Submitted to: International Marek's Disease Symposium Abstracts and Proceedings
Publication Type: Proceedings
Publication Acceptance Date: September 7, 1996
Publication Date: N/A
Technical Abstract: Coincident with the establishment in 1959 of Federal poultry inspection, the United States Department of Agriculture began collecting statistics on causes of condemnation of poultry at slaughter. Statistics on young chickens document a dramatic rise of condemnations for "leukosis" (the term employed for Marek's disease (MD) tumors) in broiler chickens during the 1960's. This increase occurred first in the Delmarva region but soon spread to other states. Peak incidence occurred in 1970, when losses exceeded 4% in certain states. Following the introduction of vaccines, condemnations subsided dramatically. These statistics represent a valuable tool to determine trends in disease incidence for MD but need to be interpreted with caution.