View clinical trials related to Malaria, Vivax.
Filter by:This is an open label, Phase IIa, controlled human malaria infection (CHMI) study aimed to assess whether the new vivax malaria vaccines ChAd63 PvDBP and MVA PvDBP can protect against malaria infection. The participants will receive one or two doses of ChAd63 PvDBP followed by one dose of MVA PvDBP 8 weeks later. Approximately 4 weeks after the second vacccination, the volunteers will be challenged (deliberately infected) with malaria by intravenous injection blood-stage
This study is designed as a multi-centre randomized, open label trial to compare the safety and efficacy of a high dose primaquine (PQ) treatment in G6PD normal patients with P. falciparum to reduce the risk of subsequent P. vivax episodes to current standard practice of providing only schizontocidal treatment.
This is a clinical study to assess the safety and feasibility of Plasmodium vivax (P. vivax) controlled blood-stage human malaria infection (CHMI), by inoculation using a newly created source of P. vivax malaria-infected blood. 25 healthy malaria-naïve UK volunteers, aged 18 - 50, will be recruited through the five phases of the study at the CCVTM, Oxford. Volunteers will undergo primary, secondary and tertiary P. vivax blood-stage challenges, which will be induced by injection of P. vivax infected blood. After the first challenge, the optimal dose for blood-stage CHMI will be selected and used for the second and third challenges. Through each challenge period, volunteers will have blood taken at regular intervals to measure the parasite growth, quantify the sexual parasite forms and assess the immune response to P. vivax infection. Transmission of P. vivax from volunteers to the Anopheline mosquito vectors will also be assessed. In each challenge, following diagnosis, volunteers will be treated with a standard antimalarial course of oral artemether-lumefantrine (Riamet), given over 60 hours. Volunteers who take part in this study will be involved in the trial for approximately 2 years, receiving each of the three challenges at intervals of approximately 5 (and up to 9) months. Volunteers will be followed for 3 months after their last challenge.
We plan to assess the efficacy of 3 different regimens of chloroquine and primaquine for the treatment of P. vivax infections in Cruzeiro do Sul, Acre, Brazil. Patients will be divided in 3 different groups: treatment with regular dose of primaquine (0.5 mg/kg per day for 7 days) with directly observed therapy; regular dose of primaquine without directly observed therapy; and increased total dose of primaquine (0.5 mg/kg per day for14 days) with directly observed therapy. All patients will receive chloroquine (CQ) for three days at a daily dose of approximately 25 mg/Kg in accordance with the Brazilian National Malaria Control guidelines. Clinical and parasitologic parameters will be monitored over a 28-day follow-up period to evaluate drug efficacy and for a total period of 168 days (24 weeks) to evaluate chances of recrudescence, relapse, or reinfection. Results from this drug efficacy study will be used to assist the Brazilian Ministry of Health in assessing their national malaria treatment policy for P. vivax malaria.
A clinical study to assess the safety and efficacy of alternative regimens of primaquine for radical cure of vivax malaria in glucose 6-phosphate dehydrogenase (G6PD) deficient. G6PD deficient patients with P. vivax monoinfection will be treated with either weekly or delayed one-week course of primaquine, and the currently recommended by national guideline, 12-week chloroquine regimen to compare treatment safety among groups. All groups will be actively monitored for hemolysis during treatment and will have six-month follow-up period to assess treatment efficacy.
This is a sporozoite-challenge clinical study with the primary aim of assessing the safety and feasibility of controlled human P. vivax malaria infection in two healthy volunteers. The investigators will also assess the growth of and the immune response to P. vivax infection, and assess the induction of sexual gametocytaemia post-CHMI via the natural route of malaria infection (mosquito bite). A secondary objective is to develop a blood inoculum of P. vivax-infected blood for future testing of candidate vaccines.
A clinical study designed to develop and inform an individual risk of hemolysis model based on individual red blood cell G6PD levels. Volunteers who are eligible to treatment with primaquine as per national guidelines and with confirmed normal G6PD levels as per the fluorescent spot test will be exposed to treatment regimens of either primaquine alone for 14 days or 3 day chloroquine with concomitant primaquine for 14 days. The volunteers will be followed intensively during treatment and for 14 days after treatment for haematologic measures, G6PD quantification, and drug level assays.
Historically, Plasmodium vivax has been termed "benign" due to its non-life threatening clinical course and since the 1800's this view has been cultivated as demonstrated by the use of the term "benign tertian malaria" to describe the infection.However over the last 15 years, more severe P. vivax malaria is being reported, causing concern that severe P. vivax malaria is under diagnosed. The definition of severe P. vivax malaria borrows from P. falciparum and is primarily one of exclusion. Species PCR (polymerase chain reaction) is the only way to prove P. vivax mono-infection but is expensive and requires skilled staff and technology. In resource constrained settings, diagnostic testing is not available for detection of most non-malarial infections further affecting the ability to determine whether severe symptoms are due to P. vivax malarial infection or a concomitant one. Retrospective studies from India, Pakistan, Indonesia, Papua New Guinea and Sudan support the existence of severe P. vivax malaria. However, inconsistent methodologies, definitions of severity, and use of diagnostic tests to exclude concomitant infection do not allow for standardised assessments for severe P. vivax infection across studies. A review by Baird, highlighted that the risk of being classed as suffering from severe illness was only minimally higher in P. falciparum than in P. vivax, but was unable to combine the data as a meta-analysis. The primary reported symptoms for severe P. vivax included severe anaemia particularly in children, severe thrombocytopaenia, respiratory distress, neurological syndromes (coma or seizures), renal and hepatic failure. Prospective studies have shown similar results. Tjitra et al showed that 23% (675 of 2,937) patients admitted with microscopically diagnosed P. vivax infections in Papua, Indonesia had severe disease and that the risk of severe malaria was significantly higher when admitted with P. vivax than with P. falciparum. In studies from Papua New Guinea, few differences between the clinical presentation of P. falciparum and P. vivax were found in children with severe malaria. This appears to be similar in populations from Sudan, Pakistan and India. In contrast, in Thailand, anecdotal observations note a low prevalence of severe P. vivax infections. The WHO criteria to assess severe P. falciparum have been extrapolated to P. vivax. In the 2015 WHO malaria guidelines some criteria now account for P. vivax, such as removing a minimum parasitaemia when assessing for severe anaemia. Whilst these criteria may not be the most sensitive tool to define severe P. vivax infections, it is used for this purpose. It has been suggested that additional clinical information may be necessary to define truly severe P. vivax cases. In order to describe the characteristics of the severity of P. vivax infections in north-western Thailand, we will perform a retrospective review of annual reports of the outpatient database, the inpatient database and eligible inpatient medical records from 2001 to 2016. The WHO malaria guidelines and additional clinical information will be used to assess the severity of infection and thus, a rate of severe P. vivax can be determined.
Plasmodium vivax can be cause of severe malaria and mortality. There are serious public health implications associated with cases of P. vivax resistant to Chloroquine in the Americas as well there are efforts of many countries to eliminate this disease. In this way, it is critically important to evaluate an alternative radical cure treatment efficient to amazon scenario. The objectives of this trial are to demonstrate the superiority of adequate parasitological response at D42 of Dihydroartemisinin plus Piperaquine (DHA-PQP or Eurartesim®) versus Chloroquine and to evaluate the proportion of failure until D180 considering different starting days of Primaquine (0.50 mg/kg/day) for 14 days. It is an open, 4 arms, randomised, comparative trial. Total of 460 patients are initially planned to be included. To demonstrate the superiority of DHA-PQP compared to Chloroquine, the 95% confidence interval of the difference observed between both treatment success rates will be determined. Each recurrence will be passively and actively detected for 180 days.
This will be a single-arm observational cohort study. Malaria patients with Plasmodium vivax and meeting study inclusion criteria, who give consent to be enrolled in the study, will have their G6PD status measured by the CareStart™ G6DP rapid diagnostic test (G6PD RDT), and primaquine prescribed according to the result. According to the G6PD RDT result, primaquine will be prescribed at 0.25mg/kg/day for 14 days (normal patients) or 0.75mg/kg weekly for eight weeks (deficient patients). All will receive treatment with chloroquine to clear asexual stages of infection. Patients will be reviewed at day 2, day 7 and day 14. At these visits patients will undergo a brief clinical assessment and a small blood sample will be taken for repeat haemoglobin measurement and dried blood spot for carboxyprimaquine measurement (day 7 and day 14 only). In general, antimalarial treatment will be unsupervised to reflect field conditions. However a subset of 25 G6PD normal patients at a single site will have each day of their primaquine treatment administered and observed at the treatment centre. This is to determine a calibration curve for primaquine pharmacokinetic studies. Dried blood spots will be stored appropriately. Day zero samples will be genotyped in Bangkok (MORU, Dr. Mallika Imwong) after DNA extraction. PCR-RFLP will be used to detect the allele associated with the Mediterranean variant of G6PD deficiency. In addition DNA extracts will be sent for more systematic genetic testing for known G6PD variants through existing collaborations with the Wellcome Trust Sanger Institute. The day 7 and 14 dried blood spot samples will be analysed in the MORU pharmacology laboratory for primaquine and carboxyprimaquine concentrations, from which adherence to primaquine can be determined retrospectively, using the subset of 25 patients receiving directly observed therapy to calibrate the results. Funder: WellcomeTrust, Grant reference: 107548/Z/15/Z