Naturally Occurring Co-infection of Avian Leukosis Virus (subgroups A-E) and Reticuloendotheliosis Virus in Green Peafowls (Pavo muticus)

ABSTRACT Most of the neoplastic diseases affecting poultry have a viral etiology, such as Marek’s disease, avian leukosis/sarcoma and reticuloendotheliosis. In the present paper, histopathology and molecular methods were performed, in addition of necropsy and gross morphology evaluation, for the differential diagnosis of these diseases in two green peafowls (Pavo muticus). The affected birds showed non-specific signs, such as depression, anorexia, and diarrhea. At necropsy, diffuse enlargement by several times the normal size of the liver and the spleen was observed. In one of the birds, the liver presented white to grayish discoloration was present, and focal and nodular growths in the other bird. Grossly, the other visceral organs and the peripheral nerves were normal. Microscopically, most of the tumor cells were large and uniform with pleomorphic nuclei. The PCR analysis for Marek’s disease virus (MDV), avian leukosis virus (ALV), lymphoproliferative disease virus (LPDV), and reticuloendotheliosis virus (REV)based on their specific sequences showed the presence of ALV subgroups A-E and REV. According to these results, definitive diagnosis was co-infection of ALV and REV in naturally-infected green peafowls.