Submitted to: United States Middle East Symposium on Animal Health Issues
Publication Type: Abstract Only
Publication Acceptance Date: April 28, 1995
Publication Date: N/A
Technical Abstract: The four avian viral tumors include Marek's disease (MD), caused by a herpesvirus, and lymphoid leukosis (LL), reticuloendotheliosis (RE) and lymphoproliferative disease (LPD), each caused by retroviruses. Chickens are susceptible to MD, LL and RE, whereas RE and LPD occur in turkeys. Although the viruses are distinct, the diseases have similar or overlapping gclinical, pathologic, and epidemiologic features. In the United States, MD ranked second in importance among diseases of both layers and broilers in 1994 and seems to be increasing in frequency. Avian leukosis virus (ALV), the causative agent of LL, has been nearly eradicated in layers but has reemerged as an issue in broiler breeders. Although RE virus is widely distributed, it is rarely associated with clinical disease except in one case where a contaminated fowlpox vaccine was administered to 7-day-old chickens. LPD is not known to occur in the United States. The Middle East tand the United States have complementary opportunities and expertise to solve immediate issues such as the spread and eradication of REV infection, the diagnosis and eradication of subgroup J avian leukosis virus, and the erosion of vaccine efficacy for MD. Benefits from such endeavors should favorably impact poultry production in these and other countries.