MULTIPLEX REVERSE TRANSCRIPTION PCR FOR SURVEILLANCE OF INFLUENZA-A AND INFLUENZA-B VIRUSES IN ENGLAND AND WALES IN 1995 AND 1996

Multiple-target (multiplex) reverse transcription-PCR (RT-PCR) for det ection, typing, and subtyping of tile hemagglutinin gene of influenza type A (H3N2 and H1N1) and type B viruses was developed and applied pr ospectively to virological surveillance of influenza in England in the 1995-1996 winter season, During this season both influenza A H3N2 and H1N1 viruses were circulating, although at different times. Six hundr ed nineteen combined nose and throat swabs taken by general practition ers in sentinel practices from individuals presenting with ''influenza like illness'' were analyzed by culture, multiplex RT-PCR, and immunof luorescence. Of the 619 samples, 246 (39.7%) mere positive by multiple s RT-PCR compared with 200 (32.3%) which yielded influenza viruses on culture, There was 100% correlation between multiplex RT-PCR typing an d subtyping and the influenza types acid subtypes obtained from cultur e, There was also excellent correlation between the temporal detection of influenza A H3N2 and H1N1 viruses by multiplex RT-PCR and by cultu re, During tile peak weeks of influenza virus activity, a total of 259 specimens were received, of which 101 (38.9%) yielded influenza virus es on culture while 149 (57.5%) were positive in multiples RT-PCR, pro viding an increase in detection of influenza viruses of approximately 20%. The increased detection of influenza virus occurred in all the ag e groups sampled. Samples which were positive by multiplex RT-PCR but negative by culture sere not detected significantly earlier or later i n the winter of 1995-1996 but were detected during the peak weeks of c linical influenza virus activity, Multiplex RT-PCR was successfully us ed in surveillance of influenza to provide accurate, sensitive diagnos is directly on clinical specimens sent through the post.