Molecular evidence of high rates of asymptomatic P. vivax infection and very low P. falciparum malaria in Botswana
Bibliographic record
Abstract
BACKGROUND: Botswana is one of eight SADC countries targeting malaria elimination by 2018. Through spirited upscaling of control activities and passive surveillance, significant reductions in case incidence of Plasmodium falciparum (0.96 - 0.01) was achieved between 2008 and 2012. As part of the elimination campaign, active detection of asymptomatic Plasmodium species by a highly sensitive method was deemed necessary. This study was carried out to determine asymptomatic Plasmodium species carriage by nested PCR in the country, in 2012. METHOD: A cross-sectional study involving 3924 apparently healthy participants were screened for Plasmodium species in 14 districts (5 endemic: Okavango, Ngami, Tutume, Boteti and Bobirwa; and 9 epidemic: North East, Francistown, Serowe-Palapye, Ghanzi, Kweneng West, Kweneng East, Kgatleng, South East, and Good Hope). Venous blood was taken from each participant for a nested PCR detection of Plasmodium species. RESULTS: The parasite rates of asymptomatic Plasmodium species detected were as follows: Plasmodium falciparum, 0.16 %; Plasmodium vivax, 4.66 %; Plasmodium malariae, (Pm) 0.16 %; Plasmodium ovale, 0 %, mixed infections (P. falciparum and P. vivax), 0.055 %; and (P. vivax and P. malariae), 0.027 %, (total: 5.062 %). The high proportion of asymptomatic reservoir of P. vivax was clustered in the East, South Eastern and Central districts of the country. There appeared to be a correlation between the occurrence of P. malariae infection with P. vivax infection, with the former only occurring in districts that had substantial P. vivax circulation. The median age among 2-12 year olds for P. vivax infection was 5 years (Mean 5.13 years, interquartile range 3-7 years). The odds of being infected with P. vivax decreased by 7 % for each year increase in age (OR 0.93, 95 % CI 0.87-1.00, p = 0.056). CONCLUSION: We have confirmed low parasite rate of asymptomatic Plasmodium species in Botswana, with the exception of P.vivax which was unexpectedly high. This has implication for the elimination campaign so a follow up study is warranted to inform decisions on new strategies that take this evidence into account in the elimination campaign.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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 teacher head, 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".