Evaluating the performance of an ultra-sensitive rapid diagnostic test (uRDT) to detect asymptomatic malaria infections in the low transmission setting of Zambezi Region, Namibia

Objectives

The aims of this population cross sectional survey are to:

1. Measure the prevalence of asymptomatic malaria infections and the numerical distribution of parasite densities/ parasite-specific antigen concentrations in the low endemic setting of Zambezi Region, Namibia.

Measures include:

• Prevalence of malaria infections by quantitative polymerase chain reaction (qPCR), parasite-specific antigen concentration, highly-sensitive RDT, and CareStart RDT,
• Distribution of parasite densities among all infections by qPCR,
• Distribution of parasite-specific antigen concentrations among all infections and their correlation to parasitemia.

2. Evaluate the performance of Alere’s highly-sensitive RDT for detection of Pf infections in the low endemic setting of Zambezi region, Namibia.

Measures include:

• Diagnostic accuracy (sensitivity, specificity, positive predictive value, and negative predictive value) of the uRDT using histidine-rich protein II (HRP2) concentration and qPCR as the reference standards (overall and by parasite density categories and HRP2 concentration categories),
• Proportion of asymptomatic infections detectable by CareStart RDT, uRDT, qPCR, and HRP2 concentration.

3. To determine the length of time that standard and highly-sensitive HRP-2 RDTs (uRDTs) remain positive following successful treatment for uncomplicated P. falciparum malaria.