Preventing the Spread of Malaria in Mali

This study is ongoing, but not recruiting participants.
Sponsor:
Information provided by:
National Institutes of Health Clinical Center (CC)
ClinicalTrials.gov Identifier:
NCT01360112
First received: May 20, 2011
Last updated: March 14, 2014
Last verified: December 2013
  Purpose

Background:

- The Malaria Research and Training Center in Mali is involved in research to make a malaria vaccine. The vaccine is being designed to help interrupt the spread of malaria. Researchers want to study the different tests that can determine whether these vaccines will block the development of malaria parasites in the mosquito. To help develop these vaccines, researchers are studying children and adults from a village in Mali. They want to see whether the area will be a good place to test the malaria blocking vaccine in the future.

Objectives:

  • To study different tests of malaria spread and malaria blocking vaccines.
  • To see how many people in the Mali village have malaria parasites in their blood that can infect other people.

Eligibility:

- Healthy people between 3 months and 50 years of age who live in a Mali village.

Design:

  • Participants will have a physical exam and medical history. They will give a blood sample that will be tested for malaria parasites. Participants who have malaria in the blood that can be transmitted to others will have more blood tests.
  • All participants will have regular blood tests and checkups to see if malaria parasites have grown. Their response to malaria infections and treatments will also be tested.
  • Participants at least 5 years of age will have tests that involve being bitten by laboratory-grown mosquitoes. These insects have never been infected with malaria or other diseases. Researchers will study the effectiveness of different vaccines meant to block the spread of malaria.
  • Researchers may collect mosquitoes from participants' houses to see if these mosquitoes have bitten someone nearby. They will try to learn more about what makes mosquitoes more likely to become infected with malaria when they bite someone. Researchers may also map the house to study the areas where malaria infection is more common.
  • Participants will be followed for up to 1 year.

Condition
Malaria

Study Type: Observational
Study Design: Time Perspective: Prospective
Official Title: Malaria Transmission Blocking Assay Development and Gametocyte Carriage in a Vaccine Testing Site in Mali

Resource links provided by NLM:


Further study details as provided by National Institutes of Health Clinical Center (CC):

Estimated Enrollment: 1000
Study Start Date: April 2011
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 data are needed to determine target populations and sample sizes. This protocol will use a nested case-control 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 and age-matched gametocyte negative 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 carriage rates through the year. A total of 250 volunteers from Bancoumana, ages 3 months to 50 years, were enrolled in 2011. In 2012, an additional 250 adults from Bancoumana were enrolled and participants older than 5 years of age were continued. A transmission blocking vaccine trial started in May 2013, and had enrolled participants from the adult cohort in this study. Up to 50 adults from Bancoumana and surrounding villages will be enrolled in 2013.

  Eligibility

Ages Eligible for Study:   3 Months to 50 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria
  • INCLUSION CRITERIA:

All of the following criteria must be fulfilled for a volunteer to participate in the study:

  1. Age between 3 months and 50 years, inclusive
  2. Good general health as a result of review of medical history and/or clinical testing at the time of screening
  3. Available for the duration of the study (1 year)
  4. Willingness to participate in the study as evidenced by signing the informed consent document, or by fingerprinting the consent document with the signature of a witness
  5. Known resident of the village of the study
  6. Willingness to allow stored laboratory specimens to be used for future research.
  7. In addition to the above criteria, the expanded adult cohort must be willing to consider participation in a future malaria vaccine trial.

EXCLUSION CRITERIA:

A volunteer will be excluded from participating in this study if any one of the following criteria is fulfilled:

  1. Pregnancy as determined by history or a positive urine Beta-hCG test at any point during the study.
  2. Behavioral, cognitive, or psychiatric disease that in the opinion of the investigator affects the ability of the subject to understand and cooperate with the study protocol.
  3. Other condition that, in the opinion of the investigator, would jeopardize the safety or rights of a volunteer participating in the trial or would render the subject unable to comply with the protocol.
  4. Participation in another investigational vaccine or drug trial while this study is ongoing.
  5. Previous receipt of experimental malaria vaccine.
  6. Baseline hemoglobin < 8.5 g/dL

    In addition to above criteria, a volunteer will be excluded from participating in the transmission blocking assay part of the study if the following criteria is fulfilled:

  7. History of reactions to mosquito bites with severe itching or swelling, or lasting longer than 3 days
  Contacts and Locations
Please refer to this study by its ClinicalTrials.gov identifier: NCT01360112

Locations
Mali
University of Bamako, Faculty of Medicine, Pharmacy and Odontostomatology
Bamako, Mali
Sponsors and Collaborators
Investigators
Principal Investigator: Yimin Wu, Ph.D. National Institute of Allergy and Infectious Diseases (NIAID)