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Bosevska G, Panovski N, Janceska E, Mikik V, Topuzovska IK, Milenkovik Z. Comparison of Directigen Flu A+B with Real Time PCR in the Diagnosis of Influenza. Folia Med (Plovdiv) 2016; 57:104-10. [PMID: 26933779 DOI: 10.1515/folmed-2015-0027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 02/18/2015] [Indexed: 11/15/2022] Open
Abstract
UNLABELLED Early diagnosis and treatment of patients with influenza is the reason why physicians need rapid high-sensitivity influenza diagnostic tests that require no complex lab equipment and can be performed and interpreted within 15 min. The Aim of this study was to compare the rapid Directigen Flu A+B test with real time PCR for detection of influenza viruses in the Republic of Macedonia. MATERIALS AND METHODS One-hundred-eight respiratory samples (combined nose and throat swabs) were routinely collected for detection of influenza virus during influenza seasons. Forty-one patients were pediatric cases and 59 were adult. Their mean age was 23 years. The patients were allocated into 6 age groups: 0-4 yrs, 5-9 yrs, 10-14 yrs, 15-19 yrs, 20-64 yrs and > 65 yrs. Each sample was tested with Directigen Flu A+B and CDC real time PCR kit for detection and typisation/subtypisation of influenza according to the lab diagnostic protocol. RESULTS Directigen Flu A+B identified influenza A virus in 20 (18.5%) samples and influenza B virus in two 2 (1.9%) samples. The high specificity (100%) and PPV of Directigen Flu A+B we found in our study shows that the positive results do not need to be confirmed. The overall sensitivity of Directigen Flu A+B is 35.1% for influenza A virus and 33.0% for influenza B virus. The sensitivity for influenza A is higher among children hospitalized (45.0%) and outpatients (40.0%) versus adults. CONCLUSION Directigen Flu A+B has relatively low sensitivity for detection of influenza viruses in combined nose and throat swabs. Negative results must be confirmed.
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Affiliation(s)
| | - Nikola Panovski
- Institute of Microbiology and Parasitology, Medical Faculty, Sts. Cyril and Methodius University
| | | | | | - Irena Kondova Topuzovska
- Clinic for Infectious Diseases and Febrile Conditions, Medical Faculty, Sts. Cyril and Methodius University, Republic of Macedonia
| | - Zvonko Milenkovik
- Clinic for Infectious Diseases and Febrile Conditions, Medical Faculty, Sts. Cyril and Methodius University, Republic of Macedonia
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2
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Correctly Using Sensitivity, Specificity, and Predictive Values in Clinical Practice: How to Avoid Three Common Pitfalls. AJR Am J Roentgenol 2013; 200:W566-70. [DOI: 10.2214/ajr.12.9888] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Chauhan N, Narang J, Pundir S, Singh S, Pundir CS. Laboratory diagnosis of swine flu: a review. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2012; 41:189-95. [PMID: 23140089 DOI: 10.3109/10731199.2012.716063] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Human swine influenza A [H1N1], also referred to as "swine flu," is highly transmissible. The emergence of new strains will continue to pose challenges to public health and the scientific communities will have to prepare to detect them for appropriate treatment. Most sophisticated methods include immunofluorescence staining and antigen subtyping based on hemagglutination inhibition (HI). Another standard method is RT-PCR targeting hemagglutinin and neuraminidase genes. The recent availability of rapid, reliable, and easy-to-perform tests for detecting influenza virus infections has introduced rapid viral diagnosis. This review thus summarizes the current information on the present diagnostic methods for influenza virus H1N1.
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Affiliation(s)
- Nidhi Chauhan
- Department of Biochemistry, M. D. University, Rohtak, Haryana, India
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Taylor J, McPhie K, Druce J, Birch C, Dwyer DE. Evaluation of twenty rapid antigen tests for the detection of human influenza A H5N1, H3N2, H1N1, and B viruses. J Med Virol 2009; 81:1918-22. [PMID: 19774693 DOI: 10.1002/jmv.21604] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Twenty rapid antigen assays were compared for their ability to detect influenza using dilutions of virus culture supernatants from human isolates of influenza A H5N1 (clade 1 and 2 strains), H3N2 and H1N1 viruses, and influenza B. There was variation amongst the rapid antigen assays in their ability to detect different influenza viruses. Six of the 12 assays labeled as distinguishing between influenza A and B had comparable analytical sensitivities for detecting both influenza A H5N1 strains, although their ability to detect influenza A H3N2 and H1N1 strains varied. The two assays claiming H5 specificity did not detect either influenza A H5N1 strains, and the two avian influenza-specific assays detected influenza A H5N1, but missed some influenza A H3N2 virus supernatants. Clinical trials of rapid antigen tests for influenza A H5N1 are limited. For use in a pandemic where novel influenza strains are circulating (such as the current novel influenza A H1N1 09 virus), rapid antigen tests should ideally have comparable sensitivity and specificity for the new strains as for co-circulating seasonal influenza strains.
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Affiliation(s)
- Janette Taylor
- Center for Virus Research, Westmead Millennium Institute, Westmead Hospital, Westmead, New South Wales 2145, Australia
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5
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The limitations of point of care testing for pandemic influenza: what clinicians and public health professionals need to know. Canadian Journal of Public Health 2009. [PMID: 19507723 DOI: 10.1007/bf03405541] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
As the world prepares for the next influenza pandemic, governments have made significant funding commitments to vaccine development and antiviral stockpiling. While these are essential components to pandemic response, rapid and accurate diagnostic testing remains an often neglected cornerstone of pandemic influenza preparedness. Clinicians and Public Health Practitioners need to understand the benefits and drawbacks of different influenza tests in both seasonal and pandemic settings. Culture has been the traditional gold standard for influenza diagnosis but requires from 1-10 days to generate a positive result, compared to nucleic acid detection methods such as real time reverse transcriptase polymerase chain reaction (RT-PCR). Although the currently available rapid antigen detection kits can generate results in less than 30 minutes, their sensitivity is suboptimal and they are not recommended for the detection of novel influenza viruses. Until point-of-care (POC) tests are improved, PILPN recommends that the best option for pandemic influenza preparation is the enhancement of nucleic acid-based testing capabilities across Canada.
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Maďarová L, Feiková S, Kissová R, Klement C, Blaškovičová H, Takáč B, Dluholucký S. Polymerase Chain Reaction (PCR) - an Efficient Tool for Diagnosis of Influenza and Acute Respiratory Illnesses During Influenza Season. Cent Eur J Public Health 2008; 16:59-64. [DOI: 10.21101/cejph.a3443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Petric M, Comanor L, Petti CA. Role of the laboratory in diagnosis of influenza during seasonal epidemics and potential pandemics. J Infect Dis 2007; 194 Suppl 2:S98-110. [PMID: 17163396 DOI: 10.1086/507554] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Laboratory diagnosis of influenza is critical to its treatment and surveillance. With the emergence of novel and highly pathogenic avian influenza viruses, the role of the laboratory has been further extended to include isolation and subtyping of the virus to monitor its appearance and facilitate appropriate vaccine development. Recent progress in enhancing testing for influenza promises to both improve the management of patients with influenza and decrease associated health care costs. The present review covers the technological characteristics and utilization features of currently available diagnostic tests, the factors that influence the selection of such tests, and the developments that are essential for pandemic preparedness.
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Affiliation(s)
- Martin Petric
- British Columbia Centre for Disease Control, Vancouver, Canada
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Kent J, Bailey T, Silvanose CD, McKeown S, Wernery U, Kinne J, Manvell R. An outbreak of low pathogenic avian influenza in a mixed-species aviculture unit in Dubai in 2005. Vet Clin North Am Exot Anim Pract 2006; 9:523-31. [PMID: 16931369 DOI: 10.1016/j.cvex.2006.05.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This case describes an outbreak of low pathogenic hemagglutinin 9 neuraminidase 2 avian influenza virus (AIV) in two white-bellied bustards (Eupodotis senegalensis), one stone curlew (Burhinus oedicnemius), and a blacksmith plover (Antibyx armatus) in a private zoologic collection in Dubai, United Arab Emirates. The four birds showed signs of respiratory disease, and all died as a result of disease or euthanasia. Attention has been paid to the diagnostic process and common differential diagnosis for upper respiratory tract disease in bustards, curlews, and plovers. To the knowledge of the authors, AIV has not been previously described in these species.
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Affiliation(s)
- Jo Kent
- The Dubai Falcon Hospital, Dubai, United Arab Emirates.
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Booth S, Baleriola C, Rawlinson WD. Comparison of two rapid influenza A/B test kits with reference methods showing high specificity and sensitivity for influenza A infection. J Med Virol 2006; 78:619-22. [PMID: 16555288 DOI: 10.1002/jmv.20584] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The rapid detection of influenza viruses is important for forming preventative strategies, directing initiation of anti-viral therapy, detecting potential avian influenza viruses, and excluding influenza-like pathogens, such as SARS. The ImmunoCard STAT! Flu A and B Plus test (Meridian Bioscience, Cincinnati, OH) is a new point of care (POC) test utilizing influenza-specific monoclonal antibodies for rapid diagnosis. The performance of this assay was compared to the established POC Binax NowFlu A and NowFlu B test, and the reference diagnostic standards of viral culture, indirect immunofluorescence (IFA), and RT-PCR where appropriate. Testing of nasopharyngeal aspirates (NPA) from children, throat swabs, and nasal swabs from adults indicated ImmunoCard STAT! specificity of 98% and 100% for influenza A and B, respectively in 224 specimens. The Binax test showed specificity of 99% and 100%, respectively for influenza A and B. Sensitivity results were identical for both rapid detection kits (80% and 47% for Flu A and B, respectively). Overall results were very similar for both testing devices with the advantage of ImmunoCard STAT! Flu A and B Plus test detecting influenza A and B with sharp and easy to read results.
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Affiliation(s)
- Susanne Booth
- Virology Division, Department of Microbiology, South Eastern Area Laboratory Services, Prince of Wales Hospital, Randwick, New South Wales, Australia
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Woolcock PR, Cardona CJ. Commercial Immunoassay Kits for the Detection of Influenza Virus Type A: Evaluation of Their Use with Poultry. Avian Dis 2005; 49:477-81. [PMID: 16404986 DOI: 10.1637/7357-031605r.1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Five antigen capture immunoassay test kits, Directigen Flu A (Becton Dickinson), QuickVue Influenza test kit (Quidel), FLU OIA (ThermoBiostar), Zstat Flu (ZymeTx, Inc.) and NOW FLU A Test (Binax) were used to detect avian influenza virus (AIV) in clinical specimens as per manufacturers' protocols. Each kit was shown to be specific for AIV propagated in embryonating chicken eggs (ECE); other respiratory viruses of poultry tested gave negative results. The Directigen Flu A kit proved to be 10-fold more sensitive than the other kits, capable of detecting 10(4.7) mean embryo lethal dose (ELD50)/ml in allantoic fluid; this is more sensitive than the hemagglutination test using chicken erythrocytes. None of the kits proved to be sufficiently sensitive to reliably detect AIV in oropharyngeal and cloacal swabs collected from chickens experimentally infected with AIV subtype H6N2. In two different experiments, individual swabs and pools of five or six swabs were tested. By virus isolation, 39 individual oropharyngeal swabs tested positive for AIV, but Directigen and Flu OIA only detected 2/39 and NOW FLU A 1/39. Zstat and QuickVue did not detect any. Five individual cloacal swabs positive by virus isolation were negative with all five kits. In a second experiment using pools of five swabs, 26 swab pools were positive by virus isolation and 5/26 were positive by Directigen, the only kit to provide any positive results. Five cloacal swab pools were also positive by virus isolation and 1/5 was positive by Directigen; all other test kits were negative. All of these experiments were performed using the H6N2 subtype of AIV. The results are disappointing, as the kits have proven to be insensitive for detecting AIV when compared with the gold standard, virus isolation. This limits their use in diagnostic field investigations. Individual or groups of chickens could be assumed to be positive for AIV if positive by any of the kits, but a negative result with any of the kits would not prove that birds were AIV free.
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Affiliation(s)
- Peter R Woolcock
- California Animal Health and Food Safety Laboratory System-Fresno Branch, University of California, Davis, USA
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11
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Gröndahl B, Puppe W, Weigl J, Schmitt HJ. Comparison of the BD Directigen Flu A+B Kit and the Abbott TestPack RSV with a multiplex RT-PCR ELISA for rapid detection of influenza viruses and respiratory syncytial virus. Clin Microbiol Infect 2005; 11:848-50. [PMID: 16153263 DOI: 10.1111/j.1469-0691.2005.01223.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Directigen Flu A+B enzyme immunoassay and the Abbott TestPack RSV enzyme immunoassay were each compared with a multiplex RT-PCR ELISA by testing 635 nasopharyngeal aspirates collected from children aged < 16 years who had been hospitalised with acute respiratory tract infection during the epidemic season 2002-2003. In this study, the sensitivity of the Directigen Flu A+B assay was unacceptably low (29.3% and 10.0%, respectively) for the detection of influenza A and B viruses. The sensitivity of the Abbott TestPack RSV assay (77.4%) was acceptable and in agreement with the multiplex RT-PCR ELISA.
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Affiliation(s)
- B Gröndahl
- Johannes Gutenberg University, Department of Paediatrics, Mainz, Germany.
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12
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Abstract
A variety of antigen-capture assays are commercially available for the detection of influenza. In addition, real-time multiplex polymerase chain reaction (PCR) has been used to detect influenza A and B in clinical specimens. The commercial assays can be completed in less than 30 minutes and have a sensitivity of at least 70% and a specificity of 90%, compared with viral isolation. They are useful not only in the diagnosis and treatment of individual patients with influenza-like illness but also in surveillance for influenza, decreasing the time of nosocomial outbreaks, decreasing the use of laboratory tests, and decreasing antibiotic use in patients with influenza. Some of the rapid antigen assays, and PCR, can detect the H5N1 and H9N1 viruses. Real-time multiplex PCR also detects a variety of respiratory viruses within 6 hours, with only 1 hour of hands-on technician time. The widespread use of the rapid tests for influenza is changing the practice pattern of physicians who care for patients with influenza.
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Affiliation(s)
- Constance T Pachucki
- Stritch School of Medicine, Loyola University; Edward Hines VA Hospital, Section of Infectious Diseases, 111-P, Hines, IL 60141, USA.
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13
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Steed LL, Salmon VC, Overall JC. Identification of influenza A virus by shell vial culture and two commercially available antigen detection methods. ACTA ACUST UNITED AC 2005; 2:261-9. [PMID: 15566771 DOI: 10.1016/0928-0197(94)90050-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/1993] [Accepted: 12/29/1993] [Indexed: 11/23/2022]
Abstract
BACKGROUND Effective use of amantidine and rimantidine for treating patients and for reducing transmission requires rapid diagnosis of influenza A. Rapid culture methods require 1-2 days to detect influenza A virus. Direct fluorescent antibody (DFA) staining and enzyme immunoassay (EIA) can detect influenza A antigen within 1-4 h. OBJECTIVES We compared DFA staining using the Bartels viral respiratory panel and the Directigen FLU-A EIA with shell vial centrifugation culture. STUDY DESIGN Ninety-seven fresh specimens from a variety of respiratory sources and transported from hospitals throughout the USA to our national referral laboratory were tested. A true positive was defined as culture positive or both antigen tests positive. RESULTS Fifteen specimens were true positive. Sensitivity with culture was 93%, EIA 67%, and DFA 47%. Specificity was excellent with all three methods: 100%, 98%, 99%. Culture detected additional viruses that can cause respiratory tract disease: herpes simplex, cytomegalovirus, respiratory syncytial, influenza B, and adenovirus. Fourteen (70%) of 20 frozen specimens previously positive for influenza A were positive on retest by EIA. Overall sensitivity of EIA compared with culture using 35 positive specimens was 69%. CONCLUSIONS These results suggest that the rapid EIA is useful to screen for influenza A, but that critical antigen-negative specimens should be submitted to a virology laboratory for culture for optimal sensitivity and for recovery of other viruses.
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Affiliation(s)
- L L Steed
- Diagnostic Virology Laboratory, Associated Regional and University Pathologists, Inc., Salt Lake City, UT 84108, USA
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Steed LL, Salmon VC, Overall JC. Identification of influenza A virus by shell vial culture and two commercially available antigen detection methods. ACTA ACUST UNITED AC 2005; 2:181-9. [PMID: 15566764 DOI: 10.1016/0928-0197(94)90021-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/1993] [Revised: 11/24/1993] [Indexed: 10/27/2022]
Abstract
BACKGROUND Influenza continues to be a major cause of morbidity and mortality especially in the elderly and persons with underlying disease. Shell vial cell culture and antigen detection techniques may speed up diagnosis and enable better patient treatment and management. OBJECTIVES To compare shell vial centrifugation culture with commercially available direct fluorescence and enzyme immunoassay kits using a variety of respiratory specimens. STUDY DESIGN To detect influenza A virus, we compared direct fluorescent antibody (DFA) staining using the Bartels Viral Respiratory Panel and the Directigen FLU-A enzyme immunoassay (EIA) with shell vial centrifugation culture. Ninety-seven fresh specimens from a variety of respiratory sources, and transported from hospitals throughout the U.S. to our national referral laboratory, were tested. RESULTS Fifteen specimens were true positives: culture positive or both antigen tests positive. Sensitivity with culture was 93%, EIA 67%, and DFA 47%. Specificity was excellent with all three methods: 100%, 98%, 99%. Culture detected additional viruses that can cause respiratory tract disease: herpes simplex, cytomegalovirus, respiratory syncytial, influenza B, and adenovirus. Fourteen (70%) of 20 frozen specimens previously positive for influenza A were positive on retest by EIA. Overall sensitivity of EIA compared with culture using 35 positive specimens was 69%. CONCLUSIONS The rapid EIA is useful to screen for influenza A, but critical antigen-negative specimens should be submitted to a virology laboratory for culture. Shell vial cultures can provide a sensitive and universal diagnostic system for influenza A and a variety of other viruses.
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Affiliation(s)
- L L Steed
- Diagnostic Virology Laboratory, Associated Regional and University Pathologists, Inc., Salt Lake City, UT 84108, USA
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Glikmann G, Chen SN, Mordhorst CH, Koch C. Monoclonal antibodies for the rapid diagnosis of influenza-B virus infections by ELISA: production and characterization. ACTA ACUST UNITED AC 2005; 4:27-42. [PMID: 15566825 DOI: 10.1016/0928-0197(94)00053-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/1994] [Revised: 09/08/1994] [Accepted: 10/13/1994] [Indexed: 10/17/2022]
Abstract
BACKGROUND Monoclonal antibodies directed against conserved epitopes of viral proteins have substantially improved the accuracy of several immunochemical methods in diagnostic virology. OBJECTIVES To characterize mouse monoclonal antibodies directed against structural protein antigens of influenza-B virus and evaluate their use as diagnostic reagents for the direct detection of such antigens in clinical specimens from patients with respiratory infections of unknown aetiology. STUDY DESIGN (a) Production and characterization of monoclonal antibodies against influenza-B viral antigens, and (b) their use in two different ELISA systems for detecting influenza-B antigen either directly in clinical specimens or after confirmation by rapid culture in MDCK cells. RESULTS Four monoclonal antibodies were selected for their specificity for the nucleoprotein antigen as demonstrated by Western blot analysis. The specificity of these antibodies for different epitopes of the nucleoprotein was demonstrated by competition experiments, using unlabelled and biotin-labelled purified antibodies in a sandwich assay. All four antibodies belong to the mouse IgG(2a) isotype, lack haemagglutination inhibition and neutralization properties and exhibit titres as high as 10(-6) in ELISA with as little as 30 ng purified influenza-B virus. ELISA methods using these antibodies detected only influenza-B viral antigens in direct testing of clinical specimens from patients with known influenza-B or influenza-A infections, or after reisolating virus from such specimens in tissue culture of MDCK cells. CONCLUSION The antibodies were suitable for the direct detection and typing of influenza-B virus in clinical specimens or for use in rapid confirmation cultures.
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Affiliation(s)
- G Glikmann
- Department of Virology, Statens Seruminstitut, Artillerivej 5, DK-2300 Copenhagen S, Denmark
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Landry ML, Cohen S, Ferguson D. Comparison of Binax NOW and Directigen for rapid detection of influenza A and B. J Clin Virol 2004; 31:113-5. [PMID: 15364266 DOI: 10.1016/j.jcv.2004.04.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/23/2004] [Accepted: 04/16/2004] [Indexed: 11/21/2022]
Abstract
Directigen Flu A + B and Binax NOW Flu A and Flu B tests detected 33 (55.9%) and 31 (52.5%) of 59 influenza-positive samples, respectively. In children under 2 years of age, sensitivity increased to 75% for both tests. Three samples tested falsely-positive for influenza B using Binax NOW.
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Affiliation(s)
- Marie L Landry
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA.
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Ward CL, Dempsey MH, Ring CJA, Kempson RE, Zhang L, Gor D, Snowden BW, Tisdale M. Design and performance testing of quantitative real time PCR assays for influenza A and B viral load measurement. J Clin Virol 2004; 29:179-88. [PMID: 14962787 PMCID: PMC7128145 DOI: 10.1016/s1386-6532(03)00122-7] [Citation(s) in RCA: 235] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2002] [Revised: 04/28/2003] [Accepted: 05/06/2003] [Indexed: 11/27/2022]
Abstract
BACKGROUND The antiviral effect of anti-influenza drugs such as zanamivir may be demonstrated in patients as an increased rate of decline in viral load over a time course of treatment as compared with placebo. Historically this was measured using plaque assays, or Culture Enhanced Enzyme Linked Immunosorbent Assay (CE-ELISA). OBJECTIVES to develop and characterise real time quantitative PCR (qPCR) assays to measure influenza A and B viral load in clinical samples, that offer improvements over existing methods, in particular virus infectivity assays. STUDY DESIGN The dynamic range and robustness were established for the real time qPCR assays along with stability of the assay components. Cross validation of the real time PCR assays with CE-ELISA was performed by parallel testing of both serial dilutions of three different subtypes of cultured virus and a panel of influenza positive throat swab specimens. RESULTS the assays were specific for influenza A and B and the dynamic ranges were at least seven logs. The assay variability was within acceptable limits but increased towards the lower limit of quantification, which was 3.33 log(10) viral cDNA copies/ml of virus transport medium (ten viral RNA copies/PCR). The components of the assay were robust enough to withstand extended storage and several freeze-thaw cycles. For the real time PCR assays the limit of quantification was equivalent to the virus infectivity cut off, which equates to a 93-fold increase in sensitivity. CONCLUSION Well characterised real time PCR assays offer significant improvements over the existing methods for measuring the viral load of strains of influenza A and B in clinical specimens.
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Affiliation(s)
- C L Ward
- International Clinical Virology, GlaxoSmithKline Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK.
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Quinlivan M, Cullinane A, Nelly M, Van Maanen K, Heldens J, Arkins S. Comparison of sensitivities of virus isolation, antigen detection, and nucleic acid amplification for detection of equine influenza virus. J Clin Microbiol 2004; 42:759-63. [PMID: 14766849 PMCID: PMC344455 DOI: 10.1128/jcm.42.2.759-763.2004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Four seronegative foals aged 6 to 7 months were exposed to an aerosol of influenza strain A/Equi/2/Kildare/89 at 10(6) 50% egg infective doses (EID(50))/ml. Nasopharyngeal swabs were collected for 10 consecutive days after challenge. Virus isolation was performed in embryonated eggs, and the EID(50) was determined for all positive samples. The 50% tissue culture infective dose was determined using Madin-Darby canine kidney (MDCK) cells. Samples were also tested by an in vitro enzyme immunoassay test, Directigen Flu A, and by reverse transcription-PCR (RT-PCR) using nested primers from the nucleoprotein gene and a single set of primers from the matrix gene. RT-PCR using the matrix primers and virus isolation in embryonated eggs proved to be the most sensitive methods for the detection of virus. The Directigen Flu A test was the least sensitive method. The inclusion of 2% fetal calf serum in the viral transport medium inhibited the growth of virus from undiluted samples in MDCK cells but was essential for the maintenance of the virus titer in samples subjected to repeated freeze-thaw cycles.
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Affiliation(s)
- Michelle Quinlivan
- Virology Unit, Irish Equine Centre, Johnstown, Naas, County Kildare, Ireland
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Maeda T, Shintani Y, Nakano K, Terashima K, Yamada Y. Failure of inactivated influenza A vaccine to protect healthy children aged 6-24 months. Pediatr Int 2004; 46:122-5. [PMID: 15056235 DOI: 10.1046/j.1442-200x.2004.01852.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The efficacy of inactivated influenza vaccine in healthy infants and children younger than 24 months has not been confirmed. The aim of the present study was to determine the prophylactic effect of inactivated influenza vaccine against influenza A in healthy children aged 6-24 months. METHODS Healthy infants and young children (6-24 months old) were immunized by subcutaneous injection of inactivated influenza vaccine before influenza seasons. Age matched children were randomly assigned as the control. These children were followed up from January to April in each year (2000, 2001 and 2002). The attack rates of influenza A infection was compared and statistically assessed. RESULTS The attack rate of influenza A virus infection in the vaccine group and the control group were 14.8% (n = 27) vs 12.5% (n = 32) in 2000 (P = 0.526); 2.8% (n = 72) vs 7.2% (n = 69) in 2001 (P = 0.203); and 3.4% (n = 52) vs 8.9% (n = 56) in 2002 (P = 0.205). The attack rates of influenza A between the two groups were not significantly different. CONCLUSIONS Inactivated influenza vaccine did not reduce the attack rate of influenza A infection in 6-24 month old children.
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Affiliation(s)
- Taro Maeda
- Department of Pediatrics, Public Shisou General Hospital, Shisou, Japan.
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21
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Rawlinson WD, Waliuzzaman ZM, Fennell M, Appleman JR, Shimasaki CD, Carter IW. New point of care test is highly specific but less sensitive for influenza virus A and B in children and adults. J Med Virol 2004; 74:127-31. [PMID: 15258978 DOI: 10.1002/jmv.20155] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The importance of rapid diagnosis of influenza has increased with the availability of neuraminidase inhibitors, which need to be commenced within 48 hr of symptom onset. Furthermore, the recent development of influenza-like clinical syndromes with novel aetiologies (severe acute respiratory syndrome, SARS) has increased the need for rapid and accurate near-patient diagnosis. A new, modified point of care (POC) diagnostic test (ZstatFlu) was assessed on 469 nasopharyngeal aspirates (NPAs) and 260 nose/throat swabs (TS) taken from children and adults. The test was specific (77-98%) for all specimen types for influenza virus A and B, depending upon incubation conditions. However, it was less sensitive, detecting 65-77% of specimens confirmed as positive on culture, direct immunofluorescence or PCR testing. A positive test is useful, for both directing initiation of therapy in the clinician's office, and making a positive diagnosis of influenza in patients with influenza-like clinical syndromes.
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Affiliation(s)
- William D Rawlinson
- Virology Division, Department of Microbiology, SEALS, The Prince of Wales Hospital, Randwick, and School of Medical Sciences, University of New South Wales, Kensington, Sydney, Australia.
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22
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Affiliation(s)
- Mahmoud Shorman
- James H. Quillen VA Medical Center and the Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA
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23
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Landry ML, Ferguson D. Suboptimal detection of influenza virus in adults by the Directigen Flu A+B enzyme immunoassay and correlation of results with the number of antigen-positive cells detected by cytospin immunofluorescence. J Clin Microbiol 2003; 41:3407-9. [PMID: 12843105 PMCID: PMC165325 DOI: 10.1128/jcm.41.7.3407-3409.2003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To provide 24-h influenza diagnosis for adults presenting to the emergency department, the Directigen Flu A+B enzyme immunoassay (EIA) was performed in the chemistry laboratory during the night shift. Nasopharyngeal swabs were retested by cytospin-enhanced direct immunofluorescence (DFA; SimulFluor respiratory screen) when the virology laboratory opened. The influenza EIA detected 16 influenza A virus infections, whereas cytospin-enhanced DFA detected 31 influenza A virus infections as well as 3 respiratory syncytial virus, 2 adenovirus, and 1 parainfluenza virus infections. A positive EIA result usually correlated with 50 or more influenza virus cells positive by DFA.
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Affiliation(s)
- Marie L Landry
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, and Clinical Virology Laboratory, Yale New Haven Hospital, New Haven, Connecticut 06504, USA.
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24
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Abstract
A monoclonal antibody (MAb)-based dot-enzyme-linked immunosorbent assay (ELISA) has been developed that detected the epitopes specifically associated with avian influenza virus (AIV). The dot-ELISA detected the antigens of AIV directly from clinical and field specimens. Data obtained from experimentally AIV-infected specific-pathogen-free chickens and also the 2001/02 AIV outbreak of serotype H7N2 positive flocks in Pennsylvania indicated that the mean sensitivity (Se) of the dot-ELISA ranged between 45% and 68% and the mean specificity (Sp), between 85% and 90%. The values were derived from various clinical and field specimens when compared with virus isolation with embryonating chicken eggs. On routine AIV surveillance samples, the dot-ELISA achieved a 92%-100% Sp on the basis of resting over 1500 AIV surveillance samples that were confirmed negative by virus isolation. The dot-ELISA detected AIV antigens with a 5-microl allantoic fluid sample that contained a concentration of 0.4 hemagglutinating units. Furthermore, the dot-ELISA retained its specificity for AIV because no cross-reactions were obtained with various other avian viruses. The findings in this study indicated that the dot-ELISA was highly sensitive and specific and comparable with the commercial Directigen test in the detection of AIV obtained from clinical and field specimens.
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Affiliation(s)
- Huaguang Lu
- Animal Diagnostic Laboratory, Department of Veterinary Science, The Pennsylvania State University, University Park, PA 16802, USA
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25
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Abstract
In recent years, seven rapid tests for influenza have become commercially available. These tests offer the promise of making rapid influenza diagnosis much more widely available than in the past, when rapid diagnosis could be made only by fluorescent antibody staining, a demanding technique available only in advanced laboratories. Two of the rapid tests have waived status under the Clinical Laboratory Improvements Amendments of 1988. This article describes each of the seven tests and reviews English-language publications that have evaluated the performance of these tests on specimens from children. A discussion of the implications of the tests for clinical decision-making is included.
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Affiliation(s)
- Gregory A Storch
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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26
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Uyeki TM. Influenza diagnosis and treatment in children: a review of studies on clinically useful tests and antiviral treatment for influenza. Pediatr Infect Dis J 2003; 22:164-77. [PMID: 12586981 DOI: 10.1097/01.inf.0000050458.35010.b6] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Prompt testing for influenza can help guide clinical management of patients with suspected influenza. Three antiviral medications, amantadine, oseltamivir and zanamivir, are approved for treatment of influenza in children. Rimantadine and ribavirin have also been used. OBJECTIVES To review the published evidence on clinically useful diagnostic tests and antiviral treatment for influenza virus infections in children. METHODS Studies published from 1966 through September 2002 were reviewed on clinical diagnosis, immunofluorescence and rapid influenza tests and on antiviral treatment of influenza virus infections among pediatric populations. RESULTS No studies assessed the accuracy of clinical diagnosis of influenza in children compared with viral culture. Compared with viral culture, direct immunofluorescence antibody and indirect immunofluorescence antibody tests for influenza had fair to moderate median sensitivities and high median specificities, whereas rapid influenza diagnostic tests had moderate median sensitivities and moderately high median specificities. No randomized, placebo-controlled studies were found of amantadine or rimantadine for treatment of influenza A. In a few separate controlled studies, oseltamivir, zanamivir and ribavirin each reduced symptom duration of influenza compared with placebo. CONCLUSIONS Additional data are needed about the accuracy of clinical diagnosis of influenza in children. Although direct immunofluorescence antibody staining, indirect immunofluorescence antibody staining and rapid tests are moderately to reasonably accurate in detecting influenza virus infections in children, physicians should use clinical judgment and local surveillance data about circulating influenza viruses when interpreting test results. Further controlled studies of the efficacy, adverse effects and emergence of antiviral resistance during treatment of influenza are needed for all of the antiviral drugs.
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Affiliation(s)
- Timothy M Uyeki
- Influenza Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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27
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Abstract
Influenza remains an important cause of morbidity and mortality in the United States. Although signs and symptoms of individual influenza cases are nonspecific, the epidemiology is characteristic, and a clinical diagnosis can be made accurately during epidemics. Several tests can be used to confirm influenza infection. Antiviral medications may be used for both treatment and prophylaxis, but prevention of influenza is most reliably achieved through vaccination.
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Affiliation(s)
- Scott Harper
- National Center for Infectious Diseases, Division of Viral and Rickettsial Diseases, Influenza Branch, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30333, USA.
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28
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Affiliation(s)
| | - Daniel P Fedorko
- Clinical Pathology Department National Institutes of Health Bethesda, MD 20892, USA
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29
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Newton DW, Mellen CF, Baxter BD, Atmar RL, Menegus MA. Practical and sensitive screening strategy for detection of influenza virus. J Clin Microbiol 2002; 40:4353-6. [PMID: 12409430 PMCID: PMC139677 DOI: 10.1128/jcm.40.11.4353-4356.2002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study evaluated the performance of Directigen FluA combined with a 3-day flu screening culture for the detection of influenza virus. This abbreviated protocol was a useful and effective tool and resulted in a substantial reduction in time, effort, and money spent, while not compromising sensitivity of influenza virus detection.
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Affiliation(s)
- Duane W Newton
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14607, USA
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30
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Simor AE. Influenza outbreaks in long-term-care facilities: how can we do better? Infect Control Hosp Epidemiol 2002; 23:564-7. [PMID: 12400883 DOI: 10.1086/501971] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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31
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Reina J, Padilla E, Alonso F, Ruiz De Gopegui E, Munar M, Mari M. Evaluation of a new dot blot enzyme immunoassay (directigen flu A+B) for simultaneous and differential detection of influenza a and B virus antigens from respiratory samples. J Clin Microbiol 2002; 40:3515-7. [PMID: 12202608 PMCID: PMC130707 DOI: 10.1128/jcm.40.9.3515-3517.2002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report a prospective evaluation of a new dot blot enzyme immunoassay (EIA) method for the direct, rapid, qualitative, simultaneous, and differential detection of the influenza A (IA) and B (IB) virus antigen in different respiratory samples. The EIA method was compared with the shell vial culture system (MDCK cell line) used with the same samples. We studied 160 samples from 93 (58.1%) pediatric patients (hospital emergency room) and from 67 (41.9%) adult patients (sentinel network). Seventy-four(46.2%) samples were considered positive; of them, 46 (62.2%) were from pediatric patients and 28 (37.8%) were from an adult group (P < 0.05), with overall positive values of 49.9% and 41.7%, respectively. All 74 (100%) of the positive samples were isolated in cell culture versus the 68.9% that were detected as positive by the new EIA method (P < 0.05). Of the 41 samples positive for the IA virus, the EIA detected 34 (82.9%) positive samples; of the 33 samples positive for the IB virus, the EIA detected 17 (51.5%) positive samples (P < 0.05). No false-positive reaction was detected with the EIA method (specificity and positive predictive value of 100%). The overall results obtained in the comparison between the new EIA and the shell vial culture had a sensibility of 82.9% and predictive negative values of 92.4% for the IA virus and 51.5% and 84.3%, respectively, for the IB virus. This evaluation shows sensitivity and specificity percentages for the new EIA method that is acceptable for routine use in IA virus detection. The results obtained were worse for IB virus detection, but this new EIA method is actually the only one with the capacity to differentiate between the two influenza viruses.
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Affiliation(s)
- Jordi Reina
- Virology Unit, Clinical Microbiology Service, University Hospital Son Dureta (Universitat Illes Balears), 07014 Palma de Mallorca, Spain.
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32
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Chan KH, Maldeis N, Pope W, Yup A, Ozinskas A, Gill J, Seto WH, Shortridge KF, Peiris JSM. Evaluation of the Directigen FluA+B test for rapid diagnosis of influenza virus type A and B infections. J Clin Microbiol 2002; 40:1675-80. [PMID: 11980941 PMCID: PMC130655 DOI: 10.1128/jcm.40.5.1675-1680.2002] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Directigen FluA+B (BD Diagnostic Systems, Sparks, Md.), a new rapid test for the detection of influenza virus types A and B, was evaluated with nasopharyngeal aspirate specimens collected from 250 patients in comparison with culture and direct fluorescent antigen (DFA) detection tests. The patients studied were predominantly children, 80% being </=6 years old. Specimens negative by culture but positive by the Directigen FluA+B or DFA tests were analyzed by reverse transcription-PCR to resolve the discrepant results. The resolved sensitivity, specificity, and positive and negative predictive values of the Directigen FluA+B test for influenza virus type A were 96%, 99.6%, 96%, and 99.6%, respectively, and for influenza virus type B they were 87.5%, 96.8%, 80%, and 98%, respectively. Storage of nasopharyngeal aspirates in virus transport medium at 2 to 8 degrees C for 48 h had little adverse effect on the detection of influenza virus type A, but diagnosis of influenza virus type B is best carried out with fresh specimens. The test detected a range of human and animal influenza virus A subtypes, including the H5N1 and H9N2 viruses that recently caused human disease in Hong Kong.
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Affiliation(s)
- K H Chan
- Department of Microbiology, The University of Hong Kong and Queen Mary Hospital, Pokfulam, Hong Kong, SAR
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33
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Demmler GJ. Laboratory diagnosis of influenza: recent advances. SEMINARS IN PEDIATRIC INFECTIOUS DISEASES 2002; 13:85-9. [PMID: 12122957 DOI: 10.1053/spid.2002.122994] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The rapid and accurate diagnosis of influenza virus infection now is available to clinicians practicing in both outpatient and inpatient settings. Newly licensed reagents are reliable and "user friendly" and may impact care by providing an immediate diagnosis that allows appropriate antiviral therapy to be given and encourages judicious use of antibiotics. The diagnosis of influenza by viral culture also has become more mainstream, allowing health professionals to confirm diagnoses in individual patients, as well as to track the pattern of each "flu season" in the community.
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Affiliation(s)
- Gail J Demmler
- Department of Pediatrics, Baylor College of Medicine, Diagnostic Virology Laboratory, Texas Children's Hospital, Houston, TX, USA.
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34
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Ison MG, Gnann JW, Nagy-Agren S, Treanor J, Paya C, Steigbigel R, Elliott M, Weiss HL, Hayden FG. Safety and Efficacy of Nebulized Zanamivir in Hospitalized Patients with Serious Influenza. Antivir Ther 2002. [DOI: 10.1177/135965350300800301] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Influenza is an important cause of hospitalization due to lower respiratory tract involvement for which there is no specific antiviral treatment with proven efficacy. We conducted a double-blind, randomized, placebo-controlled trial to assess the tolerability and efficacy of nebulized zanamivir (16 mg four times a day) in combination with rimantadine compared to rimantadine with nebulized saline for treating influenza in adults hospitalized with influenza. Twenty patients tolerated the inhaled zanamivir (ZNV) plus rimantadine without decline in peak expiratory flow rates compared to the 21 who received inhaled saline. The study was terminated early because the approval of ZNV made further enrolment untenable. No significant differences were observed in the proportion of patients shedding virus by treatment day 3 (57% ZNV plus rimantadine, 67% placebo plus rimantadine), or in the durations of hospitalization and supplemental oxygen use. More ZNV plus rimantadine recipients exhibited no or mild cough on day 3 of treatment (94 vs 55%, P=0.01). Two rimantadine-resistant viruses emerged during rimantadine monotherapy; no ZNV resistance was observed. Nebulized ZNV appears to be well tolerated in this hospitalized population but further studies are needed to assess its efficacy.
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Affiliation(s)
| | | | - John W Gnann
- University of Alabama-Birmingham, Birmingham, Ala., USA
| | | | | | | | | | | | - Heidi L Weiss
- University of Alabama-Birmingham, Birmingham, Ala., USA
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35
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Affiliation(s)
- E Geoffrey Playford
- Centre for Infectious Disease and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, Westmead Hospital, NSW, Australia.
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36
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Church DL, Davies HD, Mitton C, Semeniuk H, Logue M, Maxwell C, Donaldson C. Clinical and economic evaluation of rapid influenza a virus testing in nursing homes in calgary, Canada. Clin Infect Dis 2002; 34:790-5. [PMID: 11830797 DOI: 10.1086/338960] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2001] [Revised: 10/30/2001] [Indexed: 11/04/2022] Open
Abstract
The incremental benefits and costs of a rapid influenza A virus infection diagnostic service were studied in nursing homes in Calgary, Canada, during a single influenza season. The service was used to test 159 patients with suspected infection in a group of "experimental" nursing homes and results were compared with those for a group of "control" homes. An equal number of cases of influenza were identified in each group. Twenty-eight patients (17.6%) had confirmed cases, and 63 patients (39.6%) had probable cases. A rapid viral test result was provided much faster for patients in the experimental homes (P=.005). Both groups had the same median attack rate for influenza A virus. In experimental homes, the duration of the outbreak was shorter (P=.03), and the cost of laboratory testing and the total cost (less the hospital cost) tended to be lower (P<.2). The rapid testing service also tended to lower the overall use of resources.
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Affiliation(s)
- Deirdre L Church
- Calgary Laboratory Services, Department of Pathology and Laboratory Medicine and Department of Medicine, University of Calgary, Calgary, Canada.
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37
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Salgado CD, Farr BM, Hall KK, Hayden FG. Influenza in the acute hospital setting. THE LANCET. INFECTIOUS DISEASES 2002; 2:145-55. [PMID: 11944184 DOI: 10.1016/s1473-3099(02)00221-9] [Citation(s) in RCA: 302] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Influenza poses special hazards inside healthcare facilities and can cause explosive outbreaks of illness. Healthcare workers are at risk of acquiring influenza and thus serve as an important reservoir for patients under their care. Annual influenza immunisation of high-risk persons and their contacts, including healthcare workers, is the primary means of preventing nosocomial influenza. Despite influenza vaccine effectiveness, it is substantially underused by healthcare providers. Influenza can be diagnosed by culturing the virus from respiratory secretions and by rapid antigen detection kits; recognition of a nosocomial outbreak is important in order to employ infection-control efforts. Optimal control of influenza in the acute-care setting should focus upon reducing potential influenza reservoirs in the hospital, including: isolating patients with suspected or documented influenza, sending home healthcare providers or staff who exhibit typical symptoms of influenza, and discouraging persons with febrile respiratory illness from visiting the hospital during a known influenza outbreak in the community. (Note: influenza and other respiratory viruses can cause non-febrile illness but are still transmissible.) The antiviral M2 protein inhibitors (amantadine, rimantadine) and neuraminidase inhibitors (zanamivir, oseltamivir) have proven efficacy in treating and preventing influenza illness; however, their role in the prevention and control of influenza in the acute hospital setting remains to be more fully studied.
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38
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Maeda T, Shintani Y, Miyamoto H, Kawagoe H, Nakano K, Nishiyama A, Yamada Y. Prophylactic effect of inactivated influenza vaccine on young children. Pediatr Int 2002; 44:43-6. [PMID: 11982870 DOI: 10.1046/j.1442-200x.2002.01503.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The effectiveness of inactivated influenza vaccine in healthy infants and young children has been controversial. The aim of this study was to determine the prophylactic effect of inactivated influenza vaccine in young children. METHODS Eighty-six healthy infants and children younger than 7-years-old were immunized by a subcutaneous injection of inactivated influenza vaccine before the 1999/2000 influenza season. Ninety-four age-matched children were randomly assigned as the control. These children were followed-up from January to April, 2000. A diagnosis of influenza A virus infection was made rapidly by a positive result of the the enzyme immunoassay membrane test using enzyme-conjugated monoclonal antibodies specific for a conserved epitope of influenza A nucleoprotein. The incidence of influenza A infection was compared and statistically assessed. RESULTS The prevalence of influenza A virus infection, diagnosed by the influenza A rapid detection test, was 5.8% in the vaccine group and 17.0% in the control group, that is significantly lower in the vaccine receiving group than the non-receiving group (P = 0.016). However, four out of five infected children in the vaccine group were younger than 2-years-old. CONCLUSION We conclude that inactivated influenza vaccine reduces the incidence of influenza A virus infection in 2-6-year-old children.
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Affiliation(s)
- Taro Maeda
- Department of Pediatrics, Public Shisou General Hospital, Sikazawa 93, Yamasaki-Cho, Shisou-Gun, 671-2576 Hyogo, Japan.
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Alexander R, Lamb D, White D, Wentzel T, Politis S, Rijnsburger J, van Ruyven D, Kelly N, Garland SM. 'RETCIF': a rapid, sensitive method for detection of viruses, applicable for large numbers of clinical samples. J Virol Methods 2001; 97:77-85. [PMID: 11483219 DOI: 10.1016/s0166-0934(01)00344-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rapid detection of viruses in clinical samples is important for continuing appropriate antiviral treatment and discontinuing unnecessary antibacterial treatment, as well as for excluding viral pathogens. Yet detection of viral agents may require numerous susceptible cell lines. Even with the shell vial culture method, it is cumbersome for handling large volumes of specimens. A procedure has been developed, which is time and cost-saving and uses specific cell lines in a 96-well microtitre plate and monoclonal antibodies (RETCIF-rapid enhanced tissue culture immunofluorescence). Each clinical sample was inoculated into 12 different wells with five different cell lines. Enhancement was achieved by sonication, centrifugation and hormonal supplementation to the medium used. Cytomegalovirus (CMV), herpes simplex virus (HSV) and respiratory viruses were detected by monoclonal antibodies on day 2, whilst varicella zoster virus (VZV) and enteroviruses were detected on days 5 and 7, respectively. During July-December 1998, 3298 patient specimens were compared by RETCIF and a modified shell vial method. Either or both methods isolated 779 viruses (24% positivity rate), whilst both methods detected 621. Of the 779 viruses, 87% (679) were isolated by the shell vial method in an average time of 4.9 days. For RETCIF the respective rate was 92.5% (721), in an average time of 3.0 days. The RETCIF method is a time-saving procedure, with higher isolation rates than the shell vial method.
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Affiliation(s)
- R Alexander
- Department of Microbiology & Infectious Diseases, Women's & Children's Health Care Network, Royal Children's Hospital, Flemington Road, Parkville, 3052, Vic., Melbourne, Australia.
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40
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Simor AE. The role of the laboratory in infection prevention and control programs in long-term-care facilities for the elderly. Infect Control Hosp Epidemiol 2001; 22:459-63. [PMID: 11583217 DOI: 10.1086/501935] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Hospital infection prevention and control programs rely extensively on diagnostic microbiology laboratory testing. However, specimens for microbiological evaluation are less likely to be obtained from elderly residents of long-term-care facilities (LTCFs). In this article, issues regarding laboratory utilization and the potential role of the microbiology laboratory in infection prevention and control programs in LTCFs are reviewed. The role of the laboratory in infection surveillance, in the management of antimicrobial resistance, and in outbreak investigation are highlighted.
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Affiliation(s)
- A E Simor
- Department of Microbiology, Sunnybrook and Women's College Health Sciences Centre, North York, Ontario, Canada
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41
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Laurel VL, De Witt CC, Geddie YA, Yip MC, Dolan DM, Canas LC, Dolan MJ, Walter EA. An outbreak of influenza a caused by imported virus in the United States, July 1999. Clin Infect Dis 2001; 32:1639-42. [PMID: 11340538 DOI: 10.1086/320513] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2000] [Revised: 09/05/2000] [Indexed: 11/03/2022] Open
Abstract
We report 32 cases of culture-proven influenza A (A/Sydney) caused by virus imported into mainland US military barracks from Puerto Rico in July 1999. Despite the fact that the shelf life of the influenza vaccine is 18 months and that the outbreak strain was a component of the previous year's vaccine, no vaccine was available from manufacturers, owing to US Food and Drug Administration regulations. Formal consideration should be given to extending the date of expiration and to maintaining a supply of the influenza vaccine year-round.
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Affiliation(s)
- V L Laurel
- Division of Infectious Diseases, Department of Medicine, Wilford Hall Medical Center, Lackland Air Force Base, TX 78236-5300, USA.
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43
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Swenson SL, Vincent LL, Lute BM, Janke BH, Lechtenberg KE, Landgraf JG, Schmitt BJ, Kinker DR, McMillen JK. A comparison of diagnostic assays for the detection of type A swine influenza virus from nasal swabs and lungs. J Vet Diagn Invest 2001; 13:36-42. [PMID: 11243361 DOI: 10.1177/104063870101300108] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Nasal swabs and lung samples from pigs experimentally infected with H1N1 swine influenza virus (SIV) were examined for the presence of SIV by the indirect fluorescent antibody assay, immunohistochemistry, cell culture virus isolation, egg inoculation, and 2 human enzyme immunoassays (membrane enzyme immunoassay, microwell enzyme immunoassay). Egg inoculation was considered to be the gold standard for assay evaluation. The 2 human enzyme immunoassays (EIA) and egg inoculation agreed 100% for the prechallenge nasal swabs. Agreement on SIV identification in nasal swabs with egg inoculation following challenge was considered to be good to excellent for membrane EIA (kappa = 0.85) and microwell EIA (kappa = 0.86). Agreement on SIV identification in lung tissue with egg inoculation following challenge was good to excellent for membrane EIA (kappa = 0.75), fair for microwell EIA, fluorescent antibody, and cell culture virus isolation (kappa = 0.48, 0.64, 0.62, respectively), and poor for immunohistochemistry (kappa = 0.36). No assay was 100% accurate, including the "gold standard," egg inoculation. In light of this information, it is important to consider clinical signs of disease and a thorough herd history in conjunction with diagnostic results to make a diagnosis of SIV infection.
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Vabret A, Sapin G, Lezin B, Mosnier A, Cohen J, Burnouf L, Petitjean J, Gouarin S, Campet M, Freymuth F. Comparison of three non-nested RT-PCR for the detection of influenza A viruses. J Clin Virol 2000; 17:167-75. [PMID: 10996113 DOI: 10.1016/s1386-6532(00)00095-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The viral isolation technique (VIT) is largely used as a gold standard for the detection of influenza A and B viruses in respiratory samples. Some recent studies have pointed out that the polymerase chain reaction (PCR) assays allow sensitive and rapid detection of influenza viruses, also providing excellent correlation with traditional methods. OBJECTIVES AND DESIGN STUDY The aim of this study was to evaluate the efficiency of three non-nested PCR, two PCR-hybridization assays using primers defined in M and NS genes, and one PCR which uses primers defined in NP, NS and HA genes and combines the detection of H3N2 and H1N1 hemagglutinin genes using defined primers in NP, NS and HA genes (PCR3), in comparison with an IF assay (IFA) and viral isolation technique (VIT). The study was carried out on 244 nasal samples collected mainly by practitioners of the GROG surveillance network during winter 1998-1999 for the detection of influenza A virus. RESULTS Overall influenza viruses were detected more frequently by PCR techniques in 157 (64.3%), 147 (60.2%), 110 (45%) cases for PCR1, PCR2, PCR3, respectively, than by VIT or IFA, in 100 (40.9%) and 74 (30.3%) cases, respectively. Taking the positive culture samples as a reference, 100 (41.8%) samples were found to be positive for influenza A, and the sensitivity of IFA, PCR 1, PCR 2 and PCR3 techniques were 70, 100, 99, and 90%, respectively as compared with viral isolation cultures. On the other hand, as 86.5% of positive samples were positive with at least two different techniques, the sensitivity, specificity, VPP and VPN of each technique were recalculated taking into account a further criterion defining a positive sample: positivity with two techniques. We observe that techniques PCR 2 and particularly PCR 1 have very good sensitivity, respectively 98.6 and 100%, far better than the traditional techniques, IFA and culture, whilst maintaining acceptable specificity: 94.1 and 86.1%, respectively. In both cases they enable 141 (57.7%) A-positive influenza samples to be detected instead of the 100 (40.9%) obtained when culture is the reference test. IFA, culture and PCR 3 are highly specific (VPP=100%), but in comparison with PCR 1 and 2 their sensitivity, respectively 51.7, 69. 9, 77.6%, and negative predictive value are unsatisfactory. PCR 1 and 2 are superior to the other techniques to a statistically highly significant degree in terms of sensitivity, but the difference between the two is not significant.
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Affiliation(s)
- A Vabret
- Laboratory of Human and Molecular Virology, University Hospital, av. G. Clemenceau, 14033, Caen, France
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Abstract
Diagnostic virology has now entered the mainstream of medical practice. Multiple methods are used for the laboratory diagnosis of viral infections, including viral culture, antigen detection, nucleic acid detection, and serology. The role of culture is diminishing as new immunologic and molecular tests are developed that provide more rapid results and are able to detect a larger number of viruses. This review provides specific recommendations for the diagnostic approach to clinically important viral infections.
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Affiliation(s)
- G A Storch
- Departments of Pediatrics, Medicine, and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Abstract
BACKGROUND Few studies have examined the impact of rapid viral diagnostic tests on patient management. OBJECTIVE To assess the effect of rapid diagnosis of influenza A infections on patient management. METHODS The medical records of children with respiratory infections who were evaluated at a children's hospital between July 1, 1995, and June 30, 1997, were reviewed. Children (n = 56) evaluated in the Emergency Department (ED) who had a positive influenza A enzyme immunoassay (EIA) were compared with two control groups for the likelihood of admission, antibiotic use and duration of hospitalization and antibiotic administration. RESULTS Patients discharged from the ED with a positive EIA test were less likely to receive antibiotics than those with a negative EIA test (20% vs. 53%; P = 0.04). Patients admitted to the hospital with a positive EIA test were as likely to receive antibiotics as those without a rapid diagnosis, but the duration of antibiotic administration was significantly shorter in the group with a positive EIA test (3.5 vs. 5.4 days; P = 0.03). Patients with a positive EIA test also were more likely to receive antiviral therapy than either control group (25% vs. 0 and 1.8%; P < 0.001). CONCLUSIONS The detection of influenza A by EIA has a positive impact on medical management by decreasing antibiotic use in pediatric patients evaluated in an ED, by decreasing the duration of antibiotic use in hospitalized patients and by encouraging antiviral therapy.
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Affiliation(s)
- D E Noyola
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
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Noyola DE, Clark B, O'Donnell FT, Atmar RL, Greer J, Demmler GJ. Comparison of a new neuraminidase detection assay with an enzyme immunoassay, immunofluorescence, and culture for rapid detection of influenza A and B viruses in nasal wash specimens. J Clin Microbiol 2000; 38:1161-5. [PMID: 10699013 PMCID: PMC86363 DOI: 10.1128/jcm.38.3.1161-1165.2000] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The performance of a new, rapid, easy-to-perform assay based on neuraminidase enzyme activity for detection of influenza virus types A and B was compared to detection by culture, indirect immunofluorescence, and enzyme immunoassay in 479 nasal wash specimens from children with respiratory infections. Compared to isolation of influenza virus by culture, the neuraminidase assay had a sensitivity of 70.1%, specificity of 92.4%, positive predictive value of 76.3%, and negative predictive value of 89.9%. There was a higher sensitivity for the detection of influenza A virus (76.4%) than for influenza B virus (40.9%). Indirect immunofluorescence showed a sensitivity of 59.8% and specificity of 97% compared to culture isolation for detection of influenza A and B viruses. Enzyme immunoassay showed a sensitivity of 89.7% and specificity of 98.1% for the detection of influenza A alone. The quality of the nasal wash specimen had a significant effect on the detection of influenza virus by all of the assays. A strong response of the neuraminidase assay was more likely to represent a culture-confirmed influenza infection. This new rapid neuraminidase assay was useful for the detection of influenza A and B viruses in nasal wash specimens.
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Affiliation(s)
- D E Noyola
- Departments of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.
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Landry ML, Cohen S, Ferguson D. Impact of sample type on rapid detection of influenza virus A by cytospin-enhanced immunofluorescence and membrane enzyme-linked immunosorbent assay. J Clin Microbiol 2000; 38:429-30. [PMID: 10618134 PMCID: PMC88742 DOI: 10.1128/jcm.38.1.429-430.2000] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytospin-enhanced direct fluorescent-antibody assay (DFA) detected 49 (92.5%) and rapid membrane enzyme-linked immunosorbent assay (ELISA) detected 40 (75.5%) of 53 influenza virus A-positive samples. All 15 positive nasopharyngeal aspirates from children were detected by both tests. In contrast, 34 of 38 (89.5%) positive swabs from adults were detected by DFA, but only 25 (66%) were detected by ELISA.
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Affiliation(s)
- M L Landry
- Clinical Virology Laboratory, Yale New Haven Hospital, New Haven, Connecticut 06520, USA.
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Kaiser L, Briones MS, Hayden FG. Performance of virus isolation and Directigen Flu A to detect influenza A virus in experimental human infection. J Clin Virol 1999; 14:191-7. [PMID: 10614856 DOI: 10.1016/s1386-6532(99)00058-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Few data exist to assess the sensitivity of different specimen types for viral detection during the course of influenza virus infection. OBJECTIVES This study assessed the relationships between quantitative influenza A virus replication and antigen detectability by the enzyme immunosorbent assay (EIA) Directigen Flu A in different type of samples during experimental human infection. STUDY DESIGN Fourteen volunteers were inoculated with influenza A virus A/Texas/36/91 (H1N1). Four specimens types were collected in sequence for quantitative isolation in cell culture and antigen testing from days 1 to 8 after inoculation. RESULTS Seventy-one (63%) of nasopharyngeal wash specimens were culture positive, compared to 51 (46%) of throat gargles, 51 (46%) of nasal swabs, and 27 (24%) of throat swabs. All subjects shed virus in their nasopharyngeal wash at least one day and 86% of subjects had a positive nasopharyngeal wash culture on day 2 after inoculation. The mean viral titers were highest on day 2 post inoculation for all specimen types and averaged 3.6 log10 TCID50/ml for nasal washes, 1.2 log10 TCID50/ml for throat gargles, 1.8 log10 TCID50/ml for the nasopharyngeal swabs, and 0.6 log10 TCID50/ml for the throat swabs. Mean viral titers in the nasal washes were significantly different (P<0.05) compared to other specimen types. The peak of sensitivity of EIA (compared to culture) was the second day after inoculation. Nasopharyngeal and throat swab results were combined for this analysis and considered positive by culture if positive in either or both samples. Thus, on day 2 the number of EIA positive samples relative to the number culture positive was 9/12 (75%) for nasopharyngeal wash specimens, 2/9 (22%) for throat gargles, and 7/11 (64%) for the combined throat and nasal swabs specimens. CONCLUSIONS Nasopharyngeal washes are the most sensitive sample type detecting influenza A virus in adults. For rapid diagnosis the Directigen Flu A is an alternative with a sensitivity compared to culture ranging between 64 and 78% if performed on nasopharyngeal specimens on day two or three after experimental infection in adults. However, if performed on other specimens or later in the course of infection the sensitivity is lower.
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Affiliation(s)
- L Kaiser
- Department of Medicine, University of Virginia School of Medicine, Charlottesville 22908, USA.
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Bradley SF. Prevention of influenza in long-term-care facilities. Long-Term-Care Committee of the Society for Healthcare Epidemiology of America. Infect Control Hosp Epidemiol 1999; 20:629-37. [PMID: 10501266 DOI: 10.1086/501687] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Influenza is a frequent cause of epidemic and endemic respiratory illness in long-term-care facilities (LTCFs), resulting in considerable morbidity and mortality. Detection of influenza outbreaks in this setting can be difficult, because the clinical presentation in older adults is atypical and other pathogens also cause influenza-like illness (ILI) during the influenza season. Use of the standard case definition for influenza has not been effective in detecting episodes in residents of LTCFs. Alternative case-definitions that reflect the atypical presentation of influenza in this population have been recommended but not validated. The use of rapid tests for the detection of influenza in conjunction with more sensitive case definitions of ILI may lead to the earlier detection of influenza outbreaks in LTCFs, earlier initiation of infection control measures, and reduction in transmission. The definition of outbreak, eg, the number of episodes of ILI or episodes of confirmed influenza A that would result in the initiation of antiviral chemoprophylaxis, remains controversial in this setting. The use of newer antivirals could limit the side effects seen in older adults in LTCFs. However, annual vaccination of residents and staff remains the most effective way to prevent the introduction of influenza A or influenza B into LTCFs. In addition, vaccination of LTCF residents reduces rates of illness and pneumonia due to influenza, as well as cardiopulmonary exacerbation, hospitalization, and death.
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Affiliation(s)
- S F Bradley
- Department of Internal Medicine, Veterans' Affairs Health Systems, and University of Michigan Medical School, Ann Arbor 48105, USA
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