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United States Department of Agriculture

Agricultural Research Service

Title: Update on the Viruses of Myeloid Leukosis

Author
item Fadly, Aly

Submitted to: International Seminar of Avian Pathology
Publication Type: Proceedings
Publication Acceptance Date: May 26, 1998
Publication Date: N/A

Interpretive Summary: Infection with a new subgroup of avian leukosis virus (ALV) termed ALV-J, previously not identified in flocks in the U.S., was diagnosed in several broiler and broiler breeder flocks experiencing a cancer-like disease known as myeloid leukosis. Using biological as well as molecular assays, we have isolated and identified several strains of ALV-J from samples submitted from affected flocks. Virological and serological surveys suggested that infection with ALV-J is widespread in affected meat-type chickens. Further, transmission experiements revealed that unlike other strains of ALV, contact transmission of ALV-J is highly efficient and therefore may interfere with current efforts to control this virus infection by eradication. Preliminary characterization studies have suggested that the U.S. isolates of ALV-J are related, but not identical to the strain originally isolated in 1991 from flocks in the United Kingdom. In order to develop more effective strategies for diagnosis and control of ALV-J, biological and molecular variations among strains of ALV-J are being studied.

Technical Abstract: Avian myeloid leukosis is induced by subgroup J avian leukosis virus (ALV-J) and is considered as a serious cause of mortality and other production problems in meat-type chickens. Several strains of ALV-J were isolated from affected broiler breeder and commercial broiler flocks in the United States. Field observations suggest that ALV-J, previously not identified in flocks in the U.S., is gaining virulence, as losses in affected flocks are occurring earlier and at a higher rate. Control of this virus infection is complicated by the lack of specific diagnostics, the antigenic and molecular variation among strains, and the unusually high rate of horizontal transmission. This paper is focused on the diagnosis, incidence and control of ALV-J infection in meat-type chickens.

Last Modified: 11/27/2014
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