Further Studies Upon the Etiology of Measles.

Abstract

In a previous communication 1 we reported having obtained in pure culture a hemophilic diplococcus from the unfiltered blood of human measles, which apparently was identical to the coccus isolated by Tunnicliff 2 and similar in some respects to the coccus described later by Coronia. 3 These workers regard their respective isolation as the active exciting agent in measles. In our earlier report we reserved opinion regarding the possible causal relation that the coccus might bear to measles, inasmuch as it was obtained from the unfiltered blood, and did not conform with our conception of the excitant of measles (filterable virus).

A recent epidemic of measles in New Orleans has afforded the opportunity to make further studies concerning the incidence of this coccus in the disease.

Blood was secured by veni-puncture from 6 children in the active eruptive stage of measles, and immediately defibrinated. Within 3 hours after the blood was collected 1 cc. portions of both filtered and unfiltered was cultured upon a variety of nutrient media. At the same time rabbits were intravenously inoculated with 1 cc. quantities of the filtered and unfiltered measles blood. The purpose of the animal injections was to serve as controls upon the infectiousness of the blood employed, and also to attempt the cultivation of the coccus in question from the blood of those reacting to the inoculation.

The special nutrient medium which was found most suitable for the initial growth of the coccus was semi-solid sheep serum agar, which had been prepared in tall sterile tubes, and the reaction adjusted to approximately 0.6 per cent acid to phenothalein. The culture medium was inoculated with the measles blood by means of a long fine capillary pipette. This was introduced to the bottom of the culture tube and the content slowly ejected from the pipette as it was withdrawn through the column of medium.