title: Rapid and sensitive detection of H7N9 avian influenza virus by use of reverse transcription-loop-mediated isothermal amplification.
abstract: An epidemic of human H7N9 influenza virus infection recently emerged in China whose clinical features include high mortality and which has also resulted in serious economic loss. The novel reassortant avian-origin influenza A (H7N9) virus which was the causative agent of this epidemic raised the possibility of triggering a large-scale influenza pandemic worldwide. It seemed likely that fast molecular detection assays specific for this virus would be in great demand. Here, we report a one-step reverse transcription-loop-mediated isothermal amplification (RT-LAMP) method for rapid detection of the hemagglutinin (HA) and neuraminidase (NA) genes of H7N9 virus, the minimum detection limit of which was evaluated using in vitro RNA transcription templates. In total, 135 samples from clinical specimens (from either patients or poultry) were tested using this method in comparison with the real-time PCR recommended by the World Health Organization (WHO). Our results showed that (i) RT-LAMP-based trials can be completed in approximately 12 to 23 min and (ii) the detection limit for the H7 gene is around 10 copies per reaction, similar to that of the real-time PCR, whereas the detection limit for its counterpart the N9 gene is 5 copies per reaction, a 100-fold-higher sensitivity than the WHO-recommended method. Indeed, this excellent performance of our method was also validated by the results for a series of clinical specimens. Therefore, we believe that the simple, fast, and sensitive method of RT-LAMP might be widely applied for detection of H7N9 infections and may play a role in prevention of an influenza pandemic.
authors.affiliation: Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China.
authors.forename: Jinhai
authors.initials: J
authors.lastname: Zhang
authors.forename: Youjun
authors.initials: Y
authors.lastname: Feng
authors.forename: Dan
authors.initials: D
authors.lastname: Hu
authors.forename: Heng
authors.initials: H
authors.lastname: Lv
authors.forename: Jing
authors.initials: J
authors.lastname: Zhu
authors.forename: Min
authors.initials: M
authors.lastname: Cao
authors.forename: Feng
authors.initials: F
authors.lastname: Zheng
authors.forename: Jin
authors.initials: J
authors.lastname: Zhu
authors.forename: Xiufang
authors.initials: X
authors.lastname: Gong
authors.forename: Lina
authors.initials: L
authors.lastname: Hao
authors.forename: Swaminath
authors.initials: S
authors.lastname: Srinivas
authors.forename: Hao
authors.initials: H
authors.lastname: Ren
authors.forename: Zhongtian
authors.initials: Z
authors.lastname: Qi
authors.forename: Bingjun
authors.initials: B
authors.lastname: Li
authors.forename: Changjun
authors.initials: C
authors.lastname: Wang
mesh_terms: D000818:Animals; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D006801:Humans; D064766:Influenza A Virus, H7N9 Subtype / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000175:diagnosis* / Q000821:virology*; D007251:Influenza, Human / Q000175:diagnosis* / Q000453:epidemiology / Q000821:virology*; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D011200:Poultry; D012680:Sensitivity and Specificity; D013997:Time Factors; D014773:Virology / Q000379:methods