Outbreak of Trypanosoma vivax in Dairy Cattle from São Paulo, Brazil: Haematological and Molecular Diagnostic Approaches
Bibliographic record
Abstract
Trypanosoma vivax, a haemoprotozoan of African origin, has spread throughout Latin America, mainly affecting cattle through mechanical transmission by flies. This study reports an outbreak of T. vivax on a dairy farm in the midwestern region of São Paulo State, Brazil. Clinical signs included progressive weight loss, lethargy, hyporexia, reduced milk production, abortions, neurological signs, and deaths. The herd comprised 238 crossbred Holstein-Gir cattle (200 cows, 38 calves). Blood samples were collected from 104 randomly selected cows and all 38 calves to assess hematocrit (HCT) and total plasma protein (TPP), and detect trypomastigote forms using blood and buffy coat smears. PCR was performed on EDTA blood from 30 smear-negative cows. Trypanosoma sp. was identified in 51.9% (54/104) of the smear samples, with morphometric confirmation of T. vivax infection. About 66.6% (20/30) of the smear-negative cows tested positive by PCR, showing the higher sensitivity of molecular tests. Anemia was observed in 56.8% of infected cows, with significantly lower HCT and TPP values than in uninfected animals. The absence of quarantine for new animals, high fly density, and shared needles for oxytocin injections were likely contributing factors. This study underscores the crucial role of molecular diagnostics in accurately investigating outbreaks.
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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 | 0.001 | 0.001 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 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".