Rhinovirus Infections in an Industrial Population. Iv. Infections Within Families of Employees During Two Fall Peaks of Respiratory Illness1

Recurrent fall epidemics of rhinovirus respiratory illness have occurred in office workers in Charlottesville. Employee families were investigated during two consecutive fall outbreaks to delineate the role of children in the spread of colds into and in the home. School openings did not apear to be the determining factor in the timing of the illness peaks, although school children frequently introduced rhinoviruses into families. Rhinoviruses were isolated from 21% of children with respiratory disease in September, 1966. One-half of the rhinovirus-positive children yielded virus from nasal secretion samples but not from simultaneously collected throat secretions. Three-fourths of rhinovirus-positive individuals had a fourfold or greater rise to the homologous or a homotypic virus strain. In addition, 40% of persons exposed to a rhinovirus within the family who had a virus-negative illness had a serum antibody rise to the family's rhinovirus serotype. Twenty % of rhinovirus infections detected in the families were diagnosed only with serology. Rhinovirus serum neutralizing antibody tilers of 8 or greater were associated with protection from infection after natural exposure to rhinoviruses within the home. Identifiable agents other than rhinoviruses did not cause an important amount of respiratory illness in these early fall studies, although some infections with enteroviruses were seen.