Population-Wide Malaria Testing and Treatment with Rapid Diagnostic Tests and Artemether-Lumefantrine in Southern Zambia: A Community Randomized Step-Wedge Control Trial Design

Abstract

Reducing the human reservoir of malaria parasites is critical for elimination. We conducted a community randomized controlled trial in Southern Province, Zambia to assess the impact of three rounds of a mass test and treatment (MTAT) intervention on malaria prevalence and health facility outpatient case incidence using random effects logistic regression and negative binomial regression, respectively. Following the intervention, children in the intervention group had lower odds of a malaria infection than individuals in the control group (adjusted odds ratio = 0.47, 95% confidence interval [CI] = 0.24–0.90). Malaria outpatient case incidence decreased 17% in the intervention group relative to the control group (incidence rate ratio = 0.83, 95% CI = 0.68–1.01). Although a single year of MTAT reduced malaria prevalence and incidence, the impact of the intervention was insufficient to reduce transmission to a level approaching elimination where a strategy of aggressive case investigations could be used. Mass drug administration, more sensitive diagnostics, and gametocidal drugs may potentially improve interventions targeting the human reservoir of malaria parasites.

Short-term Impact of Mass Drug Administration With Dihydroartemisinin Plus Piperaquine on Malaria in Southern Province Zambia: A Cluster-Randomized Controlled Trial

“…First, mean monthly cumulative rainfall (117.5 mm) was lower during the rainy season just after the mass treatment rounds (January–April 2015) than during the previous rainy season in 2014 (137.3 mm), before the mass treatment rounds (Supplementary Figure 4). However, the rainfall in 2015 was very similar to that in 2012 (120.5 mm) before a parasite survey in the study area (conducted April–May) that showed malaria infection prevalence in children to be 35.6% [4], compared with an overall 7.9% in the parasite survey in 2015 (across lower- and higher-transmission areas). Although the decrease in rainfall probably played a role in the malaria decline in control areas between 2014 and 2015, it does not seem to fully explain it.…”

Location, location, location: environmental factors better predict malaria-positive individuals during reactive case detection than index case demographics in Southern Province, Zambia

“…The districts near Lake Kariba have the highest malaria transmission intensity, with transmission intensity waning further inland (north and northwest) from the Lake [24]. Due to such low transmission, Southern Province contains the first districts targeted for elimination in the national strategic plan.…”

Treatment of Chronic Asymptomatic Plasmodium falciparum Infection Does Not Increase the Risk of Clinical Malaria Upon Reinfection

“…Similarly, a trial in Burkina Faso randomized villages to screening and treatment of asymptomatic P. falciparum infection with artemether-lumefantrine (AL) or no intervention and found no difference in the subsequent incidence of malaria [24]. In contrast, a study in the Zambia-where malaria transmission is year-round-randomized health districts during the low transmission season to screening and treatment of infected individuals with AL or no intervention and found a modest decrease in malaria risk in the intervention group [25].…”