Nodular gill disease causing proliferative branchitis and mortality in Chinook salmon (<i>Oncorhynchus tshawytscha</i>)
Bibliographic record
Abstract
CASE HISTORY: A period of escalating mortality occurred among Chinook salmon (1-5 g) held in freshwater raceways at a commercial culture facility. The mortality rate peaked at 1.5% of the population per day, water temperature was 9-10 degrees C, and water quality had recently deteriorated due to an influx of suspended solids. The affected fish did not respond to several chloramine-T bath treatments (10 ppm for 1 hour). CLINICAL FINDINGS: The dead fish did not exhibit flared opercula typical of infection with bacterial gill disease (BGD) nor did the remaining fish show obvious signs of respiratory distress. Clinical lesions were limited to the gills of the fish, and were consistent with a proliferative branchitis, including substantial hyperplasia and fusion of lamellae. DIAGNOSIS: Numerous angular amoebic organisms (approximately 10 x 8 microm), with a central, large vesicular nucleus and faintly acidophilic cytoplasm, visible on H&E-stained sections, were located on the hyperplastic epithelia of the lamellae, filaments, and remaining lining of the branchial cavity. Morphologically, the amoebae were similar to representatives of the genus Cochliopodia spp. described from North American salmonids, that presented similar lesions and clinical signs; consequently, the disease was diagnosed as nodular gill disease (NGD). CLINICAL RELEVANCE: Grossly, NGD can be mistaken for BGD; the distinction is important because chloramine-T, routinely used in the treatment of BGD, is ineffective for the treatment of NGD. Static formalin baths of 170 ppm (37% formaldehyde) for 1 hour, supplemented with oxygen, may reduce amoebic infections but should be used cautiously as treatment can precipitate mortality in fish with gill disease. Cues for the onset of NGD are not completely understood, although poor water quality and elevations in temperature are likely to exacerbate infections. Similarly, the prevalence of this disease is not accurately known, but it is possible that it may be more common among salmonids in New Zealand than is presently recognised.
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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) | 0.000 | 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 | 0.001 |
| 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 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".