Evidence for the F200Y (TAC) mutation conferring benzimidazole resistance in a southern USA cattle population of <i>Haemonchus placei</i> spreading from a single emergence
Bibliographic record
Abstract
Abstract The benzimidazoles are one of the most important broad-spectrum anthelmintic drug classes for the control of parasitic nematodes of domestic animals and humans. They have been widely used in the livestock sector, particularly in small ruminants for over 40 years. This has resulted in the development and wide spread of resistance in small ruminant gastrointestinal nematode parasite species, including Haemonchus contortus. Recently, resistance to benzimidazole drugs has been reported in Haemonchus placei , but there is relatively little information on its prevalence. It is important to develop a molecular tools to identify resistance mutations in H. placei early in their development in order to understand the emergence and spread. Our previous study demonstrated the F200Y (T A C) mutation at their early stage in 6/9 H. placei populations derived from southern USA, albeit at low frequencies between 2 and 10%. The present study analysis the phylogenetics of the isotype-1 β-tubulin locus to suggest that F200Y (T A C) mutation has been spread from a single emergence in H. placei ; likely by the anthroprogenic movement of ruminant livestock in southern USA. Population genetic data of H. placei using a panel of microsatellite markers revealed little genetic sub-structure, consistent with a high level of gene flow in this region. Overall, these results provide clear genetic evidence for the spread of F200Y (T A C) benzimidazoles resistance mutation to multiple different locations from a single emergence in H. placei .
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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 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".