Abstract
Inasmuch as immunity to various diseases is often found among persons in whom no previous exposure to infection has been established, several authors have postulated the existence of a physiological process of “serological ripening” to explain this phenomenon. 1 , 2 , 3 , 4 , 5
The widespread immunity to diphtheria among Eskimos was repeatedly quoted as an instance of such phenomenon and seemed particularly suitable for study. Materials collected by one of us (P.H.) from 7 groups of these people in 1930 were examined, and the results already reported 6 indicated that it was a true antitoxic immunity, and suggested the importance of carriers. Additional materials were collected in 8 such communities during the summer of 1931 by one of us (P.H.) and examined.
From the 214 available throat cultures, 34 strains of diphtherialike organisms were, isolated, but it was not possible to demonstrate toxin production at the time of isolation (after 60-80 days maintenance on artificial media). Three strains were morphologically and culturally typical (apparently “R”) organisms, while the remainder gave atypical fermentation reactions. The throat flora in general was similar to that found in persons living in other latitudes. 7 , 8
The results of Schick tests (Table I) and serum antitoxin titrations (Table II) showed in general a somewhat higher incidence of susceptibility (Schick positive) than is found among persons living in regions where clinical diphtheria is more common. This is seen by a comparison of these results with the included Schick figures, compiled from von Groer's data 9 for Vienna and the antitoxin titrations of a St. Louis group, respectively.
In the few instances (18) where the amount of serum available was sufficient, adequately controlled complement-fixation tests were performed by the method of Krah and Witebsky, 10 using a lecithinized alcoholic extract of a mixture of 8 known virulent strains of C. diphtheriae.
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