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Evaluation of Indirect Fluorescent Antibody Assays Compared to Rapid Influenza Diagnostic Tests for the Detection of Pandemic Influenza A (H1N1) pdm09  [PDF]
Sandra Nutter,Michele Cheung,Felice C. Adler-Shohet,Kathryn Krusel,Kate Vogel,Hildy Meyers
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0033097
Abstract: Performance of indirect fluorescent antibody (IFA) assays and rapid influenza diagnostic tests (RIDT) during the 2009 H1N1 pandemic was evaluated, along with the relative effects of age and illness severity on test accuracy. Clinicians and laboratories submitted specimens on patients with respiratory illness to public health from April to mid October 2009 for polymerase chain reaction (PCR) testing as part of pandemic H1N1 surveillance efforts in Orange County, CA; IFA and RIDT were performed in clinical settings. Sensitivity and specificity for detection of the 2009 pandemic H1N1 strain, now officially named influenza A(H1N1)pdm09, were calculated for 638 specimens. Overall, approximately 30% of IFA tests and RIDTs tested by PCR were falsely negative (sensitivity 71% and 69%, respectively). Sensitivity of RIDT ranged from 45% to 84% depending on severity and age of patients. In hospitalized children, sensitivity of IFA (75%) was similar to RIDT (84%). Specificity of tests performed on hospitalized children was 94% for IFA and 80% for RIDT. Overall sensitivity of RIDT in this study was comparable to previously published studies on pandemic H1N1 influenza and sensitivity of IFA was similar to what has been reported in children for seasonal influenza. Both diagnostic tests produced a high number of false negatives and should not be used to rule out influenza infection.
Performance of the QuickVue Influenza A+B Rapid Test for Pandemic H1N1 (2009) Virus Infection in Adults  [PDF]
Wolfgang Poeppl, Harald Herkner, Heinz Burgmann, Tom Pustelnik, Gerhard Mooseder, Theresia Popow-Kraupp, Monika Redlberger-Fritz
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0028089
Abstract: To investigate the diagnostic accuracy of the QuickVue? Influenza A+B rapid test we conducted a prospective observational study in which this rapid test was compared with a real-time reverse transcription polymerase chain reaction (RT-PCR) for pandemic influenza A H1N1 (2009) infection in Austrian adults. The sensitivity, specificity, and positive and negative predictive values of the QuickVue test compared with the RT-PCR were 26% (95% CI 18–35), 98% (95% CI 92–100), 94% (95% CI 80–99) and 50% (95% CI 42–58), respectively. The prevalence of pandemic H1N1 (2009) virus infection among the 209 patients included in the study was 57%. Our data suggest that a positive QuickVue test provides considerable information for the diagnosis of pandemic influenza A H1N1 (2009) virus infection in young adults but that a negative QuickVue test result should, if relevant for patient management or public health measures, be verified using PCR.
Evaluation of a rapid diagnostic test, NanoSign? Influenza A/B Antigen, for detection of the 2009 pandemic influenza A/H1N1 viruses
Gyu-Cheol Lee, Eun-Sung Jeon, Won-Shik Kim, Dung Le, Jong-Ha Yoo, Chom-Kyu Chong
Virology Journal , 2010, DOI: 10.1186/1743-422x-7-244
Abstract: The NanoSign? Influenza A/B kit resulted in 79.4% sensitivity and 97.2% specificity compared to RT-PCR in the detection of the viruses from 1,023 specimens. In addition, the kit was able to detect two strains of novel influenza viruses, Influenza A/California/12/2009(H1N1) and clinically isolated wild-type novel influenza A/H1N1, both of which are spreading epidemically throughout the world. In addition, the correlation between NanoSign? Influenza A/B test and conventional RT-PCR was approximately 94%, indicating a high concordance rate. Analytical sensitivity of the kit was approximately 73 ± 3.65 ng/mL of the purified viral proteins and 1.13 ± 0.11 hemagglutination units for the cultured virus.As the NanoSign? Influenza A/B kit showed relatively high sensitivity and specificity and the good correlation with RT-PCR, it will be very useful in the early control of influenza infection and in helping physicians in making early treatment decisions.The novel influenza A/H1N1 virus has spread to most of the world's populations, and its spread has led to a pandemic alert situation [1-3]. As a result, at the end of 2009, the World Health Organization announced that the novel influenza A/H1N1 had reached pandemic status [4].A variety of different diagnostic methods can be used to detect the presence of influenza viruses in respiratory specimens such as nasopharyngeal aspirates, including direct antigen detection tests, virus isolation in cell cultures, and detection of influenza-specific RNA by real-time reverse transcriptase (RT)-polymerase chain reaction (PCR) [5-10]. Albeit the gold standard for the diagnosis of influenza is virus isolation using chicken embryos or tissue culture method, it has the shortcomings such as time consuming and labor intensiveness; it takes between two to 14 days before results are available. Detection of virus-infected cells in nasopharyngeal secretions by direct or indirect immunofluorescent staining is widely used, but it is a difficult and t
One-Step Detection of the 2009 Pandemic Influenza A(H1N1) Virus by the RT-SmartAmp Assay and Its Clinical Validation  [PDF]
Yuki Kawai, Yasumasa Kimura, Alexander Lezhava, Hajime Kanamori, Kengo Usui, Takeshi Hanami, Takahiro Soma, Jean-étienne Morlighem, Satomi Saga, Yuri Ishizu, Shintaro Aoki, Ryuta Endo, Atsuko Oguchi-Katayama, Yasushi Kogo, Yasumasa Mitani, Takefumi Ishidao, Chiharu Kawakami, Hideshi Kurata, Yumiko Furuya, Takayuki Saito, Norio Okazaki, Masatsugu Chikahira, Eiji Hayashi, Sei-ichi Tsuruoka, Tokumichi Toguchi, Yoshitomo Saito, Toshiaki Ban, Shinyu Izumi, Hideko Uryu, Koichiro Kudo, Yuko Sakai-Tagawa, Yoshihiro Kawaoka, Aizan Hirai, Yoshihide Hayashizaki, Toshihisa Ishikawa
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0030236
Abstract: Background In 2009, a pandemic (pdm) influenza A(H1N1) virus infection quickly circulated globally resulting in about 18,000 deaths around the world. In Japan, infected patients accounted for 16% of the total population. The possibility of human-to-human transmission of highly pathogenic novel influenza viruses is becoming a fear for human health and society. Methodology To address the clinical need for rapid diagnosis, we have developed a new method, the “RT-SmartAmp assay”, to rapidly detect the 2009 pandemic influenza A(H1N1) virus from patient swab samples. The RT-SmartAmp assay comprises both reverse transcriptase (RT) and isothermal DNA amplification reactions in one step, where RNA extraction and PCR reaction are not required. We used an exciton-controlled hybridization-sensitive fluorescent primer to specifically detect the HA segment of the 2009 pdm influenza A(H1N1) virus within 40 minutes without cross-reacting with the seasonal A(H1N1), A(H3N2), or B-type (Victoria) viruses. Results and Conclusions We evaluated the RT-SmartAmp method in clinical research carried out in Japan during a pandemic period of October 2009 to January 2010. A total of 255 swab samples were collected from outpatients with influenza-like illness at three hospitals and eleven clinics located in the Tokyo and Chiba areas in Japan. The 2009 pdm influenza A(H1N1) virus was detected by the RT-SmartAmp assay, and the detection results were subsequently compared with data of current influenza diagnostic tests (lateral flow immuno-chromatographic tests) and viral genome sequence analysis. In conclusion, by the RT-SmartAmp assay we could detect the 2009 pdm influenza A(H1N1) virus in patients' swab samples even in early stages after the initial onset of influenza symptoms. Thus, the RT-SmartAmp assay is considered to provide a simple and practical tool to rapidly detect the 2009 pdm influenza A(H1N1) virus.
Fever screening during the influenza (H1N1-2009) pandemic at Narita International Airport, Japan
Hiroshi Nishiura, Kazuko Kamiya
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-111
Abstract: Two datasets were collected at Narita International Airport during the 2009 pandemic. The first contained confirmed influenza cases (n = 16) whose diagnosis took place at the airport during the early stages of the pandemic, and the second contained a selected and suspected fraction of passengers (self-reported or detected by an infrared thermoscanner; n = 1,049) screened from September 2009 to January 2010. The sensitivity of fever (38.0°C) for detecting H1N1-2009 was estimated, and the diagnostic performances of the infrared thermoscanners in detecting hyperthermia at cut-off levels of 37.5°C, 38.0°C and 38.5°C were also estimated.The sensitivity of fever for detecting H1N1-2009 cases upon arrival was estimated to be 22.2% (95% confidence interval: 0, 55.6) among nine confirmed H1N1-2009 cases, and 55.6% of the H1N1-2009 cases were under antipyretic medications upon arrival. The sensitivity and specificity of the infrared thermoscanners in detecting hyperthermia ranged from 50.8-70.4% and 63.6-81.7%, respectively. The positive predictive value appeared to be as low as 37.3-68.0%.The sensitivity of entry screening is a product of the sensitivity of fever for detecting influenza cases and the sensitivity of the infrared thermoscanners in detecting fever. Given the additional presence of confounding factors and unrestricted medications among passengers, reliance on fever alone is unlikely to be feasible as an entry screening measure.The rapid international spread of severe acute respiratory syndrome (SARS) from 2002 to 2003 led countries around the world to extensively assess the entry screening measures at their international borders as one of the countermeasures to prevent the global spread of infectious diseases [1,2]. Pandemic influenza has been one of the most important subjects for entry screening [3]. Including an analysis of the historical records of maritime quarantine during the 1918-1919 influenza pandemic [4], many scientific discussions concerning the sci
Role of laboratory in the virological diagnosis of pandemic Influenza A(H1N1)v
I. Lahlou Amine,S. Zouhair
Technologies de Laboratoire , 2009,
Abstract: The new pandemic influenza, occurred in april 2009 in Mexico is also called swine Influenza. It is caused by a new Influenza virus A(H1N1)v, completely new, never before found in any species and results from complex genetic reassortment. The role of the laboratory is essential for the virological diagnosis of this emerging flu. It can provide the definitive diagnosis in patients whose clinical and epidemiological context is suggestive of infection with virus A(H1N1)v. The virological confirmation of an infection case caused by this virus is provided by the positivity of the laboratory following tests: RT-PCR and/or viral culture and/or four-fold rise in the rate of specific neutralizing antibodies directed against A(H1N1)v virus on a pair of sera collected two weeks apart. The real time RT-PCR is currently the tool of choice because of its rapidity, sensitivity and specificity. Immunological rapid diagnostic tests (RDTs) can detect the presence of the nucleoprotein antigens of seasonal influenza viruses type A and B. The evaluation of these tests showed, in the current pandemic context, a low sensitivity which not confer them a negative predictive value compatible with widespread use. Their results must be interpreted with caution and despite their good positive predictive value, they allow a presumptive diagnosis, confirmation by real time RT-PCR will be conducted whenever necessary.
Diagnostic Approach for the Differentiation of the Pandemic Influenza A(H1N1)v Virus from Recent Human Influenza Viruses by Real-Time PCR  [PDF]
Martin Schulze,Andreas Nitsche,Brunhilde Schweiger,Barbara Biere
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0009966
Abstract: The current spread of pandemic influenza A(H1N1)v virus necessitates an intensified surveillance of influenza virus infections worldwide. So far, in many laboratories routine diagnostics were limited to generic influenza virus detection only. To provide interested laboratories with real-time PCR assays for type and subtype identification, we present a bundle of PCR assays with which any human influenza A and B virus can be easily identified, including assays for the detection of the pandemic A(H1N1)v virus.
Polymeric LabChip Real-Time PCR as a Point-of-Care-Potential Diagnostic Tool for Rapid Detection of Influenza A/H1N1 Virus in Human Clinical Specimens  [PDF]
Hyun-Ok Song, Je-Hyoung Kim, Ho-Sun Ryu, Dong-Hoon Lee, Sun-Jin Kim, Deog-Joong Kim, In Bum Suh, Du Young Choi, Kwang-Ho In, Sung-Woo Kim, Hyun Park
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0053325
Abstract: It is clinically important to be able to detect influenza A/H1N1 virus using a fast, portable, and accurate system that has high specificity and sensitivity. To achieve this goal, it is necessary to develop a highly specific primer set that recognizes only influenza A viral genes and a rapid real-time PCR system that can detect even a single copy of the viral gene. In this study, we developed and validated a novel fluidic chip-type real-time PCR (LabChip real-time PCR) system that is sensitive and specific for the detection of influenza A/H1N1, including the pandemic influenza strain A/H1N1 of 2009. This LabChip real-time PCR system has several remarkable features: (1) It allows rapid quantitative analysis, requiring only 15 min to perform 30 cycles of real-time PCR. (2) It is portable, with a weight of only 5.5 kg. (3) The reaction cost is low, since it uses disposable plastic chips. (4) Its high efficiency is equivalent to that of commercially available tube-type real-time PCR systems. The developed disposable LabChip is an economic, heat-transferable, light-transparent, and easy-to-fabricate polymeric chip compared to conventional silicon- or glass-based labchip. In addition, our LabChip has large surface-to-volume ratios in micro channels that are required for overcoming time consumed for temperature control during real-time PCR. The efficiency of the LabChip real-time PCR system was confirmed using novel primer sets specifically targeted to the hemagglutinin (HA) gene of influenza A/H1N1 and clinical specimens. Eighty-five human clinical swab samples were tested using the LabChip real-time PCR. The results demonstrated 100% sensitivity and specificity, showing 72 positive and 13 negative cases. These results were identical to those from a tube-type real-time PCR system. This indicates that the novel LabChip real-time PCR may be an ultra-fast, quantitative, point-of-care-potential diagnostic tool for influenza A/H1N1 with a high sensitivity and specificity.
Mutations in NA That Induced Low pH-Stability and Enhanced the Replication of Pandemic (H1N1) 2009 Influenza A Virus at an Early Stage of the Pandemic  [PDF]
Tadanobu Takahashi, Jiasheng Song, Takashi Suzuki, Yoshihiro Kawaoka
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064439
Abstract: An influenza A virus that originated in pigs caused a pandemic in 2009. The sialidase activity of the neuraminidase (NA) of previous pandemic influenza A viruses are stable at low pH (≤5). Here, we identified the amino acids responsible for this property. We found differences in low-pH stability at pH 5.0 among pandemic (H1N1) 2009 viruses, which enhanced the replication of these viruses. Low-pH-stable NA enhancement of virus replication may have contributed to the rapid worldwide spread and adaptation to humans of pandemic (H1N1) 2009 viruses during the early stages of the 2009 pandemic.
Accuracy of rapid influenza diagnostic test and immunofluorescence assay compared to real time RT-PCR in children with influenza A(H1N1)pdm09 infection
Aneta Nitsch-Osuch,Agnieszka Wo?niak-Kosek,Lidia Bernadeta Brydak
Post?py Higieny i Medycyny Do?wiadczalnej , 2012,
Abstract: Introduction:The influenza burden among children is underestimated. The aim of our study was to estimate the accuracy of the rapid influenza detection test (RIDT) BD Directigen EZ Flu A B and direct immunofluorescence assay (DFA) used among children with influenza-like illness (ILI) consulted in the ambulatory care clinic.Material/Methods:A total of 150 patients were enrolled in the study. Inclusion criteria were: age less than 59 months, presentation of ILI according to the CDC (Centers for Disease Control and Prevention) definition (fever >37.8°C, cough and/or sore throat in the absence of another known cause of illness), duration of symptoms shorter than 96 hours. Two nasal swabs and one pharyngeal swab were obtained from patients and tested by RIDT, DFA and real time RT-PCR as the reference method.Results:For influenza A (H1N1)pdm09 virus sensitivity of RIDT was 62.2 0(95 0CI 46.5–76.2 specificity 97.1 0(95 0CI 91.8–99.4 PPV 90.3 0(95 0CI 74.3–98 NPV 85.7 0(95 0CI 78.1–91.5 for DFA sensitivity was 60 0(95 0CI 51.9–63.2 specificity 96 0(95 0CI 88.7–98.8 PPV 93.1 0(95 0CI 80.5–98 NPV 72.7 0(95 0CI 67.2–74.9 Analysis of logistic regression revealed that the chance of receiving a true positive result of RIDT was twice as high when the test was conducted during the first 48 hours of symptoms (OR 0.40 vs OR 0.22).Conclusions:The accuracy of RIDT is comparable with DFA and both methods are very specific but moderately sensitive in diagnosis of influenza in young children. Both methods may be recommended for screening for influenza among children.
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