SURVEILLANCE OF RESPIRATORY VIRUSES - A 10-YEAR LABORATORY-BASED STUDY

Respiratory virus isolates made at the National Institute for Virology from 1982 to 1991 were studied. An active virus surveillance programm e, 'viral watch', which recruits throat swab specimens from a network of monitoring centres - mainly in the Witwatersrand and Vereeniging ar ea with one centre in Middelburg - that represent a cross-section of t he population, provided 68% of the specimens and 74% of the isolates, with an isolation rate of 25,5%. This was significantly higher than th at of routine specimens (17,7%). Of the 966 isolates, influenza viruse s accounted for 527 (54,7%), para-influenza for 122 (12,6%), respirato ry syncytial virus for 34 (3,4%) and adenovirus for 106 (11,0%). Influ enza viruses showed a definite seasonal peak between June and August w hereas the other viruses, although they showed a winter predominance, were isolated throughout the year. An active virus surveillance progra mme is particularly valuable in monitoring respiratory virus epidemiol ogy in the population.