Patrick C Reading1, Vivian K Leung2, Iwona Buettner2, Leah Gillespie2, Yi-Mo Deng2, Robert Shaw2, Natalie Spirason2, Angela Todd2, Aparna Singh Shah3, Frank Konings4, Ian G Barr2. 1. WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, 3000, Australia. Electronic address: Patrick.Reading@influenzacentre.org. 2. WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, 3000, Australia. 3. Health Laboratory Services and Blood Safety - Communicable Diseases Department, World Health Organization Regional Office for the South East-Asia, New Delhi, India. 4. World Health Organization Health Emergencies Programme, Country Health Emergency Preparedness and International Health Regulations, World Health Organization Regional Office for the Western Pacific, Manila, Philippines.
Abstract
BACKGROUND: The isolation and propagation of influenza viruses from clinical specimens are essential tools for comprehensive virologic surveillance. Influenza viruses must be amplified in cell culture for detailed antigenic analysis and for phenotypic assays assessing susceptibility to antiviral drugs or for other assays. OBJECTIVES: To conduct an external quality assessment (EQA) of proficiency for isolation and identification of influenza viruses using cell culture techniques among National Influenza Centres (NICs) in the World Health Organisation (WHO) South East Asia and Western Pacific Regions. STUDY DESIGN: Twenty-one NICs performed routine influenza virus isolation and identification techniques on a proficiency testing panel comprising 16 samples, containing influenza A or B viruses and negative control samples. One sample was used exclusively to determine their capacity to measure hemagglutination titer and the other 15 samples were used for virus isolation and identification. RESULTS: All NICs performed influenza virus isolation using Madin Darby canine kidney (MDCK) or MDCK-SIAT-1 cells. If virus growth was detected, the type, subtype and/or lineage of virus present in isolates was determined using immunofluorescence, RT-PCR and/or hemagglutination inhibition (HI) assays. Most participating laboratories could detect influenza virus growth and could identify virus amplified from EQA samples. However, some laboratories failed to isolate and identify viruses from EQA samples that contained lower titres of virus, highlighting issues regarding the sensitivity of influenza virus isolation methods between laboratories. CONCLUSION: This first round of EQA was successfully conducted by NICs in the Asia Pacific Region, revealing good proficiency in influenza virus isolation and identification.
BACKGROUND: The isolation and propagation of influenza viruses from clinical specimens are essential tools for comprehensive virologic surveillance. Influenza viruses must be amplified in cell culture for detailed antigenic analysis and for phenotypic assays assessing susceptibility to antiviral drugs or for other assays. OBJECTIVES: To conduct an external quality assessment (EQA) of proficiency for isolation and identification of influenza viruses using cell culture techniques among National Influenza Centres (NICs) in the World Health Organisation (WHO) South East Asia and Western Pacific Regions. STUDY DESIGN: Twenty-one NICs performed routine influenza virus isolation and identification techniques on a proficiency testing panel comprising 16 samples, containing influenza A or B viruses and negative control samples. One sample was used exclusively to determine their capacity to measure hemagglutination titer and the other 15 samples were used for virus isolation and identification. RESULTS: All NICs performed influenza virus isolation using Madin Darby canine kidney (MDCK) or MDCK-SIAT-1 cells. If virus growth was detected, the type, subtype and/or lineage of virus present in isolates was determined using immunofluorescence, RT-PCR and/or hemagglutination inhibition (HI) assays. Most participating laboratories could detect influenza virus growth and could identify virus amplified from EQA samples. However, some laboratories failed to isolate and identify viruses from EQA samples that contained lower titres of virus, highlighting issues regarding the sensitivity of influenza virus isolation methods between laboratories. CONCLUSION: This first round of EQA was successfully conducted by NICs in the Asia Pacific Region, revealing good proficiency in influenza virus isolation and identification.