Prevalence of pfhrp2 and/or pfhrp3 Gene Deletion in Plasmodium falciparum Population in Eight Highly Endemic States in India

Abstract

BackgroundPlasmodium falciparum encoded histidine rich protein (HRP2) based malaria rapid diagnostic tests (RDTs) are used in India. Deletion of pfhrp2 and pfhrp3 genes contributes to false negative test results, and large numbers of such deletions have been reported from South America, highlighting the importance of surveillance to detect such deletions.MethodsThis is the first prospective field study carried out at 16 sites located in eight endemic states of India to assess the performance of PfHRP2 based RDT kits used in the national malaria control programme. In this study, microscopically confirmed P. falciparum but RDT negative samples were assessed for presence of pfhrp2, pfhrp3, and their flanking genes using PCR.ResultsAmong 1521 microscopically positive P. falciparum samples screened, 50 were negative by HRP2 based RDT test. Molecular testing was carried out using these 50 RDT negative samples by assuming that 1471 RDT positive samples carried pfhrp2 gene. It was found that 2.4% (36/1521) and 1.8% (27/1521) of samples were negative for pfhrp2 and pfhrp3 genes, respectively. However, the frequency of pfhrp2 deletions varied between the sites ranging from 0–25% (2.4, 95% CI; 1.6–3.3). The frequency of both pfhrp2 and pfhrp3 gene deletion varied from 0–8% (1.6, 95% CI; 1.0–2.4).ConclusionThis study provides evidence for low level presence of pfhrp2 and pfhrp3 deleted P. falciparum parasites in different endemic regions of India, and periodic surveillance is warranted for reliable use of PfHRP2 based RDTs.

A national health facility survey of malaria infection among febrile patients in Kenya, 2014

“…However, the associated risk of overtreatment of uninfected cases is considered more acceptable in malaria endemic zones than taking the risk of failing to detect cases. Recently, there has been reports of deletion of HRP2 gene which may lead to false RDT negative results [47, 48]. However, studies conducted in Africa showed HRP2 deletion in very small numbers of parasite isolates [49, 50], hence highly unlikely that the phenomenon may have influenced the results of this survey.…”

Performance of Rapid Diagnostic Testing in Patients with Suspected Malaria in Cambodia, a Low-Endemicity Country Aiming for Malaria Elimination

“…With the large sample size of 4382 patients, sampling of all RDT negatives (vs selective sampling employed in our study), and use of quantitative PCR, the study is a useful addition to the few published studies on performance of RDT to assess symptomatic malaria in low-transmission settings [1,3,4]. As malaria transmission declines, the proportion of low-density infection among symptomatic as well as asymptomatic individuals increases [5][6][7]. It is generally assumed that symptomatic individuals will present with high-density infection; however, low-density infections accounted for 24% of all PCRpositive cases, compared to 22% in our study (taking into accounting the sampling of RDT negatives).…”

“…In both analyses, specificity was 99.7%, and the PPV scored 89.0% and 88.5%, respectively. Low parasitemia was the main reason for false-negative RDT 5], the deletions of pfhrp2 and/or pfhrp3 genes are currently investigated.…”

An open dataset of Plasmodium falciparum genome variation in 7,000 worldwide samples

“…The most widely used RDTs are designed to detect P. falciparum histidine-rich protein 2 and cross-react with histidine-rich protein 3, encoded by the hrp2 and hrp3 genes respectively. Parasites with gene deletions of hrp2 and/or hrp3 have emerged as an important cause of RDT failure in a number of locations [75][76][77][78][79] . It is difficult to devise a simple genetic assay to monitor for risk of RDT failure because hrp2 and hrp3 deletions comprise a diverse mixture of large structural variations with multiple independent origins, and both genes are located in subtelomeric regions of the genome with very high levels of natural variation 29,[80][81][82][83] .…”