Epidemiology of multiple Plasmodium falciparum infections - 4. Age dependence of the multiplicity of Plasmodium falciparum infections and of other malariological indices in an area of high endemicity

The relationship between age and various malariological indices in the Kilo mbero valley of Tanzania were examined by compiling data from 6 different c ommunity studies carried out between 1989 and 1996. The rate of acquisition of Plasmodium falciparum infection was highest in children 1-5 years of ag e, while recovery rates were lowest between the first birthday and early ad olescence. As a result, peak prevalence was reached in 3-5 years old childr en. However, the prevalence of clinical malaria (estimated from the excess risk of axillary temperatures greater than or equal to 375 degrees C attrib utable to parasitaemia) was highest in children under one year of age. The peak in multiplicity of infection (identified by polymerase chain reaction- restriction fragment length polymorphism of the msp2 locus) occurred in 3-7 years old children. There was a significant correlation between parasite d ensity and multiplicity of infection in infants and young children (1-2 yea rs of age) but not in older individuals.