Neoplastic diseases: Marek's disease, avian leukosis
Formalin-fixed paraffin-embedded neoplastic tissue as well as frozen liver and spleen were negative by polymerase chain reaction for avian leukosis
virus and reticuloendo-theliosis virus.
14,15) In budgerigars with renal adenocarcinoma, an association with avian leukosis
virus infection has not been demonstrated.
The genomic DNA was analyzed by polymerase chain reaction for the presence of Marek's disease virus, lymphoid leukosis
virus, and reticuloendothelial viruses, but none were detected.
13-15) Additionally, mesotheliomas have been induced in chickens by several viruses, most notably a strain of avian leukosis
Chickens may be infected with 3 different oncogenic viruses: avian leukosis
virus (ALY), reticuloendotheliosis virus (REV), and Marek's disease herpesvirus (MDV).
0008%) as measured by leukosis
condemnation rates in broilers at slaughter.
13,14) Likewise, avian leukosis
virus A, (15) reticuloendotheliosis virus, (16) avian influenza A.
In both cases, test results were negative for Marek's disease virus, avian leukosis
virus, and reticuloendotheliosis virus.
10,11) Severe leukocytosis in birds is often associated with diseases such as aspergillosis, avian mycobacteriosis, salmonellosis, chlamydiosis, and sepsis, (12) but herpesviruses (ie, Marek disease) and retroviruses (ie, avian leukosis
virus, reticuloendotheliosis virus) can specifically cause a lymphocytic leukocytosis in chickens.
46,47) Interestingly, osteopetrosis is caused by the avian leukosis
/sarcoma group of viruses in poultry and is frequently associated with lymphoid leukosis
(a lymphoid neoplasia with a leukemic component).
The development and improvement of standards and regulatory requirements to address mycoplasma, leukosis
, and other extraneous virus contaminations in chicken embryo origin products are reviewed.