Plasmodium falciparum diagnostic tools in HIV-positive under-5-year-olds in two ART clinics in Ghana: are there missed infections?

Abstract

BackgroundPlasmodium falciparum, the most dominant species in sub-Saharan Africa, causes the most severe clinical malaria manifestations. In resource-limited Ghana, where malaria and HIV geographically overlap, histidine-rich protein 2 (HRP2)-based rapid diagnostic test (RDT) is a faster, easier and cheaper alternative to clinical gold standard light microscopy. However, mutations in parasite hrp2 gene may result in missed infections, which have severe implications for malaria control.MethodsThe performance of a common HRP2-based RDT and expert light microscopy in HIV-positive and HIV-negative children under 5 years old was compared with PCR as laboratory gold standard. Finger-prick capillary blood was tested with First Response® Malaria Ag P. falciparum (HRP2). Giemsa-stained thick and thin blood films were examined with ≥ 200 high power fields and parasites counted per 200 white blood cells. Nested PCR species identification of P. falciparum was performed and resolved on agarose gel. False negatives from RDT were further tested for deleted pfhrp2/3 and flanking genes, using PCR. The study was performed in two anti-retroviral therapy clinics in Accra and Atibie.ResultsOut of 401 participants enrolled, 150 were HIV positive and 251 HIV negative. Malaria was more prevalent in children without HIV. Microscopy had a higher sensitivity [100% (99–100)] than RDT [83% (53.5–100)]. Parasites with pfhrp2/3 deletions contributed to missed infections from RDT false negatives.ConclusionCirculation of malaria parasites with pfrhp2/3 deletions in this population played a role in missed infections with RDT. This ought to be addressed if further strides in malaria control are to be made.Electronic supplementary materialThe online version of this article (10.1186/s12936-018-2231-7) contains supplementary material, which is available to authorized users.

First evidence of the deletion in the pfhrp2 and pfhrp3 genes in Plasmodium falciparum from Equatorial Guinea

“…This study provides the first evidence of pfhrp2 and pfhrp3 deletions in P. falciparum in EG. The pfhrp2 deletion prevalence found in the samples was 5.3%; this prevalence is low when compared to that of Ghana (30%), but is very similar to Mali (5%) [15,29,30]. As yet, there are no data available for pfhrp2 and pfhrp3 deletion in neighbouring Cameroon and Gabon.…”

Contribution of P. falciparum parasites with Pfhrp 2 gene deletions to false negative PfHRP 2 based malaria RDT results in Ghana: A nationwide study of symptomatic malaria patients

“…False negative RDT results amongst symptomatic malaria patients can lead to febrile malaria cases being treated as either bacterial or viral infections [ 30 ], which can lead to an increase in morbidity as well as a loss of patient confidence in the health system [ 31 ]. Increasing reports of the presence of Pfhrp 2 gene deletions in parasites circulating in malaria endemic countries including Ghana [ 19 , 20 , 32 – 34 ] lead to this systematic study in which the WHO recommended surveillance protocol was used to estimate the prevalence of Pfhrp 2 and Pfhrp 3 gene deletions in parasites from febrile malaria patients attending selected health facilities across all the Regions of Ghana.…”

“…False negative RDT results amongst symptomatic malaria patients can lead to febrile malaria cases being treated as either bacterial or viral infections [30], which can lead to an increase in morbidity as well as a loss of patient confidence in the health system [31]. Increasing reports of the presence of Pfhrp 2 gene deletions in parasites circulating in malaria endemic countries including Ghana [19,20,[32][33][34] lead to this systematic study in which the WHO recommended surveillance protocol was used to estimate the prevalence of Pfhrp 2 and Pfhrp 3 gene deletions in parasites from febrile malaria patients attending selected health facilities across all the Regions of Ghana. The PfHRP 2 based malaria RDTs presently in use in Ghana remains very effective as the prevalence of false negative RDT results identified in this study was less than 5%, out of which about 10% were contained in infections with parasite densities below 200 p/μl and likely below the detection threshold of the RDT.…”

“…The first reports of the existence of parasites with deletions in the Pfhrp 2 gene was in the Amazon region of Peru [9] and has presently been reported in numerous malaria endemic countries [16], including Ghana [18]. To date there have been very few reports of the existence of parasites with deletions in Pfhrp 2 in Ghana, most of which have been conducted on asymptomatic malaria carriers and also without implementing the WHO recommendations [18,19]. Due to the implications of the presence of such parasites amongst symptomatic malaria patients, a nationwide survey was conducted on suspected malaria patients attending 100 health facilities across the country to identify the presence and distribution of parasites with deletions in the Pfhrp 2 and or Pfhrp 3 gene that result in false negative PfHRP 2-based malaria RDT results.…”

Editorial: Artemisinin—From Traditional Chinese Medicine to Artemisinin Combination Therapies; Four Decades of Research on the Biochemistry, Physiology, and Breeding of Artemisia annua

“…The introduction of ACTs (it is estimated that 3 billion treatment courses have been procured worldwide between 2010 and 2018), rapid diagnostic tests (RDTs) and malaria vector controls, including insecticide-treated mosquito nets, reduced the number of cases significantly over the past 10 years ( World malaria report, 2019 ). However, artemisinin resistance conferred by genetic mutations in Plasmodium falciparum recently emerged in the Greater Mekong sub-region ( Ariey et al., 2014 ) together with Pfhrp2/3 gene deletions that render parasites undetectable by RDT ( Owusu et al., 2018 ), represent major new threats in the global fight against malaria.…”