Mirjam GrogerLuzia VeletzkyAlbert LalremruataChiara CattaneoJohannes MischlingerRella Manego ZolekoJohanna KimAnna KlicperaElias L. MeyerDaniel BlessbornMarkus WinterbergAyola A. AdegnikaSelidji T. AgnandjiPeter G. KremsnerBenjamin MordmüllerGhyslain Mombo-NgomaHans Peter FuehrerMichael RamharterUniversität TübingenMahidol UniversityMedizinische Universitat WienNuffield Department of Clinical MedicineUniversitätsklinikum Hamburg-Eppendorf und Medizinische FakultätVeterinarmedizinische Universitat WienGerman Center for Infection Research (DZIF), Partner Site TübingenGerman Centre for Infection Research (DZIF), Partner Site Hamburg-Luebeck-BorstelCentre de Recherches Médicales de Lambaréné2020-01-272020-01-272019-11-27Clinical Infectious Diseases. Vol.69, No.12 (2019), 2119-212615376591105848382-s2.0-85070458352https://repository.li.mahidol.ac.th/handle/123456789/51300© 2019 The Author(s). Background: Plasmodium ovale curtisi and wallikeri are perceived as relapsing malarial parasites. Contrary to Plasmodium vivax, direct evidence for this hypothesis is scarce. The aim of this prospective study was to characterize the reappearance patterns of ovale parasites. Methods: P. ovale spp. infected patients were treated with artemether-lumefantrine and followed biweekly for up to 1 year for the detection of reappearing parasitemia. Molecular analysis of reappearing isolates was performed to identify homologous isolates by genotyping and to define cases of relapse following predefined criteria. Results: At inclusion, 26 participants were positive for P. ovale curtisi and/or P. ovale wallikeri. The median duration of follow-up was 35 weeks. Reappearance of the same P. ovale species was observed in 46% of participants; 61% of P. ovale curtisi and 19% of P. ovale wallikeri infection-free intervals were estimated to end with reappearance by week 32. Based on the predefined criteria, 23% of participants were identified with 1 or 2 relapses, all induced by P. ovale curtisi. Conclusion: These findings are in line with the currently accepted relapse theory inasmuch as the reappearance of P. ovale curtisi strains following initial blood clearance was conclusively demonstrated. Interestingly, no relapse of P. ovale wallikeri was observed.Mahidol UniversityMedicineArticleSCOPUS10.1093/cid/ciz131