Seasonal Changes in the Frequency of False-Negative Rapid Diagnostic Tests for Malaria based on Histidine-rich Protein 2 (HRP2)

Aim: Rapid diagnostic tests (RDTs) for Plasmodium falciparum infection provide an essential alternative in areas where skilled microscopists are not available and therefore have a central role in the diagnosis of malaria and assessment of malaria control.The sensitivities of HRP2based RDTs are reported to be 93-98% with false-negative rates of 5-8%.The study aimed to evaluate the seasonality related to the sensitivity of HRP2 -based RDT in the commune of Dioro (Mali). Subjects and methods:We performed RDTs and thick smears to detect P. falciparum from 691 persons who sought diagnosis and treatment because they had fever or chills between May 2012 and June 2013.The RDTs used were based on histidine-rich protein 2 (HRP2). Results:The frequency of false-negative RDTs was highest in the dry season (peaked at 86-88% in May-June of 2012 and 2013), fell to 20-25% with the onset of seasonal rains in July-August and was lowest (1-2%) at the peak of the transmission season between September and November. Conclusion:False-negative RDTs are a serious problem in the diagnosis of individual patients and the assessment of malaria control programmes.These results indicate HRP2-based RDTs in the Sahel region of Mali are most sensitive during the peak transmission (rainy) season and least sensitive in the low transmission (dry) season.They suggest that better mass diagnostic strategies will be necessary during the dry season to identify and treat infected persons and thus prevent the return of transmission when rains resume, and vector populations increase.