View clinical trials related to Plasmodium Falciparum.
Filter by:Elimination of P. falciparum (PF) malaria across a territory requires universal access to treatment of clinical cases for communities, and specific targeting of places or population groups where malaria transmission persists in spite of generalized access to treatment. In particular, a large prevalence of carriers of PF parasites is suspected to be one of the reasons for malaria persistence. The fact that these carriers are not developing symptoms allow them to harbour and transmit parasites over long periods of time. They are likely to contribute significantly the transmission in their community and even beyond it according to their movement patterns. Identifying these pockets of high asymptomatic carriage is a key component of the malaria elimination strategy, as it allows targeting specific interventions, such as targeted mass-treatment, to quickly drain the asymptomatic reservoir. Strategically to achieve this goal we need to be able to identify quickly and reliably the villages or groups of villages in which the asymptomatic reservoir is large and should be addressed by targeted mass drug administration (MDA). There are no point of care tests currently available to detect asymptomatic carriers accurately. The available Rapid Diagnostic Tests (normal RDT) are designed to diagnose clinically relevant malaria infections. However their sensitivity for asymptomatic malaria carriers is low, since most of these individuals harbor parasitaemias below RDT detection thresholds. Currently, we are relying on high volume blood surveys, in which a small sample of the village population provides a 2mL venous blood sample that can be analysed by ultra-sensitive qPCR. This technique allows detecting very low parasitaemias. However it is a high cost test and technical requirements to use qPCR limit the number of samples that can be tested. In addition as the analysis must be done in a laboratory, the time needed for shipment and analysis results in delays of 4 to 8 weeks between survey and result. Surveying remote, poorly resourced areas adds to the challenge as the samples must be shipped from the field to the laboratory, on cold chain, within 24 to 48h from blood draw. To ensure that asymptomatic individuals are diagnosed in a cost effect and feasible manner, it is vital that a more sensitive RDT is made available for use in the field. Depending on its performance, a sensitive RDT could be used for prevalence surveys to target MDA, or directly for interventions based on treatment of positive individuals (reactive case detection or mass screening and treatment). A new hypersensitive RDT (hsRDT) has now been developed but before it can be utilised for elimination surveys we need to validate both its technical properties (sensitivity and specificity) and its usefulness in the field to detect PfHRP2 presence compared to a gold standard control ELISA (Enzyme Linked Immuno-Sorbent Assay) test. This will allow confirmation of false- and true- positive among samples.
This study is to measure prevalence of established and candidate molecular markers of drug resistant malaria at Komé, Doba, Republic of Chad.
The Bacillus Calmette-Guérin (BCG) vaccine, a live attenuated Mycobacterium bovis vaccine, has been used to prevent tuberculosis for almost a century, and it is still the most used vaccine in the world. There is also circumstantial and indirect evidence that BCG vaccination can protect against malaria. Investigators hypothesize that BCG vaccination can offer protection against malaria in the Controlled Human Malaria Infection (CHMI) model. A total of 20 healthy male and female volunteers will participate in this randomized, single-blind clinical trial. Volunteers will be randomized to receive either BCG vaccination (BCG vaccine SSI) (group 1, n=10) or no treatment (group 2, n=10). Five weeks after vaccination of group 1 volunteers, all volunteers will undergo a CHMI administered by the bites of five P. falciparum infected Anopheles mosquitoes.
This is a single center, randomized, placebo-controlled, double-blind trial to assess the safety and immunogenicity of PfSPZ Vaccine administered by direct venous inoculation (DVI). The study to be conducted in Baney District, Bioko Island, Equatorial Guinea (EG), will be to establish whether three doses of the higher regimen - three doses of 2.7x10^5 PfSPZ of the PfSPZ Vaccine administered at 8 week intervals - is as well-tolerated and efficacious in malaria exposed African adults as the five dose regimens. Specifically, the trial will address the following objectives: is the three dose regimen: 1. Safe and well tolerated in Equatoguinean (EG) adults. 2. As immunogenic in EG adults as is the five-dose regimen of 1.35x10^5 PfSPZ in Tanzanian and U.S. adults or as three-, four- and five-dose regimens of 2.7x10^5 PfSPZ being tested in Tanzanian, Malian and U.S. adults. In addition, as an exploratory objective, the volunteers in the EG trial will be followed longitudinally to measure the incidence of malaria during the initial six months following immunization, providing a preliminary assessment of efficacy.
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.
The purpose of this study is to assess two new malaria vaccines, ChAd63 RH5 and MVA RH5, at different doses and alone or in combination. The study will enable us to assess the safety of the vaccines and the extent of the immune response in healthy volunteers. We will do this by giving volunteers one or two vaccinations, doing blood tests and collecting information about any symptoms that occur after vaccination. This is the first trial to use these vaccines in humans.
The purpose of this study is to assess efficacy and safety of a single low-dose Primaquine added to standard artemether/lumefantrine treatment for the clearance of Plasmodium falciparum gametocytes among patients with uncomplicated malaria aged 1 year and above regardless of their G6PD status.
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
Phase IV, single center, 2 arms randomized controlled, open label study. Study will be conducted over a period of 42 days to determine the safety, tolerability, pharmacokinetics and efficacy of ARCO.
Resistance of Plasmodium falciparum toward Artemisinins, the most important drug for the successful treatment of malaria, has been confirmed in Cambodia. There are few reports from neighbouring countries about delayed parasite rates. The investigators therefore aim to assess parasite clearance in malaria patients in central Vietnam when treated according to national standard guidelines.