title: High number of previous Plasmodium falciparum clinical episodes increases risk of future episodes in a sub-group of individuals.
abstract: There exists great disparity in the number of clinical P. falciparum episodes among children of the same age and living in similar conditions. The epidemiological determinants of such disparity are unclear. We used a data-mining approach to explore a nineteen-year longitudinal malaria cohort study dataset from Senegal and identify variables associated with increased risk of malaria episodes. These were then verified using classical statistics and replicated in a second cohort. In addition to age, we identified a novel high-risk group of children in whom the history of P. falciparum clinical episodes greatly increased risk of further episodes. Age and a high number of previous falciparum clinical episodes not only play major roles in explaining the risk of P. falciparum episodes but also are risk factors for different groups of people. Combined, they explain the majority of falciparum clinical attacks. Contrary to what is widely believed, clinical immunity to P. falciparum does not de facto occur following many P. falciparum clinical episodes. There exist a sub-group of children who suffer repeated clinical episodes. In addition to posing an important challenge for population stratification during clinical trials, this sub-group disproportionally contributes to the disease burden and may necessitate specific prevention and control measures.
authors: Institut Pasteur, Department Genome and Genetics, Unité de Génétique Fonctionnelle des Maladies Infectieuses, Paris, France.
authors: Cheikh
authors: C
authors: Loucoubar
authors: Laura
authors: L
authors: Grange
authors: Richard
authors: R
authors: Paul
authors: Augustin
authors: A
authors: Huret
authors: Adama
authors: A
authors: Tall
authors: Olivier
authors: O
authors: Telle
authors: Christian
authors: C
authors: Roussilhon
authors: Joseph
authors: J
authors: Faye
authors: Fatoumata
authors: F
authors: Diene-Sarr
authors: Jean-François
authors: JF
authors: Trape
authors: Odile
authors: O
authors: Mercereau-Puijalon
authors: Anavaj
authors: A
authors: Sakuntabhai
authors: Jean-François
authors: JF
authors: Bureau
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004777:Environment; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D016778:Malaria, Falciparum / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000302:isolation & purification / Q000472:pathogenicity*; D012307:Risk Factors; D012675:Senegal / Q000453:epidemiology; D055815:Young Adult