THE EPIDEMIOLOGY OF ACUTE RESPIRATORY DISEASES

Abstract

In a study on the natural histories of infection from viruses associated with respiratory infections, answers were sought for two principal questions: a) when, during the life history of individuals, and b) how often was primary infection with each virus acquired? In 1957, 25 infants, 6 weeks of age, and in 1958, 107 family associates were entered into a study that lasted 2½ years and that was principally designed to measure seropositive and seroconversion rates for 19 respiratory viruses, and the primary atypical pneumonia agent. During an epidemic of influenza type A" the entire population was at risk; 75% of infants, and all adults converted. Other respiratory viruses associated with high conversion rates during infancy and often continuing into childhood were HA types 1 and 2, Sendai, ECHO type 11, RS, CA, and adenovirus types 1, 2 and 5. For many of these viruses all, or a majority, of members of families were seropositive. Influenza types B and C viruses were associated with sporadic family outbreaks during 1958-1959. Other viruses, namely, influenza types A and A, Coe, ECHO virus types 10, 20, 25 and 28, and the agent of primary atypical pneumonia were associated with low conversion rates at any specified age. The risk of acquiring infection from adenoviruses indicated gradual recruitment of susceptibles at discrete intervals; adenoviruses (types 1 and 5) were present in the oropharynx of seropositive children; their presence was not always associated with appearance of demonstrable antibodies.