There are a significant number of low-density Plasmodium infections in endemic populations, and the proportion of this type of infection appears to increase with decreasing transmission intensity. However, most studies to date have assessed these infections at a single time point or at infrequent time points, which offers little to no information on the dynamics of these infections and their possible contribution to malaria transmission. Recent data suggest that asymptomatic parasite densities may be much more dynamic than previously known. The goal of this project is to demonstrate the feasibility and quality of daily dried blood spot (DBS) sampling in order to quantify parasite and gametocyte density kinetics of low-density asymptomatic Plasmodium falciparum infections to better understand their possible contribution to malaria transmission by studying the natural history of such infections in a population experiencing intermediate transmission. We will measure the proportion of subjects who successfully collect daily DBS over a 28-day period, and quantify the quality of the samples collected over time. Ultrasensitive quantitative reverse transcription PCR for P. falciparum 18S rRNA and gametocyte mRNA will be combined to cost-effectively identify infected participants and then deconvolute daily samples to illustrate the parasite density kinetics. If successful, the results from this study will offer a technique to further study the dynamics of low-density parasite carriage and be generalizable to other malaria-endemic countries confronting the public health problem of asymptomatic malaria for malaria control and elimination.
The natural history of asymptomatic Plasmodium infection in endemic populations is poorly understood. The objective of this project is to evaluate the feasibility and quality of a daily blood sampling approach intended to reveal the dynamics of asymptomatic infections using ultrasensitive molecular diagnostics. The results will inform future malaria control strategies relevant to carriage of submicroscopic infections in malaria-endemic communities in Uganda and other malaria-endemic countries.
