A Direct from Blood Reverse Transcriptase Polymerase Chain Reaction Assay for Monitoring Falciparum Malaria Parasite Transmission in Elimination Settings
Bibliographic record
Abstract
malaria parasites that amplifies RNA targets directly from blood. We developed the assay to identify gametocyte-specific transcripts in parasites from patient blood samples, as a means of monitoring malaria parasite transmission in field settings. To perform the test, blood is added directly to a master mix in PCR tubes and analyzed by real-time PCR. The limit of detection of the assay on both conventional and portable real-time PCR instruments was 100 parasites/mL for 18S rRNA, and 1,000 parasites/mL for asexual (PFE0065W) and gametocyte (PF14_0367, PFGEXP5) mRNA targets. The usefulness of this assay in field studies was explored in samples from individuals living in a high-transmission region in Cameroon. The sensitivity and specificity of the assay compared with a standard two-step RT-PCR was 100% for 18S rRNA on both conventional and portable instruments. For PF14_0367, the sensitivity and specificity were 85.7% and 70.0%, respectively, on the conventional instrument and 78.6% and 90%, respectively, on the portable instrument. The concordance for assays run on the two instruments was 100% for 18S rRNA, and 79.2% for PF14_0367, with most discrepancies resulting from samples with low transcript levels. The results show asexual and sexual stage RNA targets can be detected directly from blood samples in a simple one-step test on a field-friendly instrument. This assay may be useful for monitoring malaria parasite transmission potential in elimination settings, where sensitive diagnostics are needed to evaluate the progress of malaria eradication initiatives.
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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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
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".