Thrasher Research Fund - Medical research grants to improve the lives of children

Project Details

Early Career

Status: Funded - Closed

Malaria in school-age children: Defining new interventions to improve health and reduce transmission

Lauren Cohee, MD, MS

Summary

BACKGROUND: Malaria remains a leading cause of death and illness among children in sub-Saharan Africa. In community-based surveys in Malawi, the prevalence of malaria in school-age children is 25%, which is 2.5 times higher than the prevalence in younger children and adults. School-age children also have the highest rates of infections containing gametocytes, the stage of the parasite that transmits malaria to mosquitoes and perpetuates infection to the next human host. GAP: School-based malaria interventions have been shown to improve health and educational outcomes, however the optimal type of intervention has not been established and the possibility that school-based interventions can reduce malaria transmission has never been evaluated. HYPOTHESIS: We postulate that prevalence of malaria infection among children attending school may be slightly less than school-age children in the community, but will still represent the largest portion of infection and the largest reservoir of gametocytes in the community. Rapid diagnostic tests will fail to detect a significant portion of these infections including infections that contain gametocytes. METHODS: School-based cohort studies of malaria will be conducted simultaneously with cross-sectional household surveys in the surrounding communities. Primary school students will be tested for malaria infection using rapid diagnostic tests as well as molecular methods to detect all malaria infections and infections containing gametocytes. RESULTS: Prevalence of infection by RDT at screening was 37% (range among schools 9-64%). There was a significant reduction at six weeks in infections by microscopy (adjusted absolute reduction (aAR) 6.4%, adjusted relative reduction (aRR) 47.1%, p<0.0001) and PCR (aAR 7.2%, aRR 23.1%, p<0.0001), but no reduction in anemia. In low, seasonal prevalence areas, sub-patent infections (detected by PCR, but not RDT) at screening (9% prevalence) limited the intervention impact and were associated with persistent infection, but not disease, during follow-up. In high transmission settings, incident infections limited impact duration. While gametocyte burden remained constant in untreated children, treatment with artemether-lumefantrine reduced the gametocyte prevalence (p<0.0001) from 51.8% to 9.7% and geometric mean gametocyte density (p=0.008) from 0.52 to 0.05 gametocytes/microliter. Based on these estimates, the gametocyte burden in the community could be reduced by 25-55% depending on the season and the measure used to characterize gametocyte carriage. IMPACT: Results from this study provide the evidence to design school-based malaria control interventions to improve the health and educational outcomes of the students as well as decrease malaria transmission in the community. Screen-and-treat approaches using more sensitive tests for screening require further evaluation but may be useful for improving the health of students and decreasing malaria transmission in the community.

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