INFLUENZA-A VIRUS-INDUCED ACUTE OTITIS-MEDIA

To better understand the significance of viral upper respiratory tract infections in the pathogenesis of acute otitis media (OM), 27 adults underwent intranasal inoculation with influenza A virus, Monitoring co nsisted of antibody titer determination, tympanometry, and otoscopy. M icrobiologic analysis consisted of cultures and polymerase chain react ion (PCR)-based detection for influenza A virus, Streptococcus pneumon iae, Haemophilus influenzae, and Moraxella catarrhalis. All subjects b ecame infected with the challenge virus. By day 4, 16 (59%) developed middle ear pressures of -100 mm H2O or below and 4 (25%) of them devel oped OM. One subject (4%) developed purulent OM requiring myringotomy for pain relief. Middle ear effusion cultures were negative. PCR analy sis of that subject's middle ear effusion and nasal washes were positi ve for influenza A virus and S. pneumoniae. These findings support a c ausal role for viral upper respiratory tract infections in the pathoge nesis of OM, possibly mediated by middle ear underpressures and viral and bacterial middle ear infection.