View clinical trials related to Plasmodium Falciparum.
Filter by:Plasmodium falciparum isolates display a wide genetic diversity with possibly different properties to induce immune responses. These properties could directly influence the ability to induce protective efficacy. Since 1998 an experimental human malaria infection model at the Radboud University Nijmegen Medical Center (RUNMC) has been very successful in answering questions with regards to immunological mechanisms of human Pf infection. To date only the NF54 strain of Pf has been deployed in this Nijmegen model. However, investigation of heterologous Pf challenge is not only highly informative for our basic understanding of induction of immune responses but also provides an essential model for protective capacity testing in the clinical development of candidate malaria vaccines. Recently, the parasite culture laboratory of the RUNMC has been able to overcome technical hurdles to produce infectious mosquitoes of two genetically different isolates from different geographical regions to increase the portfolio for Phase IIa trials. These isolates, PfA and PfB will be compared with the NF54 strain for parasitic, immunological and clinical features in humans.
The purpose of this study is to determine the safety and tolerability of a non-replicating, metabolically active Plasmodium falciparum sporozoite (PfSPZ) vaccine in malaria-naïve healthy volunteers following multiple-dose subcutaneous (SC) or intradermal (ID) administration. In addition, the investigators wish to evaluate PfSPZ vaccine-mediated protection against P. falciparum challenge in the following 4 groups (see below) and compare protective efficacy of the PfSPZ vaccine when given by SC v ID administration in all these groups: - Group 1: 4 doses of 7,500 PfSPZ/immunization, - Group 2: 4 doses of 30,000 PfSPZ/immunization, - Group 3: 4 doses of 135,000 PfSPZ/immunization - Group 4: 4 or 6 doses of 135,000 PfSPZ/immunization. If > 80% protective efficacy is not achieved in Groups 1, 2, or 3, volunteers in Group 4 will receive a fifth and sixth dose.
In many areas of the world most severely affected by the HIV/AIDS pandemic, insect and water-borne diseases such as malaria and diarrheal disease are common causes of illness and death. In addition, diarrhea and malaria are more common and more severe among adults and children infected with HIV. These infections may modulate the immune system, affect the replication of the HIV virus and could result in more rapid HIV disease progression in co-infected individuals. Access to practical, inexpensive and easy to use interventions to prevent these diseases may be effective in delaying HIV progression. Current Kenya government and World Health Organization guidelines recommend the use of cotrimoxazole (trimethoprim-sulfamethoxazole [TMP/SMX]) to prevent co-infections, including malaria. Despite the provision of TMP/SMX to HIV-infected adults, infections with malaria and pathogens causing diarrhea remain common causes of morbidity and mortality in many resource-limited settings. In addition, TMP/SMX may not prevent all infections with malaria or other pathogens due to alternative mechanisms of action, antimicrobial resistance and non-compliance due to adverse events or other reasons. We propose a study to evaluate the impact of providing insecticide treated bednets and a simple water filtration device on markers of HIV disease progression among a cohort of ART naïve, HIV infected adults prescribed TMP/SMX in Kenya. In addition, we propose to evaluate the effect of these interventions on malaria and diarrheal disease incidence and on compliance with TMP/SMX.
The malaria parasite Plasmodium falciparum remains at sub-patent level throughout the dry season in areas of seasonal malaria transmission. Targeting this parasite reservoir before the transmission season could be a good strategy for malaria control. We are conducting a randomized double blind placebo controlled mass drug administration trial in eight village to clear the dry season low level parasitaemia with an ultimate aim of controlling malaria in eastern Sudan.
The purpose of this study is to determine whether a new investigational malaria vaccine is safe, well tolerated and effective against experimental exposure to malaria when given to healthy people with no previous exposure to malaria. The vaccine consists of a modified form of a relatively common virus, adenovirus, that has been rendered incapable of replicating itself and modified to deliver the malaria gene of interest to the body's cells allowing the cell to manufacture the protein encoded by the gene and present it to the body's immune system in a more natural and presumably effective way.
This study, conducted at Johns Hopkins University Center for Immunization Research in Washington DC, will test the safety and immune response of healthy volunteers to two experimental malaria vaccines. Malaria is a disease of red blood cells caused by a parasite that spreads from person to person by mosquitoes. It affects people of all ages, but is particularly severe in children. Patients may have a high fever, chills and muscle aches. They sometimes can have severe complications that may even result in death. The vaccines in this study are called "transmission blocking" vaccines. These vaccines stimulate the person's immune system to produce antibodies against malaria. When a mosquito bites a vaccinated person, it ingests some of the person's blood. The antibodies in the ingested blood stop the malaria parasite from developing inside the mosquito. The mosquito would not be able to transmit malaria to other people. PpPfs25/ISA51 (Vaccine A) stimulates production of antibodies against the malaria parasite Plasmodium falciparum, and ScPvs25/ISA51 (Vaccine B) stimulates antibodies against the malaria parasite Plasmodium vivax. The vaccines also contain a substance called Montanide ISA51, which boosts the immune response to the vaccine. Healthy volunteers between 18 and 50 years of age may be eligible for this study. Candidates are screened with a medical history, physical examination, and blood and urine tests. Women who are able to become pregnant have a urine pregnancy test before each immunization. Participants are randomly assigned to receive two injections, spaced 4 months apart, of either Vaccine A or Vaccine B at one of three doses-high, medium, or low. Two subjects in each dose group additionally serve as "controls" and receive only Montanide ISA51 mixed with saline. The vaccine is injected into the muscle of the upper arm. Subjects are monitored for 30 minutes after each injection for possible side effects and take home a diary card to record their temperature and any symptoms that may appear over the next 13 days. A blood sample is drawn before and on several occasions after each vaccination to check the subject's health and to evaluate the immune response to the vaccine. At 1, 3, 7, 14, and 21 days after each vaccination, participants come to the clinic for a check of vital signs (temperature, pulse, respiration, and blood pressure), brief physical examination, and history of symptoms since the previous visit.
The candidate malaria vaccine RTS,S/AS02A developed by GSK Biologicals demonstrated 30% efficacy against clinical episodes of malaria and approximately 58% efficacy against severe malaria disease. As a potential improvement to RTS,S/AS02A, another candidate vaccine RTS,S/AS01B is being developed in parallel in collaboration with the Walter Reed Army Institute of Research (WRAIR). This study will be the first administration of the RTS,S/AS01B vaccine to the African adults to establish safety and immunogenicity in this population. Preliminary indication of vaccine efficacy with this adjuvant will be established by monitoring the time to the first infection with Plasmodium falciparum.