title: Rapid detection and differentiation of dengue virus serotypes by a real-time reverse transcription-loop-mediated isothermal amplification assay.
abstract: The development and validation of a one-step, real-time, and quantitative dengue virus serotype-specific reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay targeting the 3' noncoding region for the rapid detection and differentiation of dengue virus serotypes are reported. The RT-LAMP assay is very simple and rapid, wherein the amplification can be obtained in 30 min under isothermal conditions at 63 degrees C by employing a set of four serotype-specific primer mixtures through real-time monitoring in an inexpensive turbidimeter. The evaluation of the RT-LAMP assay for use for clinical diagnosis with a limited number of patient serum samples, confirmed to be infected with each serotype, revealed a higher sensitivity by picking up 100% samples as positive, whereas 87% and 81% of the samples were positive by reverse transcription-PCR and virus isolation, respectively. The sensitivity and specificity of the RT-LAMP assay for the detection of viral RNA in patient serum samples with reference to virus isolation were 100% and 93%, respectively. The optimal assay conditions with zero background and no cross-reaction with other closely related members of the Flavivirus family (Japanese encephalitis, West Nile, and St. Louis encephalitis viruses) as well as within the four serotypes of dengue virus were established. None of the serum samples from healthy individuals screened in this study showed any cross-reaction with the four dengue virus serotype-specific RT-LAMP assay primers. These findings demonstrate that RT-LAMP assay has the potential clinical application for detection and differentiation of dengue virus serotypes, especially in developing countries.
authors.affiliation: Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
authors.forename: Manmohan
authors.initials: M
authors.lastname: Parida
authors.forename: Kouhei
authors.initials: K
authors.lastname: Horioke
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ishida
authors.forename: Paban Kumar
authors.initials: PK
authors.lastname: Dash
authors.forename: Parag
authors.initials: P
authors.lastname: Saxena
authors.forename: Asha Mukul
authors.initials: AM
authors.lastname: Jana
authors.forename: Mohammed Alimul
authors.initials: MA
authors.lastname: Islam
authors.forename: Shingo
authors.initials: S
authors.lastname: Inoue
authors.forename: Norimitsu
authors.initials: N
authors.lastname: Hosaka
authors.forename: Kouichi
authors.initials: K
authors.lastname: Morita
mesh_terms: D003715:Dengue / Q000175:diagnosis* / Q000821:virology; D003716:Dengue Virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D012703:Serotyping; D013997:Time Factors