View clinical trials related to Plasmodium Vivax.
Filter by:Plasmodium vivax has become the predominant species in the Greater Mekong Subregion and is a major challenge for regional malaria elimination. Mass primaquine administration has played a decisive role in malaria elimination in many temperate zone countries, but its efficacy in tropical areas remains to be evaluated. This study aims to assess the efficacy of targeted primaquine mass treatment (TPT) for eliminating P. vivax malaria in northern Myanmar.
Malaria remains the world's leading parasitic endemic. Almost half of the world's population lives in endemic areas. Many at-risk people in African countries remain without access to malaria control. Malaria kills approximately 400,000 people each year, most of whom are children under the age of 5 in Africa. Since 2005, an increasing number of Plasmodium vivax infections have been observed in Duffy-negative populations in South America and Africa, calling into question the essential role of the PvDBP-DARC interaction. The objective of the investigators is therefore to study and understand the invasion pathways used by Plasmodium vivax in Duffy-negative subjects.
The Malaria Heart Disease Study is a prospective longitudinal cohort study of a random sample of approximately 1200 individuals from the state of Acre in Brazil. The overall hypothesis is that patients who have (i) previously suffered from a malaria infection or (ii) patients with ongoing symptomatic malaria will benefit from having an echocardiogram and blood tests performed as a screening tool to diagnose early cardiac impairment and prevent future cardiovascular disease.
Health care facility based, randomized, controlled, open label, superiority trial with 3 arms
This study aims to determine whether a 14 day course of 0.5 mg/kg/day primaquine can eliminate subclinical P. vivax infections detected by high volume ultra-sensitive PCR (uPCR).
Understanding the extent and regional distribution of CQR vivax malaria and detecting early signs of resistance is critical to prevent the spread of resistant strains, optimize treatment guidelines, and reduce the risk of recurrent and severe malaria. In Vietnam, CQR in P.vivax has been reported sporadically. One study carried out in Binh Thuan province (central-south Vietnam) at the end of the 1990s demonstrated early P.vivax recurrences (7%) by Day 16 after a 3-day CQ treatment. However, in a summary report to World Health Organization (WHO) including data from 11 sentinel sites, from studies conducted between 2006 and 2011 in central and southern Vietnam (total 350 patients), P.vivax is still considered sensitive to CQ. More recently in a cohort study conducted in Quang Nam province (Central Vietnam) in which P.vivax patients were treated radically with CQ and primaquine (10-day at 0.5mg/kg/day) following national guidelines, the 28-day failure rate was measured at 3.45% and CQ blood concentrations measured at day of recurrence (>100ng/ml) confirmed resistance in three patients. The current national guidelines for the radical cure regimen of P.vivax infections recommends 3 days of CQ (total 25 mg/kg body weight (bw)) together with 14 days of primaquine at 0.25 mg/kg bw/ day. The current WHO protocol recommends a 28-day follow-up to assess the efficacy of CQ for the treatment of P.vivax infections. However, recurrence of early stage resistant parasites may occur after Day 28 in the presence of CQ blood levels above the minimum efficacy concentration (MEC, ≥100ng/ml) and relapses could occur as early as 36 days after standard CQ treatment. Therefore, in order to confirm CQR it is recommended to extend the follow-up period, to Day 42 or 63 and measure whole blood CQ level at Day 28 and at the time of recurrence. Moreover, it has been shown that emerging drug resistance in P.vivax is associated with delayed parasite clearance after treatment, i.e. some parasites are still detectable at Day 3. The aim of the present study is to assess the in vivo and ex vivo susceptibility of P.vivax to CQ in Central Vietnam following the currently recommended radical cure regimen and using GMP certified CQ.
This study specifically seeks to provide data on the safety, tolerability and pilot efficacy of short course, high dose primaquine treatment in Papua New Guinean children aged 5-10 years, in a cross-sectional study design. Community screened asymptomatic cases and/or cases of clinically diagnosed malaria admitted to the out-patient units of the health center, will be screened for Glucose-6-phosphate dehydrogenase deficiency (G6PD) and malaria illness by rapid diagnostic test and P. vivax infection confirmed by light microscopy. Following treatment with artemether-lumefantrine (Coartem), G6PD normal children will be enrolled into the study and followed for 2 months. Primaquine treatment will be allocated to study participants in a step-wise design; firstly receiving the current 14 day treatment regimen of 0.5 mg/kg total dose (n=40); secondly, a 7 day treatment regimen receiving a total dose of 1.0 mg/kg/day; then thirdly, receive 1.0 mg/kg twice daily dose (bd) for a total of 3.5 days, should the 7 day treatment prove to be safe and well tolerated. In addition to this dose-escalation study, the pharmacokinetic profiles of single doses of 0.5 mg/kg and 1.0 mg/kg will be determined using an intensive sampling protocol, in children aged 5-10 years. The pharmacokinetic profiles obtained by this sub-study will be essential for modeling the population pharmacokinetic data obtained from the dose-escalation study. As there is currently no data on the safety, tolerability and efficacy of primaquine in children, the present study will validate previous observation and contribute to the knowledge of primaquine as a treatment for liver stages of Plasmodium vivax infection.
This is an open label phase Ia study, to assess the safety of two novel malaria vaccines, ChAd63 PvDBP, with or without MVA PvDBP. Heterologous prime-boost with ChAd63-MVA is, to our knowledge, one of the most potent T cell-inducing subunit vaccine regimens which can importantly also induce antibodies. Previous clinical trials using this regimen expressing ME-TRAP, AMA1 & MSP1, have shown that administering ChAd63 as a prime followed 8 weeks later by MVA as a boost is a very immunogenic schedule (32-34). For this reason, and to provide comparability with previous ChAd63-MVA trials, we propose to use a similar administration schedule.
This Phase II study is designed to determine whether a single 600 mg dose or 400mg/day for 3 days of tafenoquine is efficacious, and well tolerated for clearing P. vivax malaria infection (blood schizontocidal and gametocytocidal activity) and preventing P. vivax relapse (hypnozoite eradication). It will also further establish the safety and tolerability of these doses of tafenoquine.
This is a first-in-humans safety, immunogenicity and efficacy study with recombinant protein VMP001, a Plasmodium vivax circumsporozoite (CS) protein based vaccine. This open label study will be performed in malaria-naïve adults in the United States. Three doses of VMP001 formulated in AS01B (adjuvant system) will be given intramuscularly at different intervals followed by a challenge with P. vivax infected mosquitoes. Safety, immunogenicity and efficacy parameters will be studied.