Following the diagnosis of a falciparum malaria case imported from Djibouti and not detected by a pfHRP2-based rapid diagnostic test (RDT), we investigated the prevalence of the pfhrp2/pfhrp3-deleted parasites in Djibouti using 378 blood samples collected between January and May 2019, from Djiboutian patients with suspected malaria. Malaria diagnosis by quantitative PCR confirmed the presence of Plasmodium falciparum for 20.9% (79/378) samples while RDTs did not detect HRP2 antigen in 83.5% (66/79) of these samples. Quantitative PCRs targeting the pfhrp2/pfhrp3 genes confirmed the absence of both genes for 86.5% of P. falciparum strains. The very large number (86.5%) of falciparum parasites lacking the pfhrp2/pfhrp3 genes observed in this study, now justifies the use of non-HRP2 alternative RDTs in Djibouti. In this area and in most countries where HRP2-based RDTs constitute the main arsenal for falciparum malaria diagnosis, it is important to implement a systematic surveillance and to inform biologists and clinicians about the risk of malaria misdiagnosis. Further investigations are needed to better understand the mechanism of selection and diffusion of the pfhrp2/pfhrp3-deleted parasites.

在诊断出从吉布提进口且未经基于pfHRP2的快速诊断测试（RDT）检测到的恶性疟疾病例后，我们使用2019年1月至2019年5月间收集的378份血液样本调查了吉布提pfhrp2 / pfhrp3缺失的寄生虫的患病率，来自吉布提的可疑疟疾患者。通过定量PCR进行的疟疾诊断证实了20.9％（79/378）样品中存在恶性疟原虫，而在这些样品中83.5％（66/79）的RDTs未检测到HRP2抗原。靶向pfhrp2 / pfhrp3基因的定量PCR证实了86.5％的恶性疟原虫菌株都没有这两个基因。恶性疟原虫数量非常多（86.5％）这项研究中观察到的缺少pfhrp2 / pfhrp3基因的寄生虫现在证明了在吉布提使用非HRP2替代RDT的合理性。在该地区以及大多数基于HRP2的RDT构成恶性疟疾诊断主要武器库的国家中，重要的是进行系统的监视，并告知生物学家和临床医生有关疟疾误诊的风险。需要进一步的研究，以更好地了解pfhrp2 / pfhrp3删除的寄生虫的选择和扩散的机制。