Kalifabougou Malaria Cohort

Background: Plasmodium falciparum malaria remains a global public health threat, while leading 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. Since May 2011 this observational cohort study has been conducted in Kalifabougou, Mali as a close collaboration between the Malaria Research and Training Center at the University of Sciences, Techniques and Technologies of Bamako and the National Institute of Allergy and Infectious Diseases, National Institutes of Health. Kalifabougou is a rural village of approximately 5000 inhabitants located 48 km northwest of Bamako in a region of Mali that typically experiences intense, seasonal P. falciparum transmission from July through December.

Objectives: Better understand fundamental aspects of malaria epidemiology, the human immune response to malaria, and the biology of the Plasmodium falciparum parasite in the context of intense seasonal malaria transmission.

Methodology:

Geographic Location/Study Sites: Kalifabougou, Mali

Dates of Data Collection: May 2011 to present (ongoing)

Study Design: Longitudinal cohort study

Eligibility Criteria: From an age-stratified, random sample of the entire village population, 695 healthy individuals aged 3 months-25 years were initially enrolled, with periodic enrollment of new healthy volunteers subsequently. The disproportionate sample size of each age group reflects the design of this ongoing study of malaria immunity, which focuses on older children as they transition from malaria susceptibility to immunity. Enrollment exclusion criteria are hemoglobin level <7 g/dL, axillary temperature ≥37.5°C, acute systemic illness, use of antimalarial or immunosuppressive medications in the past 30 days, and pregnancy.

Data Collection: Clinical malaria episodes are detected prospectively by self-referral and by weekly or monthly active clinical surveillance visits depending on the study year. All individuals with signs and symptoms of malaria and any level of Plasmodium parasitemia detected by light microscopy are treated according to the National Malaria Control Program guidelines in Mali. In general, the research definition of malaria is an axillary temperature of ≥37.5°C, ≥2500 asexual parasites/µL of blood, and no other cause of fever discernible by physical exam. During the scheduled clinic visits that occur before, during and after each malaria season, and at the first research-defined malaria episode of each malaria season, blood is collected by finger prick to prepare blood smears and dried blood spots on filter paper, and venous blood is collected to isolate and cryopresrve peripheral blood mononuclear cells and plasma.

Study Documentation:

Case report forms (zip file)
Data dictionaries (zip file)

ClinEpiDB Data Integration: Data files were provided to ClinEpiDB as flat txt files. These datasets were merged by unique ID and redundant or administrative columns were dropped from presentation on ClinEpiDB.org. All dates were obfuscated per participant through the application of a random number algorithm that shifted dates no more than seven days to comply with the ethical conduct of human subjects research.

Financial Support: Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health

Ethics Statement: The Ethics Committee of the Faculty of Medicine, Pharmacy and Dentistry at the University of Sciences, Techniques and Technology of Bamako, and the Institutional Review Board of NIAID NIH approved this study (ClinicalTrials.gov NCT01322581). Written, informed consent was obtained from the parents or guardians of participating children or from adult participants.

Last Updated: December 23, 2021A longitudinal cohort study of malaria was conducted in Kalifabougou, Mali. Healthy individuals 3-25 years were initally enrolled, with subsequent periodic enrollment of additional healthy volunteers. Participants had monthly or weekly scheduled visits and would come to the clinic for unscheduled visits when sick.