Abstract
During 1963 (January through April) 96 children with pseudocroup in Gothenburg were virologically investigated by means of isolation attempts from throat swabs and faecal specimens. Paired sera obtained from 51 cases were tested for complement-fixing antibodies against parainfluenza, influenza and adeno virus antigens. Evidence for infection with parainfluenza 1 virus was obtained in 18 cases, parainfluenza 2 in 2, influenza A in 5 and adenovirus in 2 cases. In most clinical respects the cases with evidence of the different viral infections were similar to those with unknown etiology.