Distribution systems as reservoirs of <i>Naegleria fowleri</i> and other amoebae
Bibliographic record
Abstract
Naegleria fowleri is the etiologic agent of primary amoebic meningoencephalitis (PAM), a rapidly fatal disease. Although PAM generally occurs after recreational exposure to contaminated water, two fatal cases of PAM were linked to a drinking water supply in Arizona. This study tested the ability of distribution system biofilms to be reservoirs for N. fowleri and other amoebae. When introduced to laboratory pipe loops, N. fowleri attached to biofilms and survived for five months. In two fullscale distribution systems, amoebic activity was detected in 67% of biofilm samples tested, regardless of chlorination. Amoebic activity occurred mostly in locations associated with stagnant water and high bacterial counts. Legionella was also found in 65% of biofilm samples. Although N. fowleri was never detected in field samples, the observed risk factors—high bacterial counts, amoebic activity, and the presence of Legionella in biofilms—suggest that N. fowleri could thrive in both systems if introduced.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".