Spores of two fish microsporidia (Pseudoloma neurophilia and Glugea anomala) are highly resistant to chlorine
Bibliographic record
Abstract
Pseudoloma neurophilia (Microsporidia) is the most common pathogen found in zebrafish Danio rerio research facilities. The parasite is associated with marked emaciation. Zebrafish laboratories usually disinfect eggs to prevent transmission of pathogens, typically with chlorine at 25 to 50 ppm for 10 min. The ability of chlorine to kill spores of P. neurophilia and 2 other microsporidia, Glugea anomala and Encephalitozoon cuniculi, was evaluated using 2 viability stains. SYTOX Green was used to visualize dead spores, and live spores were identified by their ability to extrude polar tubes in Fungi-Fluor solution following UV exposure. Results with both stains were similar at various chlorine concentrations for P. neurophilia and G. anomala, but Fungi-Fluor was not useful for E. cuniculi, due to the much smaller spore size. Using the SYTOX stain, we found that 5 ppm chlorine for 10 min causes 100% death in spores of E. cuniculi, which was similar to findings in other studies. In contrast, the spores of P. neurophilia and G. anomala were much more resistant to chlorine, requiring >100 or 1500 ppm chlorine, respectively, to achieve >95% spore death. Repeating chlorine exposures with spores of P. neurophilia using solutions adjusted to pH 7 increased the efficacy of 100 ppm chlorine, achieving >99% spore inactivation. We corroborated our viability staining results with experimental exposures of zebrafish fry, achieving heavy infections in fry at 5 to 7 d post-exposure in fish fed spores treated at 50 ppm (pH 9). Some fish still became infected with spores exposed to 100 ppm chlorine (pH 9.5). This study demonstrates that spores of certain fish microsporidia are highly resistant to chlorine, and indicates that the egg disinfection protocols presently used by most zebrafish research facilities will not prevent transmission of P. neurophilia to progeny.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".