A transovarian transmission study of Marek's disease in Japanese quail

Experiments were conducted to determine if transovarian transmission of the JM strain of Marek's disease virus (MDV) occurs in Japanese quail. In one experiment, parent quail were infected with MDV when one-day-old; in another experiment, parent quail were infected when seven weeks old. No precipitating antigen or cytopathic or infective agent was isolated from the egg yolks, embryos, newly hatched quail, or progeny quail of the infected parents. During the eight weeks observation period, the progeny of infected parents showed no clinical symptoms, mortality, gross or microscopic lesions, MD viremia, or antibody. However, an MD-specific fluorescent antigen was observed in fibroblast and kidney cell cultures from embryos of parents infected at one day of age. Approximately 10% of the embryos contained this fluorescent antigen. Fluorescent antigen was not observed in cultures from embryos of quail infected at the age of seven weeks or control quail.