PNEUMOCOCCIC INFECTIONS IN FAMILIES 1

Abstract

Study of 33 groups of multiple cases of pneumococcic infections indicated that they resulted from contact with an antecedent case. With 2 exceptions, these infections occurred in families. 23 of the groups included 54 individuals ill of pneumococcic infections of homologous types. The majority of infections occurred in less than 14 days after exposure and were of similar severity. Types I and II pneumo-cocci were most frequent but a significant proportion was due to type-specific pneumococci formerly classified in Group IV. Instances of empyema, primary meningitis, acute otitis media, simple upper respiratory tract infections, and bronchopneumonia were encountered in which the causative pneumococcus was of the same type as that which gave rise to lobar pneumonia in other members of the family.