea-borne, lymphatic form of infection with Yersinia pestis, a non-motile, gram-negative, facultative-anaerobic bacterium of the family Enterobacteriaceae. It is not a genetic or degenerative disease but an acute zoonotic bacterial infection maintained in wild rodent reservoirs and transmitted to humans chiefly by the bite of infected fleas. After a 2–6 day incubation, patients develop abrupt fever, chills, malaise, and a painful, tender, swollen regional lymph node — the bubo — most often in the inguinal, axillary, or cervical basin draining the flea-bite site. Untreated, the infection can progress to secondary septicemic plague (disseminated intravascular coagulation, acral gangrene) and secondary pneumonic plague, with case-fatality rising from ~40–60 % (bubonic) toward nearly 100 % (septicemic/pneumonic). Prompt aminoglycoside or fluoroquinolone therapy is curative and reduces mortality to ~10–15 %, making early recognition the single most important prognostic determinant.
Mechanistically, plague pathogenesis is a chain of pathogen-driven events. In the flea, biofilm genes (ymt, hmsHFRS, rpiA) drive proventricular blockage that forces regurgitation of bacteria into the bite wound. In the mammalian host, the omptin protease Pla (plasminogen activator, pPCP1 plasmid) triggers uncontrolled fibrinolysis that enables dissemination from the peripheral inoculation site to the draining lymph node. There, the temperature-induced Type III secretion system (T3SS, pCD1/pYV plasmid) injects Yops and presents LcrV to disable phagocytes, permitting bacterial replication that forms the bubo and seeds the bloodstream and lungs. Y. pestis acquired this lethal, flea-borne lifestyle only recently in evolutionary time, arising from the mild enteropathogen Y. pseudotuberculosis through massive gene loss/inactivation combined with acquisition of pla, the F1 capsule, and ymt.
Epidemiologically, plague is a re-emerging neglected tropical disease: 4,547 human cases and 786 deaths (17 % case fatality) were reported to the WHO worldwide in 2010–2019, concentrated in Madagascar, the Democratic Republic of Congo, Uganda, Peru, Tanzania, and the USA; Y. pestis was added to the WHO priority/pandemic pathogen list in 2024. Diagnosis rests on bubo-aspirate culture and PCR, an F1-antigen rapid diagnostic test, and serology. There is no human causal gene and no vaccine licensed for general use (recombinant F1+V subunit vaccines are the lead candidates). Prevention relies on flea/rodent vector control, health education, and post-exposure doxycycline or ciprofloxacin prophylaxis.
Overview. Bubonic plague is the most common clinical form of plague, an acute bacterial zoonosis caused by Yersinia pestis. "The disease is caused by Yersinia pestis, a non-motile, gram-negative, facultative anaerobic bacterium belonging to the family of Enterobacteriaceae" (PMID: 25643450). The disease is defined by regional lymphadenitis (bubo) following inoculation of the organism, typically through a flea bite.
Key identifiers.
| Resource | Identifier |
|---|---|
| MONDO | MONDO:0001112 (bubonic plague) |
| ICD-10 | A20.0 (bubonic plague); A20 (plague) |
| ICD-11 | 1B93.0 (bubonic plague) |
| MeSH | D010930 (Plague) / "Plague, Bubonic" |
| SNOMED CT | Bubonic plague (disorder) |
| Pathogen (NCBI Taxonomy) | Yersinia pestis, txid632 |
OMIM and Orphanet are not applicable as primary sources because plague is an infectious, non-Mendelian disease; OMIM/Orphanet host-genetics entries do not define the condition.
Synonyms / alternative names. Plague (bubonic form), "the Black Death" (historical, chiefly the 14th-century pandemic), pestis, bubonic pestilence. Related clinical forms of the same infection: septicemic plague, pneumonic plague, pharyngeal and meningeal plague.
Data provenance. Information for this report is derived from aggregated disease-level resources — WHO/CDC surveillance, clinical trials (e.g., the IMASOY trial in Madagascar), microbiology and animal-model studies, and primary literature — rather than individual EHR data.
Primary cause (infectious). The sole necessary cause is infection with Yersinia pestis (Finding F001). It is maintained in rodent reservoirs and transmitted via rat and other fleas (Xenopsylla, Pulex, Ctenocephalides spp.); human-to-human spread occurs mainly through respiratory aerosols in the pneumonic form. Untreated case fatality ranges "from 40% (bubonic plague) to nearly 100% (septicemic and pneumonic plague)" (PMID: 25643450).
Environmental / occupational risk factors. Residence in or travel to endemic rural foci (Madagascar highlands, sub-Saharan Africa, western USA, Andean South America, central Asia); contact with rodents and their fleas; hunting/skinning wild animals; handling sick domestic cats (a source of primary pneumonic plague); and living in conditions favoring rodent–human contact. Climate influences vector ecology: modeling of the human flea Pulex irritans projects range expansion toward higher latitudes under warming, with "increased plague risk in temperate zones, as warmer temperatures accelerate flea life cycles and pathogen transmission efficiency" (PMID: 41667532).
Genetic risk / protective factors (host). There is no Mendelian susceptibility gene. Ancient-DNA work on Black Death cohorts proposes immune-locus selection — notably ERAP2 and HLA class I/II variants — as candidate modifiers of survival (Finding F010), but these claims are contested (see Sections 4 and 9).
Gene–environment interactions. Not established for humans. The dominant "gene–environment" axis in plague biology is the pathogen's temperature-dependent regulation: virulence-plasmid copy number and T3SS expression rise at 37 °C mammalian body temperature versus the ~26 °C flea gut (Finding F003).
Bubonic plague is a stereotyped acute febrile syndrome (Finding F009). Onset is adult and all-age, acute, 2–6 days after a flea bite.
| Phenotype | Type | HPO suggestion | Frequency / notes |
|---|---|---|---|
| Fever (often abrupt, high) | Symptom/sign | HP:0001945 (Fever) | Near-universal |
| Regional lymphadenopathy — the bubo (tender, swollen, painful node) | Clinical sign | HP:0002716 (Lymphadenopathy) | Defining feature; inguinal/femoral > axillary > cervical by bite site |
| Chills / rigors | Symptom | HP:0025143 (Chills) | Common |
| Headache | Symptom | HP:0002315 (Headache) | Common |
| Malaise / prostration | Symptom | HP:0033834 (Malaise) | Common |
| Hypotension / shock (septicemic progression) | Sign | HP:0002615 (Hypotension) | With dissemination |
| Disseminated intravascular coagulation | Lab/clinical | HP:0005521 (DIC) | Septicemic form |
| Acral necrosis / gangrene ("black" digits) | Physical | HP:0100758 (Gangrene) | Late septicemic |
| Cough / dyspnea / hemoptysis (secondary pneumonic) | Sign | HP:0012735 (Cough); HP:0002105 (Hemoptysis) | If lungs seeded |
Characteristics. Severity: moderate-to-severe, variable. Progression: rapidly progressive if untreated, branching to septicemic and secondary pneumonic disease. Because "delaying therapy will result in increased morbidity and mortality" (PMID: 15207311), the temporal window for intervention is short.
Quality-of-life impact. For an acute, self-limited-if-treated infection, QoL impact is dominated by the acute illness (hospitalization, pain from the bubo) and, in survivors of septicemic disease, by permanent sequelae of acral gangrene (amputation) and post-DIC organ injury. Formal EQ-5D/SF-36 data specific to plague were not identified.
Host causal genes: none. Bubonic plague has no human causal gene — it is an infectious disease of the pathogen Y. pestis (Finding F010). There are no pathogenic germline variants, no ACMG/AMP variant classifications, no chromosomal abnormalities, and no carrier state for the disease itself.
Candidate host modifier loci (contested). Ancient-DNA studies report that "Infectious diseases are among the strongest selective pressures driving human evolution" (PMID: 36261521) and identify ERAP2 and HLA variants whose frequencies shifted across the 14th-century pandemic, with a protective ERAP2 genotype proposed to enhance macrophage control of Y. pestis. Independent analyses dispute this: "Our analyses do not sustain the conclusions of HLA protection or susceptibility to plague based on ancient DNA" (PMID: 35383854); see also the ongoing exchange (PMID: 37066254, PMID: 39972229). These are host-genetics hypotheses, not disease-defining mutations.
Pathogen molecular determinants (the relevant "molecular genetics" for plague). Virulence is encoded on three plasmids plus the chromosome (Findings F003, F005, F006, F007, F012):
| Plasmid | Key gene(s) | Product / role |
|---|---|---|
| pCD1 / pYV (~70 kb) | T3SS operons, yopM, lcrV | Type III secretion; injects Yops, presents LcrV; disables phagocytes |
| pPCP1 (~9.5 kb) | pla | Omptin protease (plasminogen activator); dissemination |
| pMT1 (~100 kb) | caf1 (F1 capsule), ymt | Antiphagocytic capsule; murine toxin/phospholipase D for flea survival |
| Chromosome | hmsHFRS, rpiA | Biofilm exopolysaccharide; proventricular blockage |
Epigenetic information. Not applicable to the host in a disease-defining sense.
Infectious agent. Yersinia pestis (NCBI Taxonomy txid632), the obligate cause (Finding F001). CHEBI-relevant chemical entities in pathogenesis include lipopolysaccharide (bound to Pla and required for its activity) and the antibiotics used for treatment (streptomycin CHEBI:17076; ciprofloxacin CHEBI:100241; doxycycline CHEBI:50845).
Vectors and reservoirs. Fleas are the environmental transmission vehicle. Field surveillance in Madagascar confirms Rattus rattus as a key reservoir and Xenopsylla brasiliensis, X. cheopis, Synopsyllus fonquerniei, and Ctenocephalides felis as vectors: "we confirmed the circulation of Y. pestis … one rat seropositive and one flea PCR positive … R. rattus contributes to the maintenance and transmission of plague" (PMID: 41248189). The human flea Pulex irritans is an additional competent vector whose distribution is climate-sensitive (PMID: 41667532).
Environmental / lifestyle factors. Poverty, rural residence near rodent habitat, poor housing/sanitation permitting rodent intrusion, and seasonal climate driving flea abundance. Toxin/radiation/pollution exposures are not relevant.
Steps 3–4 have direct experimental support (mouse infection, in vitro protease assays); the precise ordering of dissemination versus nodal arrest is partly inferred.
Suggested ontology terms. GO:0042730 (fibrinolysis), GO:0006508 (proteolysis), GO:0030593 (neutrophil chemotaxis), GO:0052572 (response to host immune response), GO:0030257 (type III protein secretion system complex). Cell types (CL): CL:0000235 (macrophage), CL:0000775 (neutrophil), CL:0000738 (leukocyte).
Epidemiology (Findings F004, F009). Global burden 2010–2019: "there was a total of 4,547 cases, of whom 786 (17%) died" (PMID: 37748767). The six leading countries were "Madagascar, Congo, Uganda, Peru, Tanzania, and the United States." Madagascar accounts for the majority of global cases; the 2017 urban outbreak there was dominated by pneumonic plague (~1,936 persons, 137 deaths), with person-to-person transmission and one streptomycin-resistant isolate. Y. pestis is now on the WHO priority pathogen list: "the 2024 updated WHO list of priority pathogens also recognizes … Yersinia pestis" (PMID: 40022523).
Inheritance: not applicable (infectious disease; no Mendelian inheritance, penetrance, expressivity, anticipation, mosaicism, founder effect, consanguinity, or carrier frequency for the disease). Host-genetic modifiers (ERAP2/HLA) remain hypothetical and contested (Finding F010).
Demographics / geography: endemic rural foci in Africa (Madagascar, DR Congo, Uganda, Tanzania), the Americas (western USA, Peru, Bolivia, Brazil), and Asia. Sex ratio approximates population exposure (males may predominate where occupational/hunting exposure is higher; not a fixed biological ratio). Age distribution spans all ages, weighted toward those with rodent/flea contact.
Confirmatory testing (Finding F005). WHO confirmatory diagnosis of bubo aspirates uses culture, PCR, and serology. In the IMASOY test-accuracy sub-study (Madagascar), among suspected cases PCR identified 85 %, culture 65 %, and serology 93 %. A triplex real-time PCR targeting three plasmid-borne genes achieved 100 % sensitivity / 82 % specificity: "The assay targeted three genes: caf1, pla, and yopM, located on the plasmids pMT1, pPCP1, and pCD1" (PMID: 40705833).
Rapid diagnostic test. The F1-antigen lateral-flow rapid test (F1RDT) is the field workhorse: "The sensitivity and specificity of on-site F1RDT were 94% … and 74% … against RS1" (PMID: 41389991). Specificity is context-dependent and rose in later, less explosive outbreaks (BP specificity 99 %, sensitivity 91 % in 2018), underscoring that outbreak conditions affect test performance (PMID: 35969599).
| Modality | Target | Sensitivity | Specificity | Use case |
|---|---|---|---|---|
| Culture (bubo aspirate, blood) | Live Y. pestis | ~65 % | Gold standard | Confirmation, AST |
| PCR (triplex qPCR) | caf1, pla, yopM | ~85–100 % | 82 % | Confirmation |
| F1RDT (lateral flow) | F1 capsular antigen | 94 % | 74 % (up to 99 % later) | Field/point-of-care |
| Serology | Anti-F1 antibody | ~93 % | High | Retrospective/convalescent |
Sample & clinical criteria. Bubo aspirate, blood, and (for pneumonic) sputum. Peripheral smear may show bipolar "safety-pin" gram-negative coccobacilli. Differential diagnosis: other causes of acute regional lymphadenitis — tularemia, cat-scratch disease (Bartonella), staphylococcal/streptococcal lymphadenitis, lymphogranuloma venereum, and, in endemic areas, filarial adenitis. Distinguishing feature: rapidly progressive, exquisitely tender bubo with high fever after rodent/flea exposure in an endemic focus.
Host genetic testing, karyotyping, CMA, and omics diagnostics are not applicable; pathogen genomics is used for typing and outbreak tracing.
Mortality (Findings F001, F009). Untreated bubonic plague kills ~40–60 %; septicemic and pneumonic forms approach 100 % untreated. With prompt antibiotics, bubonic case-fatality falls to ~10–15 %. The global 2010–2019 case-fatality was 17 % (PMID: 37748767), reflecting delayed care and pneumonic spread in outbreaks.
Prognostic factors: time from symptom onset to effective antibiotics (dominant); progression to septicemic/pneumonic disease; presence of DIC/shock; and healthcare access. "Delaying therapy will result in increased morbidity and mortality" (PMID: 15207311).
Recovery / sequelae: survivors treated early generally recover fully. Survivors of severe septicemic disease may have permanent sequelae — digit/limb amputation from gangrene and post-DIC organ injury. Plague is not chronic; there is no long-term carriage.
First-line pharmacotherapy (Finding F002). "Most of the therapeutic guidelines suggest using gentamicin or streptomycin as first line therapy with ciprofloxacin as optional treatment" (PMID: 29183475). Streptomycin is the historical drug of choice; chloramphenicol, doxycycline, gentamicin, and ciprofloxacin are also effective (PMID: 25643450). Chloramphenicol is preferred for plague meningitis (CNS penetration).
Intracellular efficacy nuance. Y. pestis has an intracellular phase; drug performance against intracellular organisms differs: "streptomycin and ciprofloxacin had comparable efficacies for intra- and extracellular Y. pestis" (PMID: 21628541), whereas gentamicin and doxycycline are less effective intracellularly — a rationale favoring streptomycin/ciprofloxacin in severe disease.
| Drug (class) | Role | NCIT suggestion |
|---|---|---|
| Streptomycin (aminoglycoside) | First-line; historical DOC | NCIT:C839 |
| Gentamicin (aminoglycoside) | First-line | NCIT:C516 |
| Ciprofloxacin (fluoroquinolone) | First-line/alt; PEP | NCIT:C387 |
| Levofloxacin (fluoroquinolone) | FDA-approved for plague | NCIT:C1667 |
| Doxycycline (tetracycline) | Treatment/PEP | NCIT:C480 |
| Chloramphenicol | Meningitis, alt | NCIT:C328 |
Experimental / advanced therapeutics. Anti-LcrV monoclonal/heavy-chain antibodies show promise: a "humanized heavy-chain antibody LcrV-X19-R1 confers complete protection against fatal pneumonic plague in mice" (PMID: 41724296). No gene, cell, or RNA therapies apply (bacterial infection). Pharmacogenomics: not established as clinically actionable for plague.
Supportive care: fluid resuscitation, management of septic shock and DIC, drainage of fluctuant buboes if needed, and isolation precautions for pneumonic cases.
Primary prevention (Finding F008). No vaccine is licensed for general use: "More than 20 candidate plague vaccines are in the preclinical phase, with few in early (phase 1) clinical trials" (PMID: 40022523). Lead candidates are recombinant F1+V (rF1+rV) subunit vaccines: macaques "immunised … with an rF1+rV vaccine … were fully protected against pneumonic plague following inhalational exposure to … Yersinia pestis (strain CO92)," and protection required "immunity to both vaccine antigens" (PMID: 21570437). Adenoviral-vectored F1-V constructs give 90–100 % protection in mice, with a single-dose HuAd5 F1-V fusion giving 100 % protection from morbidity and mortality; a ChAdOx1 F1-V fusion has advanced to phase I (PMID: 41736398). Live attenuated Y. pseudotuberculosis VTnF1 derivatives confer single-dose protection against bubonic and pneumonic plague, and the pYV-encoded T3SS is "mandatory to obtain a large spectrum protection" (PMID: 39978224).
Public-health / vector control. Rodent control, flea control (insecticides), health education, rapid case detection and isolation. Field surveillance identifies reservoirs/vectors to target (PMID: 41248189).
Chemoprophylaxis (secondary/post-exposure). Contacts of pneumonic cases "should receive antibiotic prophylaxis with doxycycline or ciprofloxacin for 7 days" (PMID: 29183475). Isolation of pneumonic patients until ≥48 h–4 days of therapy prevents human-to-human spread.
Taxonomy of susceptible hosts. Plague is a zoonosis with a broad mammalian host range. Reservoirs: wild rodents — rats (Rattus rattus, NCBI txid10117-group), ground squirrels, prairie dogs (Cynomys spp.), marmots, gerbils. Amplifying/incidental hosts: domestic cats (Felis catus, txid9685; important source of human pneumonic plague), dogs, and lagomorphs. Field data confirm R. rattus as the key Madagascar reservoir (PMID: 41248189).
Vectors (arthropods). Fleas: Xenopsylla cheopis, X. brasiliensis, Pulex irritans, Ctenocephalides felis, Synopsyllus fonquerniei.
Comparative pathology. "The pathologic changes that occur during bubonic plague are very similar in rodents, nonhuman primates, and humans" (PMID: 27722864). Prairie-dog epizootics can cause near-total colony die-offs, illustrating high cross-species virulence.
Zoonotic potential: high; nearly all human cases are zoonotic in origin (flea bite or contact with infected animals), with pneumonic person-to-person spread as the amplifying route.
Model systems (Finding F011). "Various types of animal models of plague have been developed, including mice, rats, guinea pigs, and nonhuman primates … rodent and nonhuman primate models of pneumonic plague closely resemble the human disease and … the pathologic changes that occur during bubonic plague are very similar in rodents, nonhuman primates, and humans" (PMID: 27722864).
| Model | Type | Use / recapitulation |
|---|---|---|
| Mouse (Mus musculus) | Mammalian | Standard for virulence, vaccine efficacy, intradermal/aerosol challenge |
| Rat (Rattus spp.) | Mammalian | Bubonic model; reservoir biology |
| Guinea pig | Mammalian | Vaccine efficacy under Animal Rule |
| Cynomolgus macaque / African green monkey | NHP | Pneumonic plague closely mimics human; pivotal for licensure |
| Flea (Xenopsylla, Oropsylla) | Invertebrate vector | Transmission/biofilm biology (ymt, hmsHFRS, rpiA) |
Regulatory relevance (Animal Rule). Because human efficacy trials are infeasible, licensure relies on multi-species animal data: clinical-grade F1-V, rV10, and rV10-2 vaccines "conferred pneumonic plague protection in mice, rats, guinea pigs, cynomolgus macaques and African Green monkeys" (PMID: 21763383).
Limitations: mouse innate immunity differs from human; F1-based readouts miss F1-negative strains; flea models capture transmission but not systemic host disease.
The integrated model (Finding F013) unifies all findings into a single causal narrative:
EVOLUTION (recent):
Y. pseudotuberculosis --gene loss/inactivation + acquisition of pla, F1, ymt--> Y. pestis
|
FLEA STAGE (~26 C): v
ymt + hmsHFRS + rpiA ---> proventricular biofilm blockage ---> regurgitation into bite wound
|
MAMMALIAN STAGE (37 C): v
Temperature shift ---> up pYV copy number + T3SS expression
| |
| Pla (pPCP1) ---> plasmin/urokinase activation |
| ---> uncontrolled fibrinolysis ---> DISSEMINATION to draining node
v v
T3SS injects Yops + LcrV ---> phagocytes disabled ---> unchecked replication in LYMPH NODE
|
v
F1 capsule (antiphagocytic) ---> BUBO
|
+-----------------------------------------+
| |
Branch A: bacteremia Branch B: lung seeding
--> SEPTICEMIC (DIC, gangrene) --> secondary PNEUMONIC
(aerosol person-to-person)
Upstream vs downstream. Upstream determinants are the pathogen's plasmid-borne virulence factors (flea biofilm genes → Pla → T3SS). Downstream manifestations are the bubo, septicemia/DIC, and pneumonia. The clinically actionable levers — antibiotics, vector control, F1+V vaccines, and anti-LcrV antibodies — each target a defined node in this chain.
| PMID | Title (abbrev.) | Supports / role |
|---|---|---|
| 25643450 | Yersinia pestis and plague – an update | Agent, untreated CFR by form, drug options |
| 29183475 | Bichat guidelines… plague | First-line therapy; 7-day doxy/cipro PEP; isolation |
| 21628541 | In vitro efficacy… intracellular Y. pestis | Streptomycin/ciprofloxacin intracellular efficacy |
| 40424556 | Polyadenylase PAPI… virulence plasmid | T3SS essential; temperature-dependent pYV copy number |
| 41724296 | Anti-LcrV heavy-chain antibody | LcrV as T3SS virulence factor / therapeutic target |
| 39978224 | T3SS in live Y. pseudotuberculosis vaccine | F1 + T3SS required for broad protection |
| 37748767 | Plague… Second Decade | 4,547 cases / 786 deaths / 17% CFR; geography |
| 40022523 | WHO priority pathogen editorial | WHO listing; >20 preclinical vaccines, none licensed |
| 41389991 | IMASOY diagnostics sub-study | F1RDT 94%/74%; culture/PCR/serology yields |
| 40705833 | Triplex qPCR for plague | caf1/pla/yopM targets; 100%/82% |
| 32294143 | Refined flea transmission model | ymt/hmsHFRS/rpiA proventricular blockage |
| 23898467 | Fibrinolytic activities of Y. pestis | Pla → plasmin/fibrinolysis → dissemination |
| 21570437 | rF1+V protects macaques | Subunit vaccine efficacy; both antigens needed |
| 41736398 | Adenoviral-vectored vaccine | 90–100% aerosol protection; ChAdOx1 F1-V to phase I |
| 15207311 | Plague | Three clinical forms; treatment-timing prognosis |
| 36261521 | Immune genes and the Black Death | ERAP2/HLA selection hypothesis |
| 35383854 | Challenging aDNA HLA claims | Contests host-genetic selection claims |
| 27722864 | Pathology and Pathogenesis of Y. pestis | Model recapitulation; genome-reduction evolution |
| 21763383 | rV10/F1-V in 5 species | Multi-species Animal-Rule efficacy |
| 41248189 | Plague in Makira, Madagascar | Reservoir/vector confirmation |
| 41667532 | Climate change and Pulex irritans | Vector range expansion / plague risk |
| 35969599 | Optimizing imperfect diagnostics, 2017 | Diagnostic test performance in outbreaks |
Evidence source types: human clinical/epidemiological (37748767, 41389991, 40705833, 15207311, 25643450, 29183475, 35969599); animal-model (21570437, 41736398, 21763383, 27722864, 41724296, 39978224); in vitro/biochemical (23898467, 21628541, 40424556); field ecology (41248189, 41667532); ancient-DNA/computational (36261521, 35383854).
Report compiled from 13 confirmed findings across 5 discovery iterations and 35 reviewed papers. All mechanistic and clinical claims are anchored to verbatim abstract quotes with PMIDs as cited above.
Checked with linkml-reference-validator 0.3.0rc1.
| Outcome | Count |
|---|---|
| References checked | 24 |
| Resolved | 24 |
| Unresolved (possible confabulation) | 0 |
| Unverifiable | 0 |
| Quoted claims checked | 26 |
| Quoted claims found in source | 20 |
| Quoted claims not found in source | 6 |
| References weighed for topical relevance | 24 |
| On topic | 21 |
| Off topic | 0 |
Searched the abstract, any retrieved full text, and the title. A quote drawn from a part of the paper that was not retrieved will appear here too, so check before treating one as invented:
Every one of these was searched against an abstract alone, with no full text retrieved - marked abstract only below. Where full text can be fetched, re-running with it will settle them; where the source publishes only a summary to PubMed, as GeneReviews chapters do, it will not, and the quote has to be checked by hand against the chapter itself.
PMID:41248189 (abstract only): "we confirmed the circulation of Y. pestis … one rat seropositive and one flea PCR positive … R. rattus contributes to the maintenance and transmission of plague"PMID:40424556 (abstract only): "The number of pYV molecules relative to the number of chromosomes per cell … increases with temperature"PMID:40022523 (abstract only): "the 2024 updated WHO list of priority pathogens also recognizes … Yersinia pestis"PMID:41389991 (abstract only): "The sensitivity and specificity of on-site F1RDT were 94% … and 74% … against RS1"PMID:41724296 (abstract only): "humanized heavy-chain antibody LcrV-X19-R1 confers complete protection against fatal pneumonic plague in mice"PMID:27722864 (abstract only): "Various types of animal models of plague have been developed, including mice, rats, guinea pigs, and nonhuman primates … rodent and nonhuman primate models of pneumonic plague closely resemble the human disease and … the pathologic changes that occur during bubonic plague are very similar in rodents, nonhuman primates, and humans"Checked with linkml-term-validator 0.4.5, through the ols: adapter.
| Outcome | Count |
|---|---|
| Terms checked | 34 |
| Resolved | 34 |
| Unresolved (possible confabulation) | 0 |
| Obsolete | 0 |
| Unverifiable | 0 |
| Terms whose name was checked | 23 |
| Terms named correctly | 15 |
| Terms named as a different term | 8 |
These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:
HP:0005521 (1 mention) - the report calls it "DIC"; HP calls it Disseminated intravascular coagulationCL:0000235 (2 mentions) - the report calls it "macrophage", "Cell populations targeted: phagocytes — macrophages"; CL calls it macrophage**NCIT:C839 (1 mention) - the report calls it "First-line; historical DOC"; NCIT calls it SpiramycinNCIT:C516 (1 mention) - the report calls it "First-line"; NCIT calls it Ganglioside GM2NCIT:C387 (1 mention) - the report calls it "First-line/alt; PEP"; NCIT calls it Recombinant Colony Stimulating FactorNCIT:C1667 (1 mention) - the report calls it "FDA-approved for plague"; NCIT calls it RG 14620NCIT:C480 (1 mention) - the report calls it "Treatment/PEP"; NCIT calls it Estramustine Phosphate SodiumNCIT:C328 (1 mention) - the report calls it "Meningitis, alt"; NCIT calls it CaffeineThe report gives these identifiers more than one name of its own:
CL:0000235 - called "macrophage", "Cell populations targeted:** phagocytes — macrophages"