A Study of the Familial Spread of Hemophilus influenzae, Type B *

In 1931, Pittman5 recognized that a type specificity existed among invasive strains of Hemophilus influenzae and later demonstrated that strains from meningitis' almost invariably belonged to a single serological type which she designated type b. In 1939 Alexander', 2, developed a therapeutic type-specific rabbit serum which is highly effective against the type b influenza bacillus. We have become especially interested in this organism, since infections by it appear to be on the increase in this locality7 and because a specific therapy is now available. Accordingly, epidemiological methods were employed to determine the presence of H. influenzae, type b, in the upper respiratory tracts of familial members who had been exposed to a carrier of this organism. The carriers, sick or "healthy," were children who were admitted to the pediatric service of the New Haven Hospital, which during the past two years has had approximately 1,000 admissions yearly.