Preventing the Spread of Malaria in Mali
- Conditions
- Malaria
- Registration Number
- NCT01360112
- Brief Summary
A vaccine which interrupts malaria transmission is a critical tool to achieve the ultimate goal of eradication of this disease. Transmission blocking vaccines work by inducing antibody in vaccinated individuals that inhibits the development of malaria parasites in the mosquito, thus interrupting the cycle of transmission to the next human host. Efficacy of these vaccines may be estimated by in vitro membrane feeding assays using immune sera and laboratory strain mosquitoes, but these assays need to be qualified to determine to what extent they are predictive of transmission blocking in the field. Clinical trials of transmission blocking vaccines are also anticipated and have started in this community. This protocol will use a nested casecontrol cohort design to compare results of mosquito feeding assays in a malaria exposed population in Bancoumana and surrounding villages in Mali. Households will be identified using census data and individuals will be consented for participation. Malaria smears will be obtained at monthly visits, and gametocytemic individuals will be asked to participate in direct feed experiments using insectary-raised mosquitoes. Infectivity in these mosquitoes will be compared against those of mosquitoes fed in membrane feeding assays in Mali and the USA. Data will also be obtained on gametocyte and parasite carriage rates through the year. A total of 250 volunteers from Bancoumana, ages 3 months to 50 years, were initially enrolled in 2011. In 2012, an additional 250 adults from Bancoumana were enrolled and participants older than 5 years of age who were enrolled in 2011 and wanted to continue participation were re-enrolled into the study. A transmission blocking vaccine trial started in May 2013, and has enrolled participants from this adult cohort in that study. Up to 50 new adults from Bancoumana and surrounding villages will be enrolled in 2014 and those volunteers previously enrolled into the study over theage of 5 years old will be offered re-enrollment into the study.
- Detailed Description
A vaccine which interrupts malaria transmission is a critical tool to achieve the ultimate goal of eradication of this disease. Transmission blocking vaccines work by inducing antibody in vaccinated individuals that inhibits the development of malaria parasites in the mosquito, thus interrupting the cycle of transmission to the next human host. Efficacy of these vaccines may be estimated by in vitro membrane feeding assays using immune sera and laboratory strain mosquitoes, but these assays need to be qualified to determine to what extent they are predictive of transmission blocking in the field. Clinical trials of transmission blocking vaccines are also anticipated and have started in this community. This protocol will use a nested casecontrol cohort design to compare results of mosquito feeding assays in a malaria exposed population in Bancoumana and surrounding villages in Mali. Households will be identified using census data and individuals will be consented for participation. Malaria smears will be obtained at monthly visits, and gametocytemic individuals will be asked to participate in direct feed experiments using insectary-raised mosquitoes. Infectivity in these mosquitoes will be compared against those of mosquitoes fed in membrane feeding assays in Mali and the USA. Data will also be obtained on gametocyte and parasite carriage rates through the year. A total of 250 volunteers from Bancoumana, ages 3 months to 50 years, were initially enrolled in 2011. In 2012, an additional 250 adults from Bancoumana were enrolled and participants older than 5 years of age who were enrolled in 2011 and wanted to continue participation were re-enrolled into the study. A transmission blocking vaccine trial started in May 2013, and has enrolled participants from this adult cohort in that study. Up to 50 new adults from Bancoumana and surrounding villages will be enrolled in 2014 and those volunteers previously enrolled into the study over theage of 5 years old will be offered re-enrollment into the study.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 816
Not provided
Not provided
Study & Design
- Study Type
- OBSERVATIONAL
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method b) The period prevalence and density of gametocytes throughout the study period, as detected by thick smear and nucleic acid based techniques 24 months a) Mosquito infectivity by DF, DMFA (a, b, and c), and SMFA (d and e), as measured by infection rate (number of infected vs. un- nfected mosquitoes), and oocyst counts in infected mosquitoes, both determined using microscopy. 24 months
- Secondary Outcome Measures
Name Time Method a)Antibody levels to sexual P. falciparum antigens, and other antigens of interest. 24 months b)Mosquito infectivity as measured by circumsporozoite protein (CSP) ELISA. 24 months c)Hemoglobin level as measured by HemoCue. 24 months d)Hemoglobin variants (hemoglobin S, C, alpha thalassemia), G6PD status, blood group/Rh. 24 months
Trial Locations
- Locations (1)
University of Bamako, Faculty of Medicine, Pharmacy and Odontostomatology
🇲🇱Bamako, Mali