High proportions of pfhrp2 gene deletion and performance of HRP2-based rapid diagnostic test in Plasmodium falciparum field isolates of Odisha

Abstract

BackgroundWith the documentation of cases of falciparum malaria negative by rapid diagnostic tests (RDT), though at low frequency from natural isolates in a small pocket of Odisha, it became absolutely necessary to investigate the status of HRP-2 based RDT throughout the state and in different seasons of the year.MethodsSuspected individuals were screened for malaria infection by microscopy and RDT in 25/30 districts of Odisha, India. Discrepancies in results were confirmed by PCR. False negative RDT samples for Plasmodium falciparum mono-infection were evaluated for detection of HRP2 antigen in ELISA and genotyped for pfhrp2, pfhrp3 and their flanking genes. Multiplicity of infection was ascertained based on msp1 and msp2 genotyping and parasitaemia level was determined by microscopy.ResultsOf the total 1058 patients suspected for malaria, 384 were microscopically confirmed for P. falciparum mono-infection and RDT failure was observed in 58 samples at varying proportion in different regions of the state. The failure in detection was due to undetectable level of HRP-2. Although most of these samples were screened during rainy season (45/345), significantly high proportion (9/17) of RDT negative samples were obtained during the summer compared to rainy season (P = 0.0002; OR = 7.5). PCR genotyping of pfhrp2 and pfhrp3 in RDT negative samples showed 38/58 (65.5) samples to be pfhrp2 negative and 24/58 (41.4) to be pfhrp3 negative including dual negative in 17/58 (29.3). Most of the RDT negative samples (39/58) were with single genotype infection and high proportions of pfhrp2 deletion (7/9) was observed in summer. No difference in parasitaemia level was observed between RDT positive and RDT negative patients.ConclusionHigh prevalence of parasites with pfhrp2 deletion including dual deletions (pfhrp2 and pfhrp3) is a serious cause of concern, as these patients could not be given a correct diagnosis and treatment. Therefore, HRP2-based RDT for diagnosing P. falciparum infection in Odisha is non-reliable and must be performed in addition to or replaced by other appropriate diagnostic tools for clinical management of the disease.Electronic supplementary materialThe online version of this article (10.1186/s12936-018-2502-3) contains supplementary material, which is available to authorized users.

Glutamate dehydrogenase: a novel candidate to diagnose Plasmodium falciparum through rapid diagnostic test in blood specimen from fever patients

“…In recent years, increase in the prevalence of hrp2 gene deletion has been observed [5][6][7] . HRP2/3 based RDT kits are commercially available and a key tool in malaria diagnosis before the treatment is given.…”

Prevalence of Plasmodium falciparum field isolates with deletions in histidine-rich protein 2 and 3 genes in context with sub-Saharan Africa and India: a systematic review and meta-analysis

“…In India, the lowest and highest values for prevalence of pfhrp2 gene deletions reported were 2.4 and 9.9% (see Fig. 3) [43,44]. In Africa, these values were 0 and 62% in Nigeria and Eritrea, respectively [35,37].…”

“…Eight studies were excluded from the analysis on the proportion of P. falciparum isolates with deletions in pfhrp2/3 genes among false negative PfHRP2-based RDT results because of small sample size and the topic not being addressed. Sixteen and 10 studies were included in the meta-analysis to determine the prevalence of deletions in pfhrp2/3 genes and their proportion among false negative PfHRP2-based RDT results, respectively [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] (Fig. 1, Additional file 2).…”

“…The 16 studies from 13 SSA countries: Mali, Senegal, Ghana, Kenya, Mozambique, Rwanda, Zambia, Eritrea, Eswatini (Swaziland), Nigeria, Sudan, Madagascar and Democratic Republic of Congo, were conducted locally with one exception which was conducted at national level ( Table 1) [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. Three studies found deletions in pfhrp2 in Uganda, Gambia and Tanzania [45][46][47], but these were excluded from the systematic review (Additional file 5).…”

“…From the three Indian studies only one included samples from several regions, whereas the other two studies did analysis in samples collected locally [42][43][44]. The blood samples in the studies were collected from symptomatic and/or asymptomatic patients, including adults, children or both between 1996 and 2018 in SSA and between 2010 and 2016 in India ( Table 2).…”