Post-outbreak dynamics and persistence of Actinobacillus pleuropneumoniae serotype 15 in finisher pigs in Iowa
Bibliographic record
Abstract
In 2021, Actinobacillus pleuropneumoniae serotype 15 (App15) mediated a high mortality respiratory outbreak in finisher hogs, affecting multiple companies within a 30-km radius of Iowa, USA. The atypical regional spread raised concerns for the strain's unusual environmental persistence and survivability. This prospective longitudinal study aimed to determine the duration of App15 persistence in convalescent pigs at a naturally infected 1200 head site. Sixty-seven pigs were sampled individually for 6 weeks using nasal swabs (NS), tonsil scrapings (TS), and serum samples (SS); pen-based oral fluids (OF) were also collected. NS, TS, and OF were tested for App by rtPCR, while serum was screened with the Swinecheck mix-App ELISA. All 67 pigs tested App PCR positive in TS ≥ 1 during the sampling period, with progressive increases in detection from 53.3% to 95.8% between the first and last sampling week, respectively. Only 23 pigs (34.3%) were PCR positive by NS ≥ 1 during the sampling period, with decaying detection rates from a peak of 51.2% positivity in the first sampling week. Fifty-three of 73 pens (72.6%) tested App PCR positive in OF ≥ 1 during the sampling period. Seropositivity decreased from 93% on week 4- to 33% on week 8. TS had the highest PCR detection rate at all time points evaluated, representing the best antemortem sample type for App PCR detection in this study. The results reported here generated new important knowledge related to App15 ecology and epidemiology, prospectively informing disease diagnosis, surveillance, and biosecurity practices.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".