Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: October 24, 2005
Publication Date: June 20, 2008
Citation: Fadly, A.M., Witter, R.L., Hunt, H.D. 2008. Oncornaviruses: leukosis/sarcomas and reticuloendotheliosis. In: Dufour-Zavala, L., Swayne, D.E., Glisson, J.R., Pearson, J.E., Reed, W.M., Jackwood, M.W., Woolcock, P.R., editors. A Laboratory Manual for the Isolation, Identification and Characterization of Avian Pathogens. 5th edition. Jacksonville, FL: American Association of Avian Pathologists. p. 164-172. Technical Abstract: Avian leukosis virus (ALV), and reticuloendotheliosis virus (REV) are the most common naturally occurring avian oncornaviruses associated with neoplastic disease conditions in poultry. ALV infects primarily chickens, whereas REV infects chickens, turkeys, ducks, geese, pheasants, quail, and probably many other avian species. In addition to causing tumors, both ALV and REV can reduce productivity and induce immunosuppression and other production problems in affected flocks. A number of biological assays can be used for the detection of ALV and REV infection. Virologic and serologic criteria, such as assays for virus, antigens or antibodies are very useful in identification and classification of new isolates, surveillance of pathogen-free and other breeder flocks for freedom of virus infection, establishing infection with one virus and excluding others, and in safety testing of vaccines. However, such virologic and serologic assays are not particularly helpful in the differential diagnosis of virus-induced neoplastic diseases of poultry because avian oncogenic viruses are ubiquitous and infection in the absence of tumor formation is common. Current technology based on molecular hybridization or immunocytochemistry with monoclonal antibodies to cellular and tumor specific antigens is being used to develop more sensitive and specific procedures for the differential diagnosis of virus-induced avian neoplasms. No vaccines that protect chickens and turkeys from infection with ALV or REV are available commercially.