[Delayed diagnosis of Plasmodium falciparum in a soldier in Uganda: false-positive rapid diagnostic test associated with reduced repeats in pfhrp2].

Rapid diagnostic tests (RDTs) are the best alternative for malaria diagnosis where a microscopic examination cannot be performed. We report here the first case of P. falciparum (false-negative) misdiagnosis in a soldier stationed in Uganda, associated with a reduced number of repeats in the P. falciparum histidine-rich protein 2 gene (pfhrp2). This gene was subsequently sequenced to determine the reason for the discordance between the RDT results and the later microscopic examination. Ten repeats of the type 2 motif AHHAHHAAD and four repeats of the type 7 motif AHHAAD were found. This isolate belongs to the group of non-sensitive parasites (<43 repeats) that are not detected by HRP2 RDTs. This inappropriate case management could have been fatal for the patient. This case confirms the problem of negative RDT results in isolated situations and of basing a therapeutic strategy on these negative results. Investigations should be conducted in Uganda and other areas of Africa to determine the presence and the geographical spread of parasites with pfhrp2 gene deletion to ensure the best performance of RDTs.