|Crespo, Rocio - UNIV OF CALIFORNIA-DAVIS|
|Woolcock, Peter - UNIV OF CALIFORNIA-DAVIS|
|Hall, Cheryl - ZACKY FARMS|
|Shivaprasad, H L - UNIV OF CALIFORNIA-DAVIS|
Submitted to: Avian Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 21, 2002
Publication Date: August 1, 2002
Citation: CRESPO, R., WOOLCOCK, P.R., FADLY, A.M., HALL, C., SHIVAPRASAD, H. CHARACTERIZATION OF T-CELL LYMPHOMAS ASSOCIATED WITH AN OUTBREAK OF RETICULOENDOTHELIOSIS IN TURKEYS. AVIAN PATHOLOGY. 2002. v. 31. p. 355-361. Interpretive Summary: Reticuloendotheliosis, a cancer-like disease of chickens, turkeys and other avian species is caused by a virus termed reticuloendotheliosis virus (REV). We investigated the cause of increased mortality and decreased egg production associated with disseminated lymphomas (cancer-like lesions) in a turkey breeding flock for over 20 weeks. We also found that unrelated meat turkey flocks, from the same integrator, experienced increased condemnation due to such lymphomas. Virological assays including DNA-based tests revealed the isolation of an REV from affected turkeys. Although we were able to identify the type of tumor cells involved in this REV outbreak, the source of this REV infection was not determined. The information should help turkey breeders and growers and poultry disease diagnosticians in the diagnosis of similar REV outbreaks.
Technical Abstract: Increased mortality and decreased egg production associated with disseminated lymphoma were observed in a turkey breeding flock for over 20 weeks. A few unrelated meat turkey flocks, from the same integrator, experienced increased condemnation due to neoplasia in a few organs. Lymphoma was characterized by uniform population of large lymphocytes with large vesicular nuclei containing one or two nucleoli and with little, faintly staining, basophilic cytoplasm. Neoplastic cells replaced normal tissue and were consistent with lesions seen with reticuloendotheliosis virus (REV) infection. Immunoperoxidase and fluorescent antibody staining characterized the neoplastic cells as CD3+, CD4+ and CD8- lymphocytes. Infection with REV was confirmed by virus isolation, polymerase chain reaction, serology and indirect fluorescent antibody. Poults hatched from these breeders tested positive for REV antibodies at hatch, but the performance of these flocks was normal and lymphoma was not observed. The origin of REV infection in this outbreak could not have been determined. This is the first documented report of T-cell lymphomas associated with REV in commercial flocks. Furthermore, this is the first time that lymphomas have been characterized as T helper cells (CD3+ CD4+ and CD8-)in an outbreak of REV in turkeys.