Cyriaque Dossou Affoukou

From June to December 2022, a therapeutic efficacy study of Benin’s first-line antimalarial, artemether-lumefantrine (AL), was conducted in three sit

Background: Accurate interpretation and recording of malaria rapid diagnostic tests (RDTs) are critical for case management and surveillance in malaria-endemic settings. In Benin, where over 90% of malaria diagnoses rely on RDTs, concerns remain about the accuracy of the reporting and recording of RDT results. This study assessed the fidelity of RDT recording by healthcare workers (HCWs) in public health facilities and explored associated factors. Methods: A six-month mixed-methods, prospective observational study was conducted in 16 public health facilities across two departments in Benin. For each RDT performed, an image was captured using a digital RDT reader (HealthPulse, Audere, Seattle, WA USA) and independently interpreted by an external trained panel. HCW-recorded results were compared to panel interpretations. A knowledge, attitudes, practices, and beliefs (KAPB) survey and structured observations of RDT performance were conducted, alongside in-depth interviews with selected HCWs. Results: Of 35,720 RDTs assessed, overall agreement between HCW and reference panel interpretations was 94.3% (Cohen’s kappa = 0.88). Results misrecorded as positive (5.0%) were more frequent than results misrecorded as negative (0.7%). Agreement varied by patient age, HCW experience, and facility characteristics. Accuracy was highest with children under 5 years (96.7%) and lowest with patients over 15 years (91.6%). HCWs with ≥ 10 years of experience, and access to electricity and internet performed better. From 226 HCWs surveyed, 89.4% believed a patient with malaria could have a negative RDT, though only 19.5% supported treating such cases with antimalarials. While most HCWs were proficient in performing RDTs, only 40.5% waited the recommended time before reading results, and glove use was low (15.6%) highlighting safety gaps. RDT use was primarily motivated by adherence to guidelines (60.2%), rather than patient or supervisor expectations. Qualitative interviews highlighted contextual challenges including workload, lighting conditions in health facilities, and resource constraints. Conclusion: HCWs in Benin showed high accuracy in interpreting and reporting malaria RDT results, likely supported by recent nationwide RDT cassette validations. Performance was strongest among those with more experience, training, and adequate infrastructure. However, negative results misrecorded as positive, especially in adult patients, remains a concern. Targeted training and supportive supervision may help strengthen confidence in negative results and improve overall diagnostic accuracy.

Entomological surveillance in Benin has historically been limited to zones where indoor residual spraying was performed or where long-standing sentinel surveillance sites existed. However, there are significant country-wide gaps in entomological knowledge. The National Malaria Control Program (NMCP) assessed population dynamics of Anopheles vectors and malaria transmission in each of Benin’s 12 departments to create an entomological risk profile. Two communes per department (24/77 communes) were chosen to reflect diverse geographies, ecologies and malaria prevalence. Two villages per commune were selected from which four households (HH) per village were used for human landing catches (HLCs). In each HH, an indoor and outdoor HLC occurred between 7 p.m. and 7 a.m. on two consecutive nights between July–September 2017. Captured Anopheles were identified, and ovaries were dissected to determine parous rate. Heads and thoraces were tested for Plasmodium falciparum sporozoites by ELISA. The Entomological Inoculation Rate (EIR) was calculated as the product of mosquito bite rate and sporozoite index. Bite rates from An. gambiae s.l., the primary vector species complex, differed considerably between communes; average sporozoite infection index was 3.5%. The EIR ranged from 0.02 infectious bites (ib) per human per night in the departments of Ouémé and Plateau to 1.66 ib/human/night in Collines. Based on transmission risk scales, Avrankou, Sakété and Nikki are areas of low transmission (0 < EIR < 3 ib/human/year), Adjarra, Adja Ouèrè, Zè, Toffo, Bopa, Pehunco, Pèrèrè and Kandi are of medium transmission (3 < EIR < 30 ib/human/year), and the other remaining districts are high transmission (EIR > 30 ib/human/year). The heterogeneous and diverse nature of malaria transmission in Benin was not readily apparent when only assessing entomological surveillance from sentinel sites. Prospectively, the NMCP will use study results to stratify and deploy targeted vector control interventions in districts with high EIRs to better protect populations most at-risk.

: In 2005, artemether-lumefantrine (AL), an artemisinin-based combination therapy, was introduced as the first-line treatment of uncomplicated Plasmodium falciparum malaria in Benin. Per World Health Organization recommendations to monitor the efficacy of antimalarial treatment, we conducted a therapeutic efficacy study with AL for uncomplicated P. falciparum malaria in Bohicon and Kandi, Benin, from 2018 to 2019. Febrile patients aged 6 to 59 months with confirmed P. falciparum monoinfection received supervised doses of AL for 3 days. We monitored patients clinically and parasitologically on days 1, 2, 3, 7, 14, 21, and 28. A molecular analysis to detect mutations in the P. falciparum Kelch propeller gene (Pfk13) gene was carried out on day 0 samples. A total of 205 patients were included in the study. In Bohicon, the uncorrected adequate clinical and parasitological response (ACPR) proportion was 91.3% (95% confidence interval [CI]: 84.6–95.8%), whereas in Kandi this proportion was 96.7% (95% CI: 90.6–99.3%). Genotype-corrected ACPR proportions were 96.3% (95% CI: 90.9–99.0%) and 96.7% (95% CI: 90.6–99.3%) in Bohicon and Kandi, respectively. On day 3, 100% of patients in Bohicon and 98.9% of patients in Kandi had undetectable parasitemia. The C580Y mutation in the Pfk13 gene was not observed. AL remains effective for P. falciparum malaria in these two sites in Benin. Monitoring antimalarial efficacy and prevalence of molecular-resistance markers in Benin should be continued to allow for early detection of antimalarial resistance and to guide treatment policies.