Shell-Less Egg Syndrome (SES) Widespread in Western Canadian Layer Operations Is Linked to a Massachusetts (Mass) Type Infectious Bronchitis Virus (IBV) Isolate
Bibliographic record
Abstract
A disease with a sudden drop in egg production and shell-less eggs called, shell-less egg syndrome (SES) has been observed in Western Canada egg layer flocks since 2010. The etiology of this disease is not known. We hypothesize that SES is caused by an infectious bronchitis virus (IBV) strain since it is known that IBV replicates in the shell gland causing various eggshell abnormalities. In this study, we screened egg layer flocks, in the provinces of Alberta (AB) and Saskatchewan (SK), with and without a history of SES for the presence of IBV infection. During 2015–2016, a total of 27 egg layer flocks were screened in AB (n = 7) and SK (n = 20). Eighty-one percent of the screened flocks (n = 22) were positive for IBV infection. Thirty of these isolates were successfully characterized using molecular tools targeting the most variable spike (S) 1 gene. IBV isolates from this study clustered into three genotypes based on partial S1 gene variability. The majority of the IBV isolates (70%) were Massachusetts (Mass) type, and the rest were either Connecticut (Conn) type or an uncharacterized genotype with genetic characteristics of Mass and Conn types. Since the majority of the IBV isolates included within the Mass type, we used a Mass type IBV isolate to reproduce SES in specific pathogen free (SPF) white leghorn chickens in lay. Further studies are warranted to investigate whether other IBV isolates can cause SES, to clarify the pathogenesis of SES and to develop a vaccine in order to prevent SES as observed in Western Canadian layer flocks.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".