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Ethiopia has a diverse ecology and geography resulting in spatial and temporal variation in malaria transmission. Evidence-based strategies are thus needed to monitor transmission intensity and target interventions. A purposive selection of dried blood spots collected during cross-sectional school-based surveys in Oromia Regional State, Ethiopia, were tested for presence of antibodies against Plasmodium falciparum and P. vivax antigens. Spatially explicit binomial models of seroprevalence were created for each species using a Bayesian framework, and used to predict seroprevalence at 5 km resolution across Oromia. School seroprevalence showed a wider prevalence range than microscopy for both P. falciparum (0-50% versus 0-12.7%) and P. vivax (0-53.7% versus 0-4.5%), respectively. The P. falciparum model incorporated environmental predictors and spatial random effects, while P. vivax seroprevalence first-order trends were not adequately explained by environmental variables, and a spatial smoothing model was developed. This is the first demonstration of serological indicators being used to detect large-scale heterogeneity in malaria transmission using samples from cross-sectional school-based surveys. The findings support the incorporation of serological indicators into periodic large-scale surveillance such as Malaria Indicator Surveys, and with particular utility for low transmission and elimination settings., (© The American Society of Tropical Medicine and Hygiene.)

Background: The development of drug resistance to chloroquine is posing a challenge in the prevention and control efforts of malaria globally. Chloroquine is the first-line treatment for uncomplicated P.vivax in Ethiopia. Regular monitoring of anti-malarial drugs is recommended to help early detection of drug-resistant strains of malaria parasites before widely distributed. The emergence of P.vivax resistance to chloroquine in the country endangers the efficacy of P.vivax treatment. This study aimed to assess the therapeutic efficacy of chloroquine among uncomplicated P.vivax infections at Shewa Robit Health Center, northeast Ethiopia. Methods: One-arm in vivo prospective chloroquine efficacy study was conducted from November 2020 to March 2021. Ninety participants aged between 16 months to 60 years confirmed with P.vivax mono-infection microscopically were selected and treated with a 25 mg/kg standard dose of chloroquine over three days. Thick and thin blood smears were prepared and examined. Clinical examination was performed over 28 follow-up days. Hemoglobin concentration level was measured on days 0, 14, and 28. Result: Of the 90 enrolled participants, 86 (96%) completed their 28 days follow-up period. The overall cure rate of the drug was 98.8% (95% CI: 95.3–100%). All asexual stages and gametocytes were cleared within 48 hours with rapid clearance of fever. Hemoglobin concentration had significantly recovered between days 0 and 14, 0 and 28, and 14 and 28 days (P = 0.032, P<0.001, and P = 0.005), respectively. Fast resolution of clinical signs and symptoms was also observed. Severe adverse events were not recorded. Conclusion: The present study revealed that chloroquine remains an efficacious and safe drug in the study setting for treating uncomplicated P.vivax in the study area. Large-scale continuous surveillance is needed to monitor the development of resistance in due time. [ABSTRACT FROM AUTHOR]

Background: Declining efficacy of chloroquine for the treatment Plasmodium vivax malaria has been reported in different endemic settings in Ethiopia. This highlights the need to assess alternative options for P. vivax treatment with artemisinin-based combination therapy, such as pyronaridine-artesunate. This treatment regimen has shown high efficacy for uncomplicated malaria in both Africa and Asia. However, limited data are available from Ethiopia. This study was conducted to assess the efficacy and safety of pyronaridine-artesunate for the treatment of uncomplicated P. vivax malaria in Northwest Ethiopia. Methods: A single arm prospective efficacy study was conducted in the Hamusite area, Northwest Ethiopia. Fifty-one febrile adult patients with uncomplicated P. vivax malaria were enrolled between March and July 2021. Patients were treated with pyronaridine-artesunate once daily for three days. Clinical and parasitological parameters were monitored over a 42-day follow-up period using the standard World Health Organization protocol for therapeutic efficacy studies. Results: A total of 4372 febrile patients were screened with 51 patients enrolled and 49 completing the 42-day follow-up period. The PCR-uncorrected adequate clinical and parasitological response (ACPR) was 95.9% (47/49; 95% CI 84.9–99.0) on day 42. Two patients had recurrences [4.0% (2/49); 95% CI 0.7–12.1] on days 35 and 42. The parasite clearance rate was rapid with fast resolution of clinical symptoms; 100% of participants had cleared parasitaemia on day 1 and fever on day 2. All 16 (31.4%) patients with gametocyte carriage on day 0 had cleared by day 1. There were no serious adverse events. Conclusion: In this small study, pyronaridine-artesunate was efficacious and well-tolerated for the treatment of uncomplicated P. vivax malaria. In adults in the study setting, it would be a suitable alternative option for case management. [ABSTRACT FROM AUTHOR]

Background: Declining efficacy of chloroquine against Plasmodium vivax malaria has been documented in Ethiopia. Thus, there is a need to assess the efficacy of alternative schizontocidal anti-malarials such as dihydroartemisinin–piperaquine (DHA–PPQ) in P. vivax malaria-infected patients. This study was conducted to evaluate the therapeutic efficacy of DHA–PPQ drug in South West Ethiopia. Methods: This is a single-arm, prospective therapeutic efficacy study in patients with uncomplicated P. vivax malaria. The study was conducted from May 2021 to August 2021, based on the standard World Health Organization study protocol for surveillance of anti-malarial therapeutic efficacy. The study endpoint was adequate clinical and parasitological response on day 42. Results: A total of 86 patients with uncomplicated vivax malaria were enrolled. Of these, 79 patients completed the scheduled follow up; all showing adequate clinical and parasitological responses to day 42, with a successful cure rate of 100% (95% CI 96–100). Parasitaemias were cleared rapidly (86% by day 1 and 100% by day 3), as were clinical symptoms (100% by day 1). Gametocyte carriage decreased from 44% on Day 0 to 1% on day 1 and 0% on Day 2. Mean haemoglobin concentrations increased between day 0 (mean 12.2 g/dL) and day 42 (mean 13.3 g/dL). Treatment was well tolerated and no severe adverse events were observed. Conclusion: In summary, treatment with DHA–PPQ demonstrated excellent efficacy for uncomplicated P. vivax, with no recurrences to day 42, and no safety concerns. This treatment, which is also effective against P. falciparum, appears to be an ideal alternative for P. vivax as part of the malaria elimination programme. [ABSTRACT FROM AUTHOR]

Background: Determining malaria transmission within regions of low, heterogenous prevalence is difficult. A variety of malaria tests exist and range from identification of diagnostic infection to testing for prior exposure. This study describes the concordance of multiple malaria tests using data from a 2015 household survey conducted in Ethiopia.Methods: Blood samples (n=2279) from 3 regions in northern Ethiopia were assessed for Plasmodium falciparum and Plasmodium vivax by means of microscopy, rapid diagnostic test, multiplex antigen assay, and multiplex assay for immunoglobulin G (IgG) antibodies. Geospatial analysis was conducted with spatial scan statistics and kernel density estimation to identify malaria hot spots by different test results.Results: The prevalence of malaria infection was low (1.4% by rapid diagnostic test, 1.0% by microscopy, and 1.8% by laboratory antigen assay). For P. falciparum, overlapping spatial clusters for all tests and an additional 5 unique IgG clusters were identified. For P. vivax, clusters identified with bead antigen assay, microscopy, and IgG partially overlapped.Conclusions: Assessing the spatial distribution of malaria exposure using multiple metrics can improve the understanding of malaria transmission dynamics in a region. The relative abundance of antibody clusters indicates that in areas of low transmission, IgG antibodies are a more useful marker to assess malaria exposure. [ABSTRACT FROM AUTHOR]

Background: Measures of malaria burden using microscopy and rapid diagnostic tests (RDTs) in cross-sectional household surveys may incompletely describe the burden of malaria in low-transmission settings. This study describes the pattern of malaria transmission in Ethiopia using serological antibody estimates derived from a nationwide household survey completed in 2015. Methods: Dried blood spot (DBS) samples were collected during the Ethiopian Malaria Indicator Survey in 2015 from malarious areas across Ethiopia. Samples were analysed using bead-based multiplex assays for IgG antibodies for six Plasmodium antigens: four human malaria species-specific merozoite surface protein-1 19kD antigens (MSP-1) and Apical Membrane Antigen-1 (AMA-1) for Plasmodium falciparum and Plasmodium vivax. Seroprevalence was estimated by age, elevation and region. The seroconversion rate was estimated using a reversible catalytic model fitted with maximum likelihood methods. Results: Of the 10,278 DBS samples available, 93.6% (9622/10,278) had valid serological results. The mean age of participants was 15.8 years and 53.3% were female. National seroprevalence for antibodies to P. falciparum was 32.1% (95% confidence interval (CI) 29.8–34.4) and 25.0% (95% CI 22.7–27.3) to P. vivax. Estimated seroprevalences for Plasmodium malariae and Plasmodium ovale were 8.6% (95% CI 7.6–9.7) and 3.1% (95% CI 2.5–3.8), respectively. For P. falciparum seroprevalence estimates were significantly higher at lower elevations (< 2000 m) compared to higher (2000–2500 m) (aOR 4.4; p < 0.01). Among regions, P. falciparum seroprevalence ranged from 11.0% (95% CI 8.8–13.7) in Somali to 65.0% (95% CI 58.0–71.4) in Gambela Region and for P. vivax from 4.0% (95% CI 2.6–6.2) in Somali to 36.7% (95% CI 30.0–44.1) in Amhara Region. Models fitted to measure seroconversion rates showed variation nationally and by elevation, region, antigen type, and within species. Conclusion: Using multiplex serology assays, this study explored the cumulative malaria burden and regional dynamics of the four human malarias in Ethiopia. High malaria burden was observed in the northwest compared to the east. High transmission in the Gambela and Benishangul-Gumuz Regions and the neglected presence of P. malariae and P. ovale may require programmatic attention. The use of a multiplex assay for antibody detection in low transmission settings has the potential to act as a more sensitive biomarker. [ABSTRACT FROM AUTHOR]