Abstract
Acute respiratory infections constitute the commonest cause of illness,1 yet progress in the identification of the viruses responsible for the great majority of these poorly differentiated infections has been slow and tedious. Isolation of the adenoviruses 2-4 represented the first significant contribution to the specific definition of the etiology of the common respiratory diseases since the discovery of the influenza viruses. The studies summarized by the papers of this symposium were all done during the last four years, and the scope of the data indicates how much has been achieved in this short period of time. The adenoviruses comprise a group of agents possessing a common complementfixing antigen, the group being separable into different types through the use of specific neutralizing antisera.5 Types 4 and 7 have been related etiologically to an important respiratory disease of military recruits, acute respiratory disease (ARD),2,6-8 a discovery which has permitted