title: Using Rapid Diagnostic Tests as a Source of Viral RNA for Dengue Serotyping by RT-PCR - A Novel Epidemiological Tool.
abstract: Dengue virus infection causes major public health problems in tropical and subtropical areas. In many endemic areas, including the Lao PDR, inadequate access to laboratory facilities is a major obstacle to surveillance and study of dengue epidemiology. Filter paper is widely used for blood collection for subsequent laboratory testing for antibody and nucleic acid detection. For the first time, we demonstrate that dengue viral RNA can be extracted from dengue rapid diagnostic tests (RDT) and then submitted to real-time RT-PCR for serotyping.
  
  
  
  We evaluated the Standard Diagnostics (SD) Bioline Dengue Duo RDT, a commonly used test in dengue endemic areas. First, using the QIAamp RNA kit, dengue RNA was purified from the sample pad of the NS1 RDT loaded with virus isolates of the four serotypes, then quantified by RT-PCR. We observed greater recovery of virus, with a mean of 27 times more RNA recovered from RDT, than from filter paper. Second, we evaluated dengue NS1 RDTs from patients at Mahosot Hospital, Vientiane, (99 patients) and from rural Salavan Provincial Hospital (362 patients). There was good agreement between dengue RT-PCR from NS1 RDT with RT-PCR performed on RNA extracted from patient sera, either using RDT loaded with blood (82.8% and 91.4%, in Vientiane and Salavan, respectively) or serum (91.9% and 93.9%). There was 100% concordance between RDT and serum RT-PCR of infecting dengue serotype.
  
  
  
  Therefore, the collection of NS1 positive RDTs, which do not require cold storage, may be a novel approach for dengue serotyping by RT-PCR and offers promising prospects for the collection of epidemiological data from previously inaccessible tropical areas to aid surveillance and public health interventions.
authors.affiliation: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Salaya, Thailand.|Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.
authors.forename: Manivanh
authors.initials: M
authors.lastname: Vongsouvath
authors.affiliation: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.
authors.forename: Koukeo
authors.initials: K
authors.lastname: Phommasone
authors.affiliation: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.
authors.forename: Onanong
authors.initials: O
authors.lastname: Sengvilaipaseuth
authors.affiliation: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Salaya, Thailand.
authors.forename: Nathamon
authors.initials: N
authors.lastname: Kosoltanapiwat
authors.affiliation: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Salaya, Thailand.|Mahidol - Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Salaya, Thailand.
authors.forename: Narisara
authors.initials: N
authors.lastname: Chantratita
authors.affiliation: Mahidol - Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Salaya, Thailand.|Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom.
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Blacksell
authors.affiliation: Mahidol - Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Salaya, Thailand.|Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom.
authors.forename: Sue J
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: UMR "Emergence des Pathologies Virales" (EPV: Aix-Marseille University - IRD 190 - Inserm 1207 - EHESP) & Fondation IHU Méditerranée Infection, APHM Public Hospitals of Marseille, Marseille, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: de Lamballerie
authors.affiliation: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.|Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom.|Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Lao PDR.
authors.forename: Mayfong
authors.initials: M
authors.lastname: Mayxay
authors.affiliation: Salavan Provincial Hospital, Salavan Provincial Health Department, Salavan Province, Laos.
authors.forename: Sommay
authors.initials: S
authors.lastname: Keomany
authors.affiliation: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.|Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom.
authors.forename: Paul N
authors.initials: PN
authors.lastname: Newton
authors.affiliation: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.|Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom.|UMR "Emergence des Pathologies Virales" (EPV: Aix-Marseille University - IRD 190 - Inserm 1207 - EHESP) & Fondation IHU Méditerranée Infection, APHM Public Hospitals of Marseille, Marseille, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Dubot-Pérès
mesh_terms: D000818:Animals; D002522:Chlorocebus aethiops; D002846:Chromatography, Affinity / Q000379:methods*; D003715:Dengue / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology*; D003716:Dengue Virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D012367:RNA, Viral / Q000302:isolation & purification*; D011933:Reagent Kits, Diagnostic; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012703:Serotyping / Q000379:methods*; D013997:Time Factors; D014709:Vero Cells; D014744:Vietnam / Q000453:epidemiology
chemical_list: D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic