A Study on the Epizootiology of Newcastle Disease (Pneumoencephalitis)

NEWCASTLE disease has spread rapidly in the U. S. since its first recognition. The means by which the disease has spread is not clearly understood. Hatcheries have been incriminated in disseminating Newcastle disease. DeLay (1947) isolated Newcastle disease (pneumonecephalitis) virus from eggs and chicks hatched from eggs laid by an infected flock. Jungherr (1947) has isolated Newcastle virus from yolks of eggs from presumably recovered hens. The present study was made in cooperation with a large hatchery in Iowa to determine what part the hatchery might play in the spread of Newcastle disease. The objectives were to determine the presence or absence of Newcastle disease virus in (1) eggs laid by hens during the decline in production and in (2) first eggs laid by hens during their return to production after recovery from Newcastle disease infection. The study was made on three large breeding flocks where Newcastle disease was diagosed . . .