Frequent and persistent, asymptomatic Plasmodium falciparum infections in African infants, characterized by multilocus genotyping.
To determine the duration and complexity of naturally acquired Plasmodium falciparum infections in small children, a longitudinal cohort study of 143 newborns was conducted in coastal Ghana. On average, children experienced 2 episodes of infection in their first 2 years of life, the median duration of an asymptomatic infection was <4 weeks, and estimates of the mean number of parasite genotypes per infection were 1.15-2.28. Nevertheless, 40% of the children experienced infections lasting </=12 weeks, and both the duration and complexity of infections increased with age. The longest period of continual infection was 64 weeks, and the maximum persistence of a single parasite genotype was 40 weeks. Thus, malaria infections in infants <5 months old tend to be asymptomatic and rapidly cleared; persistent asymptomatic parasitemia is more common in children >5 months old. The ability of very young children to clear or control malaria infections indicates the presence of effective innate or immune antiparasite mechanisms.
Franks
S
S
Institute of Cell, Animal, and Population Biology, Division of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom.
Koram
K A
KA
Wagner
G E
GE
Tetteh
K
K
McGuinness
D
D
Wheeler
J G
JG
Nkrumah
F
F
Ranford-Cartwright
L
L
Riley
E M
EM
D000367:Age Factors; D000818:Animals; D015331:Cohort Studies; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D005869:Ghana / Q000453:epidemiology; D006790:Host-Parasite Interactions; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000235:genetics / Q000469:parasitology*; D008297:Male; D010963:Plasmodium falciparum / Q000235:genetics* / Q000276:immunology / Q000469:parasitology; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D013997:Time Factors