Epidemiology of Malaria and Performance of a New Highly-Sensitive Malaria Diagnostic Tool in Jimma Zone, Ethiopia”

Abstract

Background: Despite significant progress in malaria control efforts, the disease continues to pose a major public health challenge in Ethiopia due to its complex epidemiological landscape. A critical concern is the presence of a large proportion of the population, such as schoolchildren, who have asymptomatic malaria infections that go undiagnosed and untreated. This, coupled with a dearth of evidence on the performance of new, highly-sensitive histidine- rich protein-2 (HRP-2)-based malaria rapid diagnostic tests (hsRDTs), such as the NxTek™ Eliminate Malaria-Pf test, in detecting Plasmodium falciparum (P. falciparum) infections in asymptomatic schoolchildren, hinders accurate diagnosis and treatment. This contributes to the persistence of asymptomatic infections, which act as a silent reservoir, fueling ongoing transmission and thwarting the ambitious goal of malaria elimination. Furthermore, a comprehensive examination of the spatiotemporal clustering of malaria incidence through modeling a decade of epidemiological data from the Jimma Zone is critical for informing resource allocation and targeted, locally effective intervention strategies. Taken together, this PhD project was aimed to investigate the epidemiology of malaria and evaluate the performance of a novel, highly-sensitive malaria diagnostic tool within the Jimma Zone of Southwest Oromia, Ethiopia. Methods: To achieve this aim, a school-based cross-sectional study was conducted from September 2021 to January 2022, involving 994 healthy schoolchildren aged 6–15 years. A multi-stage sampling technique was employed to select schools and participants, with sample allocation done proportionally to each school and grade. Participants were randomly chosen from student records using a lottery method. Finger-pricked blood samples were collected for various diagnostic tests: microscopy, conventional rapid diagnostic test (cRDT) (SD Bioline Malaria Ag Pf/Pv), and the hsRDT. Additionally, dry blood spots (DBSs) were prepared on filter papers for quantitative real-time polymerase chain reaction (qPCR) assay. For the prevalence study, all diagnostic methods except hsRDT were utilized. Data on demographic and risk factors for asymptomatic malaria were collected through face-to-face interviews with the child’s head of household by trained data collectors. The hsRDT was then compared to cRDT and microscopy. qPCR and microscopy were used as reference methods. Furthermore, to understand the broader epidemiological context, a decade of retrospective malaria data (2012-2021) from 15 districts in the Jimma Zone was analyzed. District-level annual parasite incidence (API) and standardized incidence ratio (SIR) were calculated, and malaria risk maps