View clinical trials related to Asymptomatic Malaria.
Filter by:The study is a Phase 2 randomized controlled, partial-blind, parallel group study in plasmodium infected asymptomatic adults 18 years and older, with 8 study arms. It will use the adapted Zelen design, which has two steps in the consent process. In the first step, there is an informed consent from all participants for a cohort lifestyle study. According to this consent, participants are randomized without knowledge about the detailed protocol. In the second step, only participants from the intervention group will receive the information about the intervention and the second consent will be obtained from them. The participants who will decline to participate to an intervention will continue in the cohort study, as the control group.
Primaquine (PQ) is currently the only available drug that can clear the mature transmission stages of P. falciparum parasites. PQ was previously shown to clear gametocytes that persist after artemisinin-combination therapy. A major caveat to the use of primaquine in mass adminsitrations for the reduction of malaria transmission is that metabolism of the drug in individuals with glucose-6 phosphate dehydrogenase (G6PD) deficiency can lead to transient haemolysis. The haemolytic side effect of PQ is dose-related. Haemolysis is more commonly observed after prolonged PQ treatment but has also been observed in African populations following a single dose of PQ. This haemolysis was self-limiting, largely restricted to G6PD deficient individuals and did not lead to clinical symptoms. Nevertheless, any drug-induced haemolysis is reason for concern and the World Health Organization has therefore reduced the recommended dose of single low dose primaquine from 0.75mg/kg to 0.25mg/kg. This dosage is deemed safe without prior G6PD or Hb screening. However, there is limited direct evidence on the extent to which this dosage of PQ prevents malaria transmission to mosquitoes. In the current study, the investigators will assess the efficacy of DP in combination with low-dose PQ to prevent onward malaria transmission. The investigators will perform the investigators study in individuals aged 5-15 years who are carry microscopically detectable densities of P. falciparum gametocytes. This age group is chosen because asexual parasite carriage and gametocyte carriage are common in this age group. All enrolled individuals will receive a full three-day course of DP, and will be randomized to receive a dose of primaquine or placebo with their third dose. Efficacy will be determined based on gametocyte carriage during follow-up, measured by molecular methods. For all individuals, the effect of treatment on infectivity to mosquitoes will be assessed by membrane feeding assays at two time points.
Primaquine (PQ) is currently the only available drug that can clear mature transmission stages of P. falciparum parasites. PQ was previously shown to clear gametocytes that persist after artemisinin-combination therapy. However, there are safety concerns about the use of PQ at the currently recommended dose of 0.75mg/kg in individuals who are glucose-6-phosphate dehydrogenase (G6PD) deficient. PQ causes transient but significant haemolysis in G6PD deficient individuals; this side-effect is dose dependent. There are indications that a lower dosing of PQ may effectively reduce gametocyte carriage but the lowest efficacious dose for gametocyte clearance is currently unknown. Recently, the World Health Organization changed their recommendation to a low dose of primaquine, 0.25mg/kg. However, there is no direct evidence on the extent to which (low dose) PQ prevents malaria transmission to mosquitoes and what the lowest efficacious dose is. In the current study we aim to identify the lowest efficacious dose of PQ in individuals with normal G6PD function. Children with asymptomatic malaria and normal G6PD enzyme function will be randomized to treatment with artemether-lumefantrine alone or in combination with low doses of PQ. All enrolled individuals will receive a full three-day course of AL, and will be randomized to receive a dose of primaquine or placebo with their fifth dose of AL. Efficacy will be determined based on gametocyte carriage during follow-up, measured by molecular methods. For a subset of participants with patent gametocytes, primaquine effect on infectivity to mosquitoes will be assessed by membrane feeding assays