Primary Amebic Meningoencephalitis

1. Disease Information

Overview. Primary amebic meningoencephalitis (PAM) is a rapidly progressive, fulminant, almost universally fatal infection of the central nervous system caused by the thermophilic, free-living amoeba Naegleria fowleri ("brain-eating amoeba"). Infection occurs when warm fresh water containing the amoeba is forced into the nose; the organism crosses the cribriform plate along the olfactory nerve and invades the brain, producing a hemorrhagic, necrotizing meningoencephalitis (PMID: 22919000). Death typically occurs within ~1–2 weeks of symptom onset, with a case-fatality rate >95–97% (PMID: 39432113).

Key identifiers. - Mondo: MONDO:0000290 - ICD-10: B60.2 (Naegleriasis / primary amebic meningoencephalitis) - ICD-11: 1F55 (Acanthamoebiasis / free-living amoeba infections) → Naegleria meningoencephalitis - MeSH: D008836 Meningoencephalitis; organism MeSH D009258 Naegleria; D054314 Central Nervous System Protozoal Infections - SNOMED CT: 36649002 (Primary amebic meningoencephalitis) - Orphanet: Not a classic rare-genetic ORPHA entry; covered under free-living amoebic infections - OMIM: Not applicable (no Mendelian locus) - NCBI Taxonomy (agent): Naegleria fowleri Taxon:5763

Synonyms / alternative names. Naegleriasis; Naegleria fowleri infection; "brain-eating amoeba" infection; amebic meningoencephalitis (primary); PAM; PAME.

Information source type. Disease-level, aggregated from case reports, CDC Free-Living Ameba (FLA) surveillance, and systematic reviews (PMID: 32369575, 26582886). Because PAM is extremely rare, there are no large EHR cohorts; evidence is predominantly individual case/autopsy data pooled at the disease level.

2. Etiology

Primary cause (infectious). The sole cause is infection with Naegleria fowleri, a thermophilic free-living amoeba found worldwide in warm fresh water (lakes, ponds, rivers, hot springs, geothermal water) and in inadequately disinfected recreational/treated water (pools, splash pads, tap water) (PMID: 40146665, 22919000, 27123690). The amoeba has three life stages: trophozoite (invasive, feeding), flagellate (transient), and cyst (environmentally resistant). Only the trophozoite invades tissue.

Route of entry. Intranasal instillation of contaminated water (swimming, diving, splashing, hot-spring bathing, religious ablution/wudu, and nasal/sinus irrigation with neti pots using contaminated tap water) (PMID: 22919000, 21291600). In Karachi, Pakistan, a cluster of 13 PAM cases occurred in people with no aquatic exposure, with infection attributed to ablution with tap water; N. fowleri was subsequently detected in Karachi municipal tap water (11/39 samples) under conditions of high temperature, low chlorine, and high coliform counts (PMID: 21291600, 39780139).

Risk factors (environmental/behavioral). - Warm-freshwater nasal exposure — strongest risk; swimming/diving is the most common exposure and lakes/ponds/reservoirs the most common source (PMID: 32369575). - Male sex (~75–76% of cases) (PMID: 32369575, 26582886). - Young age (children/adolescents; median 12–14 years) (PMID: 32369575, 26582886). - Warm climate / summer months / southern latitudes, with geographic expansion northward attributed to climate warming (PMID: 22919000, 26582886). - Inadequately disinfected treated water (splash pads, pools, household plumbing) (PMID: 40146665, 22919000). - Nasal irrigation with non-sterile tap water (PMID: 22919000).

Genetic risk/protective factors (host). None established — PAM is not a heritable disorder and no human susceptibility/protective loci are validated. (Not applicable.)

Protective factors (environmental). Keeping water out of the nose; using nose clips; using sterile/distilled/boiled water for nasal irrigation; adequate water chlorination (free chlorine ≥1 ppm) — all reduce risk (CDC guidance; PMID: 40146665).

Gene–environment interactions (host). Not applicable (no human genetic component). The relevant interaction is pathogen virulence gene expression × host nasal exposure/temperature: thermophilic growth (optimal ~42–45 °C) and virulence-gene upregulation on contact with host cells drive invasion (PMID: 40096149, 33843581).

3. Phenotypes

PAM is clinically biphasic, progressing from nonspecific flu-like illness to fulminant meningoencephalitis (PMID: 26582886). Onset is acute, typically 1–9 days (median ~5 days) after exposure; course is rapidly progressive, death in a median of ~5 days from symptom onset.

Frequencies from Indian systematic review (fever 79.2%, headache 58.3%, seizures 41.6%; PMID: 42764041) and Kerala series (fever 91.7%, headache 83.3%, altered mental status 50%; PMID: 41873284).

Laboratory-abnormality phenotypes (CSF). Resembles bacterial meningitis: elevated opening pressure, neutrophilic pleocytosis (median 2400 cells/µL), low glucose (median 23 mg/dL), high protein (median 365 mg/dL); motile trophozoites on wet mount are diagnostic (PMID: 26582886). HPO: HP:0002922 Increased CSF protein; HP:0003112 (abnormal CSF); low CSF glucose.

Severity / progression. Uniformly severe and progressive; essentially no stable or episodic course. Quality-of-life impact: for the few survivors, outcomes range from full recovery to severe neurological sequelae (cognitive, motor deficits); for the vast majority the outcome is death, so QoL instruments (EQ-5D/SF-36) are not meaningfully applied at the population level.

4. Genetic / Molecular Information

Human causal genes: None (not a genetic disease).

Pathogen (amoeba) "virulence genes" (the functional equivalent of causal molecular drivers): - nfa1 — encodes a ~13.1 kDa pseudopod/food-cup protein central to contact-dependent cytolysis; a validated virulence/vaccine antigen (PMID: 22955499). - Naegleriapores / Npa (A and B) — pore-forming, membrane-permeabilizing polypeptides causing host-cell lysis (PMID: 39432113). - Cathepsin B and serine/cysteine proteases — degrade host extracellular matrix and tissue; secreted and packaged in extracellular vesicles (PMID: 39432113, 40312759). - Leishmanolysin (GP63-like metalloprotease) — adhesion/enzymatic virulence, identified in EV proteome (PMID: 40312759). - Mp2CL5 membrane protein; lysozyme, cystatin, hemerythrin (host-defense evasion, brain migration, lethal infection) (PMID: 40096149). - Lectins mediating adhesion (PMID: 32716210).

Genome. N. fowleri genome sequenced; comparative genomics distinguishes pathogenic N. fowleri from non-pathogenic N. gruberi, though several "virulence" homologs are shared, implying regulation/expression (not mere presence) determines pathogenicity (PMID: 33843581, 31797948).

Variant classification / allele frequency / somatic-vs-germline / modifier genes / epigenetics / chromosomal abnormalities (human): Not applicable — there are no human pathogenic variants, ClinVar entries, gnomAD frequencies, or chromosomal findings for this infectious disease.

5. Environmental Information

• Environmental reservoir: warm fresh water worldwide — lakes, ponds, rivers, hot springs, geothermal discharge, poorly maintained pools/splash pads, and warm tap/plumbing water (PMID: 40146665, 22919000). Thermophilic: thrives up to ~45 °C.
• Climate sensitivity: warming water temperatures expand the amoeba's range; northward spread of US cases documented (PMID: 22919000, 26582886).
• Lifestyle/behavioral factors: recreational freshwater activities (swimming, diving, water-skiing, splash pads), hot-spring bathing, and nasal/sinus irrigation with untreated tap water (PMID: 22919000).
• Infectious agent (NCBI Taxonomy): Naegleria fowleri (Taxon:5763), phylum Percolozoa, class Heterolobosea. Related non-pathogenic congener: N. gruberi. Other pathogenic FLA causing distinct CNS disease: Acanthamoeba spp., Balamuthia mandrillaris (granulomatous amebic encephalitis), Sappinia (PMID: 33843581).

6. Mechanism / Pathophysiology

Ordered causal chain (initiating exposure → clinical manifestation):

1. Contaminated warm freshwater is forced into the nasal cavity (swimming, diving, hot-spring bathing, or nasal irrigation) → deposits N. fowleri trophozoites on the olfactory/nasal mucosa (demonstrated, PMID: 22919000).
2. Trophozoites adhere to nasal mucosa via lectins/food-cup (Nfa1) structures and begin feeding on epithelium → local mucosal damage (demonstrated in vitro/animal, PMID: 32716210, 22955499).
3. Amoebae migrate along olfactory nerve fibers through the cribriform plate into the olfactory bulbs (demonstrated; explains early anosmia, PMID: 22919000).
4. In the CNS, trophozoites perform contact-dependent trogocytosis/phagocytosis ("food-cup" ingestion of neural cells), driven by actin dynamics regulated by Arp2/3 and Src kinase (demonstrated, PMID: 40096149).
5. Simultaneously, contact-independent cytolysis occurs via secreted and extracellular-vesicle–delivered virulence factors — naegleriapores (pore formation), cathepsin B/serine proteases, phospholipases, leishmanolysin — causing hemolysis, increased membrane permeability, and necrosis (demonstrated in vitro, PMID: 40312759, 39432113).
6. Tissue destruction + amoebic antigens trigger a massive innate inflammatory response (neutrophil and eosinophil influx, cytokine release) → necrotizing, hemorrhagic meningoencephalitis with cerebral edema (demonstrated; neutrophils central to host defense, PMID: 2628288, 27525348).
7. Cerebral edema and inflammation → raised intracranial pressure, uncal/tonsillar herniation → brainstem compression (inferred from clinical/autopsy data, PMID: 25667249).
8. → Coma and death, typically within days (demonstrated clinical outcome, PMID: 26582886).

Branch: Beyond primary olfactory-bulb invasion, autopsy and animal data indicate extra-CNS hematogenous dissemination can occur (relevant to transplant-transmission risk) (PMID: 24279908).

Molecular pathways / cellular processes. - Host-cell ingestion: actin cytoskeleton remodeling (Arp2/3, Src kinase) — GO:0030041 actin filament polymerization; GO:0006909 phagocytosis; "trogocytosis" (PMID: 40096149). - Cytolysis: pore-forming/membrane permeabilization (naegleriapores) — GO:0051715 cytolysis in another organism; GO:0006887 EV/exocytosis. - Proteolysis: cysteine/serine protease activity — GO:0006508 proteolysis (PMID: 39432113). - Metabolic shift: brain-passaged amoebae show altered lipid storage/utilization vs axenic culture (Raman microspectroscopy) (PMID: 40096149). - Immune involvement: innate-dominant neutrophilic/eosinophilic inflammation; adaptive immunity can be protective in animal models (PMID: 2628288, 646016).

Tissue-damage mechanisms: necrosis, hemorrhage, phagocytic "nibbling" of neurons, protease-mediated matrix degradation, oxidative inflammatory injury.

Molecular profiling (transcriptomics/proteomics). RNA-seq across life stages shows stage-specific regulation of the cytoskeletal machinery: nf-profilin (actin-binding regulator) is high in cysts and membrane-localized, whereas nf-actin localizes to cytoplasm, pseudopodia, and food-cup structures of trophozoites; during cyst→trophozoite conversion on host-cell contact, profilin falls and actin rises — directly linking the transcriptome to the invasive food-cup apparatus (PMID: 40016342, 36839446). Secretome/EV proteomics identified >1000 proteins including leishmanolysin and serine proteases (PMID: 40312759). Brain-passaged vs axenic amoebae differ metabolically in lipid storage/utilization (Raman spectroscopy) (PMID: 40096149). Transcriptomic profiling of the "brain-eating amoeba" host interaction further catalogs virulence-associated expression (PMID: 39735262). Phylogenomics places N. fowleri in phylum Heterolobosea, new order Naegleriida (PMID: 39826589).

Suggested ontology terms: GO:0006909 (phagocytosis), GO:0030041 (actin polymerization), GO:0006508 (proteolysis), GO:0019835 (cytolysis), GO:0006954 (inflammatory response); CL:0000540 neuron, CL:0000127 astrocyte, CL:0000775 neutrophil; UBERON:0002264 olfactory bulb, UBERON:0000955 brain.

7. Anatomical Structures Affected

• Primary organ: Brain (UBERON:0000955), especially olfactory bulbs (UBERON:0002264), frontal lobes, and basal cisterns; meninges (UBERON:0002360). Nervous system (central).
• Portal of entry tissue: nasal/olfactory epithelium (UBERON:0001707 nasal cavity; UBERON:0001997 olfactory epithelium) and cribriform plate / olfactory nerve (UBERON:0001675).
• Secondary / disseminated involvement: rare extra-CNS spread (lung, heart, kidney reported at autopsy), relevant to transplant risk (PMID: 24279908).
• Tissue/cell level: nervous tissue — neurons (CL:0000540), astrocytes/glia (CL:0000125); inflammatory infiltrate of neutrophils (CL:0000775) and eosinophils (CL:0000771).
• Subcellular (host damage): plasma-membrane disruption (pore-forming peptides); for the amoeba, food cup / pseudopod (amoebic phagocytic structure), lysosomes/EVs (GO:0005764 lysosome; GO:1903561 extracellular vesicle).
• Lateralization: typically bilateral but may begin asymmetric reflecting unilateral olfactory-tract seeding; progresses to diffuse cerebral involvement.

8. Temporal Development

• Onset: Acute. Incubation ~1–9 days (median ~5) after nasal exposure (PMID: 26582886).
• Stages: (i) Early — nonspecific flu-like: fever, headache, nausea/vomiting, altered smell/taste; (ii) Late — CNS: meningismus, confusion, seizures, focal deficits, coma (PMID: 26582886).
• Progression rate: Rapid/fulminant. Median time from symptom onset to death ~5 days; most die within 1–2 weeks (PMID: 32369575, 26582886).
• Course pattern: monophasic, progressive; no relapsing–remitting or episodic form.
• Duration/remission: self-limited only in the sense of rapid death; treatment-induced survival is rare and depends on very early recognition (PMID: 25667249).
• Critical window for intervention: the first 24–72 hours after symptom onset — survival correlates with early diagnosis and immediate combination therapy (PMID: 27525348, 25667249).

9. Inheritance and Population

• Inheritance: Not applicable (infectious; no germline transmission, penetrance, anticipation, founder effects, or carrier frequency).
• Incidence/prevalence: Extremely rare. ~0–8 US cases/year (CDC); ~381 global cases reported through 2018 (PMID: 32369575); ~142 US cases 1937–2013 (PMID: 26582886). True incidence likely underestimated due to misdiagnosis.
• Case-fatality rate: >95–97%; only ~7 confirmed survivors globally in the 2018 review (PMID: 32369575, 39432113).
• Sex ratio: male-predominant ~3:1 (75–76% male) (PMID: 32369575, 26582886).
• Age distribution: predominantly children and adolescents, median 12–14 years, though cases span 13 days to 85 years (PMID: 42764041).
• Geographic distribution: worldwide in warm climates; US cases concentrated in southern-tier states (Texas, Florida — Florida accounts for >25% of US cases) with northward expansion (Minnesota, Kansas, Indiana) linked to warming (PMID: 23621053, 22919000). Substantial case loads reported from Pakistan, India, Australia, and other warm regions (PMID: 42764041, 41873284). Pakistan (Karachi) is notable for a non-recreational, ablution/tap-water–associated disease pattern (13-case cluster; N. fowleri confirmed in municipal tap water), reflecting high ambient temperature, under-chlorination, and degraded distribution systems (PMID: 21291600, 39780139).

10. Diagnostics

• CSF analysis: bacterial-meningitis-like profile — neutrophilic pleocytosis, low glucose, high protein, raised opening pressure (PMID: 26582886).
• Direct microscopy (first-line, rapid): wet-mount of fresh CSF showing motile trophozoites — positive in 95.8% of Indian cases; Giemsa/Wright/trichrome staining (do NOT rely on Gram stain) (PMID: 42764041, 23710088).
• Molecular confirmation: real-time PCR of CSF/tissue (CDC) — definitive; LAMP assays for rapid water/clinical detection (PMID: 35020127, 25822175). PCR confirmation is underused in resource-limited settings (only 2/24 Indian cases) (PMID: 42764041).
• Culture: CSF on non-nutrient agar with E. coli overlay; flagellation test (trophozoite→flagellate in distilled water) (PMID: 35020127).
• Immunologic: immunohistochemistry/indirect immunofluorescence on tissue; antigen detection.
• Imaging: CT/MRI shows nonspecific cerebral edema, basal meningeal enhancement, hemorrhage; often normal early (PMID: 26582886).
• Clinical criteria / differential diagnosis: PAM should be suspected in acute meningoencephalitis with recent freshwater nasal exposure (PMID: 40146665). Differential: bacterial meningitis, viral/herpes encephalitis, fungal meningitis, tuberculous meningitis — distinguished by motile amoebae on wet mount and PCR, and by negative bacterial/viral cultures (PMID: 27123690).
• Screening: No asymptomatic screening exists (too rare, too rapid); environmental water testing (PCR/LAMP) supports outbreak investigation (PMID: 25822175).
• Suggested LOINC concepts: CSF cell count/differential, CSF glucose, CSF protein, Naegleria PCR.

11. Outcome / Prognosis

• Mortality: >95–97%; historically near-uniformly fatal (PMID: 32369575, 39432113).
• Survival: only a handful of confirmed survivors worldwide; 3 well-documented North American survivors by mid-2010s (PMID: 25667249, 27525348).
• Prognostic factors: time to diagnosis and treatment is the dominant determinant; early presentation (flu-like stage), prompt combination antimicrobials, aggressive ICP control, and therapeutic hypothermia are associated with survival (PMID: 25667249, 27525348).
• Morbidity in survivors: variable — from near-complete recovery to permanent neurological deficits (cognitive, motor, visual).
• Complications: cerebral edema, herniation, raised ICP, seizures, status epilepticus, hydrocephalus (PMID: 25667249).
• Disease-specific mortality: essentially all deaths attributable directly to CNS infection within days–weeks.

12. Treatment

No single proven cure; management is a multidrug + neurocritical-care bundle started emergently on suspicion.

• Amphotericin B (polyene antifungal; amebicidal) — backbone, given IV and intrathecal/intraventricular; mainstay in nearly all regimens (used in 91.6% of Indian cases) (PMID: 42764041, 23710088). NCIT: Amphotericin B (C280).
• Miltefosine (alkylphosphocholine; investigational, CDC-provided) — added to regimens of recent survivors (PMID: 26679626, 25667249). NCIT: Miltefosine (C61769).
• Adjunct antimicrobials: azithromycin, fluconazole (or other azoles), rifampin — commonly combined (PMID: 27525348).
• Neurocritical care: aggressive management of elevated intracranial pressure using traumatic-brain-injury principles, CSF diversion (intraventricular shunt), and therapeutic (targeted) hypothermia — credited in survivors (PMID: 25667249, 27525348). NCIT: Therapeutic Hypothermia.
• Supportive care: mechanical ventilation, seizure control, dexamethasone for edema.
• Treatment outcomes: despite therapy, most cases are fatal; survival clusters around early-treated, miltefosine-containing, hypothermia-managed cases (PMID: 26679626).
• Experimental / preclinical pipeline: A high-throughput phenotypic screen of 12,000 ReFRAME compounds found 58 potent inhibitors (IC50 <1 µM) of free-living amoebae, including 19 active against N. fowleri; 19 compounds killed N. fowleri in vitro within 24 h — faster than current drugs — including HDAC inhibitors (quisinostat, panobinostat, pracinostat, dacinostat, fimepinostat), HSP90 inhibitors (radicicol, NVP-HSP990), halofuginone, fumagillin, bardoxolone, solithromycin, and acriflavine (PMID: 32970675). Natural products (e.g., Pinus densiflora leaf extract, IC50 62.3 µg/mL) are selectively amebicidal while sparing rat glial cells (PMID: 38835258). None are yet approved for human PAM.
• Personalized/experimental: no approved targeted therapy. Pharmacogenomics not applicable (pathogen, not host-genome driven).

Suggested chemical/intervention ontology terms: CHEBI:2682 amphotericin B; CHEBI:75291 miltefosine; CHEBI:2955 azithromycin; CHEBI:46081 fluconazole; CHEBI:28077 rifampicin; NCIT therapeutic hypothermia; NCIT ventriculostomy/CSF shunt.

13. Prevention

Prevention is primarily behavioral and environmental — there is no vaccine for human use.

• Primary prevention: keep water out of the nose during warm-freshwater activities; use nose clips or hold the nose when jumping/diving; avoid stirring up sediment in warm shallow water (CDC guidance).
• Nasal irrigation & ablution safety: use only sterile, distilled, or previously boiled-and-cooled water in neti pots / sinus-rinse devices, and for religious ablution (wudu) where tap water may be under-chlorinated (PMID: 22919000, 21291600).
• Water-system control: adequate chlorination/disinfection of pools and splash pads; proper design/operation of treated recreational water venues (PMID: 40146665).
• Secondary prevention: clinician awareness for early recognition of PAM in meningoencephalitis with freshwater exposure → faster diagnosis/treatment (PMID: 40146665, 26582886).
• Public-health measures: environmental water surveillance (PCR/LAMP), outbreak investigation, and public education in endemic/warm regions (PMID: 25822175).
• Immunization: experimental DNA vaccine against nfa1 induces protective Th1/Th2 immunity in mice — no human vaccine (PMID: 22955499).

14. Other Species / Natural Disease

• Agent taxonomy: Naegleria fowleri, NCBI Taxon:5763 (Heterolobosea, Percolozoa).
• Host range / experimental hosts: Mice are the standard experimental host and develop a disease resembling human PAM after intranasal inoculation (PMID: 646016, 669800).
• Natural disease in cattle (Bos taurus, NCBI Taxon:9913): A documented outbreak killed nine 10–20-month-old Holstein heifers in California (summers 1998–1999) that drank untreated warm surface water (>42 °C); autopsy showed necrosuppurative hemorrhagic meningoencephalitis with olfactory lobes/nerves most severely affected, N. fowleri confirmed by IHC and culture — "the disease in cattle closely resembles primary amoebic meningoencephalitis in humans" (PMID: 16475525). This establishes PAM as a genuine naturally occurring cross-species disease sharing route of entry, climate dependence, and pathology. Veterinary relevance: include Naegleria meningoencephalitis in summer bovine CNS differentials in hot regions.
• Zoonotic potential: None in the classic sense — not transmitted animal-to-human or human-to-human; acquisition is strictly environmental (waterborne via nose). (Rare iatrogenic concern: organ-transplant transmission from infected donors — PMID: 24279908.)
• Comparative biology: non-pathogenic congener N. gruberi and related Willaertia magna share some virulence-gene homologs but lack full pathogenicity, enabling comparative virulence studies (PMID: 31797948, 33843581).

15. Model Organisms

• Mouse (BALB/c, others): the principal in vivo model; intranasal inoculation reproduces olfactory-nerve invasion and lethal meningoencephalitis (PMID: 646016, 669800). Used to study innate (neutrophil) defense, protective immunity, passive immunization, and DNA vaccination (PMID: 2628288, 2486833, 22955499).
• Phenotype recapitulation: high — mirrors route of entry, CNS pathology, rapid lethality, and sex/age-dependent susceptibility (females and older mice more resistant; PMID: 669800).
• Limitations: dose/route differences (IV vs intranasal), accelerated course, and species differences in immune response.
• In vitro / cellular models: co-culture with human fibrosarcoma cells, MDCK epithelial cells, and primary nasal epithelial cells to dissect contact-dependent trogocytosis and EV-mediated cytopathy (PMID: 40096149, 40312759).
• Omics models: axenic vs brain-passaged trophozoite proteomics/transcriptomics and secretome/EV proteomics for virulence-factor discovery (PMID: 40096149, 39735262, 33843581).
• Resources: ATCC strains of N. fowleri; CDC Free-Living and Intestinal Amebas Laboratory (surveillance, PCR, strain archiving).

Evidence Source Legend

Human clinical/epidemiologic: PMID 32369575, 26582886, 42764041, 41873284, 40146665, 27123690, 23621053, 22919000, 23710088, 35020127, 25667249, 26679626, 27525348, 24279908, 21291600, 39780139. In vitro/mechanistic: PMID 40096149, 40312759, 39432113, 32716210, 40016342, 36839446, 39735262. Experimental therapeutics (in vitro/preclinical): PMID 32970675, 38835258. Model organism (mouse): PMID 646016, 669800, 2628288, 2486833, 22955499. Natural animal disease (veterinary): PMID 16475525. Genomics/phylogenomics: PMID 33843581, 31797948, 39826589.

Supported vs Refuted Hypotheses

Supported: (1) PAM is a pathogen-caused infectious disease with no human causal gene (etiology = N. fowleri). (2) Exposure is overwhelmingly warm-freshwater nasal entry with olfactory-nerve CNS invasion. (3) Disease is >95–97% fatal, predominantly in young males. (4) Cytopathy is dual — contact-dependent actin/food-cup trogocytosis plus contact-independent EV/pore-forming/protease cytolysis. (5) Non-recreational tap-water routes (ablution, neti-pot) are real and epidemiologically important. (6) PAM occurs as a natural cross-species disease (cattle) and is well modeled in intranasally-inoculated mice. Refuted / not applicable: Any human Mendelian inheritance, susceptibility/protective loci, ClinVar variants, chromosomal abnormalities, genetic testing, carrier screening, or genetic counseling role — none exist for this infectious disease. Person-to-person and classic zoonotic animal-to-human transmission are not supported (acquisition is strictly environmental; rare iatrogenic transplant risk aside).

Limitations & Future Directions

Evidence is dominated by rare case reports and pooled surveillance (no RCTs; survivorship anecdotal). Optimal drug regimen and the independent contribution of hypothermia remain undefined. Priorities: validated early rapid diagnostics (point-of-care PCR/LAMP), new amebicidal drugs crossing the blood–brain barrier, and climate-driven surveillance as the amoeba's geographic range expands.

Artifacts

• OpenScientist final report
• OpenScientist final report

Reference Validation

Checked with linkml-reference-validator 0.5.1.

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Terms the report names something else

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:

• MONDO:0000290 (3 mentions) - the report calls it "if available"; MONDO calls it primary amebic meningoencephalitis
• HP:0003112 (1 mention) - the report calls it "abnormal CSF"; HP calls it Abnormal circulating amino acid concentration
• CL:0000540 (2 mentions) - the report calls it "neurons", "Tissue/cell level: nervous tissue — neurons"; CL calls it neuron
• UBERON:0000955 (2 mentions) - the report calls it "Brain", "Primary organ: Brain"; UBERON calls it brain
• UBERON:0001675 (1 mention) - the report calls it "cribriform plate / olfactory nerve"; UBERON calls it trigeminal ganglion
• CL:0000125 (1 mention) - the report calls it "astrocytes/glia"; CL calls it glial cell

Terms whose name is worth a second look

The report's name for these is recognisably related to the term's own name without being one of them. A loose paraphrase reads the same way as a citation of the wrong sibling term - and so does a related synonym, which the ontology records precisely because it names something adjacent rather than the same thing - so these are listed rather than judged:

• GO:0030041 (2 mentions) - the report calls it "actin polymerization"; GO calls it actin filament polymerization
• UBERON:0002360 (1 mention) - the report calls it "meninges"; UBERON calls it meninx

Terms named inconsistently

The report gives these identifiers more than one name of its own:

• Taxon:5763 - called "Naegleria fowleri", "Heterolobosea, Percolozoa"
• CL:0000540 - called "neurons", "Tissue/cell level: nervous tissue — neurons"
• UBERON:0000955 - called "Brain", "Primary organ: Brain"

Prefixes with no resolver

Terms carrying these prefixes were not checked either way, because no configured ontology covers them. An unrecognised prefix may name an ontology this run could not reach as easily as one that does not exist, so nothing here is evidence of fabrication: Taxon.