title: Prevalence of pfhrp2 and/or pfhrp3 Gene Deletion in Plasmodium falciparum Population in Eight Highly Endemic States in India.
abstract: BACKGROUND
  Plasmodium 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.
  
  
  METHODS
  This 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.
  
  
  RESULTS
  Among 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).
  
  
  CONCLUSIONS
  This 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.
authors: National Institute for Research in tribal Health (NIRTH), Jabalpur, 482003, Madhya Pradesh, India.
authors: Praveen Kumar
authors: PK
authors: Bharti
authors: National Institute for Research in tribal Health (NIRTH), Jabalpur, 482003, Madhya Pradesh, India.
authors: Himanshu Singh
authors: HS
authors: Chandel
authors: National Institute for Research in tribal Health (NIRTH), Jabalpur, 482003, Madhya Pradesh, India.
authors: Amreen
authors: A
authors: Ahmad
authors: National Institute for Research in tribal Health (NIRTH), Jabalpur, 482003, Madhya Pradesh, India.
authors: Sri
authors: S
authors: Krishna
authors: Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, United States of America.
authors: Venkatachalam
authors: V
authors: Udhayakumar
authors: National Institute for Research in tribal Health (NIRTH), Jabalpur, 482003, Madhya Pradesh, India.
authors: Neeru
authors: N
authors: Singh
mesh_terms: D000953:Antigens, Protozoan / Q000235:genetics*; D003955:Diagnostic Tests, Routine; D019353:Endemic Diseases; D017353:Gene Deletion; D006801:Humans; D007194:India / Q000453:epidemiology; D016778:Malaria, Falciparum / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics / Q000469:parasitology; D010963:Plasmodium falciparum / Q000235:genetics* / Q000302:isolation & purification; D015995:Prevalence; D011446:Prospective Studies; D015800:Protozoan Proteins / Q000235:genetics*
chemical_list: D000953:Antigens, Protozoan; C514457:HRP-2 antigen, Plasmodium falciparum; C578339:HRP3 protein, Plasmodium falciparum; D015800:Protozoan Proteins