Risk of malaria associated with travel to malaria-endemic areas to visit friends and relatives: a population-based case–control study
Bibliographic record
Abstract
BACKGROUND: Reports relying on population-based data and using epidemiologic methodologies such as case-control study designs for malaria in travellers and multivariable regression analysis of risk factors are rare. The aim of this study was to investigate the epidemiologic characteristics of travellers who tested positive for malaria after visiting friends and relatives in malaria-endemic areas to determine the risk of malaria associated with such travel. METHODS: Using routinely collected data from a population-based laboratory database, we conducted a case-control study of symptomatic people returning from travel to malaria-endemic areas who presented for malaria testing in Calgary from 2013 to 2017. We used a multivariable logistic regression to analyze the association between the presence of malaria and other risk factors. RESULTS: There were 251 confirmed malaria cases during the study period, of which 219 were matched to 1129 returning travellers without malaria. Based on the multivariable regression, the odds of a traveller who visited friends and relatives in malariaendemic areas being diagnosed with malaria was 2.82 (95% confidence interval [CI] 1.42-5.92) times greater than that of other travellers to these regions. Adults (odds ratio [OR] 3.62, 95% CI 1.66-8.84), males (OR 2.70, 95% CI 1.56-4.80), travellers to Africa (OR 11.52, 95% CI 6.33-22.05) and those who did not seek pretravel advice (OR 0.38, 95% CI 0.20-0.70) were more likely to be diagnosed with malaria. Although those travelling to visit friends and relatives tended to stay longer in endemic areas than other travellers, visit duration was not associated with an increased likelihood of malaria in the model. The annual incidence of malaria was highest (13.34 per 100 000) in metropolitan wards associated with lower socioeconomic status and immigrant communities. INTERPRETATION: Travellers who visited friends and relatives in malaria-endemic areas were less likely than other travellers to these regions to seek pretravel advice, take prophylaxis and have a visit duration less than 2 weeks; travelling to Africa and being male increased the odds of being diagnosed with malaria, independent of other factors. These data suggest that targeted strategies to provide pretravel care to travellers who visit friends and relatives in malaria-endemic areas may aid in reducing the burden of malaria in this population.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".