Program Schedule

1484
Detection of Respiratory Syncytial (RSV) and Influenza Viruses in Children with WHO Defined Pneumonia and Controls from Oshikhandass Village, Gilgit-Baltistan, Northern Pakistan from 2012-2014; Sensitivity and Specificity of Rapid Tests vs. PCR

Session: Poster Abstract Session: Global Infectious Diseases
Saturday, October 11, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
Posters
  • 1484_IDWPOSTER.pdf (1.3 MB)
  • Background: Rapid viral diagnostic tests are commonly used to determine presumptive etiology of respiratory infections. Methods: From 2012-2014, weekly surveillance of 1,176 children <5 years was conducted in Oshikhandass, a remote site with extreme winter and summer temperatures and 24 hours from reference labs. Nasopharyngeal (NP) swabs (Copan® Flocked Ultra Mini Tip) were collected from 233 children with WHO defined pneumonia and 66 controls for local rapid testing, followed by transport in PrimeStore® medium for PCR testing at reference labs. From Apr 2012-Jan 2013, rapid tests were conducted using QuickVue® and from Jan 2013-Mar 2014 using Sofia FIA®.  The Luminex® platform was used from Apr 2012-Nov 2013 at AKU, Karachi, and the Taqman® Real Time PCR method from Dec 2013-Mar 2014 at NIH, Islamabad. Reported sensitivity/specificity for QuickVue® vs. cell culture is 92/92% for RSV, 83/89% for Influenza A and 62/98% for Influenza B; for Sofia these are, 100/96%, 97/95% and 90/97%, respectively. Results: Using PCR results as the gold standard, sensitivity/specificity of the various assays were compared:

     

    QuickVue & Luminex
    N = 60

    Sofia & Luminex
    N = 186

    Sofia & Taqman
    N = 42

    Sens

    Spec

    Sens

    Spec

    Sens

    Spec

    Inf A

    0%

    100%

    0%

    96%

    100%

    86%

    0/6

    53/53

    0/1

    174/181

    1/1

    32/37

    Inf B

    N/A

    100%

    100%

    91%

    100%

    89%

    0/0

    59/59

    1/1

    164/180

    1/1

    33/37

    RSV

    0%

    96%

    37%

    94%

    26%

    74%

    0/11

    47/49

    10/27

    149/159

    6/23

    14/19

    QuickVue® sensitivity was low for all 3 viruses.  The number of influenza A and B positive results were too low to calculate sensitivity meaningfully.  Sensitivity of the RSV Sofia® test was low when compared with Luminex® and Taqman®, while specificity for RSV was 74-94%, Influenza A 86-100% and influenza B 89-100%.  Conclusion: Possible reasons for poor sensitivity include low influenza circulation in the community and modest sample size. Other factors may be the inability to maintain controlled temperatures (15oC-30oC) for the kits and equipment in winter and summer month field conditions, and remoteness of reference labs.  Development of diagnostic tests that maintain stability and function over extended time periods and within a wide range of temperatures is essential to provide reliable results for appropriate and timely management of respiratory illness in resource poor environments.

    Positive rapid test and PCR results by month

    Zeba Rasmussen, MD, MPH1, Julia M. Baker, MPH1, Assis Jahan, MSc1, Uzma Bashir Aamir, MBBS, MPhil2, Fatima Aziz, MSc3, Shahida M. Qureshi, MSc3, Syed Iqbal Azam, MSc4, Syed Sohail Zahoor Zaidi, MPhil, MSc5, Khalil Ahmed, PhD, MSc6, Cecile Viboud, PhD1 and Stacey Knobler, MSc1, (1)Division of International Epidemiology and Population Studies, National Institutes of Health, Fogarty International Center, Bethesda, MD, (2)Department of Virology and Immunology, National Institute of Health, Islamabad, Pakistan, (3)Department of Paediatrics and Child Health, Aga Khan University, Karachi, Pakistan, (4)Department of Community Health Sciences, Aga Khan University, Karachi, Pakistan, (5)National Institute of Health, Islamabad, Pakistan, (6)Department of Biological Sciences, Karakoram International University, Gilgit, Pakistan

    Disclosures:

    Z. Rasmussen, None

    J. M. Baker, None

    A. Jahan, None

    U. B. Aamir, None

    F. Aziz, None

    S. M. Qureshi, None

    S. I. Azam, None

    S. S. Z. Zaidi, None

    K. Ahmed, None

    C. Viboud, None

    S. Knobler, None

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