Assessing parasite clearance during uncomplicated <em>Plasmodium falciparum </em>infection treated with artesunate monotherapy in Suriname

Abstract

BackgroundArtemisinin resistance in Plasmodium falciparum is suspected when the day 3 parasitemia is >10% when treated with artemisinin-based combination therapy or if >10% of patients treated with artemisinin-based combination therapy or artesunate monotherapy harbored parasites with half-lives ≥5 hours. Hence, a single-arm prospective efficacy trial was conducted in Suriname for uncomplicated P. falciparum infection treated with artesunate-based monotherapy for 3 days assessing day 3 parasitemia, treatment outcome after 28 days, and parasite half-life.MethodsThe study was conducted in Paramaribo, the capital of Suriname, from July 2013 until July 2014. Patients with uncomplicated Plasmodium falciparum infection were included and received artesunate mono-therapy for three days. Day 3 parasitaemia, treatment outcome after 28 days and parasite half-life were determined. The latter was assessed with the parasite clearance estimator from the WorldWide Antimalarial Resistance Network (WWARN).ResultsThirty-nine patients were included from July 2013 until July 2014. The day 3 parasitemia was 10%. Eight patients (20.5%) could be followed up until day 28 and showed adequate clinical and parasitological response. Parasite half-life could only be determined from ten data series (25.7%). The median parasite half-life was 5.16 hours, and seven of these data series had a half-life ≥5 hours, still comprising 17.9% of the total data series.ConclusionThe low follow-up rate and the limited analyzable data series preclude clear conclusions about the efficacy of artesunate monotherapy in Suriname and the parasite half-life, respectively. The emergence of at least 17.9% of data series with a parasite half-life ≥5 hours supports the possible presence of artemisinin resistance.

Malaria parasite clearance from patients following artemisinin-based combination therapy in C&ocirc;te d&rsquo;Ivoire

“…Studies conducted in Western Cambodgia on artemisinin alone have reported 84 hours for PCT which was related to artemisinin resistance. 12 , 32 , 33 The PCT with artemisinin observed in African patients is therefore much lower than that found in Western Cambodia. 34 …”

Molecular Profile of Malaria Drug Resistance Markers of Plasmodium falciparum in Suriname

“…To further investigate this possibility, from July 2013 until July 2014, a TES consisting of 3 days of artesunate monotherapy followed by mefloquine and primaquine was conducted in Suriname to determine the efficacy of artemisinin, without confounding partner drugs. In that study, the day 3 positivity rate for P. falciparum was 10%, and at least 17.9% of the samples exhibited a parasite half-life of Ն5 h, suggesting suspected partial artemisinin resistance (24).…”

Malaria serology data from the Guiana shield: first insight in IgG antibody responses to Plasmodium falciparum, Plasmodium vivax and Plasmodium malariae antigens in Suriname

“…An in vivo efficacy study conducted in 2011 demonstrated that 31% of P. falciparum -infected patients, treated with Coartem ® were still positive on day 3 [ 2 ]. An in vivo efficacy study in 2014 with artesunate further revealed that at least 17.9% of samples exhibited a parasite half-life ≥ 5 h [ 3 ]. Molecular characterizations of drug-associated markers of isolates from Suriname did not reveal noteworthy alterations in potential molecular markers in the pfATP6 [ 4 ], pfmdr1 [ 5 ] and K13 genes [ 6 ], but increased pfmdr1 copy numbers in P. falciparum isolates [ 7 ] have been observed.…”