Frequency of <i>Trypanosoma cruzi</i> parasitemia among infected blood donors with a potential association between parasite lineage and transfusion transmission
Bibliographic record
Abstract
BACKGROUND: Trypanosoma cruzi is endemic to the Americas where it demonstrates multiple lineages over a vast geographic range (i.e., United States to Argentina). These lineages possess divergent geographic and biologic characteristics, including variations in disease manifestations. Herein, we report the frequency of parasitemia among seropositive US blood donors and the potential association between parasite lineage and transfusion transmission. STUDY DESIGN AND METHODS: Blood donors identified as T. cruzi seropositive during screening were enrolled in follow-up studies, including hemoculture testing and a risk factor questionnaire. Positive hemocultures were expanded to obtain sufficient parasites for molecular lineage determination and analysis. Country of birth, obtained from the questionnaire, was used to predict parasite lineage in the absence of demonstrable parasitemia for infected donors. RESULTS: Eighteen (6.8%) of 263 seropositive donors were hemoculture positive. Among the 17 hemocultures expanded for lineage determination, TcV was identified more frequently (n = 12), compared to TcI (n = 2), TcII (n = 1), and TcVI (n = 2). When presumptive parasite lineages were compared to hemoculture results, only two of 157 (1.3%) TcI versus 13 of 38 (34.2%) TcII/TcV/TcVI non-US donors were parasitemic; three of 44 (6.8%) US donors were TcV or TcVI. CONCLUSIONS: Based on lineage determination for donors with parasitemia; hemoculture positivity associated with presumptive parasite lineage; and implicated donors from US, Canadian, and Spanish transfusion cases, donors from Southern South America are significantly more likely to have parasitemia and transmit infection to blood recipients (TcII, TcV, or TcVI vs. TcI). Thus, parasite lineage may be associated with risk of transfusion-transmitted T. cruzi.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.002 | 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".