Comparative results of respiratory virus isolation attempts in chorioallantoic membrane fragments and embryonated chicken eggs.

Attempts performed with 39 samples of nasopharyngeal secretion resulted in the isolation of 21 (54%) hemagglutinating viral agents in chorioallantoic membrane (CAM) fragments, while a single strain (2.5%) was isolated in the embryonated egg. The time interval required for virus isolation in CAM fragments ranged from 4 to 20-24 days and was longer then 10 days in the embryonated egg. Maintenance of CAM fragments in roller tubes leads to a more abundant virus multiplication and, implicitly, to a reduction of the time interval necessary for virus isolation.