Community-based surveys for Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions in selected regions of mainland Tanzania

• Published in: Malaria Journal
• Main Authors: Catherine Bakari, Sophie Jones, Gireesh Subramaniam, Celine I. Mandara, Mercy G. Chiduo, Susan Rumisha, Frank Chacky, Fabrizio Molteni, Renata Mandike, Sigsbert Mkude, Ritha Njau, Camelia Herman, Douglas P. Nace, Ally Mohamed, Venkatachalam Udhayakumar, Caleb K. Kibet, Steven G. Nyanjom, Eric Rogier, Deus S. Ishengoma
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2020
• Subjects: Tanzania; Malaria; Rapid diagnostic tests; Histidine-rich protein 2/3; Lactate dehydrogenase; Aldolase; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic; Geita
• Online Access: https://doi.org/10.1186/s12936-020-03459-3; https://doaj.org/article/b241218598884c6eb3dfabea46450b5a

Abstract Background Histidine-rich protein 2 (HRP2)-based malaria rapid diagnostic tests (RDTs) are effective and widely used for the detection of wild-type Plasmodium falciparum infections. Although recent studies have reported false negative HRP2 RDT results due to pfhrp2 and pfhrp3 gene deletions in different countries, there is a paucity of data on the deletions of these genes in Tanzania. Methods A community-based cross-sectional survey was conducted between July and November 2017 in four regions: Geita, Kigoma, Mtwara and Ruvuma. All participants had microscopy and RDT performed in the field and provided a blood sample for laboratory multiplex antigen detection (for Plasmodium lactate dehydrogenase, aldolase, and P. falciparum HRP2). Samples showing RDT false negativity or aberrant relationship of HRP2 to pan-Plasmodium antigens were genotyped to detect the presence/absence of pfhrp2/3 genes. Results Of all samples screened by the multiplex antigen assay (n = 7543), 2417 (32.0%) were positive for any Plasmodium antigens while 5126 (68.0%) were negative for all antigens. The vast majority of the antigen positive samples contained HRP2 (2411, 99.8%), but 6 (0.2%) had only pLDH and/or aldolase without HRP2. Overall, 13 samples had an atypical relationship between a pan-Plasmodium antigen and HRP2, but were positive by PCR. An additional 16 samples with negative HRP2 RDT results but P. falciparum positive by microscopy were also chosen for pfhrp2/3 genotyping. The summation of false negative RDT results and laboratory antigen results provided 35 total samples with confirmed P. falciparum DNA for pfhrp2/3 genotyping. Of the 35 samples, 4 (11.4%) failed to consistently amplify positive control genes; pfmsp1 and pfmsp2 and were excluded from the analysis. The pfhrp2 and pfhrp3 genes were successfully amplified in the remaining 31 (88.6%) samples, confirming an absence of deletions in these genes. Conclusions This study provides evidence that P. falciparum parasites in the study area have no deletions of both ...