View clinical trials related to Plasmodium Falciparum.
Filter by: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.
The purpose of the study is to determine the safety and tolerability of ID administration of PfSPZ Challenge to volunteers taking chloroquine chemoprophylaxis (an approach called PfSPZ-CVac).
This is an open label, human pilot study to optimise controlled human malaria infection (CHMI) administered by Plasmodium falciparum sporozoites (PfSPZ. Volunteers will be inoculated with PfSPZ Challenge. The route of administration and dose will vary in order to identify the optimal regimen that achieves the greatest infection rate in volunteers with Plasmodium falciparum. All volunteers recruited will be healthy adults aged between 18 and 45 years. Safety and infectivity data will be collected for each of the regimens.
Malaria is one of the major infectious diseases in the world with a tremendous impact on the quality of life, significantly contributing to the ongoing poverty in endemic countries. It causes 800.000 deaths per year, the majority of which are children under the age of five. The malaria parasite enters the human body through the skin, by the bite of an infected mosquito. Subsequently, it invades the liver and develops and multiplies inside the hepatocytes. After a week, the hepatocytes burst open and the parasites are released in the blood stream, causing the clinical phase of the disease. As a unique opportunity to study malaria immunology and efficacy of immunisation strategies, a protocol has been developed in the past to conduct controlled human malaria infections (CHMIs). CHMIs generally involve small groups of malaria-naïve volunteers infected via the bites of P. falciparum infected laboratory-reared Anopheline mosquitoes. Although potentially serious or even lethal, P. falciparum malaria can be radically cured at the earliest stages of blood infection when risks of complications are virtually absent. The investigators have shown previously that healthy human volunteers can be protected from a malaria mosquito (sporozoite) challenge by immunization with sporozoites (by mosquito bites) under chloroquine prophylaxis (CPS immunization). Interestingly, sterile protection in 100% of the human CPS immunized volunteers was achieved by a relatively miniscule dose, i.e. a total of 45 infectious mosquito bites, strikingly 20-fold more potent than the 1000 bites needed in a model using irradiated mosquitoes. One possible explanation for this efficient induction of protective immunity, is the immune modulating effect of chloroquine. The investigators aim to assess this possible immune modulating effect in CPS immunization by comparing immunization with P. falciparum sporozoites under chloroquine with immunization under mefloquine prophylaxis, which has the same antimalarial effect, but not the immune modulating effects known from chloroquine.
Plasmodium falciparum malaria remains a global public health threat. Leading malaria vaccine candidates confer only partial short-lived protection at best. An understanding of the mechanisms by which humans acquire malaria immunity through repeated P. falciparum infections may aid the development of a malaria vaccine. This pilor study is designed to initiate the epidemiological groundwork for a future prospective cohort study of acquired malaria immunity in Kalifabougou, Mali, a rural village of approximately 5 000 individuals who are exposed to seasonal P. falciparum transmission each year from July through December. This study will estimate the age-stratified point prevalence of P. falciparum infection before the malaria season and at the peak of the 6-month malaria season, and it will estimate the age-stratified incidence of symptomatic p. falciparum infection during the 6-month malaria season. The spatial distribution of asymptomatic P. falciparum infections and incident malaria cases within the village of Kalifabougou will be determined by merging the prevalence and incidence data with census and Global Positioning System (GPS) data....