Bibliographic record
Abstract
The protozoan parasite, Perkinsus marinus (Dermo), has caused significant mortality in the eastern oyster, Crassostrea virginica, along the east coast of the United States and the Gulf of Mexico, since the 1950s. Because of its current expanded distribution and increased abundance, P. marinus is now considered more prevalent in the mid-Atlantic waters and the Chesapeake Bay in particular, than another protozoan pathogen, Haplosporidium nelsoni (MSX). The susceptibility, infectivity/pathogenicity, and transmission of P. marinus in eastern oysters were investigated in numerous laboratory studies, The influence of environmental factors such as temperature, salinity, and pollution on the interaction between the host oyster and the parasite were also examined. Three P. marinus life stages, the meront, prezoosporangia, and biflagellated zoospore, were found effective in transmitting the disease. The meront stage was more effective than the prezoosporangia stage in transmitting the disease in eastern oysters, suggesting that the meront is the primary transmission agent in nature. A dose of 10-10(2) freshly isolated P. marinus cells oyster(-1) was required to cause infection by direct shell cavity injection. P. marinus susceptibility and disease progression were positively correlated with temperature, salinity, and number of infective cells the oyster encountered. Temperature appeared to be the most important factor, followed by the infective cell dose, and then salinity in determining the subsequent disease development in oysters. There was no significant interaction between temperature, salinity, and infective cell dose on the prevalence of disease in oysters. However, the interaction between either temperature and salinity or between temperature and P. marinus dose significantly intensified the disease. The Pacific oyster, Crassostrea gigas, was less susceptible, but not completely resistant, to P. marinus compared to the eastern oyster, C. virginica. However, the Pacific oyster was intolerant of high temperature (>15 degrees C) and low salinity (<10 >ppt), thus vulnerable to high mortality under high temperature and low salinity environmental conditions. Pollution has the potential to enhance P. marinus susceptibility and infection in oysters.
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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 | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.004 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.002 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.005 | 0.007 |
| Open science | 0.005 | 0.005 |
| Research integrity | 0.009 | 0.004 |
| Insufficient payload (model declined to judge) | 0.989 | 0.992 |
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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".