Tackling malaria transmission in sub-Saharan Africa
Authors: Lauren Cohee, Miriam Laufer
Journal: The Lancet Global Health (2018)

After almost two decades of substantial reductions in the global burden of malaria, progress has stagnated.1WHOWorld malaria report 2017. World Health Organization, Geneva2017Google Scholar Global scientific and policy leaders agree that to achieve malaria eradication, interventions must focus not only on preventing malaria disease but also on decreasing malaria transmission.2The malERA Refresh Consultative Panel on Characterising the Reservoir and Measuring Transmission. MalERA: an updated research agenda for characterising the reservoir and measuring transmission in malaria elimination and eradication.PLoS Med. 2017; 14: e1002452Crossref PubMed Scopus (44) Google Scholar Children younger than 5 years and pregnant women are at the highest risk of severe disease and have previously been the primary targets of malaria control interventions. However, apparently healthy older children and adults also harbour transmissible malaria parasites. Several studies from across sub-Saharan Africa have revealed an underappreciated burden of malaria in school-age children, among whom prevalence of infection is often higher than that among younger children and adults.3Walldorf JA Cohee LM Coalson JE et al.School-age children are a reservoir of malaria infection in Malawi.PLoS One. 2015; 10: e0134061Crossref PubMed Scopus (121) Google Scholar, 4Nankabirwa JI Yeka A Arinaitwe E et al.Estimating malaria parasite prevalence from community surveys in Uganda: a comparison of microscopy, rapid diagnostic tests and polymerase chain reaction.Malar J. 2015; 14: 528Crossref PubMed Scopus (45) Google Scholar, 5Zhou Z Mitchell RM Kariuki S et al.Assessment of submicroscopic infections and gametocyte carriage of Plasmodium falciparum during peak malaria transmission season in a community-based cross-sectional survey in western Kenya, 2012.Malar J. 2016; 15: 421Crossref PubMed Scopus (32) Google Scholar, 6Kashamuka Mwandagalirwa M Levitz L Thwai KL et al.Individual and household characteristics of persons with Plasmodium falciparum malaria in sites with varying endemicities in Kinshasa Province, Democratic Republic of the Congo.Malar J. 2017; 16: 456Crossref PubMed Scopus (17) Google Scholar Although infections in school-age children rarely lead to severe disease or treatment seeking, they are associated with anaemia, school absences, and decreased educational attainment.7Nankabirwa J Brooker SJ Clarke SE et al.Malaria in school-age children in Africa: an increasingly important challenge.Trop Med Int Health. 2014; 19: 1294-1309Crossref PubMed Scopus (109) Google Scholar Mass treatment of school children with effective antimalarial drugs substantially lowers the prevalence of malaria infection and anaemia and improves cognitive function.8Clarke SE Jukes MCH Njagi JK et al.Effect of intermittent preventive treatment of malaria on health and education in schoolchildren: a cluster-randomised, double-blind, placebo-controlled trial.Lancet. 2008; 372: 127-138Summary Full Text Full Text PDF PubMed Scopus (151) Google Scholar, 9Nankabirwa JI Wandera B Amuge P et al.Impact of intermittent preventive treatment with dihydroartemisinin-piperaquine on malaria in Ugandan schoolchildren: a randomized, placebo-controlled trial.Clin Infect Dis. 2014; 58: 1404-1412Crossref PubMed Scopus (73) Google Scholar, 10Matangila JR Doua JY Mitashi P da Luz RI Lutumba P Van Geertruyden JP Efficacy and safety of intermittent preventive treatment in schoolchildren with sulfadoxine/pyrimethamine (SP) and SP plus piperaquine in Democratic Republic of the Congo: a randomised controlled trial.Int J Antimicrob Agents. 2017; 49: 339-347Summary Full Text Full Text PDF PubMed Scopus (12) Google Scholar, 11Clarke SE Rouhani S Diarra S et al.Impact of a malaria intervention package in schools on Plasmodium infection, anaemia and cognitive function in schoolchildren in Mali: a pragmatic cluster-randomised trial.BMJ Glob Health. 2017; 2: e000182Crossref PubMed Scopus (27) Google Scholar School-age children are more likely than people of other ages to be infected with gametocytes, which are required for host-to-host transmission. This age group is a predominant source of parasites in infected mosquitos that perpetuate malaria transmission.12Coalson JE Walldorf JA Cohee LM et al.High prevalence of Plasmodium falciparum gametocyte infections in school-age children using molecular detection: patterns and predictors of risk from a cross-sectional study in southern Malawi.Malar J. 2016; 15: 527Crossref PubMed Scopus (36) Google Scholar, 13Lin Ouédraogo A Gonçalves BP Gnémé A et al.Dynamics of the human infectious reservoir for malaria determined by mosquito feeding assays and ultrasensitive malaria diagnosis in Burkina Faso.J Infect Dis. 2015; 213: 90-99Crossref PubMed Scopus (98) Google Scholar, 14Gonçalves BP Kapulu MC Sawa P et al.Examining the human infectious reservoir for Plasmodium falciparum malaria in areas of differing transmission intensity.Nat Commun. 2017; 8: 1133Crossref PubMed Scopus (109) Google Scholar Thus, decreasing malaria infection rates could reduce parasite transmission and thereby prevalence of infection in the community. This novel strategy is being used to advance malaria elimination in Africa. In The Lancet Global Health, Sarah Staedke and colleagues15Staedke SG Maiteki-Sebuguzi C Rehman AM et al.Assessment of community-level effects of intermittent preventive treatment for malaria in schoolchildren in Jinja, Uganda (START-IPT trial): a cluster-randomised trial.Lancet Glob Health. 2018; (published online April 13.)http://dx.doi.org/10.1016/S2214-109X(18)30126-8Summary Full Text Full Text PDF PubMed Scopus (24) Google Scholar report the results of a cluster-randomised controlled trial of intermittent preventive treatment (IPT) of schoolchildren in Uganda, which has a high burden of malaria despite wide use of insecticide-treated nets. They investigated whether IPT with dihydroartemisinin-piperaquine (DP) would reduce community parasite prevalence and entomological inoculation rates. 9286 children aged 5–20 years received at least one full course of three doses of DP. Compared with children in control clusters who received no treatment, a small but significant reduction in microscopically detected parasite prevalence was seen (19% vs 23%, adjusted risk ratio 0·85, 95% CI 0·73–1·00, p=0·05). Of note, coverage with the IPT intervention was low, with only 43% of children receiving at least one dose of DP. Thus, observing any effect is remarkable. A slightly lower annual entomological inoculation rate was seen in the IPT group than in the control group, but the difference was not significant. The authors attribute the low uptake primarily to initially poor community acceptance of the intervention and logistical difficulties in obtaining informed consent and assent from parents and children. These challenges are not unique to this study and, in fact, are particularly common in school-based research.16Okello G Jones C Bonareri M et al.Challenges for consent and community engagement in the conduct of cluster randomized trial among school children in low income settings: experiences from Kenya.Trials. 2013; 14: 142Crossref PubMed Scopus (29) Google Scholar, 17Cohee L Chilombe M Ngwira A Jemu S Mathanga D Laufer M Pilot study of the addition of mass treatment for malaria to existing school-based programs to treat neglected tropical diseases.Am J Trop Med Hyg. 2018; 98: 95-99Crossref PubMed Scopus (6) Google Scholar Schools are an attractive platform for programmatic interventions because the target population is brought together generally in a government-regulated environment. However, for research purposes, these benefits can become challenges. For example, parents are mostly not present at schools and, therefore, might be sceptical of the intent of research staff. Informed consent must be obtained from parents, for which they need to go to the school or to be found in the community, Students must be identified definitively to ensure they can be given repeated treatment doses. In some settings, identification would be simple, but schools in malaria endemic regions are often chaotic. School registration and attendance records are unreliable because many children use different names at home and at school, and the spelling of names might vary due to illiteracy of the parents or guardians. Individual teachers can be responsible for hundreds of students, limiting their ability to confirm students' identities. Thus, measuring intervention effects in the research setting might not reflect the potential of programmatic interventions.18Ladner J Besson M-H Hampshire R Tapert L Chirenje M Saba J Assessment of eight HPV vaccination programs implemented in lowest income countries.BMC Public Health. 2012; 12: 370Crossref PubMed Scopus (78) Google Scholar, 19Pannaraj PS Wang H-L Rivas H et al.School-located influenza vaccination decreases laboratory-confirmed influenza and improves school attendance.Clin Infect Dis. 2014; 59: 325-332Crossref PubMed Scopus (46) Google Scholar Creative solutions for these challenges, such as considering community-based consent for interventions with limited risks, are needed. While previous school-based intervention studies have focused on the health benefit to individual children, the results of Staedke and colleagues suggest that school-based IPT could have a broader effect by decreasing malaria in the communities where the children live. Further studies with increased coverage and in different settings are needed to support these findings. New interventions, especially those targeting key reservoirs of transmission, are essential to achieving the goal of malaria elimination. School-based malaria treatment can capitalise on existing infrastructures to deliver an intervention that improves the health of school-age children and might also serve as a novel approach to decreasing malaria transmission where other interventions have failed to lessen the burden of this disease. We declare no competing interests. Assessment of community-level effects of intermittent preventive treatment for malaria in schoolchildren in Jinja, Uganda (START-IPT trial): a cluster-randomised trialIPT of schoolchildren with DP might have a positive effect on community-level malaria indicators and be operationally feasible. Studies with greater IPT coverage are needed. Full-Text PDF Open Access