Widespread pfhrp2/3 deletions and HRP2-based false-negative results in southern Ethiopia.

BACKGROUND: Rapid diagnostic tests (RDTs) play a significant role in expanding case management in peripheral healthcare systems. Histidine-rich protein-2 (HRP2) antigen detection RDTs are predominantly used to diagnose Plasmodium falciparum infection. However, the evolution and spread of P. falciparum parasite strains with deleted hrp2/3 genes, causing false-negative results, have been reported. This study assessed the diagnostic performance of HRP2-detecting RDTs for P. falciparum cases and the prevalence of pfhrp2/3 deletions among symptomatic patients seeking malaria diagnosis at selected health facilities in southern Ethiopia. METHODS: A multi-health facilities-based cross-sectional study was conducted on self-presenting febrile patients seeking treatment in southern Ethiopia from July to September 2022. A purposive sampling strategy was used to enroll patients with microscopically confirmed P. falciparum infections. A capillary blood sample was obtained to prepare a blood film for microscopy and a RDT using the SD Bioline™ Malaria Pf/Pv Test. Dried blood spot samples were collected for further molecular analysis. DNA was extracted using gene aid kits and amplification was performed using nested PCR assay. Exon 2 of hrp2 and hrp3, which are the main protein-coding regions, was used to confirm its deletion. The diagnostic performance of RDT was evaluated using PCR as the gold standard test for P. falciparum infections. RESULTS: Of 279 P. falciparum PCR-confirmed samples, 249 (89.2%) had successful msp-2 amplification, which was then genotyped for hrp2/3 gene deletions. The study revealed that pfhrp2/3 deletions were common in all health centres, and it was estimated that 144 patients (57.8%) across all health facilities had pfhrp2/3 deletions, leading to false-negative PfHRP2 RDT results. Deletions spanning exon 2 of hrp2, exon 2 of hrp3, and double deletions (hrp2/3) accounted for 68 (27.3%), 76 (30.5%), and 33 (13.2%) of cases, respectively. The study findings revealed the prevalence of P. falciparum parasites lacking a single pfhrp2-/3-gene and that both genes varied across the study sites. This study also showed that the sensitivity of the SD Bioline PfHRP2-RDT test was 76.5% when PCR was used as the reference test. CONCLUSION: This study confirmed the existence of widespread pfhrp2/3- gene deletions, and their magnitude exceeded the WHO-recommended threshold (> 5%). False-negative RDT results resulting from deletions in Pfhrp2/3- affect a country's attempts at malaria control and elimination. Therefore, the adoption of non-HRP2-based RDTs as an alternative measure is required to avoid the consequences associated with the continued use of HRP-2-based RDTs, in the study area in particular and in Ethiopia in general.

Analysing the six-year malaria trends at Metehara Health Centre in Central Ethiopia: the impact of resurgence on the 2030 elimination goals.

BACKGROUND: Despite Ethiopia's concerted efforts to eliminate malaria by 2030, the disease continues to pose a significant public health and socioeconomic challenge in the country. The year 2021 witnessed 2.78 million malaria cases and 8041 associated deaths, emphasizing the persistent threat. Monitoring the prevalence trend of malaria is crucial for devising effective control and elimination strategies. This study aims to assess the trend of malaria prevalence at the Metehara Health Centre in the East Shoa Zone, Ethiopia. METHODS: A retrospective study, spanning from February to September 2023, utilized malaria registration laboratory logbooks at Metehara Health Centre to evaluate the prevalence of malaria from 2017/18 to 2022/23. Malaria and related data were collected using a pre-designed data collection sheet. Descriptive statistics were employed for data summarization, presented through graphs and tables. RESULTS: Out of 59,250 examined blood films, 17.4% confirmed the presence of Plasmodium infections. Among the confirmed cases, 74.3%, 23.8%, and 1.84% were attributed to Plasmodium falciparum, Plasmodium vivax, and mixed infections, respectively. The trend of malaria exhibited a steady decline from 2017/18 to 2021/22, reaching 9.8% prevalence. However, an abrupt increase to 26.5% was observed in 2022/23. Males accounted for a higher proportion (66%) of cases compared to females (34%). The age group 15-24 years experienced the highest malaria incidence at 42%. Notably, malaria cases peaked during autumn (September to November) at 43% and reached the lowest percentage during spring (March to May) at 13%. CONCLUSION: Malaria persists as a significant health challenge in and around Metehara, central Ethiopia, predominantly driven by Plasmodium falciparum. The five-year declining trend was interrupted by a notable upsurge in 2022/23, indicating a resurgence of malaria in the study area. It is imperative to adopt a reverse strategy to sustain the progress achieved by the national malaria control plan.