CHARACTERISTICS OF PARA-INFLUENZA 1 (HA-2) VIRUS

Abstract

During 1958 and 1959, 2.6% of upper respiratory disease among selected adult populations (military personnel, college students and industrial workers) in southern Louisiana and Mississippi was attributable to para-influenza 1 (HA-2) virus. The cases were not found in apparent epidemics but were distributed evenly throughout the fall and winter months. The at-tack rate differed very slightly from one group to another. Sixteen strains of para-influenza 1 virus, all closely related antigenically to the hemadsorption type 2 strain, were isolated from gargling fluids in primary monkey-kidney tissue cultures. The virus was easily detected in first passage by either hemadsorption or hemagglutination. Para-influenza 1 HI antibody was found in the sera of 93% of adults who were not afflicted with para-influenza 1 infection; titers above 1 in 8 were noted in 52% of this population. In contrast, none of the infected persons had titers above 1 in 8. Illness associated with para-influenza 1 infection were usually relatively mild and afebrile. Most patients had considerable malaise with nasal congestion and sore throat.