Infection with Influenza and Parainfluenza Viruses in Cronic Bronchitis.

Exacerbations of chronic bronchitis are often preceded by symptoms of infection of the upper respiratory tract, but little is known of the frequency with which they are precipitated by virus infections. There is evidence that bronchitics develop severe illness when infected with influenza A virus (Tyrrell, 1952; Walker, Douglas, Leckie, Pines, and Grant, 1958; Louria, Blumenfeld, Ellis, Kilbourne, and Rogers, 1959) and that the features of the influenzal illness may be modified by the pre-existing chronic bronchitis. Hennessy (1962) and Jack and Gandevia (1960) failed to demonstrate a viral aetiology for the exacerbations of bronchitis in the patients they studied. More recently, Sommerville (1963) found serological evidence of infection with respiratory syncytial virus in bronchitics in exacerbation. Carilli, Gohd, and Gordon (1964) obtained evidence of infection with many respiratory viruses, including influenza and parainfluenza, during a six-month study of 30 bronchitics. However, both virus infections and exacerbations of bronchitis are common occurrences, and some studies, such as that of Carilli et al. (1964), though demonstrating a high incidence of virus infections in bronchitics, have not shown that such infections are more frequent at the time of exacerbation. The parainfluenza viruses were first isolated from children with acute respiratory disease in 1955 and 1957, and the clinical syndromes associated with them in childhood have been well defined (Parrott, Vargosko, Luckey, Kim, Cumming, and Chanock, 1959). They probably account for a high proportion of all acute respiratory infections of children, but less is known of the frequency and effect of infection in adults. In most cases a mild upper respiratory illness seems to occur, but acute bronchitis and pneumonia have been reported (Evans, 1960; Evans and Brobst, 1961). In this investigation we have tried to assess the importance of the influenza and parainfluenza viruses in causing acute illness among a group of typical chronic bronchitics during the winter of 1961-62.