STUDIES ON INFLUENZA IN THE PANDEMIC OF 1957-1958. III. ISOLATION OF INFLUENZA A (ASIAN STRAIN) VIRUSES FROM INFLUENZA PATIENTS WITH PULMONARY COMPLICATIONS. DETAILS OF VIRUS ISOLATION AND CHARACTERIZATION OF ISOLATES, WITH QUANTITATIVE COMPARISON OF ISOLATION METHODS*

Abstract

Influenza A virus (Asian strain) was isolated from 14 patients with influenza who exhibited pulmonary complications. From 4 fatal cases it was recovered directly from lung tissue to the exclusion of any other pathogen. From 3 fatal cases virus was recovered from the lung coincident with the recovery of pneumococci or staphylococci. With the viruses studied, the chick embryo proved the most susceptible host and the allantoic route of inoculation of this host equaled the amniotic route in sensitivity. Limited studies failed to demonstrate differences in toxicity, hemagglutination capacity or morphology of isolates from fatal and nonfatal cases.