Evaluation of the protective efficacy of a spatial repellent to reduce malaria incidence in children in Mali compared to placebo: study protocol for a cluster-randomized double-blinded control trial (the AEGIS program).

BACKGROUND: Spatial repellents have been widely used for the prevention of mosquito bites but their efficacy in reducing mosquito-borne diseases has never been evaluated in Africa. Additionally, spatial repellents have the potential of being critical tools in the prevention of mosquito-borne diseases in contexts where typical vectors control efforts such as insecticide-treated nets (ITNs) and indoor residual spray (IRS) are inaccessible or underutilized such as among displaced populations or in emergency relief settings. To address this knowledge gap, Kolondieba District, Sikasso Region, Mali was selected as a site to estimate the impact of the Mosquito Shield™, a spatial repellent that incorporates transfluthrin on a plastic sheet, on malaria-related outcomes. Over the past decade, the Region of Sikasso, Health districts of Kadiolo, Yorosso, and Kolondieba have remained among the most afflicted, characterized by an annual parasite incidence of more than 116 cases per 1000 population [1] and a Plasmodium falciparum prevalence rate of 29.7% [2]. METHODS: Cluster-randomized, placebo-controlled, double-blinded clinical trial, whereby children ≥ 6 months to < 10 years old will be enrolled and followed to determine the time to malaria infection with monthly blood samples for microscopic diagnosis. A total of 1920 subjects (HHs) will be enrolled in 60 clusters (30 spatial repellent, 30 placebo). Malaria incidence will be estimated and compared to demonstrate and quantify the protective efficacy (PE) of a spatial repellent, in reducing malaria infection. Monthly mosquito collections using CDC light traps will be conducted to determine if there are entomological correlates of spatial repellent efficacy that may be useful for the evaluation of new spatial repellents. Quarterly human landing catches (HLC) will assess the behavioral effects of the intervention. DISCUSSION: Findings will serve as an efficacy trial of spatial repellent products for sub-Saharan Africa. Findings will be submitted to the World Health Organization Vector Control Advisory Group (WHO VCAG) for assessment of whether spatial repellents have "public health value." Entomological outcomes will also be measured as proxies of malaria transmission to help develop guidelines for the evaluation of future spatial repellent products. TRIAL REGISTRATION: ClinicalTrials.gov NCT04795648 . Registered on March 12, 2021.

Sample Transport Optimization: Mali Pilot Study.

In Mali, qualified laboratories for testing of dangerous pathogens are centralized in Bamako. Creating a specimen transport system respecting timeline, specimen quality, biosafety, and biosecurity standards is a challenge. The current ad hoc system that relies on untrained public transport companies carries risks of spoilage, accidental release of pathogens, and delays, which compromise specimen quality. This pilot study aimed to evaluate the effectiveness (ie, timeline, quality of specimen, and cost) of using the trained postal service for sample transportation from district to central level, compared with the current system. The postal service intervention ran from mid-2016 to mid-2017 and covered 3 districts. Data were collected in the same districts during the same period of the preceding year for comparison. In all, 41 specimens were shipped using public transportation and 51 were shipped using the postal service. These included suspected meningitis, measles, yellow fever, and polio samples. Only 46% of samples sent by public transportation were received in Bamako within 72 hours of collection, compared to 71% of samples shipped via the postal service (p < .05). Further, 93% of samples shipped by public transportation arrived in good condition at the receiving laboratory, compared to 98% by postal service. Although cost comparisons were difficult (flat fee vs per-specimen fare), the average cost per specimen was 8 times higher with the postal service. Shipment of specimens from districts to central level using the postal service was feasible and appeared to be faster than public transportation, thus allowing specimen quality to be preserved. Further analysis regarding the most efficient costing mechanism is needed.